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Title:
Nucleic acids coding for adhesion factor of group B streptococcus,
adhesion factors of group B streptococcus and further uses thereof
United States Patent: 7,485,710
Issued: February 3, 2009
Inventors: Reinscheid;
Dieter J. (Neu-Ulm, DE), Gutekunst; Heike (Biberach, DE), Schubert; Axel (Neu-Ulm,
DE), Eikmanns; Bernhard J. (Ulm, DE), Meinke; Andreas (Pressbaum, AT)
Assignee: InterCell AG
(Vienna, AT)
Appl. No.: 10/531,659
Filed: October 15, 2003
PCT Filed: October 15, 2003
PCT No.: PCT/EP03/11436
371(c)(1),(2),(4) Date: January
26, 2006
PCT Pub. No.: WO2004/035618
PCT Pub. Date: April 29,
2004
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Patheon
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Abstract
The present invention is related to
nucleic acids coding for adhesion factors of group B streptococcus,
adhesion factors of group B streptococcus and uses thereof. More
particularly, the present invention is related to a polypeptide being such
adhesion factors and comprising an amino acid sequence, whereby the amino
acid sequence is selected from the group comprising SEQ ID NO 11 to SEQ ID
NO 20, and the use of such polypeptide for the manufacture of a vaccine.
Description of the
Invention
The present invention relates to isolated
nucleic acid molecules which code for bacterial adhesion factors, the
bacterial adhesion factors and various uses thereof.
BACKGROUND OF THE INVENTION
Streptococcus agalactiae, or group B streptococcus (GBS), is a leading
cause of infant mortality. GBS encompasses an estimated prevalence of
several thousand cases per year resulting in an annual mortality rate in
the United States between about 10% and 15% (Schuchat, 1998). Studies from
the USA demonstrated a risk of 1-2 cases per 1000 live births (Zangwill,
Schuchat, and Wenger, 1992) and incidence rates for different European
countries vary between 0.24 and 1.26 per 1000 live births (Carstensen,
Henrichsen, and Jepsen, 1985; Faxelius et al., 1988). In the United
States, up to 30% of pregnant women carry GBS at least temporarily in the
vagina or rectum without symptoms (Schuchat, 1998). Infants born to these
women become colonized with GBS during delivery (Baker and Edwards, 1995).
Aspiration of infected amniotic fluid or vaginal secretions allows GBS to
gain access to the lungs. Common manifestations of this infection include
bacteraemia, pneumonia, and meningitis (Spellerberg, 2000). Even infant
survivors of GBS meningitis suffer from neurologic sequelae ranging from
deafness, learning disabilities, as well as motor, sensory, and cognitive
impairment (Baker and Edwards, 1995). Currently, antibiotic prophylaxis in
parturients is the recommended approach for the prevention of neonatal
disease by GBS (Baker, Halsey, and Schuchat, 1999); however, with the
resurgence of antibiotic resistance in other streptococcal species, a
similar plight in GBS may occur.
In addition to infant infections, GBS is also an important pathogen in the
elderly and in immunocompromised persons, in which the incidence of
invasive GBS disease is about 9 in 100,000 (Farley et al. 1993). Of these
infections, the mortality rate can be as high as 30%.
An important GBS virulence determinant is the type-specific capsular
polysaccharide, which prevents the deposition of host complement factor
C3b and thereby inhibits opsonophagocytosis of the bacteria (Rubens et al.
1987). Nine distinct capsular serotypes, Ia, Ib, and II to VIII, have been
identified so far in GBS (Wessels, 1997). Efforts are currently under way
to develop a multivalent conjugate vaccine against GBS based on the
capsule polysaccharides of the clinically relevant serotypes (Paoletti et
al. 1999; Baker et al., 1999; Baker et al., 2000; Paoletti and Kasper,
2002). However, there are a number of technical difficulties to overcome
with capsule-containing conjugate vaccines: multiple serotypes are needed,
an appropriate protein conjugate needs to be identified and validated, and
potential cross-reaction with human tissues needs to be addressed (Korzeniowska-Kowal,
Witkowska, and Gamian, 2001). The use of cell surface proteins from GBS
represents an attractive alternative to capsule polysaccharides for the
development of a vaccine against these bacteria. The surface proteins Sip,
Rib, .alpha. and .beta. from GBS have already been shown to confer
protective immunity in mice against GBS infections (Madoff et al. 1992;
Larsson, Stalhammar-Carlemalm, and Lindahl, 1997; Larsson,
Stalhammar-Carlemalm, and Lindahl, 1999; Brodeur et al., 2000). Also two
unique surface proteins from a serotype V strain were shown in a mouse
model to protect against GBS infection (Areschoug et al., 1999). Finally,
antibodies against C5a peptidase from GBS were found to initiate
macrophage killing of the bacteria (Cheng et al., 2001).
The interaction of GBS with its host is a complex process involving the
colonization and penetration of epithelial and endothelial surfaces and
the evasion of the immune defense (Spellerberg, 2000). In streptococci,
fibrinogen binding has been shown to play a significant role in the
adhesion to host surfaces (Courtney et al. 1994; Cheung et al., 1991; Ni
et al. 1998; Pei and Flock, 2001) and the protection from the immune
system (Courtney et al., 1997; Thern, Wastfelt, and Lindahl, 1998b;
Ringdahl et al., 2000a; Thern, Wastfelt, and Lindahl, 1998a; Ringdahl et
al., 2000b). Therefore, several studies have addressed the molecular basis
of fibrinogen binding in streptococci of the serological groups A, C and G
(Fischetti, 1989; Meehan, Nowlan, and Owen, 1998; Vasi et al. 2000).
Fibrinogen is a 330 kDa glycoprotein found in high concentrations in blood
plasma (Fuss, Palmaz, and Sprague, 2001; Mosesson, Siebenlist, and Meh,
2001b; Mosesson, Siebenlist, and Meh, 2001a). It is a hexamer composed of
each of two A.alpha.-, B.beta.-, and .gamma.-chains linked together by
disulfide bonds. Fibrinogen is a key player in haemostasis and mediates
platelet adherence and aggregation at sites of injury. Furthermore, it is
cleaved by thrombin to form fibrin, which is the major component of blood
clots. Fibrinogen also plays a role in opsonophagocytosis. It has been
shown to inhibit the binding of the activated complement factor C3b,
thereby blocking the activation of the alternative complement pathway (Whitnack,
Dale, and Beachey, 1984b, Whitnack and Beachey, 1985, Whitnack and Beachey,
1982; Whitnack. Dale, and Beachey, 1983; Whitnack, Dale, and Beachey,
1984a). The newborn's unique susceptibility for disseminated GBS
infections has been associated with a relative complement deficiency
(Mills, Bjorksten, and Quie, 1979; Edwards et al., 1983; Edwards, 1983).
Fibrinogen binding of GBS may thus play an important role in the
inhibition of the residual complement activity in the newborn (Noel, Katz,
and Edelson, 1991).
In several studies, the interaction of GBS with human fibrinogen has been
demonstrated (Schonbeck, Bjorck, and Kronvall, 1981; Lammler, Chhatwal,
and Blobel, 1983, Chhatwal, Lammler, and Blobel, 1984b; Spellerberg et
al., 2002). However, the molecular basis of fibrinogen binding in GBS
remained unknown.
GBS has been demonstrated to bind to and invade epithelial and endothelial
cells (Gibson et al., 1993; La Penta et al., 1997, Winram et al. 1998).
Treatment of GBS with the protease trypsin abolishes the adhesive and
invasive properties of the bacteria (Valentin-Weigand and Chhatwal, 1995;
Winram, Jonas, Chi, and Rubens, 1998), indicating a proteinacious nature
of the adhesins and invasins in GBS. As adhesins and invasins are located
on the surface of the bacteria and are important for the virulence of GBS,
they represent ideal targets for the development of a GBS vaccine.
The problem underlying the present invention was to provide means for the
development of medicaments such as vaccines against bacterial infections.
More particularly, the problem was to provide new adhesions factors of GBS
which can be used for the manufacture of said medicaments.
The problem is solved in a first aspect by an isolated nucleic acid
molecule, preferably encoding a fibrinogen-binding-polypeptide or such
protein or a fragment thereof, comprising a nucleic acid sequence which is
selected from the group comprising a) a nucleic acid having at least 70%
identity to a nucleic acid sequence which is selected from the group
comprising SEQ ID NO 1 to SEQ ID NO 6, b) a nucleic acid which is
essentially complementary to the nucleic acid of a), c) a nucleic acid
comprising at least 15 sequential bases of the nucleic acid of a) or b),
d) a nucleic acid which anneals under stringent hybridisation conditions
to the polynucleotide of a), b) or c), and e) a nucleic acid which, but
for the degeneracy of the genetic code, would hybridize to the nucleic
acid defined in a), b), c) or d).
The problem is solved in a second aspect by an isolated nucleic acid
molecule, preferably encoding an adhesion factor or a fragment thereof,
comprising a nucleic acid sequence which is selected from the group
comprising a) a nucleic acid having at least 70% identity to a nucleic
acid sequence set forth in SeqID NO 7, SeqID NO 8, SeqID NO 9 or SeqID NO
10. b) a nucleic acid which is essentially complementary to the nucleic
acid of a), c) a nucleic acid comprising at least 15 sequential bases of
the nucleic acid of a) or b), d) a nucleic acid which anneals under
stringent hybridisation conditions to the nucleic acid of a), b) or c),
and e) a nucleic acid which, but for the degeneracy of the genetic code,
would hybridize to the nucleic acid defined in a), b), c) or d).
In an embodiment of both aspects of the present invention the identity is
at least 80%, preferably at least 90%, more preferably 100%.
In a further embodiment of both aspects of the present invention the
nucleic acid is DNA.
In a still further embodiment of both aspects of the present invention the
nucleic acid is RNA.
In a preferred embodiment of both aspects of the present invention the
nucleic acid molecule is isolated from a bacterium.
In a more preferred embodiment of both aspects of the present invention
the bacterium is a species selected from the group comprising
Streptococci, Staphylococci, and Lactococci.
In an even more preferred embodiment of both aspects of the present
invention the bacterium is a species which is selected from the group
comprising Streptococcus agalactiae, Streptococcus pyogenes, Streptococcus
pneumoniae and Streptococcus mutans.
In a most preferred embodiment of both aspects of the present invention
the bacterium is Streptococcus agalactiae.
In an embodiment of the first aspect of the present invention the nucleic
acid molecule encodes a fibrinogen-binding-protein comprising at least one
repeat of an amino acid motive comprising 16 amino acids.
In an embodiment of the second aspect of the present invention the nucleic
acid molecule encodes an adhesion factor which interacts with epithelial
cells.
In a preferred embodiment of the first aspect of the present invention the
encoded fibrinogen-binding-protein comprises 19 repeats of the amino acid
motive whereby the amino acid motive is any one of the ones specified or
disclosed herein.
In a more preferred embodiment of the first aspect of the present
invention the repeats are encoded by a polynucleotide selected from the
group comprising SEQ ID NO 21 to SEQ ID NO 112.
In a third aspect the problem underlying the present invention is solved
by an isolated nucleic acid molecule comprising a nucleic acid sequence,
whereby the nucleic acid sequence is selected from the group comprising
SEQ ID NO 21 to SEQ ID NO 21 to 112.
In a fourth aspect the problem underlying the present invention is solved
by an isolated nucleic acid molecule encoding for a polypeptide whereby
the polypeptide comprises an amino acid motive, whereby the amino acid
motive is G-N/S/T-V-L-A/E/M/Q-R-R-X-K/R/W-A/D/E/N/Q-A/F/I/L/V/Y-X-X-K/R-X-
-X (SEQ ID NO 222).
In a preferred embodiment of any of the aspects 1 to 4 of the present
invention the nucleic acid is DNA, RNA or mixtures thereof, preferably the
nucleic acid molecule is isolated from a genomic DNA.
In a fifth aspect the problem underlying the present invention is solved
by a vector comprising a nucleic acid molecule according to any aspect of
the present invention.
In a preferred embodiment the vector is adapted for recombinant expression
of the polypeptide encoded by any of the nucleic acid molecules according
to any aspect of the present invention.
In a sixth aspect the problem underlying the present invention is solved
by a cell comprising the vector according to the present invention.
In a preferred embodiment the cell is a host cell.
In a seventh aspect the problem underlying the present invention is solved
by a polypeptide, preferably a fibrinogen-binding-polypeptide and/or an
adhesion factor, comprising an amino acid sequence, whereby the amino acid
sequence is encoded by a nucleic acid molecule according to any aspect of
the present invention, and fragments of said polypeptide.
In an eighth aspect the problem underlying the present invention is solved
by a polypeptide, preferably a fibrinogen-binding-polypeptide and/or an
adhesion factor, comprising an amino acid sequence, whereby the amino acid
sequence is selected from the group comprising SEQ ID NO 11 to SEQ ID NO
20.
In an embodiment of this aspect of the present invention the polypeptide,
preferably a fibrinogen-binding-polypeptide and/or an adhesion factor,
having an amino acid sequence according to any of SEQ ID NO 11 to 16 is a
fibrinogen-binding protein.
In a further embodiment of this aspect of the present invention the
polypeptide is an adhesion factor which interacts with epithelial cells.
In an even more preferred embodiment the epithelial cells are human
epithelial cells.
In a ninth aspect the problem underlying the present invention is solved
by a polypeptide comprising an amino acid sequence, whereby the amino acid
sequence is selected from the group comprising SEQ ID NO 113 to SEQ ID NO
205. In an embodiment the polypeptide comprises at least one of the amino
acid sequence according to SEQ ID NO 113 to SEQ ID NO 225 in combination
with at least one other amino acid sequence. More preferable this at least
one other amino acid sequence is an amino acid sequence according to any
of SEQ ID NO 113 to SEQ ID NO 205.
In a tenth aspect the problem underlying the present invention is solved
by a polypeptide comprising an amino acid motive, whereby the polypeptide
comprises an amino acid motive, whereby the amino acid motive is
G-N/S/T-V-L-A/E/M/Q-R-R-X-K/R/W-A/D/E/N/Q-A/F/I/L/V/Y-X-X-K/R-X-X (SEQ ID
NO 222).
In an eleventh aspect the problem underlying the present invention is
solved by a process for producing a polypeptide according to any aspect of
the present invention comprising expressing the nucleic acid molecule
according to any aspect of the present invention.
In a twelfth aspect the problem underlying the present invention is solved
by a process for producing a cell which expresses a polypeptide according
to any aspect of the present invention or a fragment thereof, comprising
transforming or transfecting a suitable host cell with the vector
according to the present invention such that the transformed or
transfected cell expresses the polypeptide encoded by the polynucleotide
contained in the vector.
In a thirteenth aspect the problem underlying the present invention is
solved by a pharmaceutical composition, especially a vaccine, comprising a
polypeptide or a fragment thereof, as defined in any aspect of the present
invention or a nucleic acid molecule according to any aspect of the
present invention.
In a preferred embodiment the pharmaceutical composition comprises an
immunostimulatory substance, whereby the immunostimulatory substance is
preferably selected from the group comprising polycationic polymers,
immunostimulatory deoxynucleotides (ODNs), synthetic KLK peptides,
neuroactive compounds, alumn, Freund's complete or incomplete adjuvants or
combinations thereof.
In a preferred embodiment the immunostimulatory substance is a combination
of either a polycationic anion and immunostimulatory deoxynucleotides or
of synthetic KLK peptides and immunostimulatory deoxynucleotides.
In a more preferred embodiment the polycationic polymer is a polycationic
peptide and/or whereby the neuroactive compound is human growth hormone.
In a fourteenth aspect the problem underlying the present invention is
solved by the use of a polypeptide according to any aspect of the present
invention or a fragment thereof for the manufacture of a medicament,
especially for the manufacture of a vaccine against bacterial infection.
In a preferred embodiment the bacterial infection is a bacterial infection
of Streptococcus agalactiae.
In a fifteenth aspect the problem underlying the present invention is
solved by the use of molecules which inhibit the binding of a polypeptide
according to any aspect of the present invention to fibrinogen for the
manufacture of a medicament to prevent and treat bacterial infection.
Preferably, the bacterial infection is a Streptococcus agalactiae
infection.
In a further embodiment the molecules are selected from the group
comprising fibrinogen receptor antibodies, fibrinogen receptor mimotopes
and fibrinogen receptor antagonists binding to a polypeptide according to
any aspect of the present invention.
In a sixteenth aspect the problem underlying the present invention is
solved by the use of molecules which inhibit the binding of a polypeptide
according to any aspect of the present invention to epithelial cells,
preferably human epithelial cells.
In a seventeenth aspect the problem underlying the present invention is
solved by an antibody, or at least an effective part thereof, which binds
at least to a selective part of the polypeptide or a fragment thereof
according to any aspect of the present invention.
In an embodiment the antibody is a monoclonal antibody.
In a further embodiment said effective part comprises Fab fragments.
In a still further embodiment the antibody is a chimeric antibody.
In a preferred embodiment the antibody is a humanized antibody.
In an eighteenth aspect the problem underlying the present invention is
solved by a hybridoma cell line, which produces the antibody according to
the present invention.
In a nineteenth aspect the problem underlying the present invention is
solved by the use of the antibody according to the present invention for
the preparation of a medicament for treating or preventing bacterial
infections, especially Streptococcus agalactiae infections.
In a twentieth aspect the problem underlying the present invention is
solved by an antagonist which reduces or inhibits the activity of the
polypeptide or a fragment thereof according to any aspects of the present
invention.
In a twenty-first aspect the problem underlying the present invention is
solved by a method for identifying an antagonist capable of reducing or
inhibiting the activity of the polypeptide or fragment thereof according
to any aspect of the present invention comprising: a) contacting an
isolated or immobilized polypeptide according to any of the aspects of the
present invention or a fragment thereof with a candidate antagonist under
conditions to permit binding of said candidate antagonist to said
polypeptide or fragment thereof, in the presence of a component capable of
providing a detectable signal in response to the binding of the candidate
antagonist to said polypeptide or fragment thereof; and b) detecting the
presence or absence of a signal generated in response to the binding of
the antagonist to the polypeptide or fragment thereof, preferably the
presence of a signal indicating a compound capable of inhibiting or
reducing the activity of the polypeptide or fragment thereof.
In a twenty-second aspect the problem underlying the present invention is
solved by a method for identifying an antagonist capable of reducing or
inhibiting the activity of a polypeptide or a fragment thereof according
to any the aspects of the present invention comprising: a) providing the
polypeptide according to any aspect of the present invention or a fragment
thereof, b) providing an interaction partner of the polypeptide according
to any aspect of the present invention, preferably the antibody according
to the present invention, c) providing a candidate antagonist, d) reacting
the polypeptide, the interaction partner of the polypeptide and the
candidate antagonist, and e) determining whether the candidate antagonist
inhibits or reduces the activity of the polypeptide.
In a twenty-third aspect the problem underlying the present invention is
solved by a method for identifying an antagonist capable of reducing or
inhibiting the interaction activity of the polypeptide according to the
present invention or a fragment thereof to its interaction partner
comprising: a) providing the polypeptide according to the present
invention or a fragment thereof, b) providing an interaction partner to
said polypeptide or a fragment thereof, preferably an antibody according
to the present invention, c) allowing interaction of said polypeptide or
fragment thereof to said interaction partner to form an interaction
complex, d) providing a candidate antagonist, e) allowing a competition
reaction to occur between the candidate antagonist and the interaction
complex, and f) determining whether the candidate antagonist inhibits or
reduces the interaction activities of the polypeptide or the fragment
thereof with the interaction partner.
In a twenty-fourth aspect the problem underlying the present invention is
solved by an antagonist identified or identifiable by a method according
to the twenty-second or twenty-third aspect of the present invention.
In a twenty-fifth aspect the problem underlying the present invention is
solved by a process for in vitro diagnosis of a disease related to
expression of the polypeptide or a fragment thereof according to any
aspect of the present invention comprising determining the presence of a
polynucleotide sequence encoding said polypeptide or the presence of a
polypeptide according to any aspect of the present invention.
In a twenty-sixth aspect the problem underlying the present invention is
solved by a process for in vitro diagnosing a disease related to
expression of the polypeptide according to the present invention or a
fragment thereof, comprising determining the presence of a nucleic acid
sequence encoding said polypeptide or a fragment thereof according to the
present invention, or the presence of the polypeptide according to the
present invention or a fragment thereof.
In a twenty-seventh aspect the problem underlying the present invention is
solved by a process for in vitro diagnosis of a bacterial infection,
preferably Streptococcus agalactiae infection, comprising the step of
determining the presence of a nucleic acid molecule according to any
aspect of the present invention, or of a polypeptide according to any
aspect of the present invention.
In a preferred embodiment of the latter three aspects of the present
invention the presence is determined in a sample which is preferably
derived from a host organism.
In a twenty-eighth aspect the problem underlying the present invention is
solved by an affinity device comprising a support material and immobilized
to said support material a polypeptide according to any aspect of the
present invention or a nucleic acid molecule according to any aspect
according to the present invention.
In a twenty-ninth aspect the problem underlying the present invention is
solved by the use of a polypeptide according to any aspect of the present
invention for the isolation and/or purification and/or identification of
an interaction partner of said polypeptide.
In a thirtieth aspect the problem underlying the present invention is
solved by the use of any of the polypeptides according to any aspect of
the present invention for the generation of a peptide binding to said
polypeptide.
In a preferred embodiment the peptide is selected from the group
comprising anticalines.
In a thirty-first aspect the problem underlying the present invention is
solved by the use of a polypeptide according to any aspect of the present
invention for the manufacture of a functional nucleic acid, whereby the
functional nucleic acid is selected from the group comprising aptamers and
spiegelmers.
In a thirty-second aspect the problem underlying the present invention is
solved by the use of a nucleic acid molecule according to any aspect of
the present invention for the manufacture of a functional ribonucleic
acid, whereby the functional ribonucleic acid is selected from the group
comprising ribozymes, antisense nucleic acids and siRNA.
In a thirty-third aspect the problem underlying the present invention is
solved by the use of a polypeptide according to the present invention or a
fragment thereof as an antigen.
In a thirty-fourth aspect the problem underlying the present invention is
solved by the use of a nucleic acid according to any aspect of the present
invention for the manufacture or generation of a functional nucleic acid,
preferably a ribonucleic acid, wherein the functional ribonucleic acid is
selected from the group comprising ribozymes, antisense nucleic acids and
siRNA.
In a thirty-fifth aspect the problem underlying the present invention is
solved by the use of the polypeptides according to the present invention
or any fragment thereof for the generation or manufacture of an antibody.
As used herein the term SEQ ID NO X to SEQ ID NO Y is an abbreviation for
any of the SEQ ID Nos comprised by X and Y including X and Y.
The present inventors have surprisingly found that the genomes of GBS
comprises a variety of adhesion factors which share a common amino acid
motive. This amino acid motive is responsible for the binding of the
adhesion factor to fibrinogen. As used herein, an adhesion factor is a
factor, preferable a peptide or a protein which mediates the binding of a
microorganism to a substrate. Preferably, the microorganism is GBS. More
preferably, the substrate is fibrinogen and a host cell, respectively. The
adhesion factor as used herein can be an adhesin or an invasin. The common
amino acid motive can be described as follows using the one letter code
for amino acids:
G-N/S/T-V-L-A/E/M/Q-R-R-X-K/R/W-A/D/E/N/Q-A/F/I/L/V/Y-X-X-K/R-X-X (SEQ ID
NO 222).
As may be taken from the above sequence the amino acid motive comprises a
total of 16 positions. Some of the positions have to be occupied by a
distinct amino acid such as, e.g., position 1 or 3 or 4. Other positions
such as positions 15 or 16 may be occupied by any amino acid, preferably
by a naturally occurring amino acid. These positions are marked in the
above sequence with an `X`. Still further positions can be occupied by
different amino acids. These different amino acids are indicated in the
above motive, whereby the various amino acids are separated by `/`.
Accordingly, at position 2 N, S or T may be present. Any permutations of
the above sequence of amino acids can be realized by the one skilled in
the art, which are thus within the scope of the present invention.
The present invention is thus related in one aspect to the above amino
acid motive. More particularly, the present invention is related to any
peptide or polypeptide which comprises this amino acid motive. It is to be
understood that the terms peptide and polypeptide are used in a synonymous
way if not indicated to the contrary.
Polypeptides, as used herein, include all polypeptides as described below.
The basic structure of polypeptides is well known and has been described
in innumerable textbooks and other publications in the art. In this
context, the term is used herein to refer to any peptide or protein
comprising two or more amino acids joined to each other in a linear chain
by peptide bonds. As used herein, unless otherwise indicated, the term
refers to both short chains, which also commonly are referred to in the
art as peptides, oligopeptides and oligomers, for example, and to longer
chains, which generally are referred to in the art as proteins, of which
there are many types. It will be appreciated that polypeptides often
contain amino acids other than the 20 amino acids commonly referred to as
the 20 naturally occurring amino acids, and that many amino acids,
including the terminal amino acids, may be modified in a given
polypeptide, either by natural processes, such as processing and other
post-translational modifications, but also by chemical modification
techniques which are well known to the art. Even the common modifications
that occur naturally in polypeptides are too numerous to list exhaustively
here, but they are well described in basic texts and in more detailed
monographs, as well as in a voluminous research literature, and they are
well known to those of skill in the art. Among the known modifications
which may be present in polypeptides of the present are, to name an
illustrative few, acetylation, acylation, ADP-ribosylation, amidation,
covalent attachment of flavin, covalent attachment of a heme moiety,
covalent attachment of a nucleotide or nucleotide derivative, covalent
attachment of a lipid or lipid derivative, covalent attachment of
phosphotidylinositol, cross-linking, cyclization, disulfide bond
formation, demethylation, formation of covalent cross-links, formation of
cystine, formation of pyroglutamate, formylation, gamma-carboxylation,
glycosylation, GPI anchor formation, hydroxylation, iodination,
methylation, myristoylation, oxidation, proteolytic processing,
phosphorylation, prenylation, racemization, selenoylation, sulfation,
transfer-RNA mediated addition of amino acids to proteins such as
arginylation, and ubiquitination. Such modifications are well known to
those of skill and have been described in great detail in the scientific
literature. Several particularly common modifications, glycosylation,
lipid attachment, sulfation, gamma-carboxylation of glutamic acid
residues, hydroxylation and ADP-ribosylation, for instance, are described
in most basic texts, such as, for instance PROTEINS--STRUCTURE AND
MOLECULAR PROPERTIES, 2.sup.nd Ed., T. E. Creighton, W.H. Freeman and
Company, New York (1993). Many detailed reviews are available on this
subject, such as, for example, those provided by Wold, F.,
Posttranslational Protein Modifications: Perspectives and Prospects, pgs.
1-12 in POSTTRANSLATIONAL COVALENT MODIFICATION OF PROTEINS, B. C.
Johnson, Ed., Academic Press, New York (1983); Seifter et al., Meth.
Enzymol. 182:626-646 (1990) and Rattan et al., Protein Synthesis:
Posttranslational Modification and Aging, Ann. N.Y. Acad. Sci. 663:48-62
(1992). It will be appreciated, as is well known and as noted above, that
polypeptides are not always entirely linear. For instance, polypeptides
may be generally as a result of posttranslational event, including natural
processing event and events brought about by human manipulation which do
not occur naturally. Circular, branched and branched circular polypeptides
may be synthesized by non-translation natural process and by entirely
synthetic methods, as well. Modifications can occur anywhere in a
polypeptide, including the peptide backbone, the amino acid side chains
and the amino or carboxyl termini. In fact, blockage of the amino or
carboxyl group in a polypeptide, or both, by a covalent modification, is
common in naturally occurring and synthetic polypeptides and such
modifications may be present in polypeptides of the present invention, as
well. For instance, the amino terminal residue of polypeptides made in E.
coli or other cells, prior to proteolytic processing, almost invariably
will be N-formylmethionine. During post-translational modification of the
peptide, a methionine residue at the NH.sub.2-terminus may be deleted.
Accordingly, this invention contemplates the use of both the methionine-containing
and the methionineless amino terminal variant of the protein of the
invention. The modifications that occur in a polypeptide often will be a
function of how it is made. For polypeptides made by expressing a cloned
gene in a host, for instance, the nature and extent of the modifications
in large part will be determined by the host cell posttranslational
modification capacity and the modification signals present in the
polypeptide amino acid sequence. For instance, as is well known,
glycosylation often does not occur in bacterial hosts such as, for
example, E. coli. Accordingly, when glycosylation is desired, a
polypeptide should be expressed in glycosylating host, generally a
eukaryotic cell. Insect cells often carry out the same posttranslational
glycosylations as mammalian cells and, for this reason, insect cell
expression systems have been developed to express efficiently mammalian
proteins having native patterns of glycosylation, inter alia. Similar
considerations apply to other modifications. It will be appreciated that
the same type of modification may be present in the same or varying degree
at several sites in a given polypeptide. Also, a given polypeptide may
contain many types of modifications. In general, as used herein, the term
polypeptide encompasses all such modifications, particularly those that
are present in polypeptides synthesized recombinantly by expressing a
polynucleotide in a host cell.
Any polypeptide comprising the amino acid motive is regarded as a
polypeptide according to the present invention. As explained in greater
detail in the examples, the present inventors have found that GBS
comprises a number of adhesion factors which comprise not only one copy of
the amino acid motive but a number thereof. Thus any polypeptide
comprising a plurality or being composed of a plurality of the amino acid
motive is a polypeptide according to the present invention. For example,
the adhesion factor referred to herein as FbsA may comprise as little as
one unit of the amino acid motive to as much as 19 copies thereof.
Other adhesion factors according to the present invention are those
referred to herein as PabA, PabB, PabC and PabD. It is to be understood
that the term polypeptides according to the present invention also
comprise any fragment, derivative or analog thereof. Further preferred
polypeptides according to the present invention are those the amino acid
sequence of which corresponds to SEQ ID 11 to 20.
The fragment, derivative or analog of the polypeptide of the present
invention may be (i) one in which one or more of the amino acid residues
are substituted with a conserved or non-conserved amino acid residue
(preferably a conserved amino acid residue) and such substituted amino
acid residue may or may not be one encoded by the genetic code, or (ii)
one in which one or more of the amino acid residues includes a substituent
group, or (iii) one in which the mature polypeptide is fused with another
compound, such as a compound to increase the half-life of the polypeptide
(for example, polyethylene glycol), or (iv) one in which the additional
amino acids are fused to the mature polypeptide, such as a leader or
secretory sequence or a sequence which is employed for purification of the
mature polypeptide or a proprotein sequence. Such fragments, derivatives
and analogs are deemed to be within the scope of those skilled in the art
from the teachings herein.
Among the particularly preferred embodiments of the invention in this
regard are polypeptides set forth in the Sequence Listing, variants,
analogs, derivatives and fragments thereof, and variants, analogs and
derivatives of the fragments. Additionally, fusion polypeptides comprising
such polypeptides, variants, analogs, derivatives and fragments thereof,
and variants, analogs and derivatives of the fragments, in addition to a
heterologous polypeptide, are contemplated by the present invention. Such
fusion polypeptides and proteins, as well as polynucleotides encoding
them, can readily be made using standard techniques, including standard
recombinant techniques for producing and expressing a recombinant
polynucleic acid encoding a fusion protein.
Among preferred variants are those that vary from a reference by
conservative amino acid substitutions. Such substitutions are those that
substitute a given amino acid in a polypeptide by another amino acid of
like characteristics. Typically seen as conservative substitutions are the
replacements, one for another, among the aliphatic amino acids Ala, Val,
Leu and Ile; interchange of the hydroxyl residues Ser and Thr, exchange of
the acidic residues Asp and Glu, substitution between the amide residues
Asn and Gln, exchange of the basic residues Lys and Arg and replacements
among the aromatic residues Phe and Tyr.
Further particularly preferred in this regard are variants, analogs,
derivatives and fragments, and variants, analogs and derivatives of the
fragment, having the amino acid sequence of any polypeptide set forth in
the Sequence Listing, in which several, a few, 5 to 10, 1 to 5, 1 to 3, 2,
1 or no amino acid residues are substituted, deleted or added, in any
combination. Especially preferred among these are silent substitutions,
additions and deletions, which do not alter the properties and activities
of the polypeptide of the present invention. Also especially preferred in
this regard are conservative substitutions. Most highly preferred
polypeptides having an amino acid sequence set forth in the Sequence
Listing without substitutions.
The polypeptides and polynucleotides of the present invention are
preferably provided in an isolated form, and preferably are purified to
homogeneity. Also the polypeptides according to the present invention are
preferably isolated polypeptides.
The polypeptides of the present invention include any polypeptide set
forth in the Sequence Listing (in particular a mature polypeptide) as well
as polypeptides which have at least 70% identity to a polypeptide set
forth in the Sequence Listing, preferably at least 80% or 85% identity to
a polypeptide set forth in the Sequence Listing, and more preferably at
least 90% similarity (more preferably at least 90% identity) to a
polypeptide set forth in the Sequence Listing and still more preferably at
least 95%, 96%, 97%, 98%, 99%, or 99.5% similarity (still more preferably
at least 95%, 96%, 97%, 98%, 99%, or 99.5% identity) to a polypeptide set
forth in the Sequence Listing and also include portions of such
polypeptides with such portion of the polypeptide generally containing at
least 5 amino acids and more preferably at least 10, 15 or 16 or multiples
thereof. Preferably, the multiples are multiples of a repeat of 16 amino
acids, whereby the 16 amino acids correspond to the amino acid motive as
disclosed herein.
Fragments or portions of the polypeptides of the present invention may be
employed for producing the corresponding full-length polypeptide by
peptide synthesis; therefore, the fragments may be employed as
intermediates for producing the full-length polypeptides. Fragments or
portions of the polynucleotides of the present invention may be used to
synthesize full-length polynucleotides of the present invention.
Also among preferred embodiments of this aspect of the present invention
are polypeptides comprising fragments of the polypeptide having the amino
acid sequence set forth in the Sequence Listing, and fragments of variants
and derivatives of the polypeptides set forth in the Sequence Listing.
As used herein a fragment is a polypeptide having an amino acid sequence
that entirely is the same as part but not all of the amino acid sequence
of the aforementioned S. agalactiae polypeptides and variants or
derivatives thereof.
Such fragments may be "free-standing", i.e., not part of or fused to
another amino acids or polypeptides, or they may be comprised within a
larger polypeptide of which they form a part or region. When comprised
within a larger polypeptide, the presently discussed fragments most
preferably form a single continuous region. However, several fragments may
be comprised within a single larger polypeptide. For instance, certain
preferred embodiments relate to a fragment of a polypeptide of the present
invention comprised within a precursor polypeptide designed for expression
in a host and having heterologous pre and pro-polypeptide regions fused to
the amino terminus of the fragment and an additional region fused to the
carboxyl terminus of the fragment. Therefore, fragments in one aspect of
the meaning intended herein, refers to the portion or portions of a fusion
polypeptide or fusion protein derived from a polypeptide of the present
invention.
Representative examples of polypeptide fragments of the invention,
include, for example, in any selected polypeptide, fragments from about
amino acid number 45-60, 61-76, 77-92, 93-108, 109-124, 125-140, 141-156,
157-172, 173-188, 189-204, 205-220, 221-236, 237-252, 253-268, 269-284,
285-300, 301-316, 317-332, 333-348, 410-414 of the amino acid sequences
disclosed herein, or any of the repeats, either alone or in combination
with one or several of the ones mentioned in the following tables 1 and 2 (see Original Patent),
optionally combined with the signal peptide or the LPXTG (SEQ ID NO: 259)
motif.
Preferred fragments of the invention include, for example, truncation
polypeptides including polypeptides having an amino acid sequence set
forth in the Sequence Listing, or of variants or derivatives thereof,
except for deletion of a continuous series of residues (that is, a
continuous region, part or portion) that includes the amino terminus, or a
continuous series of residues that includes the carboxyl terminus or, as
in double truncation mutants, deletion of two continuous series of
residues, one including the amino terminus and one including the carboxyl
terminus. Fragments having the size ranges set out above also are
preferred embodiments of truncation fragments, which are especially
preferred among fragments generally. Degradation forms of the polypeptides
of the invention in a host cell are also preferred.
Also preferred in this aspect of the invention are fragments characterized
by structural or functional attributes of the polypeptide of the present
invention. Preferred embodiments of the invention in this regard include
fragments that comprise alpha-helix and alpha-helix forming regions,
beta-sheet and beta-sheet-forming regions, turn and turn-forming regions,
coil and coil-forming regions, hydrophilic regions, hydrophobic regions,
alpha amphipathic regions, beta amphipathic regions, flexible regions,
surface-forming regions, substrate binding region, and high antigenic
index regions of the polypeptide of the present invention, and
combinations of such fragments.
Preferred regions are those that mediate activities of the polypeptide of
the present invention. Most highly preferred in this regard are fragments
that have a chemical, biological or other activity of the polypeptide of
the present invention, including those with a similar activity or an
improved activity, or with a decreased undesirable activity. Particularly
preferred are fragments comprising a receptor activity for such as, e.g.,
fibrinogen in case of FbsA or the host cell in case of PabA, PabB, PabC
und PabD that confer a function essential for the ability of S. agalactiae
to cause disease in humans and/or that are able to mediate the adherence
and/or invasion of S. agalactiae to or into epithelial cells, more
preferably human epithelial cells. Further preferred polypeptide fragments
are those that comprise or contain antigenic or immunogenic determinants
in an animal, especially in a human. A host cell as used herein is a cell
which is capable of uptaking of GBS in the natural host or in an
internalization assay such as, e.g., the one as described in example 1.
The polypeptides according to the present invention may be used for the
detection of the organism or organisms in a sample containing these
polypeptides. Preferably such detection is for diagnosis, more preferable
for the diagnosis of a disease, most preferably for the diagnosis of a
disease related or linked to the presence or abundance of Gram-positive
bacteria, especially bacteria selected from the group comprising
streptococci, staphylococci and lactococci. More preferably, the
microorganisms are selected from the group comprising Streptococcus
agalactiae, Streptococcus pyogenes, Streptococcus pneumoniae and
Streptococcus mutans.
The present invention also relates to diagnostic assays such as
quantitative and diagnostic assays for detecting levels of the polypeptide
of the present invention in cells and tissues, including determination of
normal and abnormal levels. Thus, for instance, a diagnostic assay in
accordance with the invention for detecting over-expression of the
polypeptide compared to normal control tissue samples may be used to
detect the presence of an infection, for example, and to identify the
infecting organism. Assay techniques that can be used to determine levels
of a polypeptide, in a sample derived from a host are well-known to those
of skill in the art. Such assay methods include radioimmunoassays,
competitive-binding assays, Western Blot analysis and ELISA assays. Among
these, ELISAs frequently are preferred. An ELISA assay initially comprises
preparing an antibody specific to the polypeptide, preferably a monoclonal
antibody. In addition, a reporter antibody generally is prepared which
binds to the monoclonal antibody. The reporter antibody is attached to a
detectable reagent such as radioactive, fluorescent or enzymatic reagent,
such as horseradish peroxidase enzyme.
The polypeptides according to the present invention may also be used for
the purpose of or in connection with an array. More particularly, at least
one of the polypeptides according to the present invention may be
immobilized on a support. Said support typically comprises a variety of
polypeptides whereby the variety may be created by using one or several of
the polypeptides according to the present invention and/or polypeptides
being different therefrom. The characterizing feature of such array as
well as of any array in general is the fact that at a distinct or
predefined region or position on said support or a surface thereof, a
distinct polypeptide is immobilized. Because of this any activity at a
distinct position or region of an array can be correlated with a specific
polypeptide. The number of different polypeptides immobilized on a support
may range from as little as 10 to several 1000 different polypeptides. The
density of polypeptides per cm.sup.2 is in a preferred embodiment as
little as 10 oligonucleotides per cm.sup.2 to at least 400 different
polynucleotides per cm.sup.2 and more particularly at least 1000 different
polypeptides per cm.sup.2.
The manufacture of such arrays is known to the one skilled in the art and,
for example, described in U.S. Pat. No. 5,744,309. The array preferably
comprises a planar, porous or non-porous solid support having at least a
first surface. The polypeptides as disclosed herein, are immobilized on
said surface. Preferred support materials are, among others, glass or
cellulose. It is also within the present invention that the array is used
for any of the diagnostic applications described herein. Apart from the
polypeptides according to the present invention also the nucleic acid
molecules according to the present invention may be used for the
generation of an array as described above. This applies as well to an
array made of antibodies, preferably monoclonal antibodies as, among
others, described herein.
The isolated nucleic acid molecule according to the present invention,
also referred to herein as the nucleic acid (molecule) according to the
present invention, codes for the amino acid motive and the polypeptides
according to the present invention. The nucleic acid molecule according to
the present invention can in a first alternative be a nucleic acid
(molecule) which has an identity of at least 70% to a nucleic acid
molecule which has the nucleic acid sequence as specified in SEQ ID No.1
to 10. It is also within the present invention that the isolated nucleic
acid molecule has a similarity of at least 70% of any sequence, which
encodes any of the polypeptides of the present invention. Preferably, the
identity is at least 80% and more preferably the identity is at least 90%.
Identity may also be 95%, 96%, 97%, 98%, 99% or 99.5%.
Identity, as known in the art and used herein, is the relationship between
two or more polypeptide sequences or two or more polynucleotide sequences,
as determined by comparing the sequences. In the art, identity also means
the degree of sequence relatedness between polypeptide or polynucleotide
sequences, as the case may be, as determined by the mach between strings
of such sequences. Identity can be readily calculated (Computational
Molecular Biology, Lesk, A. M., ed., Oxford University Press, New York,
1988; Biocomputing: Informatics and Genome Projects, Smith, D. W., ed.,
Academic Press, New York, 1993; Computer Analysis of Sequence Data, Part
I, Griffin, A. M., and Griffin, H. G., eds., Humana Press, New Jersey,
1994; Sequence Analysis in Molecular Biology, von Heinje, G., Academic
Press, 1987; and Sequence Analysis Primer, Gribskov, M. and Devereux, J.,
eds., M Stockton Press, New York, 1991). While there exist a number of
methods to measure identity between two polynucleotide or two polypeptide
sequences, the term is well known to skilled artisans (Sequence Analysis
in Molecular Biology, von Heinje, G., Academic Press, 1987; Sequence
Analysis Primer, Gribskov, M. and Devereux, J., eds., M Stockton Press,
New York, 1991; and Carillo, H., and Lipman, D., SIAM J. Applied Math.,
48: 1073 (1988)). Preferred methods to determine identity are designed to
give the largest match between the sequences tested. Methods to determine
identity are codified in computer programs. Preferred computer program
methods to determine identity between two sequences include, but are not
limited to, GCG program package (Devereux, J., et al., Nucleic Acids
Research 12(1): 387 (1984)), BLASTP, BLASTN, and FASTA (Atschul, S. F. et
al., J. Molec. Biol. 215: 403 (1990)).
The nucleic acid according to the present invention can as a second
alternative also be a nucleic acid which is at least essentially
complementary to the nucleic acid described as the first alternative
above. As used herein complementary means that a nucleic acid strand is
base pairing via Watson-Crick base pairing with a second nucleic acid
strand. Essentially complementary as used herein means that the base
pairing is not occurring for all of the bases of the respective strands
but leaves a certain number or percentage of the bases unpaired or wrongly
paired. The percentage of correctly pairing bases is preferably at least
70%, more preferably 80%, even more preferably 90% and most preferably any
percentage higher than 90%. It is to be noted that a percentage of 70%
matching bases is considered as homology and the hybridization having this
extent of matching base pairs is considered as stringent. Hybridization
conditions for this kind of stringent hybridization may be taken from
Current Protocols in Molecular Biology, John Wiley and Sons, Inc., 1987.
More particularly, the hybridization conditions can be as follows:
Hybridization performed e.g. in 5.times.SSPE, 5.times.Denhardt's reagent,
0.1% SDS, 100 g/mL sheared DNA at 68.degree. C. Moderate stringency wash
in 0.2.times.SSC, 0.1% SDS at 42.degree. C. High stringency wash in
0.1.times.SSC, 0.1% SDS at 68.degree. C.
Genomic DNA with a GC content of 50% has an approximate T.sub.M of
96.degree. C. For 1% mismatch, the T.sub.M is reduced by approximately
1.degree. C.
In addition, any of the further hybridization conditions described herein
are in principle applicable as well.
The nucleic acid according to the present invention can as a third
alternative also be a nucleic acid which comprises a stretch of at least
15 bases of the nucleic acid according to the first and second alternative
of the nucleic acid molecule according to the present invention as
outlined above. Preferably, the bases form a contiguous stretch of bases.
However, it is also within the present invention that the stretch consists
of two or more moieties which are separated by a number of bases.
The nucleic acid according to the present invention can as a fourth
alternative also be a nucleic acid which anneals under stringent
hybridisation conditions to any of the nucleic acids of the present
invention according to the above outlined first, second, and third
alternative. Stringent hybridisation conditions are typically those
described herein.
Finally, the nucleic acid according to the present invention can as a
fifth alternative also be a nucleic acid which, but for the degeneracy of
the genetic code, would hybridise to any of the nucleic acids according to
any of the nucleic acids of the present invention according to the first,
second, third, and fourth alternative as outlined above. This kind of
nucleic acid refers to the fact that preferably the nucleic acids
according to the present invention code for the polypeptides according to
the present invention and thus for adhesins and invasions, respectively.
This kind of nucleic acid is particularly useful in the detection and thus
diagnosis of the nucleic acid molecules according to the present invention
and thus of the respective microorganisms such as GBS and any disease or
diseased condition where this kind of microorganism is involved.
Preferably, the hybridisation would occur or be preformed under stringent
conditions as described in connection with the fourth alternative
described above.
Polynucleotide(s) as used herein generally refer to any polyribonucleotide
or polydeoxyribonucleotide, which may be unmodified RNA or DNA or modified
RNA or DNA. Thus, for instance, polynucleotides as used herein refers to,
among other, single- and double-stranded DNA, DNA that is a mixture of
single- and double-stranded RNA, and RNA that is a mixture of single- and
double-stranded regions, hybrid molecules comprising DNA and RNA that may
be single-stranded or, more typically, double-stranded, or
triple-stranded, or a mixture of single- and double-stranded regions. In
addition, polynucleotide as used herein refers to triple-stranded regions
comprising RNA or DNA or both RNA and DNA. The strands in such regions may
be from the same molecule or from different molecules. The regions may
include all of one or more of the molecules, but more typically involve
only a region of some of the molecules. One of the molecules of a
triple-helical region often is an oligonucleotide. As used herein, the
term polynucleotide includes DNAs or RNAs as described above that contain
one or more modified bases. Thus, DNAs or RNAs with backbones modified for
stability or for other reasons are "polynucleotides" as that term is
intended herein. Moreover, DNAs or RNAs comprising unusual bases, such as
inosine, or modified bases, such as tritylated bases, to name just two
examples, are polynucleotides as the term is used herein. It will be
appreciated that a great variety of modifications have been made to DNA
and RNA that serve many useful purposes known to those of skill in the
art. The term polynucleotide as it is employed herein embraces such
chemically, enzymatically or metabolically modified forms of
polynucleotides, as well as the chemical forms of DNA and RNA
characteristic of viruses and cells, including simple and complex cells,
inter alia. The term polynucleotide also embraces short polynucleotides
often referred to as oligonucleotide(s). "Polynucleotide" and "nucleic
acid" or "nucleic acid molecule" are often used interchangeably herein.
Using the information provided herein and known, standard methods, such as
those for cloning and sequencing and those for synthesizing
polynucleotides and polypeptides (see, e.g., Sambrook et al., Molecular
Cloning: A Laboratory Manual, 2.sup.nd Ed., Cold Spring Harbor Laboratory
Press, Cold Spring Harbor, N.Y. (1989)), one can generate numerous unique
fragments, both longer and shorter than the polynucleotides and
polypeptides set forth in the Sequence Listing, of the S. agalactiae
genome and the S. agalactiae coding regions, which are encompassed by the
present invention. To be unique, a fragment must be of sufficient size to
distinguish it from other known nucleic acid sequences, most readily
determined by comparing any selected S. agalactiae fragment to the
nucleotide sequences in computer databases such as GenBank. Such
comparative searches are standard in the art. Many unique fragments will
be S. agalactiae--specific. Typically, a unique fragment useful as a
primer or probe will be at least about 20 to 25 nucleotides in length,
depending upon the specific nucleotide content of the sequence.
Additionally, fragments can be, for example, at least about 30, 40, 50,
60, 75, 80, 90, 100, 150, 200, 250, 300, 400, 500 or more nucleotides in
length. The nucleic acid fragment can be single, double or triple
stranded, depending upon the purpose for which it is intended.
Additionally, as discussed above and below, modifications can be made to
the S. agalactiae polynucleotides and polypeptides that are encompassed by
the present invention. For example, nucleotide substitutions can be made
which do not affect the polypeptide encoded by the nucleic acid, and thus
any polynucleotide which encodes the polypeptides of this invention is
within the present invention. Additionally, certain amino acid
substitutions (and corresponding nucleotide substitutions to encode them)
can be made which are known in the art to be neutral (Robinson W. E. Jr.
and Mitchell, W. m., AIDS 4: S141-S162 (1990)). Such variations may arise
naturally as allelic variations (e.g. due to genetic polymorphism) or may
be produced by human intervention (e.g. by mutagenesis of cloned DNA
sequences), such as induced point, deletion, insertion and substitution
mutations. Minor changes in amino acid sequences are generally preferred,
such as conservative amino acid replacements, small internal deletions or
insertions, and additions or deletions at the ends of the molecules.
Substitutions may be designed based on, for example, the model of Dayhoff,
et al. (in Atlas of Protein Sequence and Structure 1978, Nat'l Biomed.
Res. Found., Washington D.C.). These modifications can result in changes
in the amino acid sequence, provide silent mutations, modify a restriction
site, or provide other specific mutations. Likewise, such amino acid
changes result in a different nucleic acid encoding the polypeptides and
proteins. Thus, alternative polynucleotides, which are within the
parameters of the present invention, are contemplated by such
modifications.
Furthermore, some of the polynucleotide sequences set forth in the
Sequence Listing are open reading frames (ORFs), i.e. coding regions of S.
agalactiae. The polypeptide encoded by each open reading frame can be
deduced, and the molecular weight of the polypeptide thus calculated using
amino acid residue molecular weight values well known in the art. Any
selected coding region can be functionally linked, using standard
techniques such as standard subcloning techniques, to any desired
regulatory sequence, whether a S. agalactiae regulatory sequence or a
heterologous regulatory sequence, or to a heterologous coding sequence to
create a fusion protein, as further described herein.
Polynucleotides of the present invention may be in the form of RNA, such
as mRNA or cRNA, or in the form of DNA, including, for instance, cDNA and
genomic DNA obtained by cloning or produced by chemical synthetic
techniques or by a combination thereof. The DNA may be triple-stranded,
double-stranded or single-stranded. Single-stranded DNA may be the coding
strand, also known as the sense strand, or it may be the non-coding
strand, also referred to as the anti-sense strand.
The coding sequence which encodes a S. agalactiae polypeptide of this
invention may be identical to the coding sequence of a polynucleotide set
forth in the sequence listing. It also may be a polynucleotide with a
different sequence which, as a result of the redundancy (degeneracy) of
the genetic code, encodes a S. agalactiae polypeptide set forth in the
sequence listing.
Polynucleotides of the present invention which encode a S. agalactiae
polypeptide as disclosed herein, including those set forth in the sequence
listing may include, but are not limited to, the coding sequence for a
mature polypeptide, by itself; the coding sequence for a mature
polypeptide and additional coding sequences, such as those encoding a
leader or secretory sequence, such as a pre-, or pro- or prepro-protein
sequence; the coding sequence of a mature polypeptide, with or without the
aforementioned additional coding sequences, together with additional,
non-coding sequences, including for example, but not limited to non-coding
5' and 3' sequences, such as the transcribed, non-translated sequences
that play a role in transcription (including termination signals, for
example), ribosome binding, mRNA stability elements, and additional coding
sequence which encode additional amino acids, such as those which provide
additional functionalities. Thus, for instance, a polypeptide may be fused
to a marker sequence, such as a peptide, which facilitates purification of
the fused polypeptide. In certain embodiments of this aspect of the
invention, the marker sequence is a hexa-histidine peptide (SEQ ID NO:
260), such as the tag provided in the pQE vector (Qiagen, Inc.), among
others, many of which are commercially available. As described in Gentz et
al., Proc. Natl. Acad. Sci., USA 86: 821-824 (1989), for instance,
hexa-histidine (SEQ ID NO: 260) provides for convenient purification of
the fusion protein. The HA tag may also be used to create fusion proteins
and corresponds to an epitope derived of influenza hermagglutinin protein,
which has been described by Wilson et al., Cell 37:767 (1984), for
instance. Polynucleotides of the invention also include, but are not
limited to, polynucleotides comprising a structural gene and its naturally
associated genetic elements.
In accordance with the foregoing, the term "polynucleotide encoding a
polypeptide" as used herein encompasses polynucleotides which include a
sequence encoding a polypeptide of the present invention, particularly a
polypeptide having a S. agalactiae amino acid sequence set forth in the
Sequence Listing. The term encompasses polynucleotides that include a
single continuous region or discontinuous regions encoding the polypeptide
(for example, interrupted by integrated phage or insertion sequence or
editing) together with additional regions, that also may contain coding
and/or non-coding sequences.
The present invention further relates to variants of the herein above
described polynucleotides which encode for fragments, analogs and
derivatives of the polypeptide having a deducted S. agalactiae amino acid
sequence set forth in the Sequence Listing. A variant of the
polynucleotide may be a naturally occurring variant such as a naturally
occurring allelic variant, or it may be a variant that is not known to
occur naturally. Such non-naturally occurring variants of the
polynucleotide may be made by mutagenesis techniques, including those
applied to polynucleotides, cells or organisms.
Among variants in this regard are variants that differ from the
aforementioned polynucleotides by nucleotide substitutions, deletions or
additions. The substitutions, deletions or additions may involve one or
more nucleotides. The variants may be altered in coding or on-coding
regions or both. Alterations in the coding regions may produce
conservative or non-conservative amino acid substitutions, deletions or
additions. Preferred are polynucleotides encoding a variant, analog,
derivative or fragment, or a variant, analogue or derivative of a
fragment, which have a S. agalactiae sequence as set forth in the Sequence
Listing, in which several, a few, 5 to 10, 1 to 5, 1 to 3, 2, 1 or no
amino acid(s) is substituted, deleted or added, in any combination.
Especially preferred among these are silent substitutions, additions and
deletions, which do not alter the properties and activities of the S.
agalactiae polypeptides set forth in the Sequence Listing. Also especially
preferred in this regard are conservative substitutions.
Further preferred embodiments of the invention are polynucleotides that
are at least 70% identical over their entire length to a polynucleotide
encoding a polypeptide according to the present invention and more
particularly those polypeptides having an amino acid sequence set forth in
the Sequence Listing, and polynucleotides which are complementary to such
polynucleotides. Alternatively, most highly preferred are polynucleotides
that comprise a region that is at least 80% or at least 85% identical over
their entire length to a polynucleotide encoding a S. agalactiae
polypeptide according to the present invention and more particularly those
polypeptides set forth in the Sequence Listing, including complementary
polynucleotides. In this regard, polynucleotides at least 90%, 91%, 92%,
93%, 94%, 95%, or 96% identical over their entire length to the same are
particularly preferred, and among these particularly preferred
polypeptides, those with at least 95% are especially preferred.
Furthermore, those with at least 97% are highly preferred among those with
at least 95%, and among these, those with at least 98% and at least 99%
are particularly highly preferred, with at least 99% or 99.5% being the
more preferred.
Preferred embodiments in this respect, moreover, are polynucleotides which
encode polypeptides which retain substantially the same biological
function or activity as the mature polypeptide encoded by the DNA set
forth in the Sequence Listing.
The present invention further relates to polynucleotides that hybridize to
the herein above-described sequences. In this regard, the present
invention especially relates to polynucleotides which hybridize under
stringent conditions to the herein above-described polynucleotides.
Stringent conditions are typically selective conditions. As herein used,
the term "stringent conditions" means hybridization will occur only if
there is at least 95% and preferably at least 97% identity between the
sequences. For a specific sequence, stringent conditions can be determined
empirically according to the nucleotide content, as is known in the art
and also exemplified herein. For example, a typical example of stringent
conditions is hybridization of a 48mer having 55% GC content at 42.degree.
C. in 50% formamide and 750 mM NaCl followed by washing at 55.degree. C.
in 15 mM NaCl and 0.1% SDS.
As discussed additionally herein regarding polynucleotide assays of the
invention, for instance, polynucleotides of the invention as discussed
above, may be used as a hybridization probe for RNA, cDNA and genomic DNA
to isolate full-length cDNAs and genomic clones encoding polypeptides of
the present invention and to isolate cDNA and genomic clones of other
genes that have a high sequence similarity to the polynucleotides of the
present invention. Such probes generally will comprise at least 15 bases.
Preferably, such probes will have at least 20, at least 25 or at least 30
bases, and may have at least 50 bases. Particularly preferred probes will
have at least 30 bases, and will have 50 bases or less, such as 30, 35,
40, 45, or 50 bases.
For example, the coding region of the polynucleotide of the present
invention may be isolated by screening using the known DNA sequence to
synthesize an oligonucleotide probe. A labeled oligonucleotide having a
sequence complementary to that of a gene of the present invention is then
used to screen a library of cDNA, genomic DNA or mRNA to determine to
which members of the library the probe hybridizes.
The polynucleotides and polypeptides of the present invention may be
employed as reagents and materials for development of treatments of and
diagnostics for disease, particularly human disease, as further discussed
herein relating to polynucleotide assays, inter alia.
The polynucleotides of the present invention that are oligonucleotides can
be used in the processes herein as described, but preferably for PCR, to
determine whether or not the S. agalactiae genes identified herein in
whole or in part are present and/or transcribed in infected tissue such as
blood. It is recognized that such sequences will also have utility in
diagnosis of the stage of infection and type of infection the pathogen has
attained. For this and other purposes the arrays comprising at least one
of the nucleic acids according to the present invention as described
herein, may be used.
The polynucleotides may encode a polypeptide which is the mature protein
plus additional amino or carboxyl-terminal amino acids, or amino acids
interior to the mature polypeptide (when the mature form has more than one
polypeptide chain, for instance). Such sequences may play a role in
processing of a protein from precursor to a mature form, may allow protein
transport, may lengthen or shorten protein half-life or may facilitate
manipulation of a protein for assay or production, among other things. As
generally is the case in vivo, the additional amino acids may be processed
away from the mature protein by cellular enzymes.
A precursor protein, having the mature form of the polypeptide fused to
one or more prosequences may be an inactive form of the polypeptide. When
prosequences are removed such inactive precursors generally are activated.
Some or all of the prosequences may be removed before activation.
Generally, such precursors are called proproteins.
The present invention additionally contemplates polynucleotides
functionally encoding fusion polypeptides wherein the fusion polypeptide
comprises a fragment of a S. agalactiae polypeptide and one or more
polypeptide(s) derived from another S. agalactiae polypeptide or from
another organism or a synthetic polyamino acid sequence. Such
polynucleotides may or may not encode amino acid sequences to facilitate
cleavage of the S. agalactiae polypeptide from the other polypeptide(s)
under appropriate conditions.
In sum, a polynucleotide of the present invention may preferably encode a
mature protein, a mature protein plus a leader sequence (which may be
referred to as a preprotein), a precursor of a mature protein having one
or more prosequences which are not the leader sequences of a preprotein,
or a preproprotein, which is a precursor to a proprotein, having a leader
sequence and one or more prosequences, which generally are removed during
processing steps that produce active and mature forms of the polypeptide.
Isolated as used herein means separated "by the hand of man" from its
natural state; i.e., that, if it occurs in nature, it has been changed or
removed from its original environment, or both. For example, a naturally
occurring polynucleotide or a polypeptide naturally present in a living
organism in its natural state is not "isolated," but the same
polynucleotide or polypeptide separated from the coexisting materials of
its natural state is "isolated", as the term is employed herein. As part
of or following isolation, such polynucleotides can be joined to other
polynucleotides, such as DNAs, for mutagenesis, to form fusion proteins,
and for propagation or expression in a host, for instance. The isolated
polynucleotides, alone or joined to other polynucleotides such as vectors,
can be introduced into host cells, in culture or in whole organisms.
Introduced into host cells in culture or in whole organisms, such DNAs
still would be isolated, as the term is used herein, because they would
not be in their naturally occurring form or environment. Similarly, the
polynucleotides and polypeptides may occur in a composition, such as a
media formulations, solutions for introduction of polynucleotides or
polypeptides, for example, into cells, compositions or solutions for
chemical or enzymatic reactions, for instance, which are not naturally
occurring compositions, and, therein remain isolated polynucleotides or
polypeptides within the meaning of that term as it is employed herein.
The nucleic acids according to the present invention may be chemically
synthesized. Alternatively, the nucleic acids can be isolated from various
microorganisms by methods known to the one skilled in the art. Appropriate
sources are, e.g. Streptococcus agalactiae, Streptococcus pyogenes,
Streptococcus mutans and Streptococcus pneumoniae.
The nucleic acids according to the present invention may be used for the
detection of nucleic acids and organisms or samples containing these
nucleic acids. Preferably such detection is for diagnosis, more preferable
for the diagnosis of a disease, most preferably for the diagnosis of a
disease related or linked to the present or abundance of S. agalactiae.
S. agalactiae bacteria, which have infected eukaryotes (herein also "individual(s)"),
particularly mammals, and especially humans, may be detected at the DNA
level by a variety of techniques. By selecting regions of nucleic acids
that vary among strains of S. agalactiae, preferred candidates for
distinguishing a specific strain of S. agalactiae can be obtained.
Furthermore, by selecting regions of nucleic acids that vary between S.
agalactiae and other organisms, preferred candidates for distinguishing S.
agalactiae from other organisms can be obtained. Nucleic acids for
diagnosis may be obtained from an infected individual's cells and tissues,
such as bone, blood, muscle, cartilage, and skin. Genomic DNA may be used
directly for detection or may be amplified enzymatically by using PCR
(Saiki et al., Nature, 324: 163-166 (1986) prior to analysis. RNA or cDNA
may also be used in the same ways. As an example, PCR primers
complementary to the nucleic acid forming part of the polynucleotide of
the present invention can be used to identify and analyze for its presence
and/or expression. Using PCR, characterization of the strain of S.
agalactiae present in a mammal, and especially a human, may be made by an
analysis of the genotype of the prokaryote gene. For example, deletions
and insertions can be detected by a change in size of the amplified
product in comparison to the genotype of a reference sequence. Point
mutations can be identified by hybridising amplified DNA to radiolabeled
RNA or alternatively, radiolabeled antisense DNA sequences. Perfectly
matched sequences can be distinguished form mismatched duplexes by Rnase A
digestion or by differences in melting temperatures.
Sequence differences between a reference gene and genes having mutations
also may be revealed by direct DNA sequencing. In addition, cloned DNA
segments may be employed as probes to detect specific DNA segments. The
sensitivity of such methods can be greatly enhanced by appropriate use of
PCR or another amplification method. For example, a sequencing primer can
be used with double-stranded PCR product or a single-stranded template
molecule generated by a modified PCR. The sequence determination is
performed by conventional procedures with radiolabeled nucleotide or by
automatic sequencing procedures with fluorescent-tags.
Genetic characterization based on DNA sequence differences may be achieved
by detection of alteration in electrophoretic mobility of DNA fragments in
gels, with or without denaturing agents. Small sequence deletions and
insertions can be visualised by high resolution gel electrophoresis. DNA
fragments of different sequences may be distinguished on denaturing
formamide gradient gels in which the mobilities of different DNA fragments
are retarded in the gel at different positions according to their specific
melting or partial melting temperatures (see, e.g. Myers et al., Science,
230: 1242 (1985)).
Sequence changes at specific locations also may be revealed by nuclease
protection assays, such as Rnase and S1 protection or the chemical
cleavage method (e.g., Cotton et al., Proc. Natl. Acad. Sci., USA, 85:
4397-4401 (1985)).
Thus, the detection of a specific DNA sequence may be achieved by methods
such as hybridization, Rnase protection, chemical cleavage, direct DNA
sequencing or the use of restriction enzymes, e.g., restriction fragment
length polymorphisms (RFLP) and Southern blotting of genomic DNA.
In addition to more conventional gel-electrophoresis and DNA sequencing,
mutations also can be detected by in situ analysis.
Cells carrying mutations or polymorphisms in the gene of the present
invention may also be detected at the DNA level by a variety of
techniques, to allow for serotyping, for example. For example, RT-PCR can
be used to detect mutations. It is particularly preferred to use RT-PCR in
conjunction with automated detection systems, such as, for example,
GeneScan. RNA or cDNA may also be used for the same purpose, PCR or RT-PCR.
As an example, PCR primers complementary to the nucleic acid encoding the
polypeptide of the present invention can be used to identify and analyse
mutations. The primers may be used to amplify the gene isolated from the
individual such that the gene may then be subject to various techniques
for elucidation of the DNA sequence. In this way, mutations in the DNA
sequence may be diagnosed.
The invention provides a process for diagnosing disease, arising from
infection with S. agalactiae, comprising determining from a sample
isolated or derived from an individual an increased level of expression of
a polynucleotide having the sequence of a polynucleotide set forth in the
Sequence Listing. Expression of polynucleotide can be measured using any
one of the methods well known in the art for the quantitation of
polynucleotides, such as, for example, PCR, RT-PCR, Rnase protection,
Northern blotting, other hybridisation methods and the arrays described
herein.
The present invention also relates to vectors which comprise a
polynucleotide or polynucleotides of the present invention, host cells
which are genetically engineered with vectors of the invention and the
production of polypeptides of the invention by recombinant techniques.
Cells can be genetically engineered to incorporate polynucleotides and
express polypeptides of the present invention. Introduction of
polynucleotides, into the host cell can be effected by calcium phosphate
transfection, DEAE-dextran mediated transfection, transvection,
microinjection, cationic lipid-mediated transfection, electroporation,
transduction, scrape loading, ballistic introduction, infection or other
methods. Such methods are described in many standard laboratory manuals,
such as Davis et al., BASIC METHODS IN MOLECULAR BIOLOGY, (1986) and
Sambrook et al., MOLECULAR CLONONG: A LABORATORY MANUAL, 2.sup.nd Ed.,
Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y. (1989).
Polynucleotide constructs in cells can be used in a conventional manner to
produce the gene product encoded by the recombinant sequence.
Alternatively, the polypeptides of the invention can be synthetically
produced by conventional peptide synthesizers.
Mature proteins can be expressed in mammalian cells, yeast, bacteria, or
other cells under the control of appropriate promoters. Cell-free
translation systems can also be employed to produce such proteins using
RNAs derived from the DNA constructs of the present invention. Appropriate
cloning and expression vectors for use with prokaryotic and eukaryotic
hosts are described by Sambrook et al., MOLECULAR CLONING: A LABORATORY
MANUAL, 2.sup.nd Ed., Cold Spring Harbor Laboratory Press, Cold Spring
Harbor, N.Y. (1989).
In accordance with this aspect of the invention the vector may be, for
example, a plasmid vector, a single or double-stranded phage vector, a
single or double-stranded RNA or DNA viral vector, a single or
double-stranded RNA or DNA viral vector. Plasmids generally are designated
herein by a lower case p preceded and/or followed by capital letters
and/or number, in accordance with standard naming conventions that are
familiar to those of skill in the art. Starting plasmids disclosed herein
are either commercially available, publicly available, or can be
constructed from available plasmids by routine application of well known,
published procedures, given the teachings herein. Many plasmids and other
cloning and expression vectors that can be used in accordance with the
present invention are well known and readily available to those of skill
in the art.
Preferred among vectors, in certain respects, are those for expression of
polynucleotides and polypeptides of the present invention. Generally, such
vectors comprise cis-acting control regions effective for expression in a
host operatively linked to the polynucleotide to be expressed. Appropriate
trans-acting factors either are supplied by the host, supplied by a
complementing vector or supplied by the vector itself upon introduction
into the host.
In certain preferred embodiments in this regard, the vectors provide for
specific expression. Such specific expression may be inducible expression
or expression only in certain types of cells or both inducible and
cell-specific. Particularly preferred among inducible vectors are vectors
that can be induced for expression by environmental factors that are easy
to manipulate, such as temperature and nutrient additives. A variety of
vectors suitable to this aspect of the invention, including constitutive
and inducible expression vectors for use in prokaryotic and eukaryotic
cells, are well known and employed routinely by those of skill in the art.
A great variety of expression vectors can be used to express a polypeptide
of the invention. Such vectors include, among other, chromosomal, episomal
and virus-derived vectors, e.g., vectors derived from bacterial plasmids,
from bacteriophage, from transposons, from yeast episomes, from insertion
elements, from yeast chromosomal elements, from viruses such as
baculoviruses, papova viruses, such as SV40, vaccinia viruses,
adenoviruses, fowl pox viruses, pseudorabies viruses and retroviruses, and
vectors derived from combinations thereof, such as those derived from
plasmid and bacteriophage genetic elements, such as cosmids and phagemids,
all may be used for expression in accordance with this aspect of the
present invention. Generally, any vector suitable to maintain, propagate
or express polynucleotides to express a polypeptide in a host may be used
for expression in this regard.
The appropriate DNA sequence may be inserted into the vector by any of a
variety of well-known and routine techniques, such as, for example, those
set forth in Sambrook et al., MOLECULAR CLONING, A LABORATORY MANUAL,
2.sup.nd Ed.; Cold Spring Harbor Laboratory Press, Cold Spring Harbor,
N.Y. (1989).
The DNA sequence in the expression vector is operatively linked to
appropriate expression control sequence(s), including, for instance, a
promoter to direct mRNA transcription. Representatives of such promoters
include, but are not limited to, the phage lambda PL promoter, the E. coli
lac, trp and tac promoters, the SV40 early and late promoters and
promoters of retroviral LTRs.
In general, expression constructs will contain sites for transcription
initiation and termination, and, in the transcribed region, a ribosome
binding site for translation. The coding portion of the mature transcripts
expressed by the constructs will include a translation initiating AUG or
others such as GUG and UUG at the beginning and a termination codon
appropriately positioned at the end of the polypeptide to be translated.
In addition, the constructs may contain control regions that regulate as
well as engender expression. Generally, in accordance with many commonly
practiced procedures, such regions will operate by controlling
transcription, such as transcription factors, repressor binding sites and
termination, among other.
Vectors for propagation and expression generally will include selectable
markers and amplification regions, such as, for example, those set forth
in Sambrook et al., MOLECULAR CLONING, A LABORATORY MANUAL, 2.sup.nd Ed.;
Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y. (1989)
Representative examples of appropriate cells which host said vectors
include bacterial cells, such as streptococci, staphylococci, E. coli,
streptomyces and Bacillus subtilis cells; fungal cells, such as yeast
cells and Aspergillus cells; insect cells such as Drosophila S2 and
Spodoptera Sf9 cells; animal cells such as CHO, COS, HeLa, C127, 3T3, BHK,
293 and Bowes melanoma cells; and plant cells.
The following vectors, which are commercially available, are provided by
way of example. Among vectors preferred for use in bacteria are pQE70,
pQE60 and pQE-9, available from Qiagen; pBS vectors, Phagescript vectors,
Bluescript vectors, pNH8A, pNH16a, pNH18A, pNH46A, available from
Stratagene; and ptrc99a, pKK223-3, Pkk233-3, pDR540, pRIT5 available from
Pharmacia, and pBR322 (ATCC 37017). Among preferred eukaryotic vectors are
pWLNEO, pSV2CAT, pOG44, PXT1 and pSG available from Stratagene; and pSVK3,
pBPV, pMSG and pSVL available from Pharmacia. These vectors are listed
solely by way of illustration of the many commercially available and well
known vectors that are available to those of skill in the art for use in
accordance with this aspect of the present invention. It will be
appreciated that any other plasmid or vector suitable for, for example,
introduction, maintenance, propagation or expression of a polynucleotide
or polypeptide of the invention in a host may be used in this aspect of
the invention.
Promoter regions can be selected from any desired gene using vectors that
contain a reporter transcription unit lacking a promoter region, such as a
chloramphenicol acetyl transferase ("CAT") transcription unit, downstream
of restriction site or sites for introducing a candidate promoter
fragment; i.e., a fragment that may contain a promoter. As is well known,
introduction into the vector of a promoter-containing fragment at the
restriction site upstream of the cat gene engenders production of CAT
activity, which can be detected by standard CAT assays. Vectors suitable
to this end are well known and readily available, such as pKK232-8 and
pCM7. Promoters for expression of polynucleotides of the present invention
include not only well known and readily available promoters, but also
promoters that readily may be obtained by the foregoing technique, using a
reporter gene.
Among known prokaryotic promoters suitable for expression of
polynucleotides and polypeptides in accordance with the present invention
are the E. coli lacl and lacZ and promoters, the T3 and T7 promoters, the
gpt promoter, the lambda PR, PL promoters and the trp promoter.
Among known eukaryotic promoters suitable in this regard are the CMV
immediate early promoter, the HSV thymidine kinase promoter, the early and
late SV40 promoters, the promoters of retroviral LTRs, such as those of
the Rous sarcoma virus "(RSV"), and metallothionein promoters, such as the
mouse metallothionein-I promoter.
Recombinant expression vectors will include, for example, origins of
replication, a promoter preferably derived from a highly-expressed gene to
direct transcription of a downstream structural sequence, and a selectable
marker to permit isolation of vector containing cells after exposure to
the vector.
Polynucleotides of the invention, encoding the heterologous structural
sequence of a polypeptide of the invention generally will be inserted into
the vector using standard techniques so that it is operably linked to the
promoter for expression. The polynucleotide will be positioned so that the
transcription start site will be 5' to the AUG that initiates translation
of the polypeptide to be expressed. Generally, there will be no other open
reading frames that begin with an initiation codon, usually AUG, and lie
between the ribosome binding site and the initiation codon. Also,
generally, there will be a translation stop codon at the end of the
polypeptide and there will be a polyadenylation signal in constructs for
use in eukaryotic hosts. A transcription termination signal appropriately
disposed at the 3' end of the transcribed region may also be included in
the polynucleotide construct.
For secretion of the translated protein into the lumen of the endoplasmic
reticulum, into the periplasmic space or into the extracellular
environment, appropriate secretion signals may be incorporated into the
expressed polypeptide.
These signals may be endogenous to the polypeptide or they may be
heterologous signals.
The polypeptide may be expressed in a modified form, such as a fusion
protein, and may include not only secretion signals but also additional
heterologous functional regions. Thus, for instance, a region of
additional amino acids, particularly charged amino acids, may be added to
the N- or C-terminus of the polypeptide to improve stability and
persistence in the host cell, during purification or during subsequent
handling and storage. Also, regions may be added to the polypeptide to
facilitate purification. Such regions may be removed prior to final
preparation of the polypeptide. The addition of peptide moieties to
polypeptides to engender secretion or excretion, to improve stability or
to facilitate purification, among others, are familiar and routine
techniques in the art. A preferred fusion protein comprises a heterologous
region from immunoglobulin that is useful to solubilize or purify
polypeptides. For example, EP-A-O 464 533 (Canadian counterpart 2045869)
discloses fusion proteins comprising various portions of constant region
of immunoglobin molecules together with another protein or part thereof.
In drug discovery, for example, proteins have been fused with antibody Fc
portions for the purpose of high-throughout screening assays to identify
antagonists. See, D. Bennett et al., Journal of Molecular Recognition,
Vol. 8 52-58 (1995) and K. Johanson et al., The Journal of Biological
Chemistry, Vol. 270, No. 16, pp 9459-9471 (1995).
Cells typically then are harvested by centrifugation, disrupted by
physical or chemical means, and the resulting crude extract retained for
further purification.
Microbial cells employed in expression of proteins can be disrupted by any
convenient method, including freeze-thaw cycling, sonication, mechanical
disruption, or use of cell lysing agents; such methods are well known to
those skilled in the art.
Mammalian expression vectors may comprise expression sequences, such as an
origin of replication, a suitable promoter and enhancer, and also any
necessary ribosome binding sites, polyadenylation regions, splice donor
and acceptor sites, transcriptional termination sequences, and 5' flanking
non-transcribed sequences that are useful or necessary for expression.
The polypeptide can be recovered and purified from recombinant cell
cultures by well-known methods including ammonium sulfate or ethanol
precipitation, acid extraction, anion or cation exchange chromatography,
phosphocellulose chromatography, hydrophobic interaction chromatography,
affinity chromatography, hydroxylapatite chromatography and lectin
chromatography. Most preferably, high performance liquid chromatography is
employed for purification. Well-known techniques for refolding protein may
be employed to regenerate the active conformation when the polypeptide is
denatured during isolation and or purification.
The polypeptides according to the present invention can be produced by
chemical synthesis as well as by biotechnological means. The latter
comprise the transfection or transformation of a host cell with a vector
containing a nucleic acid according to the present invention and the
cultivation of the transfected or transformed host cell under conditions,
which are known to the ones skilled in the art. The production method may
also comprise a purification step in order to purify or isolate the
polypeptide to be manufactured. In a preferred embodiment the vector is a
vector according to the present invention.
In a further aspect the present invention relates to an antibody directed
to any of the polypeptides, derivatives or fragments thereof according to
the present invention. The present invention includes, for example,
monoclonal and polyclonal antibodies, chimeric, single chain, and
humanized antibodies, as well as Fab fragments, or the product of a Fab
expression library. It is within the present invention that the antibody
may be chimeric, i.e. that different parts thereof stem from different
species or at least the respective sequences are taken from different
species.
Antibodies generated against the polypeptides corresponding to a sequence
of the present invention can be obtained by direct injection of the
polypeptides into an animal or by administering the polypeptides to an
animal, preferably a non-human. The antibody so obtained will then bind
the polypeptides itself. In this manner, even a sequence encoding only a
fragment of the polypeptides can be used to generate antibodies binding
the whole native polypeptides. Such antibodies can then be used to isolate
the polypeptide from tissue expressing that polypeptide.
For preparation of monoclonal antibodies, any technique known in the art,
which provides antibodies produced by continuous cell line cultures can be
used. Examples include various techniques, such as those in Kohler, G. and
Milstein, C., Nature 256: 495-497 (1975); Kozbor et al., Immunology Today
4: 72 (1983); Cole et al., pg. 77-96 in MONOCLONAL ANTIBODIES AND CANCER
THERAPY, Alan R. Liss, Inc. (1985); U.S. Pat. No. 5,545,403; U.S. Pat. No.
5,545,405; U.S. Pat. No. 5,654,403; U.S. Pat. No. 5,792,838; U.S. Pat. No.
5,316,938; U.S. Pat. No. 5,633,162; U.S. Pat. No. 5,644,036; U.S. Pat. No.
5,858,725.
Techniques described for the production of single chain antibodies (U.S.
Pat. No. 4,946,778) can be adapted to produce single chain antibodies to
immunogenic polypeptide products of this invention. Also, transgenic mice,
or other organisms such as other mammals, may be used to express humanized
antibodies to immunogenic polypeptide products of this invention.
Alternatively, phage display technology could be utilized to select
antibody genes with binding activities towards the polypeptide either from
repertoires of PCR amplified v-genes of lymphocytes from humans screened
for possessing anti-Fab or from naive libraries (McCafferty, J. et al.,
(1990), Nature 348, 552-554; Marks, J. et al., (1992) Biotechnology 10,
779-783). The affinity of these antibodies can also be improved by chain
shuffling (Clackson, T. et al; (1991) Nature 352, 624-628).
If two antigen binding domains are present, each domain may be directed
against a different epitope--termed `bispecific` antibodies.
The above-described antibodies may be employed to isolate or to identify
clones expressing the polypeptide or purify the polypeptide of the present
invention by attachment of the antibody to a solid support for isolation
and/or purification by affinity chromatography.
Thus, among others, antibodies against the polypeptide of the present
invention may be employed to inhibit and/or treat infections, particularly
bacterial infections and especially infections arising from S. agalactiae.
Polypeptide derivatives include antigenically, epitopically or
immunologically equivalent derivatives which form a particular aspect of
this invention. The term "antigenically equivalent derivative" as used
herein encompasses a polypeptide or its equivalent which will be
specifically recognized by certain antibodies which, when raised to the
protein or polypeptide according to the present invention, interfere with
the immediate physical interaction between pathogen and mammalian host.
The term "immunologically equivalent derivative" as used herein
encompasses a peptide or its equivalent which when used in a suitable
formulation to raise antibodies in a vertebrate, the antibodies act to
interfere with the immediate physical interaction between pathogen and
mammalian host.
The polypeptide, such as an antigenically or immunologically equivalent
derivative or a fusion protein thereof can be used as an antigen to
immunize a mouse or other animal such as a rat or chicken. The fusion
protein may provide stability to the polypeptide. The antigen may be
associated, for example by conjugation, with an immunogenic carrier
protein, for example bovine serum albumin (BSA) or keyhole limpet
haemocyanin (KLH). Alternatively, a multiple antigenic peptide comprising
multiple copies of the protein or polypeptide, or an antigenically or
immunologically equivalent polypeptide thereof, may be sufficiently
antigenic to improve immunogenicity so as to obviate the use of a carrier.
Preferably the antibody or derivative thereof is modified to make it less
immunogenic in the individual. For example, if the individual is human the
antibody may most preferably be "humanized", wherein the complementarity
determining region(s) of the hybridoma-derived antibody has been
transplanted into a human monoclonal antibody, for example as described in
Jones, P. et al. (1986), Nature 321, 522-525 or Tempest at al., (1991)
Biotechnology 9, 266-273.
The use of a polynucleotide of the invention in genetic immunization will
preferably employ a suitable delivery method such as direct injection of
plasmid DNA into muscle (Wolff et al., (1992) Hum. Mol. Genet. 1, 363;
Manthorpe et al., (1963) Hum. Gene Ther. 4, 419) delivery of DNA complexed
with specific protein carriers (Wu et al., (1989) J. Biol. Chem. 264,
16985), coprecipitation of DNA with calcium phosphate (Benvenisty & Reshef
(1986) PNAS 83, 9551), encapsulation of DNA in various forms of liposomes
(Kaneda et al., (1989) Science 243, 375), particle bombardment (Tang et
al., (1992) Nature 356, 152; Eisenbraun et al., (1993) DNA Cell. Biol. 12,
791) and in vivo infection using cloned retroviral vectors (Seeger et al.,
(1984) PNAS 81, 5849).
In a further aspect the present invention relates to a peptide binding to
any of the polypeptides according to the present invention, and a method
for the manufacture of such peptides whereby the method is characterized
by the use of the polypeptides according to the present invention and the
basic steps are known to the one skilled in the art.
Such peptides may be generated by using methods according to the state of
the art such as phage display or ribosome display. In case of phage
display, basically a library of peptide is generated, such as in form of
phages, and this kind of libraries is contacted with the target molecule,
in the present case the polypeptides according to the present invention.
Those peptides binding to the target molecule are subsequently removed,
preferably as a complex with the target molecule, from the respective
reaction. It is known to the one skilled in the art that the binding
characteristics, at least to a certain extend, depend on the particularly
realized experimental set-up such as the salt concentration and the like.
After separating those peptides binding to the target molecule with a
higher affinity or a bigger force, from the non-binding members of the
library, and optionally also after removal of the target molecule from the
complex of target molecule and peptide, the respective peptide(s) may
subsequently be characterised. Prior to the characterisation optionally an
amplification step is realized such as, e.g. by propagating the peptide
coding phages. The characterisation preferably comprises the sequencing of
the target binding peptides. Basically, the peptides are not limited in
their lengths, however, preferably peptides having a lengths from about 8
to 20 amino acids are preferably obtained in the respective methods. The
size of the libraries may be about 10.sup.2 to 10.sup.18, preferably
10.sup.8 to 10.sup.15 different peptides, however, is not limited thereto.
A particular form of target binding polypeptides are the so-called "anticalines"
which are, among others, described in German patent application DE 197 42
706.
In a further aspect the present invention relates to functional nucleic
acids interacting with any of the polypeptides according to the present
invention, and a method for the manufacture of such functional nucleic
acids whereby the method is characterized by the use of the polypeptides
according to the present invention and the basic steps are known to the
one skilled in the art. The functional nucleic acids are preferably
aptamers and spiegelmers.
Aptamers are D-nucleic acids, which are either single stranded or double
stranded and which specifically interact with a target molecule. The
manufacture or selection of aptamers is, e.g., described in European
patent EP 0 533 838. Basically the following steps are realized. First, a
mixture of nucleic acids, i.e. potential aptamers, is provided whereby
each nucleic acid typically comprises a segment of several, preferably at
least eight subsequent randomised nucleotides. This mixture is
subsequently contacted with the target molecule whereby the nucleic acid(s)
binds to the target molecule, such as based on an increased affinity
towards the target or with a bigger force thereto, compared to the
candidate mixture. The binding nucleic acid(s) are/is subsequently
separated from the remainder of the mixture. Optionally, the thus obtained
nucleic acid(s) is amplified using, e.g. polymerase chain reaction. These
steps may be repeated several times giving at the end a mixture having an
increased ratio of nucleic acids specifically binding to the target from
which the final binding nucleic acid is then optionally selected. These
specifically binding nucleic acid(s) are referred to as aptamers. It is
obvious that at any stage of the method for the generation or
identification of the aptamers samples of the mixture of individual
nucleic acids may be taken to determine the sequence thereof using
standard techniques. It is within the present invention that the aptamers
may be stabilized such as, e.g., by introducing defined chemical groups
which are known to the one skilled in the art of generating aptamers. Such
modification may for example reside in the introduction of an amino group
at the 2' position of the sugar moiety of the nucleotides. Aptamers are
currently used as therapeutical agens. However, it is also within the
present invention that the thus selected or generated aptamers may be used
for target validation and/or as lead substance for the development of
medicaments, preferably of medicaments based on small molecules. This is
actually done by a competition assay whereby the specific interaction
between the target molecule and the aptamer is inhibited by a candidate
drug whereby upon replacement of the aptamer from the complex of target
and aptamer it may be assumed that the respective drug candidate allows a
specific inhibition of the interaction between target and aptamer, and if
the interaction is specific, said candidate drug will, at least in
principle, be suitable to block the target and thus decrease its
biological availability or activity in a respective system comprising such
target. The thus obtained small molecule may then be subject to further
derivatisation and modification to optimise its physical, chemical,
biological and/or medical characteristics such as toxicity, specificity,
biodegradability and bioavailability.
Spiegelmers and their generation or manufacture is based on a similar
principle. The manufacture of spiegelmers is described in international
patent application WO 98/08856. Spiegelmers are L-nucleic acids, which
means that they are composed of L-nucleotides rather than D-nucleotides as
aptamers are. Spiegelmers are characterized by the fact that they have a
very high stability in biological systems and, comparable to aptamers,
specifically interact with the target molecule against which they are
directed. In the process of generating spiegelmers, a heterogeneous
population of D-nucleic acids is created and this population is contacted
with the optical antipode of the target molecule, in the present case for
example with the D-enantiomer of the naturally occurring L-enantiomer of
the polypeptides according to the present invention. Subsequently, those
D-nucleic acids are separated which do not interact with the optical
antipode of the target molecule. But those D-nucleic acids interacting
with the optical antipode of the target molecule are separated, optionally
determined and/or sequenced and subsequently the corresponding L-nucleic
acids are synthesized based on the nucleic acid sequence information
obtained from the D-nucleic acids. These L-nucleic acids, which are
identical in terms of sequence with the aforementioned D-nucleic acids
interacting with the optical antipode of the target molecule, will
specifically interact with the naturally occurring target molecule rather
than with the optical antipode thereof. Similar to the method for the
generation of aptamers it is also possible to repeat the various steps
several times and thus to enrich those nucleic acids specifically
interacting with the optical antipode of the target molecule.
In a further aspect the present invention relates to functional nucleic
acids interacting with any of the nucleic acid molecules according to the
present invention, and a method for the manufacture of such functional
nucleic acids whereby the method is characterized by the use of the
nucleic acid molecules and their respective sequences according to the
present invention and the basic steps are known to the one skilled in the
art. The functional nucleic acids are preferably ribozymes, antisense
oligonucleotides and siRNA.
Ribozymes are catalytically active nucleic acids, which preferably consist
of RNA which basically comprises two moieties. The first moiety shows a
catalytic activity whereas the second moiety is responsible for the
specific interaction with the target nucleic acid, in the present case the
nucleic acid coding for the polypeptides according to the present
invention. Upon interaction between the target nucleic acid and the second
moiety of the ribozyme, typically by hybridisation and Watson-Crick base
pairing of essentially complementary stretches of bases on the two
hybridising strands, the catalytically active moiety may become active
which means that it catalyses, either intramolecularly or intermolecularly,
the target nucleic acid in case the catalytic activity of the ribozyme is
a phosphodiesterase activity. Subsequently, there may be a further
degradation of the target nucleic acid which in the end results in the
degradation of the target nucleic acid as well as the protein derived from
the said target nucleic acid. Ribozymes, their use and design principles
are known to the one skilled in the art, and, for example described in
Doherty and Doudna ((2001) Ribozym structures and mechanism. Annu. Rev.
Biophys. Biomolstruct. 30, 457-475) and Lewin and Hauswirth (Ribozyme Gene
Therapy: Applications for molecular medicine. 2001 7: 221-8).
The activity and design of antisense oligonucleotides for the manufacture
of a medicament and as a diagnostic agent, respectively, is based on a
similar mode of action. Basically, antisense oligonucleotides hybridise
based on base complementarity, with a target RNA, preferably with a mRNA,
thereby activate RNase H. RNase H is activated by both phosphodiester and
phosphorothioate-coupled DNA. Phosphodiester-coupled DNA, however, is
rapidly degraded by cellular nucleases with the exception of
phosphorothioate-coupled DNA. These resistant, non-naturally occurring DNA
derivatives do not inhibit RNase H upon hybridisation with RNA. In other
words, antisense polynucleotides are only effective as DNA RNA hybride
complexes. Examples for this kind of antisense oligonucleotides are
described, among others, in U.S. Pat. No. 5,849,902 and U.S. Pat. No.
5,989,912. In other words, based on the nucleic acid sequence of the
target molecule which in the present case are the nucleic acid molecules
for the polypeptides according to the present invention, either from the
target protein from which a respective nucleic acid sequence may in
principle be deduced, or by knowing the nucleic acid sequence as such,
particularly the mRNA, suitable antisense oligonucleotides may be designed
based on the principle of base complementarity.
Particularly preferred are antisense-oligonucleotides, which have a short
stretch of phosphorothioate DNA (3 to 9 bases). A minimum of 3 DNA bases
is required for activation of bacterial RNase H and a minimum of 5 bases
is required for mammalian RNase H activation. In these chimeric
oligonucleotides there is a central region that forms a substrate for
RNase H that is flanked by hybridising "arms" comprised of modified
nucleotides that do not form substrates for RNase H. The hybridising arms
of the chimeric oligonucleotides may be modified such as by 2'-O-methyl or
2'-fluoro. Alternative approaches used methylphosphonate or
phosphoramidate linkages in said arms. Further embodiments of the
antisense oligonucleotide useful in the practice of the present invention
are P-methoxyoligonucleotides, partial P-methoxyoligodeoxyribonucleotides
or P-methoxyoligonucleotides.
Of particular relevance and usefulness for the present invention are those
antisense oligonucleotides as more particularly described in the above two
mentioned US patents. These oligonucleotides contain no naturally
occurring 5'.quadrature.3'-linked nucleotides. Rather the oligonucleotides
have two types of nucleotides: 2'-deoxyphosphorothioate, which activate
RNase H, and 2'-modified nucleotides, which do not. The linkages between
the 2'-modified nucleotides can be phosphodiesters, phosphorothioate or P-ethoxyphosphodiester.
Activation of RNase H is accomplished by a contiguous RNase H-activating
region, which contains between 3 and 5 2'-deoxyphosphorothioate
nucleotides to activate bacterial RNase H and between 5 and 10
2'-deoxyphosphorothioate nucleotides to activate eucaryotic and,
particularly, mammalian RNase H. Protection from degradation is
accomplished by making the 5' and 3' terminal bases highly nuclease
resistant and, optionally, by placing a 3' terminal blocking group.
More particularly, the antisense oligonucleotide comprises a 5' terminus
and a 3' terminus; and from 11 to 59 5'.quadrature.3'-linked nucleotides
independently selected from the group consisting of 2'-modified
phosphodiester nucleotides and 2'-modified P-alkyloxyphosphotriester
nucleotides; and wherein the 5'-terminal nucleoside is attached to an
RNase H-activating region of between three and ten contiguous
phosphorothioate-linked deoxyribonucleotides, and wherein the 3'-terminus
of said oligonucleotide is selected from the group consisting of an
inverted deoxyribonucleotide, a contiguous stretch of one to three
phosphorothioate 2'-modified ribonucleotides, a biotin group and a P-alkyloxyphosphotriester
nucleotide.
Also an antisense oligonucleotide may be used wherein not the 5' terminal
nucleoside is attached to an RNase H-activating region but the 3' terminal
nucleoside as specified above. Also, the 5' terminus is selected from the
particular group rather than the 3' terminus of said oligonucleotide.
The nucleic acids as well as the polypeptides according to the present
invention may be used as or for the manufacture of vaccines. Preferably
such vaccine is for the prevention or treatment of diseases caused by,
related to or associated with GBS. In so far another aspect of the
invention relates to a method for inducing an immunological response in an
individual, particularly a mammal, which comprises inoculating the
individual with the polypeptide of the invention, or a fragment or variant
thereof, adequate to produce antibody to protect said individual from
infection, particularly bacterial infection and most particularly
Streptococcus infections.
Yet another aspect of the invention relates to a method of inducing
immunological response in an individual which comprises, through gene
therapy or otherwise, delivering a nucleic acid functionally encoding the
polypeptide, or a fragment or a variant thereof, for expressing the
polypeptide, or a fragment or a variant thereof in vivo in order to induce
an immunological response to produce antibodies or a cell mediated T cell
response, either cytokine-producing T cells or cytotoxic T cells, to
protect said individual from disease, whether that disease is already
established within the individual or not. One way of administering the
gene is by accelerating it into the desired cells as a coating on
particles or otherwise.
A further aspect of the invention relates to an immunological composition
which, when introduced into a host capable of having induced within it an
immunological response, induces an immunological response in such host,
wherein the composition comprises recombinant DNA which codes for and
expresses an antigen of the polypeptide of the present invention. The
immunological response may be used therapeutically or prophylactically and
may take the form of antibody immunity or cellular immunity such as that
arising from CTL or CD4+ T cells.
The polypeptide of the invention or a fragment thereof may be fused with
co-protein, which may not by itself produce antibodies, but is capable of
stabilizing the first protein and producing a fused protein, which will
have immunogenic and protective properties. This fused recombinant protein
preferably further comprises an antigenic co-protein, such as
Glutathione-S-transferase (GST) or beta-galactosidase, relatively large
co-proteins which solubilize the protein and facilitate production and
purification thereof. Moreover, the co-protein may act as an adjuvant in
the sense of providing a generalized stimulation of the immune system. The
co-protein may be attached to either the amino or carboxy terminus of the
first protein.
Provided by this invention are compositions, particularly vaccine
compositions, and methods comprising the polypeptides or polynucleotides
of the invention and immunostimulatory DNA sequences, such as those
described in Sato, Y. et al., Science 273: 352 (1996).
Also, provided by this invention are methods using the described
polynucleotide or particular fragments thereof which have been shown to
encode non-variable regions of bacterial cell surface proteins in DNA
constructs used in such genetic immunization experiments in animal models
of infection with S. agalactiae. Such fragments will be particularly
useful for identifying protein epitopes able to provoke a prophylactic or
therapeutic immune response. This approach can allow for the subsequent
preparation of monoclonal antibodies of particular value from the
requisite organ of the animal successfully resisting or clearing infection
for the development of prophylactic agents or therapeutic treatments of S.
agalactiae infection in mammals, particularly humans.
The polypeptide may be used as an antigen for vaccination of a host to
produce specific antibodies which protect against invasion of bacteria,
for example by blocking adherence of bacteria to damaged tissue. Examples
of tissue damage include wounds in skin or connective tissue caused e.g.
by mechanical, chemical or thermal damage or by implantation of indwelling
devices, or wounds in the mucous membranes, such as the mouth, mammary
glands, urethra or vagina.
The present invention also includes a vaccine formulation, which comprises
the immunogenic recombinant protein together with a suitable carrier.
Since the protein may be broken down in the stomach, it is preferably
administered parenterally, including, for example, administration that is
subcutaneous, intramuscular, intravenous, or intradermal. Formulations
suitable for parenteral administration include aqueous and non-aqueous
sterile injection solutions which may contain anti-oxidants, buffers,
bacteriostats and solutes which render the formulation isotonic with the
bodily fluid, preferably the blood, of the individual; and aqueous and
non-aqueous sterile suspensions which may include suspending agents or
thickening agents. The formulations may be presented in unit-dose or
multi-dose containers, for example, sealed ampoules and vials, and may be
stored in a freeze-dried condition requiring only the addition of the
sterile liquid carrier immediately prior to use. The vaccine formulation
may also include adjuvant systems for enhancing the immunogenicity of the
formulation, such as oil-in-water systems and other systems known in the
art. The dosage will depend on the specific activity of the vaccine and
can be readily determined by routine experimentation.
It is also within the present invention that the vaccine comprises apart
from the polypeptide and/or nucleic acid molecule according to the present
invention other compounds, which are biologically or pharmaceutically
active. Preferably, the vaccine composition comprises at least one
polycationic peptide. The polycationic compound(s) to be used according to
the present invention may be any polycationic compound, which shows the
characteristic effects according to the WO 97/30721. Preferred
polycationic compounds are selected from basic polypeptides, organic
polycations, basic polyamino acids or mixtures thereof. These polyamino
acids should have a chain length of at least 4 amino acid residues (WO
97/30721). Especially preferred are substances like polylysine,
polyarginine and polypeptides containing more than 20%, especially more
than 50% of basic amino acids in a range of more than 8, especially more
than 20, amino acid residues or mixtures thereof. Other preferred
polycations and their pharmaceutical compositions are described in WO
97/30721 (e.g. polyethyleneimine) and WO 99/38528. Preferably these
polypeptides contain between 20 and 500 amino acid residues, especially
between 30 and 200 residues.
These polycationic compounds may be produced chemically or recombinantly
or may be derived from natural sources.
Cationic (poly)peptides may also be anti-microbial with properties as
reviewed in Ganz et al., 1999; Hancock, 1999. These (poly)peptides may be
of prokaryotic or animal or plant origin or may be produced chemically or
recombinantly (WO 02/13857). Peptides may also belong to the class of
defensins (WO 02/13857). Sequences of such peptides can, for example, be
found in the Antimicrobial Sequences Database under the following internet
address: http://www.bbcm.univ.trieste.it/.about.tossi/pag2.html
Such host defense peptides or defensives are also a preferred form of the
polycationic polymer according to the present invention. Generally, a
compound allowing as an end product activation (or down-regulation) of the
adaptive immune system, preferably mediated by APCs (including dendritic
cells) is used as polycationic polymer.
Especially preferred for use as polycationic substances in the present
invention are cathelicidin derived antimicrobial peptides or derivatives
thereof (International patent application WO 02/13857, incorporated herein
by reference), especially antimicrobial peptides derived from mammal
cathelicidin, preferably from human, bovine or mouse.
Polycationic compounds derived from natural sources include HIV-REV or
HIV-TAT (derived cationic peptides, antennapedia peptides, chitosan or
other derivatives of chitin) or other peptides derived from these peptides
or proteins by biochemical or recombinant production. Other preferred
polycationic compounds are cathelin or related or derived substances from
cathelin. For example, mouse cathelin is a peptide, which has the amino
acid sequence NH.sub.2-RLAGLLRKGGEKIGEKLKKIGQKIKNFFQKLVPQPE-COOH (SEQ ID
NO: 261). Related or derived cathelin substances contain the whole or
parts of the cathelin sequence with at least 15-20 amino acid residues.
Derivations may include the substitution or modification of the natural
amino acids by amino acids which are not among the 20 standard amino
acids. Moreover, further cationic residues may be introduced into such
cathelin molecules. These cathelin molecules are preferred to be combined
with the antigen. These cathelin molecules surprisingly have turned out to
be also effective as an adjuvant for an antigen without the addition of
further adjuvants. It is therefore possible to use such cathelin molecules
as efficient adjuvants in vaccine formulations with or without further
immunactivating substances.
Another preferred polycationic substance to be used according to the
present invention is a synthetic peptide containing at least 2 KLK-motifs
separated by a linker of 3 to 7 hydrophobic amino acids (International
patent application WO 02/32451, incorporated herein by reference).
The pharmaceutical composition of the present invention may further
comprise Immunostimulatory nucleic acid(s). Immunostimulatory nucleic
acids are e.g. neutral or artificial CpG containing nucleic acids, short
stretches of nucleic acid derived from non-vertebrates or in form of short
oligonucleotides (ODNs) containing non-methylated cytosine-guanine di-nucleotides
(CpG) in a certain base context (e.g. described in WO 96/02555).
Alternatively, also nucleic acids based on inosine and cytidine as e.g.
described in the WO 01/93903, or deoxynucleic acids containing
deoxy-inosine and/or deoxyuridine residues (described in WO 01/93905 and
PCT/EP 02/05448, incorporated herein by reference) may preferably be used
as immunostimulatory nucleic acids for the present invention. Preferably,
the mixtures of different immunostimulatory nucleic acids may be used
according to the present invention.
It is also within the present invention that any of the aforementioned
polycationic compounds is combined with any of the immunostimulatory
nucleic acids as aforementioned. Preferably, such combinations are
according to the ones as described in WO 01/93905, WO 02/32451, WO
01/54720, WO 01/93903, WO 02/13857 and PCT/EP 02/05448 and the Austrian
patent application A 1924/2001, incorporated herein by reference.
In addition or alternatively such vaccine composition may comprise apart
from the polypeptide/nucleic acid molecules according to the present
invention a neuroactive compound. Preferably, the neuroactive compound is
human growth factor as, e.g. described in WO 01/24822. Also preferably,
the neuroactive compound is combined with any of the polycationic
compounds and/or immunostimulatory nucleic acids as aforementioned.
In a further aspect the present invention is related to a pharmaceutical
composition. Such pharmaceutical composition is, for example, the vaccine
described herein. Also a pharmaceutical composition is a pharmaceutical
composition which comprises any of the following compounds or combinations
thereof: the nucleic acids according to the present invention, the
polypeptides according to the present invention, the vector according to
the present invention, the cells according to the present invention, the
antibody according to the present invention, the functional nucleic acids
according to the present invention and the binding peptides such as the
anticalines according to the present invention, any agonists and
antagonists screened as described herein. In connection therewith any of
these compounds may be employed in combination with a non-sterile or
sterile carrier or carriers for use with cells, tissues or organisms, such
as a pharmaceutical carrier suitable for administration to a subject. Such
compositions comprise, for instance, a media additive or a therapeutically
effective amount of a polypeptide of the invention and a pharmaceutically
acceptable carrier or excipient. Such carriers may include, but are not
limited to, saline, buffered saline, dextrose, water, glycerol, ethanol
and combinations thereof. The formulation should suit the mode of
administration.
The pharmaceutical compositions may be administered in any effective,
convenient manner including, for instance, administration by topical,
oral, anal, vaginal, intravenous, intraperitoneal, intramuscular,
subcutaneous, intranasal or intradermal routes among others.
The pharmaceutical compositions generally are administered in an amount
effective for treatment or prophylaxis of a specific indication or
indications. In general, the compositions are administered in an amount of
active agent of at least about 10 .mu.g/kg body weight. In most cases they
will be administered in one or more doses in an amount not in excess of
about 8 mg/kg body weight per day. Preferably, in most cases, dose is from
about 10 .mu.g/kg to about 1 mg/kg body weight, daily. For administration
particularly to mammals, and particularly humans, it is expected that the
daily dosage level of the active agent will be from 0.01 mg/kg to 10 mg/kg
and typically around 1 mg/kg. For example, a dose may be 1 mg/kg daily. It
will be appreciated that optimum dosage will be determined by standard
methods for each treatment modality and indication, taking into account
the indication, its severity, route of administration, complicating
conditions and the like. The physician in any event will determine the
actual dosage, which will be most suitable for an individual and will vary
with the age, weight and response of the particular individual. The above
dosages are exemplary of the average case. There can, of course, be
individual instances where higher or lower dosage ranges are merited, and
such are within the scope of this invention.
In therapy or as a prophylactic, the active agent may be administered to
an individual as an injectable composition, for example as a sterile
aqueous dispersion, preferably isotonic.
Alternatively the composition may be formulated for topical application,
for example in the form of ointments, creams, lotions, eye ointments, eye
drops, ear drops, mouthwash, impregnated dressings and sutures and
aerosols, and may contain appropriate conventional additives, including,
for example, preservatives, solvents to assist drug penetration, and
emollients in ointments and creams. Such topical formulations may also
contain compatible conventional carriers, for example cream or ointment
bases, and ethanol or oleyl alcohol for lotions. Such carriers may
constitute from about 1% to about 98% by weight of the formulation; more
usually they will constitute up to about 80% by weight of the formulation.
The pharmaceutical composition may be administered in conjunction with an
in-dwelling device. In-dwelling devices include surgical implants,
prosthetic devices and catheters, i.e., devices that are introduced to the
body of an individual and remain in position for an extended time. Such
devices include, for example, artificial joints, heart valves, pacemakers,
vascular grafts, vascular catheters, cerebrospinal fluid shunts, urinary
catheters, continuous ambulatory peritoneal dialysis (CAPD) catheters,
etc.
The composition of the invention may be administered by injection to
achieve a systematic effect against relevant bacteria shortly before
insertion of an in-dwelling device. Treatment may be continued after
surgery during the in-body time of the device. In addition, the
composition could also be used to broaden perioperative cover for any
surgical technique to prevent Streptococcus infections.
Many orthopedic surgeons consider that humans with prosthetic joints
should be considered for antibiotic prophylaxis before dental treatment
that could produce a bacteremia. Late deep infection is a serious
complication sometimes leading to loss of the prosthetic joint and is
accompanied by significant morbidity and mortality. It may therefore be
possible to extend the use of the active agent as a replacement for
prophylactic antibiotics in this situation.
In addition to the therapy described above, the compositions of this
invention may be used generally as a wound treatment agent to prevent
adhesion of bacteria to matrix proteins exposed in wound tissue and for
prophylactic use in dental treatment as an alternative to, or in
conjunction with, antibiotic prophylaxis.
Alternatively, the composition of the invention may be used to bathe an
indwelling device immediately before insertion. The active agent will
preferably be present at a concentration of 1 .mu.g/ml to 10 mg/ml for
bathing of wounds or indwelling devices.
A vaccine composition is conveniently in injectable form. Conventional
adjuvants may be employed to enhance the immune response. A suitable unit
dose for vaccination is 0.5-5 .mu.g/kg of antigen, and such dose is
preferably administered 1-3 times and with an interval of 1-3 weeks.
With the indicated dose range, no adverse toxicological effects should be
observed with the compounds of the invention, which would preclude their
administration to suitable individuals.
The antibodies described above may also be used as diagnostic reagents to
detect the presence of bacteria containing the polypeptides according to
the present invention.
In a further embodiment the present invention relates to diagnostic and
pharmaceutical packs and kits comprising one or more containers filled
with one or more of the ingredients of the aforementioned compositions of
the invention. The ingredient(s) can be present in a useful amount,
dosage, formulation or combination. Associated with such container(s) can
be a notice in the form prescribed by a governmental agency regulating the
manufacture, use or sale of pharmaceuticals or biological products,
reflecting approval by the agency of the manufacture, use or sale of the
product for human administration.
In connection with the present invention any disease related use as
disclosed herein such as, e.g. use of the pharmaceutical composition or
vaccine, is particularly a disease or diseased condition which is caused,
linked or associated with Gram-positive bacteria, more particularly
bacteria selected from the group comprising Streptococci, Staphylococci
and Lactococci. More preferably, the microorganisms are selected from the
group comprising S. agalactiae, S. pyogenes, S. pneumoniae and S. mutans.
In connection therewith it is to be noted that S. agalactiae comprises
several strains including those disclosed herein. Also, the disease may be
particularly a disease occurring in any patient selected from the group
comprising people with chronic illness such as diabetes mellitus and liver
failure, pregnant women, the fetus and the newborn. A disease related,
caused or associated with the bacterial infection to be prevented and/or
treated according to the present invention includes in neonates sepsis,
pneumonia and meningitis, and in adults sepsis and soft tissue infections.
Pregnancy-related infections are sepsis, amnionitis, urinary tract
infection and stillbirth.
In a still further embodiment the present invention is related to a
screening method using any of the polypeptides or nucleic acids according
to the present invention. Screening methods as such are known to the one
skilled in the art and can be designed such that an agonist or an
antagonist is screened. Preferably an antagonist is screened which in the
present case inhibits or prevents the binding of any polypeptide according
to the present invention to an interaction partner. Such interaction
partner can be a naturally occurring interaction partner or a
non-naturally occurring interaction partner. Preferable the interaction
partner is fibrinogen or a fragment thereof in case of FbsA or any host
cell in case of PabA, PabB, PabC, and PabD, including epithelial cells,
preferably human epithelial cells.
The invention also provides a method of screening compounds to identify
those, which enhance (agonist) or block (antagonist) the function of
polypeptides or polynucleotides of the present invention, such as its
interaction with a binding molecule. The method of screening may involve
high-throughput.
For example, to screen for agonists or antagonists, the interaction
partner of the polynucleotide and nucleic acid, respectively, according to
the present invention, a synthetic reaction mix, a cellular compartment,
such as a membrane, cell envelope or cell wall, or a preparation of any
thereof, may be prepared from a cell that expresses a molecule that binds
to the polypeptide of the present invention. The preparation is incubated
with labelled polypeptide in the absence or the presence of a candidate
molecule, which may be an agonist or antagonist. The ability of the
candidate molecule to bind the binding molecule is reflected in decreased
binding of the labelled ligand. Molecules, which bind gratuitously, i.e.,
without inducing the functional effects of the polypeptide, are most
likely to be good antagonists. Molecules that bind well and elicit
functional effects that are the same as or closely related to the
polypeptide are good agonists.
The functional effects of potential agonists and antagonists may by
measured, for instance, by determining activity of a reporter system
following interaction of the candidate molecule with a cell or appropriate
cell preparation, and comparing the effect with that of the polypeptide of
the present invention or molecules that elicit the same effects as the
polypeptide Reporter systems that may be useful in the regard include but
are not limited to colorimetric labelled substrate converted into product,
a reporter gene that is responsive to changes in the functional activity
of the polypeptide, and binding assays known in the art.
Another example of an assay for antagonists is a competitive assay that
combines the polypeptide of the present invention and a potential
antagonist with membrane bound binding molecules, recombinant binding
molecules, natural substrates or ligands, or substrate or ligand mimetics,
under appropriate conditions for a competitive inhibition assay. The
polypeptide can be labelled such as by radioactivity or a colorimetric
compound, such that the number of polypeptide molecules bound to a binding
molecule or converted to product can be determined accurately to assess
the effectiveness of the potential antagonist.
Potential antagonists include small organic molecules, peptides,
polypeptides and antibodies that bind to a polypeptide of the invention
and thereby inhibit or extinguish its activity. Potential antagonists also
may be small organic molecules, a peptide, a polypeptide such as a closely
related protein or antibody that binds to the same sites on a binding
molecule without inducing functional activity of the polypeptide of the
invention.
Potential antagonists include a small molecule, which binds to and
occupies the binding site of the polypeptide thereby preventing binding to
cellular binding molecules, such that normal biological activity is
prevented. Examples of small molecules include but are not limited to
small organic molecules, peptides or peptide-like molecules.
Other potential antagonists include antisense molecules (see Okano, J.
Neurochem. 56:560 (1991); OLIGODEOXYNUCLEOTIDES AS ANTISENSE INHIBITORS OF
GENE EXPRESSION, CRC Press, Boca Raton, Fla. (1988), for a description of
these molecules).
Preferred potential antagonists include derivatives of the polypeptides of
the invention.
As used herein the activity of a polypeptide according to the present
invention is its capability to bind to any of its interaction partner or
the extent of such capability of its binding to its or any interaction
partner.
In a particular aspect, the invention provides the use of the polypeptide,
polynucleotide or inhibitor of the invention to interfere with the initial
physical interaction between a pathogen and mammalian host responsible for
sequelae of infection. In particular the molecules of the invention may be
used: i) in the prevention of adhesion of S. agalactiae to mammalian
extracellular matrix proteins on in-dwelling devices or to extracellular
matrix proteins in wounds; ii) to block protein mediated mammalian cell
invasion by, for example, initiating phosphorylation of mammalian tyrosine
kinases (Rosenshire et al., Infect. Immun. 60:2211 (1992)). iii) to block
bacterial adhesion between mammalian extracellular matrix proteins and
bacterial proteins which mediate tissue damage; iv) to block the normal
progression of pathogenesis in infections initiated other than by the
implantation of in-dwelling devices or by other surgical techniques.
Each of the DNA coding sequence provided herein may be used in the
discovery and development of antibacterial compounds. The encoded protein
upon expression can be used as a target for the screening of antibacterial
drugs. Additionally, the DNA sequences encoding the amino terminal regions
of the encoded protein or Shine-Delgarno or other translation facilitating
sequences of the respective mRNA can be used to construct antisense
sequences to control the expression of the coding sequence of interest.
The antagonists and agonists may be employed, for instance, to inhibit
diseases arising from infection with Streptococcus, especially S.
agalactiae, such as sepsis.
In a still further aspect the present invention is related to an affinity
device such affinity device comprises at least a support material and any
of the polypeptides according to the present invention, which is attached
to the support material. Because of the specificity of the polypeptides
according to the present invention for their target cells or target
molecules or their interaction partners, the polypeptides allow a
selective removal of their interaction partner(s) from any kind of sample
applied to the support material provided that the conditions for binding
are met. The sample may be a biological or medical sample, including but
not limited to, fermentation broth, cell debris, cell preparation, tissue
preparation, organ preparation, blood, urine, lymph liquid, liquor and the
like.
The polypeptide may be attached to the matrix in a covalent or
non-covalent manner. Suitable support material is known to the one skilled
in the art and can be selected from the group comprising cellulose,
silicon, glass, aluminium, paramagnetic beads, starch and dextrane.
Claim 1 of 1 Claim
1. A fibrinogen-binding-polypeptide
comprising the amino acid sequence of SEQ ID NO: 11. ____________________________________________
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