Title: Prevention, diagnosis and treatment of lyme disease
United States Patent: 6,667,038
Issued: December 23, 2003
Inventors: Donta; Sam T. (Boston, MA); Cartwright; Mark J. (West Newton, MA)
Assignee: Boston Medical Center Corp. (Boston, MA)
Appl. No.: 553863
Filed: April 20, 2000
The present invention provides compositions and methods related to Borrelia burgdorferi toxin and antitoxin preparations. In particular, the present invention provides methods and compositions for the diagnosis of Lyme disease, as well as for use in treating subjects infected with B. burgdorferi through passive immunization, and vaccine development.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides compositions and methods related to Borrelia burgdorferi toxins. In particular, the present invention provides methods and compositions for the diagnosis, treatment and prevention of Lyme disease and/or Syphilis.
The present invention provides significant advantages and improvements over existing methods, devices, and materials related to Lyme disease. For example, as indicated above, the diagnosis of Lyme disease is often hampered by the absence of reliable tests. In addition, after initial skin infection, cultures for B. burgdorferi are rarely positive. PCR-DNA tests for OspA and other gene determinants are also rarely positive with blood, urine and spinal fluid. Furthermore, serologic tests are generally unreliable (Donta, et al., Clin. Infect. Dis., 25:552-555 (1997)). ELISA and Western blot immunoanalyses are likewise unreliable indicators of current or past infection. Thus, new tests, such as those of the present invention provide important methods and compositions for improving the diagnostic accuracy, treatment, and prevention of Lyme disease.
The compositions and methods of the present invention provide means to prevent Lyme disease through vaccine development and utilization, as well as diagnose Lyme disease in subjects suspected of being exposed to B. burgdorferi. In particular, the present invention provides the full-length sequence of a B. burgdorferi toxin, a toxin that has not been previously identified. While an understanding of the mechanism is not necessary in order to make or use the present invention, it is contemplated that this toxin may play a role in the pathogenesis of Lyme disease. Furthermore, the isolation and purification of the toxin provides methods and compositions for preventing Lyme disease through passive antibody therapy. For example, it is contemplated that the Bbtox1 of the present invention will find use in development of antitoxins suitable for use in approaches to treat Lyme disease.
The compositions and methods of the present invention provide means to prevent Syphilis through vaccine development and utilization, as well as diagnose Syphilis in subjects suspected of being exposed to T. pallidum. In particular, the present invention provides the full-length sequence of a T. pallidum toxin, a toxin that has not been previously identified. While an understanding of the mechanism is not necessary in order to make or use the present invention, it is contemplated that this toxin may play a role in the pathogenesis of Syphilis. Furthermore, the isolation and purification of the toxin provides methods and compositions for preventing Syphilis through passive antibody therapy. For example, it is contemplated that the Tptox1 of the present invention will find use in development of antitoxins suitable for use in approaches to treat Syphilis.
As used herein, a subject is a human, non-human primate, cow, horse, pig, sheep, goat, dog, cat or rodent.
Analysis of the sequence by comparison to nucleic acid and protein databases show that Bbtox1 shares a limited homology (55% at the amino acid level) to Tptox1 (SEQ ID NO:18).
The invention thus involves in one aspect an isolated Bbtox1 polypeptide, the cDNA encoding this polypeptide, an isolated Tptox1 polypeptide, the cDNA encoding this polypeptide, functional modifications and variants of the foregoing, useful fragments of the foregoing, as well as diagnostics and therapeutics relating thereto.
As used herein with respect to nucleic acids, the term "isolated" means: (i) amplified in vitro by, for example, polymerase chain reaction (PCR); (ii) recombinantly produced by cloning; (iii) purified, as by cleavage and gel separation; or (iv) synthesized by, for example, chemical synthesis. An isolated nucleic acid is one which is readily manipulable by recombinant DNA techniques well known in the art. Thus, a nucleotide sequence contained in a vector in which 5' and 3' restriction sites are known or for which polymerase chain reaction (PCR) primer sequences have been disclosed is considered isolated but a nucleic acid sequence existing in its native state in its natural host is not. An isolated nucleic acid may be substantially purified, but need not be. For example, a nucleic acid that is isolated within a cloning or expression vector is not pure in that it may comprise only a tiny percentage of the material in the cell in which it resides. Such a nucleic acid is isolated, however, as the term is used herein because it is readily manipulable by standard techniques known to those of ordinary skill in the art.
As used herein with respect to polypeptides, the term "isolated" means separated from its native environment in sufficiently pure form so that it can be manipulated or used for any one of the purposes of the invention. Thus, isolated means sufficiently pure to be used (i) to raise and/or isolate antibodies, (ii) as a reagent in an assay, or (iii) for sequencing, etc.
According to the invention, isolated nucleic acid molecules that code for a Bbtox1 and/or Tptox1 polypeptide include: (a) nucleic acid molecules which hybridize under stringent conditions to a molecule selected from the group consisting of a nucleic acid of SEQ ID NO:1, SEQ ID NO:3 (Bbtox1) and/or SEQ ID NO:17 (Tptox1), and which code for a Bbtox1 and/or Tptox1 polypeptide respectively, (b) deletions, additions and substitutions of (a) which code for a respective Bbtox1 and/or Tptox1 polypeptide, (c) nucleic acid molecules that differ from the nucleic acid molecules of (a) or (b) in codon sequence due to the degeneracy of the genetic code, and (d) full-length complements of (a), (b) or (c).
Homologs and alleles of the Bbtox1 and/or Tptox1 nucleic acids of the invention can be identified by conventional techniques. Thus, an aspect of the invention is those nucleic acid sequences which code for Bbtox1 polypeptides and which hybridize to a nucleic acid molecule consisting of the coding region of SEQ ID NO:1and/or SEQ ID NO:3 SEQ ID NO:17, under stringent conditions. Another aspect of the invention is those nucleic acid sequences which code for Tptox1 polypeptides and which hybridize to a nucleic acid molecule consisting of the coding region of SEQ ID NO:17, under stringent conditions. The term "stringent conditions" as used herein refers to parameters with which the art is familiar. Nucleic acid hybridization parameters may be found in references which compile such methods, e.g. Molecular Cloning: A Laboratory Manual, J. Sambrook, et al., eds., Second Edition, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y., 1989, or Current Protocols in Molecular Biology, F. M. Ausubel, et al., eds., John Wiley & Sons, Inc., New York. More specifically, stringent conditions, as used herein, refers, for example, to hybridization at 65oC. in hybridization buffer (3.5xSSC, 0.02% Ficoll, 0.02% polyvinyl pyrolidone, 0.02% Bovine Serum Albumin, 2.5 mM NaH2 PO4 (pH7), 0.5% SDS, 2 mM EDTA). SSC is 0.15M sodium chloride/0.15M sodium citrate, pH7; SDS is sodium dodecyl sulphate; and EDTA is ethylenediaminetetracetic acid. After hybridization, the membrane upon which the DNA is transferred is washed at 2xSSC at room temperature and then at 0.1xSSC/0.1xSDS at temperatures up to 68oC.
There are other conditions, reagents, and so forth which can be used, and would result in a similar degree of stringency. The skilled artisan will be familiar with such conditions, and thus they are not given here. It will be understood, however, that the skilled artisan will be able to manipulate the conditions in a manner to permit the clear identification of homologs and alleles of Bbtox1 nucleic acids of the invention. The skilled artisan also is familiar with the methodology for screening cells and libraries for expression of such molecules which then are routinely isolated, followed by isolation of the pertinent nucleic acid molecule and sequencing.
In general homologs and alleles typically will share at least 40% nucleotide identity and/or at least 50% amino acid identity to SEQ ID NO:1 and SEQ ID NO:2 (and/or SEQ ID NO:3 and SEQ ID NO:4, and/or or SEQ ID NO:17 and SEQ ID NO:18), respectively, in some instances will share at least 50% nucleotide identity and/or at least 65% amino acid identity and in still other instances will share at least 60% nucleotide identity and/or at least 75% amino acid identity. The homology can be calculated using various, publicly available software tools developed by NCBI (Bethesda, Md.) that can be obtained through the internet (ftp:/ncbi.nlm.nih.gov/pub/). Exemplary tools include the BLAST system available at http://wwww.ncbi.nlm.nih.gov. Pairwise and ClustalW alignments (BLOSUM30 matrix setting) as well as Kyte-Doolittle hydropathic analysis can be obtained using the MacVetor sequence analysis software (Oxford Molecular Group). Watson-Crick complements of the foregoing nucleic acids also are embraced by the invention.
In screening for Bbtox1 and/or Tptox1 related genes, such as homologs and alleles of Bbtox1 and/or Tptox1, a Southern blot may be performed using the foregoing conditions, together with a radioactive probe. After washing the membrane to which the DNA is finally transferred, the membrane can be placed against X-ray film or a phosphoimager plate to detect the radioactive signal.
The invention also includes degenerate nucleic acids which include alternative codons to those present in the native materials. For example, serine residues are encoded by the codons TCA, AGT, TCC, TCG, TCT and AGC. Each of the six codons is equivalent for the purposes of encoding a serine residue. Thus, it will be apparent to one of ordinary skill in the art that any of the serine-encoding nucleotide triplets may be employed to direct the protein synthesis apparatus, in vitro or in vivo, to incorporate a serine residue into an elongating Bbtox1 polypeptide. Similarly, nucleotide sequence triplets which encode other amino acid residues include, but are not limited to: CCA, CCC, CCG and CCT (proline codons); CGA, CGC, CGG, CGT, AGA and AGG (arginine codons); ACA, ACC, ACG and ACT (threonine codons); AAC and AAT (asparagine codons); and ATA, ATC and ATT (isoleucine codons). Other amino acid residues may be encoded similarly by multiple nucleotide sequences. Thus, the invention embraces degenerate nucleic acids that differ from the biologically isolated nucleic acids in codon sequence due to the degeneracy of the genetic code.
The invention also provides isolated unique fragments of SEQ ID NO:1, SEQ ID NO:3 and/or SEQ ID NO:17 or complements of thereof. A unique fragment is one that is a `signature` for the larger nucleic acid. For example, the unique fragment is long enough to assure that its precise sequence is not found in molecules within the human genome outside of the Bbtox1 nucleic acids defined above (and human alleles). Those of ordinary skill in the art may apply no more than routine procedures to determine if a fragment is unique within the human genome. Unique fragments, however, exclude fragments completely composed of the nucleotide sequences of any of GenBank accession numbers listed in Table I below, or other previously published sequences as of the filing date of this application.
TABLE 1 Sequences with partial homologies to Bbtox1 Sequences with GenBank accession numbers: AE000783, AE001175, and AE001252
A fragment which is completely composed of the sequence described in the foregoing GenBank deposits is one which does not include any of the nucleotides unique to the sequences of the invention. Thus, a unique fragment must contain a nucleotide sequence other than the exact sequence of those in GenBank or fragments thereof. The difference may be an addition, deletion or substitution with respect to the GenBank sequence or it may be a sequence wholly separate from the GenBank sequence.
Unique fragments can be used as probes in Southern and Northern blot assays to identify such nucleic acids, or can be used in amplification assays such as those employing PCR. As known to those skilled in the art, large probes such as 200, 250, 300 or more nucleotides are preferred for certain uses such as Southern and Northern blots, while smaller fragments will be preferred for uses such as PCR. Unique fragments also can be used to produce fusion proteins for generating antibodies or determining binding of the polypeptide fragments, as demonstrated in the Examples, or for generating immunoassay components. Likewise, unique fragments can be employed to produce nonfused fragments of the Bbtox1 polypeptides, useful, for example, in the preparation of antibodies, immunoassays or therapeutic applications. Unique fragments further can be used as antisense molecules to inhibit the expression of Bbtox1 nucleic acids and polypeptides respectively.
As will be recognized by those skilled in the art, the size of the unique fragment will depend upon its conservancy in the genetic code. Thus, some regions of SEQ ID NO:1, SEQ ID NO:3, or SEQ ID NO:17 and complements will require longer segments to be unique while others will require only short segments, typically between 12 and 32 nucleotides long (e.g. 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31 and 32 bases) or more, up to the entire length of the disclosed sequence . As mentioned above, this disclosure intends to embrace each and every fragment of each sequence, beginning at the first nucleotide, the second nucleotide and so on, up to 8 nucleotides short of the end, and ending anywhere from nucleotide number 8, 9, 10 and so on for each sequence, up to the very last nucleotide, (provided the sequence is unique as described above). Virtually any segment of the region of SEQ ID NO:1 beginning at nucleotide 1 and ending at nucleotide 957, or SEQ ID NO:3 beginning at nucleotide 1 and ending at nucleotide 957, or SEQ ID NO:17 beginning at nucleotide 1 and ending at nucleotide 762, or complements thereof, that is 20 or more nucleotides in length will be unique. Those skilled in the art are well versed in methods for selecting such sequences, typically on the basis of the ability of the unique fragment to selectively distinguish the sequence of interest from other sequences in the human genome of the fragment to those on known databases typically is all that is necessary, although in vitro confirmatory hybridization and sequencing analysis may be performed.
The invention also involves expression vectors coding for Bbtox1, or Tptox1, proteins and fragments and variants thereof and host cells containing those expression vectors. Virtually any cells, prokaryotic or eukaryotic, which can be transformed with heterologous DNA or RNA and which can be grown or maintained in culture, may be used in the practice of the invention. Examples include bacterial cells such as E.coli and mammalian cells such as mouse, hamster, pig, goat, primate, etc. They may be of a wide variety of tissue types, including mast cells, fibroblasts, oocytes and lymphocytes, and they may be primary cells or cell lines. Specific examples include CHO cells and COS cells. Cell-free transcription systems also may be used in lieu of cells.
As used herein, a "vector" may be any of a number of nucleic acids into which a desired sequence may be inserted by restriction and ligation for transport between different genetic environments or for expression in a host cell. Vectors are typically composed of DNA although RNA vectors are also available. Vectors include, but are not limited to, plasmids, phagemids and virus genomes. A cloning vector is one which is able to replicate in a host cell, and which is furrther characterized by one or more endonuclease restriction sites at which the vector may be cut in a determinable fashion and into which a desired DNA sequence may be ligated such that the new recombinant vector retains its ability to replicate in the host cell. In the case of plasmids, replication of the desired sequence may occur many times as the plasmid increases in copy number within the host bacterium or just a single time per host before the host reproduces by mitosis. In the case of phage, replication may occur actively during a lytic phase or passively during a lysogenic phase. An expression vector is one into which a desired DNA sequence may be inserted by restriction and ligation such that it is operably joined to regulatory sequences and may be expressed as an RNA transcript. Vectors may further contain one or more marker sequences suitable for use in the identification of cells which have or have not been transformed or transfected with the vector. Markers include, for example, genes encoding proteins which increase or decrease either resistance or sensitivity to antibiotics or other compounds, genes which encode enzymes whose activities are detectable by standard assays known in the art (e.g., .beta.-galactosidase or alkaline phosphatase), and genes which visibly affect the phenotype of transformed or transfected cells, hosts, colonies or plaques (e.g., green fluorescent protein). Preferred vectors are those capable of autonomous replication and expression of the structural gene products present in the DNA segments to which they are operably joined.
As used herein, a coding sequence and regulatory sequences are said to be "operably" joined when they are covalently linked in such a way as to place the expression or transcription of the coding sequence under the influence or control of the regulatory sequences. If it is desired that the coding sequences be translated into a functional protein, two DNA sequences are said to be operably joined if induction of a promoter in the 5' regulatory sequences results in the transcription of the coding sequence and if the nature of the linkage between the two DNA sequences does not (1) result in the introduction of a frame-shift mutation, (2) interfere with the ability of the promoter region to direct the transcription of the coding sequences, or (3) interfere with the ability of the corresponding RNA transcript to be translated into a protein. Thus, a promoter region would be operably joined to a coding sequence if the promoter region were capable of effecting transcription of that DNA sequence such that the resulting transcript might be translated into the desired protein or polypeptide.
The precise nature of the regulatory sequences needed for gene expression may vary between species or cell types, but shall in general include, as necessary, 5' non-transcribed and 5' non-translated sequences involved with the initiation of transcription and translation respectively, such as a TATA box, capping sequence, CAAT sequence, and the like. Especially, such 5' non-transcribed regulatory sequences will include a promoter region which includes a promoter sequence for transcriptional control of the operably joined gene. Regulatory sequences may also include enhancer sequences or upstream activator sequences as desired. The vectors of the invention may optionally include 5' leader or signal sequences. The choice and design of an appropriate vector is within the ability and discretion of one of ordinary skill in the art.
Expression vectors containing all the necessary elements for expression are commercially available and known to those skilled in the art. See, e.g., Sambrook et al., Molecular Cloning: A Laboratory Manual, Second Edition, Cold Spring Harbor Laboratory Press, 1989. Cells are genetically engineered by the introduction into the cells of heterologous DNA (RNA) encoding Bbtox1 polypeptide or fragment or variant thereof. That heterologous DNA (RNA) is placed under operable control of transcriptional elements to permit the expression of the heterologous DNA in the host cell.
Preferred systems for mRNA expression in mammalian cells are those such as pRc/CMV (available from Invitrogen, Carlsbad, Calif.) that contain a selectable marker such as a gene that confers G418 resistance (which facilitates the selection of stably transfected cell lines) and the human cytomegalovirus (CMV) enhancer-promoter sequences. Additionally, suitable for expression in primate or canine cell lines is the pCEP4 vector (Invitrogen, Carlsbad, Calif.), which contains an Epstein Barr virus (EBV) origin of replication, facilitating the maintenance of plasmid as a multicopy extrachromosomal element. Another expression vector is the pEF-BOS plasmid containing the promoter of polypeptide Elongation Factor 1.alpha., which stimulates efficiently transcription in vitro. The plasmid is described by Mishizuma and Nagata (Nuc. Acids Res. 18:5322, 1990), and its use in transfection experiments is disclosed by, for example, Demoulin (Mol. Cell. Biol. 16:4710-4716, 1996). Still another preferred expression vector is an adenovirus, described by Stratford-Perricaudet, which is defective for E1 and E3 proteins (J. Clin. Invest. 90:626-630, 1992). The use of the adenovirus as an Adeno.P1A recombinant is disclosed by Warnier et al., in intradermal injection in mice for immunization against P1A (Int. J. Cancer, 67:303-310, 1996).
The invention also embraces so-called expression kits, which allow the artisan to prepare a desired expression vector or vectors. Such expression kits include at least separate portions of each of the previously discussed coding sequences. Other components may be added, as desired, as long as the previously mentioned sequences, which are required, are included.
It will also be recognized that the invention embraces the use of the above described, Bbtox1 cDNA sequence containing expression vectors, to transfect host cells and cell lines, be these prokaryotic (e.g., E. coli), or eukaryotic (e.g., CHO cells, COS cells, yeast expression systems and recombinant baculovirus expression in insect cells). Especially useful are mammalian cells such as mouse, hamster, pig, goat, primate, etc. They may be of a wide variety of tissue types, and include primary cells and cell lines. Specific examples include dendritic cells, U293 cells, peripheral blood leukocytes, bone marrow stem cells and embryonic stem cells.
The invention also provides isolated polypeptides (including whole proteins and partial proteins), encoded by the foregoing Bbtox1 nucleic acids, and include the polypeptides of SEQ ID NO:2 and/or SEQ ID NO:4, and unique fragments thereof. Such polypeptides are useful, for example, alone or as fusion proteins that can be used as vaccines against Lyme disease. The invention further provides isolated polypeptides (including whole proteins and partial proteins), encoded by the foregoing Tptox1 nucleic acids, and include the polypeptide of SEQ ID NO:18, and unique fragments thereof. Such polypeptides are useful, for example, alone or as fusion proteins that can be used as vaccines against Syphilis. Polypeptides can be isolated from biological samples including tissue or cell homogenates, and can also be expressed recombinantly in a variety of prokaryotic and eukaryotic expression systems by constructing an expression vector appropriate to the expression system, introducing the expression vector into the expression system, and isolating the recombinantly expressed protein. Short polypeptides, including antigenic peptides (such as are presented by MHC molecules on the surface of a cell for immune recognition) also can be synthesized chemically using well-established methods of peptide synthesis.
A unique fragment of an Bbtox1, or Tptox1, polypeptide, in general, has the features and characteristics of unique fragments as discussed above in connection with nucleic acids. As will be recognized by those skilled in the art, the size of the unique fragment will depend upon factors such as whether the fragment constitutes a portion of a conserved protein domain. Thus, some regions of SEQ ID NO:2, SEQ ID NO:4, and/or SEQ ID NO:18 will require longer segments to be unique while others will require only short segments, typically between 5 and 12 amino acids [e.g. 5, 6, 7, 8, 9, 10, 11 and 12 amino acids long or more, including each integer up to the full length, 319 (Bbtox1) or 254 (Tptox1) amino acids long]. Virtually any segment of SEQ ID NO:2, SEQ ID NO:4, and/or SEQ ID NO:18, that is 9 or more amino acids in length will be unique.
Unique fragments of a polypeptide preferably are those fragments which retain a distinct functional capability of the polypeptide. Functional capabilities which can be retained in a unique fragment of a polypeptide include interaction with antibodies, interaction with other polypeptides or fragments thereof. One important activity is the ability to act as a signature for identifying the polypeptide. Another is the ability to complex with HLA and to provoke in a human an immune response. Those skilled in the art are well versed in methods for selecting unique amino acid sequences, typically on the basis of the ability of the unique fragment to selectively distinguish the sequence of interest from non-family members. A comparison of the sequence of the fragment to those on known databases typically is all that is necessary.
The invention embraces variants of the Bbtox1 and/or Tptox1 polypeptides described above. As used herein, a "variant" of a Bbtox1 (or Tptox1) polypeptide is a polypeptide which contains one or more modifications to the primary amino acid sequence of a Bbtox1 (or Tptox1) polypeptide. Modifications which create a Bbtox1 polypeptide variant are typically made to the nucleic acid which encodes the Bbtox1 (or Tptox1) polypeptide, and can include deletions, point mutations, truncations, amino acid substitutions and addition of amino acids or non-amino acid moieties to: 1) reduce or eliminate an activity of a Bbtox1 (or Tptox1) polypeptide; 2) enhance a property of a Bbtox1 (or Tptox1) polypeptide, such as protein stability in an expression system or the stability of protein-protein binding; 3) provide a novel activity or property to a Bbtox1 (or Tptox1) polypeptide, such as addition of an antigenic epitope or addition of a detectable moiety; or 4) to provide equivalent or better binding to a Bbtox1 (or Tptox1) polypeptide receptor or other molecule (e.g., heparin). Alternatively, modifications can be made directly to the polypeptide, such as by cleavage, addition of a linker molecule, addition of a detectable moiety, such as biotin, addition of a fatty acid, and the like. Modifications also embrace fusion proteins comprising all or part of the Bbtox1 (or Tptox1) amino acid sequence. One of skill in the art will be familiar with methods for predicting the effect on protein conformation of a change in protein sequence, and can thus "design" a variant Bbtox1 (or Tptox1) polypeptide according to known methods. One example of such a method is described by Dahiyat and Mayo in Science 278:82-87, 1997, whereby proteins can be designed de novo. The method can be applied to a known protein to vary a only a portion of the polypeptide sequence. By applying the computational methods of Dahiyat and Mayo, specific variants of a cancer associated antigen polypeptide can be proposed and tested to determine whether the variant retains a desired conformation.
Variants can include Bbtox1 polypeptides which are modified specifically to alter a feature of the polypeptide unrelated to its physiological activity. For example, cysteine residues can be substituted or deleted to prevent unwanted disulfide linkages. Similarly, certain amino acids can be changed to enhance expression of a Bbtox1 (or Tptox1) polypeptide by eliminating proteolysis by proteases in an expression system (e.g., dibasic amino acid residues in yeast expression systems in which KEX2 protease activity is present).
Mutations of a nucleic acid which encodes a Bbtox1 (or Tptox1) polypeptide preferably preserve the amino acid reading frame of the coding sequence, and preferably do not create regions in the nucleic acid which are likely to hybridize to form secondary structures, such a hairpins or loops, which can be deleterious to expression of the variant polypeptide.
Mutations can be made by selecting an amino acid substitution, or by random mutagenesis of a selected site in a nucleic acid which encodes the polypeptide. Variant polypeptides are then expressed and tested for one or more activities to determine which mutation provides a variant polypeptide with the desired properties. Further mutations can be made to variants (or to non-variant Bbtox1, or Tptox1, polypeptides) which are silent as to the amino acid sequence of the polypeptide, but which provide preferred codons for translation in a particular host. The preferred codons for translation of a nucleic acid in, e.g., E. coli, are well known to those of ordinary skill in the art. Still other mutations can be made to the noncoding sequences of a Bbtox1 (or Tptox1) gene or cDNA clone to enhance expression of the polypeptide.
The skilled artisan will realize that conservative amino acid substitutions may be made in Bbtox1 (or Tptox1) polypeptides to provide functionally equivalent variants of the foregoing polypeptides, i.e, the variants retain the functional capabilities of the Bbtox1 (or Tptox1) polypeptides. As used herein, a "conservative amino acid substitution" refers to an amino acid substitution which does not alter the relative charge or size characteristics of the protein in which the amino acid substitution is made. Variants can be prepared according to methods for altering polypeptide sequence known to one of ordinary skill in the art such as are found in references which compile such methods, e.g. Molecular Cloning: A Laboratory Manual, J. Sambrook, et al., eds., Second Edition, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y., 1989, or Current Protocols in Molecular Biology, F. M. Ausubel, et al., eds., John Wiley & Sons, Inc., New York. Exemplary functionally equivalent variants of the Bbtox1 polypeptides include conservative amino acid substitutions of SEQ ID NO:2 or SEQ ID NO:4. Exemplary functionally equivalent variants of the Tptox1 polypeptides include conservative amino acid substitutions of SEQ ID NO:18. Conservative substitutions of amino acids include substitutions made amongst amino acids within the following groups: (a) M, I, L, V; (b) F, Y, W; (c) K, R, H; (d) A, G; (e) S, T; (f) Q, N; and (g) E, D.
Thus functionally equivalent variants of Bbtox1 and/or Tptox1 polypeptides, i.e., variants of Bbtox1 and/or Tptox1 polypeptides which retain the function of the natural Bbtox1 and/or Tptox1 polypeptides, are contemplated by the invention. Conservative amino-acid substitutions in the amino acid sequence of Bbtox1 (and/or Tptox1) polypeptides to produce functionally equivalent variants of Bbtox1 (and/or Tptox1) polypeptides typically are made by alteration of a nucleic acid encoding Bbtox1 polypeptides (SEQ ID NOs:1, 3), and/or alteration of a nucleic acid encoding Tptox1 polypeptides (SEQ ID NO:17). Such substitutions can be made by a variety of methods known to one of ordinary skill in the art. For example, amino acid substitutions may be made by PCR-directed mutation, site-directed mutagenesis according to the method of Kunkel (Kunkel, Proc. Nat. Acad. Sci. U.S.A. 82: 488-492, 1985), or by S chemical synthesis of a gene encoding a Bbtox1 (and/or Tptox1) polypeptide. The activity of functionally equivalent fragments of Bbtox1 (and/or Tptox1) polypeptides can be tested by cloning the gene encoding the altered Bbtox1 (and/or Tptox1) polypeptide into a bacterial or mammalian expression vector, introducing the vector into an appropriate host cell, expressing the altered Bbtox1 (and/or Tptox1) polypeptide, and testing for a functional capability of the Bbtox1 (and/or Tptox1) polypeptides as disclosed herein (e.g., ADP-ribosylation activity to determine cholera toxin-like activity, etc.).
The invention as described herein has a number of uses, some of which are described elsewhere herein. First, the invention permits isolation of Bbtox1 and Tptox1 polypeptides. A variety of methodologies well-known to the skilled practitioner can be utilized to obtain isolated Bbtox1 molecules. The polypeptide may be purified from cells/organisms (e.g., Borrelia burgdorferi, Treponema pallidum) which naturally produce the polypeptide by chromatographic means or immunological recognition. Alternatively, an expression vector may be introduced into cells to cause production of the polypeptide. In another method, mRNA transcripts may be microinjected or otherwise introduced into cells to cause production of the encoded polypeptide. Translation of Bbtox1 and/or of Tptox1 mRNA in cell-free extracts such as the reticulocyte lysate system also may be used to produce Bbtox1 and/or Tptox1 polypeptides, respectively. Those skilled in the art also can readily follow known methods for isolating Bbtox1 and/or Tptox1 polypeptides. These include, but are not limited to, immunochromatography, HPLC, size-exclusion chromatography, ion-exchange chromatography and immune-affinity chromatography.
The invention also provides, in certain embodiments, "dominant negative" polypeptides derived from Bbtox1 and/or Tptox1 polypeptides. A dominant negative polypeptide is an inactive variant of a protein, which, by interacting with the cellular machinery, displaces an active protein from its interaction with the cellular machinery or competes with the active protein, thereby reducing the effect of the active protein. For example, a dominant negative receptor which binds a ligand but does not transmit a signal in response to binding of the ligand can reduce the biological effect of expression of the ligand. Likewise, a dominant negative catalytically-inactive kinase which interacts normally with target proteins but does not phosphorylate the target proteins can reduce phosphorylation of the target proteins in response to a cellular signal. Similarly, a dominant negative transcription factor which binds to a promoter site in the control region of a gene but does not increase gene transcription can reduce the effect of a normal transcription factor by occupying promoter binding sites without increasing transcription.
The end result of the expression of a dominant negative polypeptide in a cell is a reduction in function of active proteins. One of ordinary skill in the art can assess the potential for a dominant negative variant of a protein, and using standard mutagenesis techniques to create one or more dominant negative variant polypeptides. See, e.g., U.S. Pat. No. 5,580,723 and Sambrook et al., Molecular Cloning: A Laboratory Manual, Second Edition, Cold Spring Harbor Laboratory Press, 1989. The skilled artisan then can test the population of mutagenized polypeptides for diminution in a selected and/or for retention of such an activity. Other similar methods for creating and testing dominant negative variants of a protein will be apparent to one of ordinary skill in the art.
The isolation of the Bbtox1 cDNA and the Tptox1 cDNA also makes it possible for the artisan to diagnose a disorder characterized by expression of Bbtox1 (e.g., Lyme disease), or expression of Tptox1 (Syphilis). These methods involve determining expression of the Bbtox1 gene, and/or Bbtox1 polypeptides derived therefrom, and expression of the Tptox1 gene, and/or Tptox1 polypeptides derived therefrom. In the former situation, such determinations can be carried out via any standard nucleic acid determination assay, including the polymerase chain reaction, or assaying with labeled hybridization probes as exemplified below. In the latter situation, such determination can be carried out via any standard immunological assay using, for example, antibodies which bind to the secreted Bbtox1 and/or Tptox1 protein.
The invention also embraces peptide binding agents which, for example, can be antibodies or fragments of antibodies ("binding polypeptides"), having the ability to selectively bind to Bbtox1 polypeptides (e.g., SEQ ID NOs: 2 and 4), and to Tptox1 polypeptides (e.g., SEQ ID NO:18). Antibodies include polyclonal and monoclonal antibodies, prepared according to conventional methodology. In certain embodiments, the invention excludes binding agents (e.g., antibodies) that bind to the toxin polypeptides of V. cholerae, E. coli, B. pertussis, P. aeruginosa, T. pallidum, and/or C. diptheriae.
Significantly, as is well-known in the art, only a small portion of an antibody molecule, the paratope, is involved in the binding of the antibody to its epitope (see, in general, Clark, W. R. (1986) The Experimental Foundations of Modern Immunology Wiley & Sons, Inc., New York; Roitt, I. (1991) Essential Immunology, 7th Ed., Blackwell Scientific Publications, Oxford). The pFc' and Fc regions, for example, are effectors of the complement cascade but are not involved in antigen binding. An antibody from which the pFc' region has been enzymatically cleaved, or which has been produced without the pFc' region, designated an F(ab')2 fragment, retains both of the antigen binding sites of an intact antibody. Similarly, an antibody from which the Fc region has been enzymatically cleaved, or which has been produced without the Fc region, designated an Fab fragment, retains one of the antigen binding sites of an intact antibody molecule. Proceeding further, Fab fragments consist of a covalently bound antibody light chain and a portion of the antibody heavy chain denoted Fd. The Fd fragments are the major determinant of antibody specificity (a single Fd fragment may be associated with up to ten different light chains without altering antibody specificity) and Fd fragments retain epitope-binding ability in isolation.
Within the antigen-binding portion of an antibody, as is well-known in the art, there are complementarity determining regions (CDRs), which directly interact with the epitope of the antigen, and framework regions (FRs), which maintain the tertiary structure of the paratope (see, in general, Clark, 1986; Roitt, 1991). In both the heavy chain Fd fragment and the light chain of IgG immunoglobulins, there are four framework regions (FRI through FR4) separated respectively by three complementarity determining regions (CDRI through CDR3). The CDRs, and in particular the CDR3 regions, and more particularly the heavy chain CDR3, are largely responsible for antibody specificity.
It is now well-established in the art that the non-CDR regions of a mammalian antibody may be replaced with similar regions of conspecific or heterospecific antibodies while retaining the epitopic specificity of the original antibody. This is most clearly manifested in the development and use of "humanized" antibodies in which non-human CDRs are covalently joined to human FR and/or Fc/pFc' regions to produce a functional antibody. Thus, for example, PCT International Publication Number WO 92/04381 teaches the production and use of humanized murine RSV antibodies in which at least a portion of the murine FR regions have been replaced by FR regions of human origin. Such antibodies, including fragments of intact antibodies with antigen-binding ability, are often referred to as "chimeric" antibodies.
Thus, as will be apparent to one of ordinary skill in the art, the present invention also provides for F(ab')2, Fab, Fv and Fd fragments; chimeric antibodies in which the Fc and/or FR and/or CDR1 and/or CDR2 and/or light chain CDR3 regions have been replaced by homologous human or non-human sequences; chimeric F(ab')2 fragment antibodies in which the FR and/or CDR1 and/or CDR2 and/or light chain CDR3 regions have been replaced by homologous human or non-human sequences; chimeric Fab fragment antibodies in which the FR and/or CDR1 and/or CDR2 and/or light chain CDR3 regions have been replaced by homologous human or non-human sequences; and chimeric Fd fragment antibodies in which the FR and/or CDR1 and/or CDR2 regions have been replaced by homologous human or non-human sequences. The present invention also includes so-called single chain antibodies.
Thus, the invention involves polypeptides of numerous size and type that bind specifically to Bbtox1 and/or Tptox1 polypeptides, complexes of both Bbtox1 polypeptides and their binding partners, and complexes of both Tptox1 polypeptides and their binding partners. These polypeptides may be derived also from sources other than antibody technology. For example, such polypeptide binding agents can be provided by degenerate peptide libraries which can be readily prepared in solution, in immobilized form, as bacterial flagella peptide display libraries or as phage display libraries. Combinatorial libraries also can be synthesized of peptides containing one or more amino acids. Libraries further can be synthesized of peptides and non-peptide synthetic moieties.
Phage display can be particularly effective in identifying binding peptides useful according to the invention. Briefly, one prepares a phage library (using e.g. m13, fd, or lambda phage), displaying inserts from 4 to about 80 amino acid residues using conventional procedures. The inserts may represent, for example, a completely degenerate or biased array. One then can select phage-bearing inserts which bind to a Bbtox1 or Tptox1 polypeptide, or a complex of Bbtox1 and a binding partner, or a complex of Tptox1 and a binding partner. This process can be repeated through several cycles of reselection of phage that bind to the polypeptide or complex. Repeated rounds lead to enrichment of phage bearing particular sequences. DNA sequence analysis can be conducted to identify the sequences of the expressed polypeptides. The minimal linear portion of the sequence that binds to the Bbtox1 polypeptide or complex can be determined. One can repeat the procedure using a biased library containing inserts containing part or all of the minimal linear portion plus one or more additional degenerate residues upstream or downstream thereof. Yeast two-hybrid screening methods also may be used to identify polypeptides that bind to the Bbtox1 or Tptox1 polypeptides. Thus, the Bbtox1 (or Tptox1) polypeptides of the invention, or a fragment thereof, or complexes of Bbtox1 (or Tptox1) and a binding partner can be used to screen peptide libraries, including phage display libraries, to identify and select peptide binding partners of the Bbtox1 (or Tptox1) polypeptides of the invention. Such molecules can be used, as described, for screening assays, for purification protocols, for interfering directly with the functioning of Bbtox1 (or Tptox1) and for other purposes that will be apparent to those of ordinary skill in the art.
A Bbtox1 (or Tptox1) polypeptide, or a fragment thereof, also can be used to isolate their native binding partners. Isolation of binding partners may be performed according to well-known methods. For example, isolated Bbtox1 polypeptides (that include Bbtox1, or Tptox1, phosporylated polypeptides) can be attached to a substrate, and then a solution suspected of containing an Bbtox1 (or Tptox1) binding partner may be applied to the substrate. If the binding partner for Bbtox1 (or Tptox1) polypeptides is present in the solution, then it will bind to the substrate-bound Bbtox1 (or Tptox1) polypeptide. The binding partner then may be isolated. Other proteins which are binding partners for Bbtox1 (or Tptox1), may be isolated by similar methods without undue experimentation.
The invention also provides novel kits which could be used to measure the levels of the Bbtox1 nucleic acids of the invention, Bbtox1 expression products of the invention or anti-Bbtox1 antibodies. In the case of nucleic acid detection, pairs of primers for amplifying Bbtox1 nucleic acids can be included. The preferred kits would include controls such as known amounts of nucleic acid probes, Bbtox1 epitopes (such as Bbtox1 expression products) or anti-Bbtox1 antibodies, as well as instructions or other printed material. In certain embodiments the printed material can characterize risk of developing a cancer based upon the outcome of the assay. The reagents may be packaged in containers and/or coated on wells in predetermined amounts, and the kits may include standard materials such as labeled immunological reagents (such as labeled anti-IgG antibodies) and the like. One kit is a packaged polystyrene microtiter plate coated with Bbtox1 protein and a container containing labeled anti-human IgG antibodies. A well of the plate is contacted with, for example, serum, washed and then contacted with the anti-IgG antibody. The label is then detected. A kit embodying features of the present invention, generally designated by the numeral 11, is illustrated in FIG. 4. Kit 11 is comprised of the following major elements: packaging 15, an agent of the invention 17, a control agent 19 and instructions 21. Packaging 15 is a box-like structure for holding a vial (or number of vials) containing an agent of the invention 17, a vial (or number of vials) containing a control agent 19, and instructions 21. Individuals skilled in the art can readily modify packaging 15 to suit individual needs.
Similar kits are also provided which could be used to measure the levels of the Tptox 1 nucleic acids of the invention, Tptox1 expression products of the invention or anti-Tptox1 antibodies.
A. Detection and Identification of Toxin-producing B. burgdorferi
The present invention also provides methods for detecting Bbtox1 expression, including methods for quantitative analysis of toxin concentration in samples. Thus, the methods of the present invention are capable of identifying samples (e.g., various B. burgdorferi cultures) which contain expressed Bbtox1 protein. In one preferred embodiment, the methods may be conducted to determine the presence of Bbtox1 in the genome of the culture source of the test sample, or the expression of Bbtox (mRNA or protein), as well as detect the presence of abnormal or mutated Bbtox1 proteins or gene sequences in the test samples.
In other preferred embodiments, the presence of Bbtox1 is detected by immunochemical analysis. However, it is not intended that the present invention be limited to any particular antibody preparation. Thus, antibodies useful in the present invention include, but are not limited to polyclonals, monoclonals, chimerics, single chains, Fab fragments, and Fab expression libraries.
Various procedures known in the art may be used for the production of polyclonal antibodies to Bbtox1. For the production of antibody, various host animals can be immunized by injection with the peptide corresponding to the Bbtox1 epitope of interest, including but not limited to rabbits, mice, rats, sheep, goats, etc. In a preferred embodiment, the peptide is conjugated to an immunogenic carrier (e.g., diphtheria toxoid, bovine serum albumins (BSA), or keyhole limpet hemocyanin (KLH)). Various adjuvants may be used to increase the immunological response, depending on the host species, including but not limited to Freund's (complete and incomplete), mineral gels such as aluminum hydroxide, surface active substances such as lysolecithin, pluronic polyols, polyanions, peptides, oil emulsions, keyhole limpet hemocyanins, dinitrophenol, and potentially useful human adjuvants such as BCG (Bacille Calmette-Guerin) and Corynebacterium parvum.
For preparation of monoclonal antibodies directed against Bbtox1, any technique that provides for the production of antibody molecules by continuous cell lines in culture may be used (See, e.g., Harlow and Lane, Antibodies: A Laboratory Manual, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y. for descriptions of such methods). These include but are not limited to hybridoma technique originally developed by Kohler and Milstein (Kohler and Milstein, Nature 256:494-497 (1975)), as well as the trioma technique, the human B-cell hybridoma technique (See, e.g., Kozbor, et al., Immunol. Today 4:72 (1983)), and the EBV-hybridoma technique to produce human monoclonal antibodies (Cole, et al., in Monoclonal Antibodies and Cancer Therapy, Alan R. Liss, Inc., pp.77-96 (1985)).
In an additional embodiment of the invention, monoclonal antibodies can be produced in germ-free animals utilizing recent technology (See, e.g., PCT/US90/02545). According to the invention, human antibodies may be used and can be obtained by using human hybridomas (Cote, et al., Proc. Natl. Acad. Sci USA, 80:2026-2030 (1983)) or by transforming human B cells with EBV virus in vitro (Cole, et al., in Monoclonal Antibodies and Cancer Therapy, Alan R. Liss, pp. 77-96 (1985)).
According to the invention, techniques described for the production of single chain antibodies (U.S. Pat. No. 4,946,778; herein incorporated by reference) can be adapted to produce Bbtox1 single chain antibodies. An additional embodiment of the invention utilizes the techniques described for the construction of Fab expression libraries (Huse, et al., Science 246:1275-1281 (1989)) to allow rapid and easy identification of monoclonal Fab fragments with the desired specificity for Bbtox1.
Antibody fragments which contain the idiotype (antigen binding region) of the antibody molecule can be generated by known techniques. For example, such fragments include but are not limited to: F(ab')2 fragment which can be produced by pepsin digestion of the antibody molecule; the Fab' fragments which can be generated by reducing the disulfide bridges of the F(ab')2 fragment and the Fab fragments which can be generated by treating the antibody molecule with papain and a reducing agent.
In the production of antibodies, screening for the desired antibody can be accomplished by techniques known in the art, including but not limited to radioimmunoassay, ELISA (enzyme-linked immunosorbant assay), "sandwich" immunoassays, immunoradiometric assays, gel diffusion precipitin reactions, immunodiffusion assays, in situ immunoassays (e.g., using colloidal gold, enzyme or radioisotope labels), Western Blots, precipitation reactions, agglutination assays (e.g., gel agglutination assays, hemagglutination assays, etc.), complement fixation assays, immunofluorescence assays, protein A assays, and immunoelectrophoresis assays, etc.
In one embodiment, antibody binding is detected by detecting a label on the primary antibody. In another embodiment, the primary antibody is detected by detecting binding of a secondary antibody or reagent to the primary antibody. In a further embodiment, the secondary antibody is labeled. Many means are known in the art for detecting binding in an immunoassay and are within the scope of the present invention. As is well known in the art, the immunogenic peptide should be provided free of the carrier molecule used in any immunization protocol. For example, if the peptide was conjugated to KLH, it may be conjugated to BSA, or used directly, in a screening assay.
The foregoing antibodies can be used in methods known in the art relating to the localization and structure of Btox1 (e.g., for Western blotting), measuring levels thereof in appropriate biological sample, etc. The antibodies can be used to detect Bbtox1 in a biological sample from an individual or from a culture (e.g., a culture filtrate of B. burgdorferi). The biological sample can be a biological fluid, such as but not limited to, blood, serum, plasma, interstitial fluid, synovial fluid, cerebrospinal fluid, urine and the like.
The biological samples can then be tested directly for the presence of Bbtox1 using an appropriate strategy (e.g., ELISA or radioimmunoassay) and format (e.g., microwells, dipsticks [e.g., as described in International Patent Publication WO 93/03367], etc.). Alternatively, proteins in the sample can be size separated (e.g., by polyacrylamide gel electrophoresis (PAGE), in the presence or not of sodium dodecyl sulfate (SIDS), and the presence of Bbtox1 detected by immunoblotting (Western blotting)). Immunoblotting techniques are generally more effective with antibodies generated against a peptide corresponding to an epitope of a protein, and hence, are particularly suited to the present invention.
It is also contemplated that bacterial toxin be detected by pouring liquid samples over immobilized antibody which is directed against the bacterial toxin. It is contemplated that the immobilized antibody will be present in or on such supports as cartridges, columns, beads, or any other solid support medium. In one embodiment, following the exposure of the liquid to the immobilized antibody, unbound toxin is substantially removed by washing. The exposure of the liquid is then exposed to a reporter substance which detects the presence of bound toxin. In a preferred embodiment the reporter substance is an enzyme, fluorescent dye, or radioactive compound attached to an antibody which is directed against the toxin (i.e., in a "sandwich" immunoassay). It is also contemplated that the detection system will be developed as necessary (e.g, the addition of enzyme substrate in enzyme systems; observation using fluorescent light for fluorescent dye systems; and quantitation of radioactivity for radioactive systems).
Any of the foregoing methodology could be used in any of the aspects of the invention involving detection and identification of toxin-producing T. pallidum.
The foregoing explanations of particular assay systems are presented herein for purposes of illustration only, in fulfillment of the duty to present an enabling disclosure of the invention. It is to bc understood that the present invention contemplates a variety of immunochemical assay protocols within its spirit and scope.
B. Therapy of B. burgdorferi, T. pallidum Infection/Disease and Passive Immunization
The present invention contemplates antitoxin therapy for humans and other animals affected by bacterial toxins. Preferred methods of treatment are by intravenous administration or oral administration of anti-Bbtox1 and anti-Tptox antitoxins (e.g., Bbtox1 and Tptox1 binding agents). However, it is also contemplated that in some cases, other borrelial antitoxins will be administered in conjunction with anti-Bbtox1 antitoxin, and/or other Treponema antitoxins will be administered in conjunction with anti-Tptox1 antitoxin. It is further contemplated that antibiotics and/or antibacterial agents could also be co-administered.
Antibiotics and/or antibacterial agents include, but are not limited to, Acedapsone; Acetosulfone Sodium; Alamecin; Alexidine; Amdinocillin; Amdinocillin Pivoxil; Amicycline; Amifloxacin; Amifloxacin Mesylate; Amikacin; Amikacin Sulfate; Aminosalicylic acid; Aminosalicylate sodium; Amoxicillin; Amphomycin; Ampicillin; Ampicillin Sodium; Apalcillin Sodium; Apramycin; Aspartocin; Astromicin Sulfate; Avilamycin; Avoparcin; Azithromycin; Azlocillin; Azlocillin Sodium; Bacampicillin Hydrochloride; Bacitracin; Bacitracin Methylene Disalicylate; Bacitracin Zinc; Bambermycins; Benzoylpas Calcium; Berythromycin; Betamicin Sulfate; Biapenem; Biniramycin; Biphenamine Hydrochloride; Bispyrithione Magsulfex; Butikacin; Butirosin Sulfate; Capreomycin Sulfate; Carbadox; Carbenicillin Disodium; Carbenicillin Indanyl Sodium; Carbenicillin Phenyl Sodium; Carbenicillin Potassium; Carumonam Sodium; Cefaclor; Cefadroxil; Cefamandole; Cefamandole Nafate; Cefamandole Sodium; Cefaparole; Cefatrizine; Cefazaflur Sodium; Cefazolin; Cefazolin Sodium; Cefbuperazone; Cefdinir; Cefepime; Cefepime Hydrochloride; Cefetecol; Cefixime; Cefmenoxime Hydrochloride; Cefmetazole; Cefmetazole Sodium; Cefonicid Monosodium; Cefonicid Sodium; Cefoperazone Sodium; Ceforanide; Cefotaxime Sodium; Cefotetan; Cefotetan Disodium; Cefotiam Hydrochloride; Cefoxitin; Cefoxitin Sodium; Cefpimizole; Cefpimizole Sodium; Cefpiramide; Cefpiramide Sodium; Cefpirome Sulfate; Cefpodoxime Proxetil; Cefprozil; Cefroxadine; Cefsulodin Sodium; Ceftazidime; Ceftibuten; Ceftizoxime Sodium; Ceftriaxone Sodium; Cefuroxime; Cefuroxime Axetil; Cefuroxime Pivoxetil; Cefuroxime Sodium; Cephacetrile Sodium; Cephalexin; Cephalexin Hydrochloride; Cephaloglycin; Cephaloridine; Cephalothin Sodium; Cephapirin Sodium; Cephradine; Cetocycline Hydrochloride; Cetophenicol; Chloramphenicol; Chloramphenicol Palmitate; Chloramphenicol Pantothenate Complex; Chloramphenicol Sodium Succinate; Chlorhexidine Phosphanilate; Chloroxylenol; Chlortetracycline Bisulfate; Chlortetracycline Hydrochloride; Cinoxacin; Ciprofloxacin; Ciprofloxacin Hydrochloride; Cirolemycin; Clarithromycin; Clinafloxacin Hydrochloride; Clindamycin; Clindamycin Hydrochloride; Clindamycin Palmitate Hydrochloride; Clindamycin Phosphate; Clofazimine; Cloxacillin Benzathine; Cloxacillin Sodium; Cloxyquin; Colistimethate Sodium; Colistin Sulfate; Coumermycin; Coumermycin Sodium; Cyclacillin; Cycloserine; Dalfopristin; Dapsone; Daptomycin; Demeclocycline; Demeclocycline Hydrochloride; Demecycline; Denofungin; Diaveridine; Dicloxacillin; Dicloxacillin Sodium; Dihydrostreptomycin Sulfate; Dipyrithione; Dirithromycin; Doxycycline; Doxycycline Calcium; Doxycycline Fosfatex; Doxycycline Hyclate; Droxacin Sodium; Enoxacin; Epicillin; Epitetracycline Hydrochloride; Erythromycin; Erythromycin Acistrate; Erythromycin Estolate; Erythromycin Ethylsuccinate; Erythromycin Gluceptate; Erythromycin Lactobionate; Erythromycin Propionate; Erythromycin Stearate; Ethambutol Hydrochloride; Ethionamide; Fleroxacin; Floxacillin; Fludalanine; Flumequine; Fosfomycin; Fosfomycin Tromethamine; Fumoxicillin; Furazolium Chloride; Furazolium Tartrate; Fusidate Sodium; Fusidic Acid; Gentamicin Sulfate; Gloximonam; Gramicidin; Haloprogin; Hetacillin; Hetacillin Potassium; Hexedine; Ibafloxacin; Imipenem; Isoconazole; Isepamicin; Isoniazid; Josamycin; Kanamycin Sulfate; Kitasamycin; Levofuraltadone; Levopropylcillin Potassium; Lexithromycin; Lincomycin; Lincomycin Hydrochloride; Lomefloxacin; Lomefloxacin Hydrochloride; Lomefloxacin Mesylate; Loracarbef; Mafenide; Meclocycline; Meclocycline Sulfosalicylate; Megalomicin Potassium Phosphate; Mequidox; Meropenem; Methacycline; Methacycline Hydrochloride; Methenamine; Methenamine Hippurate; Methenamine Mandelate; Methicillin Sodium; Metioprim; Metronidazole Hydrochloride; Metronidazole Phosphate; Mezlocillin; Mezlocillin Sodium; Minocycline; Minocycline Hydrochloride; Mirincamycin Hydrochloride; Monensin; Monensin Sodium; Nafcillin Sodium; Nalidixate Sodium; Nalidixic Acid; Natamycin; Nebramycin; Neomycin Palmitate; Neomycin Sulfate; Neomycin Undecylenate; Netilmicin Sulfate; Neutramycin; Nifuradene; Nifuraldezone; Nifuratel; Nifuratrone; Nifurdazil; Nifurimide; Nifurpirinol; Nifurquinazol; Nifurthiazole; Nitrocycline; Nitrofurantoin; Nitromide; Norfloxacin; Novobiocin Sodium; Ofloxacin; Ormetoprim; Oxacillin Sodium; Oximonam; Oximonam Sodium; Oxolinic Acid; Oxytetracycline; Oxytetracycline Calcium; Oxytetracycline Hydrochloride; Paldimycin; Parachlorophenol; Paulomycin; Pefloxacin; Pefloxacin Mesylate; Penamecillin; Penicillin G Benzathine; Penicillin G Potassium; Penicillin G Procaine; Penicillin G Sodium; Penicillin V; Penicillin V Benzathine; Penicillin V Hydrabamine; Penicillin V Potassium; Pentizidone Sodium; Phenyl Aminosalicylate; Piperacillin Sodium; Pirbenicillin Sodium; Piridicillin Sodium; Pirlimycin Hydrochloride; Pivampicillin Hydrochloride; Pivampicillin Pamoate; Pivampicillin Probenate; Polymyxin B Sulfate; Porfiromycin; Propikacin; Pyrazinamide; Pyrithione Zinc; Quindecamine Acetate; Quinupristin; Racephenicol; Ramoplanin; Ranimycin; Relomycin; Repromicin; Rifabutin; Rifametane; Rifamexil; Rifamide; Rifampin; Rifapentine; Rifaximin; Rolitetracycline; Rolitetracycline Nitrate; Rosaramicin; Rosaramicin Butyrate; Rosaramicin Propionate; Rosaramicin Sodium Phosphate; Rosaramicin Stearate; Rosoxacin; Roxarsone; Roxithromycin; Sancycline; Sanfetrinem Sodium; Sarmoxicillin; Sarpicillin; Scopafungin; Sisomicin; Sisomicin Sulfate; Sparfloxacin; Spectinomycin Hydrochloride; Spiramycin; Stallimycin Hydrochloride; Steffimycin; Streptomycin Sulfate; Streptonicozid; Sulfabenz; Sulfabenzamide; Sulfacetamide; Sulfacetamide Sodium; Sulfacytine; Sulfadiazine; Sulfadiazine Sodium; Sulfadoxine; Sulfalene; Sulfamerazine; Sulfameter; Sulfamethazine; Sulfamethizole; Sulfamethoxazole; Sulfamonomethoxine; Sulfamoxole; Sulfanilate Zinc; Sulfanitran; Sulfasalazine; Sulfasomizole; Sulfathiazole; Sulfazamet; Sulfisoxazole; Sulfisoxazole Acetyl; Sulfisoxazole Diolamine; Sulfomyxin; Sulopenem; Sultamicillin; Suncillin Sodium; Talampicillin Hydrochloride; Teicoplanin; Temafloxacin Hydrochloride; Temocillin; Tetracycline; Tetracycline Hydrochloride; Tetracycline Phosphate Complex; Tetroxoprim; Thiamphenicol; Thiphencillin Potassium; Ticarcillin Cresyl Sodium; Ticarcillin Disodium; Ticarcillin Monosodium; Ticlatone; Tiodonium Chloride; Tobramycin; Tobramycin Sulfate; Tosufloxacin; Trimethoprim; Trimethoprim Sulfate; Trisulfapyrimidines; Troleandomycin; Trospectomycin Sulfate; Tyrothricin; Vancomycin; Vancomycin Hydrochloride; Virginiamycin; Zorbamycin.
As described above, it is contemplated that antitoxins and/or vaccine preparations of the present invention may be co-administered with an antibiotic and/or an antibacterial agent (or other antitoxins) for treating or preventing B. burgdorferi and/or T. pallidum infections. The term "co-administered," means administered substantially simultaneously with another agent. By substantially simultaneously, it is meant that an antitoxin and/or a vaccine preparation of the invention is administered to the subject close enough in time with the administration of the other agent (e.g., antibiotic, antibacterial agent, other antitoxin, etc.).
It is noted by way of background that a balance must be struck when administering antitoxins, as they are usually produced in large animals such as horses; sufficient antitoxin must be administered to neutralize the toxin, but not so much antitoxin as to increase the risk of untoward side effects. These side effects are caused by: i) patient sensitivity to foreign (e.g., horse) proteins; ii) anaphylactic or immunogenic properties of non-immunoglobulin proteins; iii) the complement fixing properties of mammalian antibodies; and/or iv) the overall burden of foreign protein administered. Those of skill in the art are familiar with methods to strike this balance.
Although it is not intended to limit the route of delivery, the present invention contemplates a method for antitoxin treatment of bacterial intoxication in which delivery of antitoxin is oral. In one embodiment, antitoxin is delivered in a solid form (e.g., tablets). In an alternative embodiment antitoxin is delivered in an aqueous solution. When an aqueous solution is used, the solution has sufficient ionic strength to solubilize antibody protein, yet is made palatable for oral administration. The delivery solution may also be buffered (e.g., carbonate buffer pH 9.5) which can neutralize stomach acids and stabilize the antibodies when the antibodies are administered orally. In one embodiment the delivery solution is an aqueous solution. In another embodiment the delivery solution is a nutritional formula. Yet another embodiment contemplates the delivery of lyophilized antibody encapsulated or microencapsulated inside acid-resistant compounds.
Methods of applying enteric coatings to pharmaceutical compounds are well known to the art (companies specializing in the coating of pharmaceutical compounds are available; for example, The Coating Place (Verona, Wis.) and AAI (Wilmington, N.C.)). Enteric coatings which are resistant to gastric fluid and whose release (i.e., dissolution of the coating to release the pharmaceutical compound) is pH dependent are commercially available (for example, the polymethacrylates Eudragit.RTM. L and Eudragit.RTM. S [Rohm GmbH]). Eudragit.RTM. S is soluble in intestinal fluid from pH 7.0; this coating can be used to micro encapsulate lyophilized antitoxin antibodies and the particles are suspended in a solution having, a pH above or below pH 7.0 for oral administration. The microparticles will remain intact and undissolved until they reach the intestines, where the intestinal pH causes them to dissolve thereby releasing the antitoxin. In this method, antitoxin is administered orally in either a delivery solution or in tablet form, in therapeutic dosage, to a subject experiencing Lyme disease, or Syphilis.
The invention also contemplates a method of treatment which can be administered prophylactically (e.g., for passive immunization of a subject known to be exposed to B. burgdorferi, T. pallidum, etc.). In one embodiment, antitoxin is administered orally, in a delivery solution, in therapeutic dosage, to a subject, to prevent the effects of Bbtox1 on the subject exposed to B. burgdorferi (or T. pallidum). In another embodiment, antitoxin is administered orally in solid form such as tablets or as microencapsulated particles. Microencapsulation of lyophilized antibody using compounds such as Eudragit.RTM. (Rohm GmbH) or polyethylene glycol, which dissolve at a wide range of pH units, allows the oral administration of solid antitoxin in a liquid form (i.e., a suspension) to recipients unable to tolerate administration of tablets (e.g., children or patients on feeding tubes). In one preferred embodiment the subject is a child. In another embodiment, antibody raised against whole bacterial organism is administered orally to a subject, in a delivery solution, in therapeutic dosage.
Bbtox1 and Tptox1 antitoxin and vaccine related compositions of the invention may be administered alone or in combination with the above-described drug therapies as part of a pharmaceutical composition. Such a pharmaceutical composition may include the foregoing isolated molecules of the invention in combination with any standard physiologically and/or pharmaceutically acceptable carriers which are known in the art. The compositions should be sterile and contain a therapeutically effective amount of the foregoing isolated molecules of the invention in a unit of weight or volume suitable for administration to a subject. The term "pharmaceutically-acceptable carrier" as used herein means one or more compatible solid or liquid filler, diluents or encapsulating substances which are suitable for administration into a human or other animal. The term "carrier" denotes an organic or inorganic ingredient, natural or synthetic, with which the active ingredient is combined to facilitate the application. The components of the pharmaceutical compositions also are capable of being co-mingled with the molecules of the present invention, and with each other, in a manner such that there is no interaction which would substantially impair the desired pharmaceutical efficacy. Pharmaceutically acceptable further means a non-toxic material that is compatible with a biological system such as a cell, cell culture, tissue, or organism. The characteristics of the carrier will depend on the route of administration. Physiologically and pharmaceutically acceptable carriers include diluents, fillers, salts, buffers, stabilizers, solubilizers, and other materials which are well known in the art.
Compositions suitable for parenteral administration conveniently comprise a sterile aqueous preparation of the foregoing isolated molecules of the invention, which are preferably isotonic with the blood of the recipient. This aqueous preparation may be formulated according to known methods using suitable dispersing or wetting agents and suspending agents. The sterile injectable preparation also may be a sterile injectable solution or suspension in a non-toxic parenterally-acceptable diluent or solvent, for example, as a solution in 1,3-butane diol. Among the acceptable vehicles and solvents that may be employed are water, Ringer's solution, and isotonic sodium chloride solution. In addition, sterile, fixed oils are conventionally employed as a solvent or suspending medium. For this purpose, any bland fixed oil may be employed including synthetic mono- or di-glycerides. In addition, fatty acids such as oleic acid may be used in the preparation of injectables. Carrier formulations suitable for oral, subcutaneous, intravenous, intramuscular, etc. administrations can be found in Remington's Pharmaceutical Sciences, Mack Publishing Co., Easton, Pa.
A variety of administration routes are available. The particular mode selected will depend, of course, upon the particular drug selected, the severity of the condition being treated, and the dosage required for therapeutic efficacy. The methods of the invention, generally speaking, may be practiced using any mode of administration that is medically acceptable, meaning any mode that produces effective levels of the active compounds without causing clinically unacceptable adverse effects. Such modes of administration include oral, rectal, topical, nasal, interdermal, or parenteral routes. The term "parenteral" includes subcutaneous, intravenous, intramuscular, or infusion. Intravenous or intramuscular routes are not particularly suitable for long-term therapy and prophylaxis. They could, however, be preferred in emergency situations. Intramyocardial administration is preferred in patients suffering form myocardial infaction. Oral administration will be preferred for prophylactic treatment because of the convenience to the patient as well as the dosing schedule.
The pharmaceutical compositions may conveniently be presented in unit dosage form and may be prepared by any of the methods well-known in the art of pharmacy. All methods include the step of bringing the foregoing isolated molecules of the invention into association with a carrier which constitutes one or more accessory ingredients. In general, the compositions are prepared by uniformly and intimately bringing the foregoing isolated molecules of the invention into association with a liquid carrier, a finely divided solid carrier, or both, and then, if necessary, shaping the product.
Compositions suitable for oral administration may be presented as discrete units, such as capsules, tablets, lozenges, each containing a predetermined amount an isolated molecule of the invention. Other compositions include suspensions in aqueous liquids or non-aqueous liquids such as a syrup, elixir or an emulsion.
Other delivery systems can include time-release, delayed release or sustained release delivery systems. Such systems can avoid repeated administrations of the isolated molecules of the invention described above, increasing convenience to the subject and the physician. Many types of release delivery systems are available and known to those of ordinary skill in the art. They include the above-described polymeric systems, as well as polymer base systems such as poly(lactide-glycolide), copolyoxalates, polycaprolactones, polyesteramides, polyorthoesters, polyhydroxybutyric acid, and polyanhydrides. Microcapsules of the foregoing polymers containing drugs are described in, for example, U.S. Pat. No. 5,075,109. Delivery systems also include non-polymer systems that are: lipids including sterols such as cholesterol, cholesterol esters and fatty acids or neutral fats such as mono- di- and tri-glycerides; hydrogel release systems; sylastic systems; peptide based systems; wax coatings; compressed tablets using conventional binders and excipients; partially fused implants; and the like. Specific examples include, but are not limited to: (a) erosional systems in which the isolated molecules of the invention are contained in a form within a matrix such as those described in U.S. Pat. Nos. 4,452,775, 4,675,189, and 5,736,152, and (b) diffusional systems in which an active component permeates at a controlled rate from a polymer such as described in U.S. Pat. Nos. 3,854,480, 5,133,974 and 5,407,686. In addition, pump-based hardware delivery systems can be used, some of which are adapted for implantation.
Use of a long-term sustained release implant may be particularly suitable for treatment of chronic conditions. Long-term release, are used herein, means that the implant is constructed and arranged to delivery therapeutic levels of the active ingredient for at least 30 days, and preferably 60 days. Long-term sustained release implants are well-known to those of ordinary skill in the art and include some of the release systems described above.
Preparations for parenteral administration include sterile aqueous or non-aqueous solutions, suspensions, and emulsions. Examples of non-aqueous solvents are propylene glycol, polyethylene glycol, vegetable oils such as olive oil, and injectable organic esters such as ethyl oleate. Aqueous carriers include water, alcoholic/aqueous solutions, emulsions or suspensions, including saline and buffered media. Parenteral vehicles include sodium chloride solution, Ringer's dextrose, dextrose and sodium chloride, lactated Ringer's or fixed oils. Intravenous vehicles include fluid and nutrient replenishers, electrolyte replenishers (such as those based on Ringer's dextrose), and the like. Preservatives and other additives may also be present such as, for example, antimicrobials, anti-oxidants, chelating agents, and inert gases and the like.
As discussed above, the invention involves methods for treating individuals with Lyme disease, at risk of developing Lyme disease, and/or treating individuals with Syphilis, or at risk of developing Syphilis. The agents are administered in immunogenically-effective amounts (vaccines) to invoke the production of protective levels of antibodies in a host upon vaccination and, thus, lower the risk of the individual developing Lyme disease or Syphilis, and/or the agents are administered in therapeutic amounts or pharmaceutically effective amounts (antitoxins) to neutralize the pathologic effects of B. burgdorferi toxin, or T. pallidum toxin in a subject.
An effective amount is a dosage of the agent sufficient to provide a medically desirable result (as described above). The effective amount will vary with the particular condition being treated, the age and physical condition of the subject being treated, the severity of the condition, the duration of the treatment, the nature of the concurrent therapy (if any), the specific route of administration and like factors within the knowledge and expertise of the health practitioner. It should be understood that the agents of the invention are used to reduce the risk of developing, or to treat Lyme disease and/or Syphilis, that is, they are used prophylactically in subjects at risk of developing Lyme disease and/or Syphilis (asymptomatic), and acutely in subjects already symptomatic for the disorder. Thus, an effective amount is that amount which can lower the risk of, slow, reverse, or perhaps prevent altogether the development of Lyme disease and/or Syphilis. It will be recognized that when the agent is used in acute circumstances, it is used to prevent one or more medically undesirable results.
Generally, doses of active compounds would be from about 0.01 mg/kg per day to 1000 mg/kg per day. It is expected that doses ranging from 50-500 mg/kg will be suitable, preferably orally and in one or several administrations per day. Lower doses will result from other forms of administration, such as intravenous administration. In the event that a response in a subject is insufficient at the initial doses applied, higher doses (or effectively higher doses by a different, more localized delivery route) may be employed to the extent that patient tolerance permits. Multiple doses per day are contemplated to achieve appropriate systemic levels of compounds.
C. Vaccines Against Borrelia and Treponema Species
The invention also contemplates the generation of mono- and multi-valent vaccines for the protection of an animal (particularly humans) against Borrelia species. Of particular interest are vaccines which stimulate the production of a humoral immune response to B. burgdorferi in humans. The antigens comprising the vaccine preparation may be native or recombinantly produced toxin proteins from the B. burgdorferi, as well as other species (e.g, B. garinii, and B. afzelii). When toxin proteins are used as immunogens, they are generally modified to reduce the toxicity. This modification may be by chemical or genetic (i.e., recombinant DNA technology) means. In general, genetic detoxification (i.e., the expression of nontoxic fragments in a host cell) is preferred as the expression of nontoxic fragments in a host cell precludes the presence of intact, active toxin in the final preparation. However, when chemical modification is desired, the preferred toxin modification is formaldehyde treatment.
The invention contemplates that recombinant Bbtox1 proteins be used as antigens in mono- and multivalent vaccine preparations. Soluble, substantially endotoxin-free recombinant Bbtox1 proteins may be used individually (i.e., as monovalent vaccines) or in combination with other proteins (i.e., as a multivalent vaccine). It is contemplated that a vaccine comprising proteins (native or recombinant or a mixture thereof) be used to stimulate an immune response against various Borrelia species, including those associated with relapsing fever, as well as other spirochetal organisms. Indeed, it is contemplated that vaccines which confer immunity against Bbtox1 will be useful as a means of protecting humans and other animals from the deleterious effects of this toxin, as well as other borrelial proteins.
Within a given serotype or species of Borrelia, it is contemplated that small variations will be observed in the primary amino acid sequence of the toxins produced by these 5 organisms. The present invention contemplates fusion proteins comprising portions of Bbtox1, as well as the variants found among different strains within a given serotype. The present invention provides oligonucleotide primers which may bc used to amplify at least a portion of the toxin from various strains of Borrelia, including any number of B. burgdorferi strains identified from clinical (including B. burgdorferi isolated from non-human animals), as well as those available from such sources as the American Type Culture Collection (ATCC Manassas, Va.).
In general, chemical detoxification of bacterial toxins using agents such as formaldehyde, glutaraldehyde or hydrogen peroxide is not optimal for the generation of vaccines or antitoxins. A delicate balance must be struck between too much and too little is chemical modification. If the treatment is insufficient, the vaccine may retain residual toxicity. If the treatment is too excessive, the vaccine may lose potency due to destruction of native immunogenic determinants. Another potentially major limitation of using Bbtox1 toxoids for the generation of antitoxins or vaccines is the high production expense (e.g., related to the production of Bbtox1). For the above reasons, the development of methods for the production of nontoxic but immunogenic Bbtox1 toxin proteins is desirable.
The present invention provides methods which allow the production of soluble Bbtox1 proteins in economical host cells (e.g., E. coli). In addition the subject invention provides methods which allow the production of soluble Bbtox1 toxin proteins in yeast and insect cells. Further, methods for the isolation of purified soluble Bbtox1 proteins which are suitable for immunization of humans and other animals are provided. These soluble, purified preparations of Bbtox1 proteins provide the basis for improved vaccine preparations and facilitate the production of antitoxin.
When recombinant Bbtox1 protein produced in gram-negative bacteria (e.g., E. coli) are used as vaccines, it is purified to remove endotoxin prior to administration to a host animal. In order to vaccinate a host, an immunogenically-effective amount of purified substantially endotoxin-free recombinant Bbtox1 protein is administered in any of a number of physiologically acceptable carriers known to the art. When administered for the purpose of vaccination, the purified substantially endotoxin-free recombinant Bbtox1 protein may be used alone or in conjunction with known adjutants, including potassium alum, aluminum phosphate, aluminum hydroxide, Gerbu adjuvant (GmDP; C.C. Biotech Corp.), RIBI adjuvant (MPL; RIBI Immunochemical Research, Inc.), QS21 (Cambridge Biotech). The alum and aluminum-based adjutants are particularly preferred when vaccines are to be administered to humans; however, any adjuvant approved for use in humans may be employed. The route of immunization may be nasal, oral, intramuscular, intraperitoneal or subcutaneous.
The invention contemplates the use of soluble, substantially endotoxin-free preparations of fusion proteins comprising at least a portion of Bbtox1 as a vaccine. In one embodiment, the vaccine comprises at least a portion of Bbtox1 and a poly-histidine tract (or "histidine tag"), In a particularly preferred embodiment, a fusion protein comprising the histidine -tagged Bbtox1 (full-length toxin or a portion of the toxin) is expressed using the pET series of expression vectors (Novagen). The pET expression system utilizes a vector containing, the T7 promoter which encodes the fusion protein and a host cell which can be induced to express the T7 DNA polymerase (i.e., a DE3 host strain). The production of Bbtox1 fragment fusion proteins containing a histidine tract is not limited to the use of a particular expression vector and host strain. Several commercially available expression vectors and host strains can be used to express the Bbtox1 protein sequences as a fusion protein containing a histidine tract. For example, the pQE series of expression vectors (pQF8, 12, 16, 17, 18, 30, 31, 32, 40, 41, 42, 50, 51, 52, 60 and 70) (Qiagen) which are used with the host strains M15[pREP4] (Qiagen) and SGI3009[pREP4] (Qiagen), can be used to express fusion proteins containing six histidine residues at the amino-terminus of the fusion protein.
Furthermore a number of commercially available expression vectors which provide a histidine tract also provide a protease cleavage site between the histidine tract and the protein of interest (e.g., Bbtox1 sequences). Cleavage of the resulting fusion protein with the appropriate protease will remove the histidine tag from the protein of interest Bbtox1 sequences). Removal of the histidine tag may be desirable prior to administration of the recombinant Bbtox1 protein to a subject (e.g, a human).
The invention also contemplates the generation of vaccines for the protection of an animal (particularly humans) against T. pallidum, utilizing the Tptox1 compositions provided by the invention, and folowing the methodology described above relating to Bbtox1.
Claim 1 of 27 Claims
1. An isolated peptide comprising SEQ ID NO:4.