Title:  Vaccine compositions including chitosan for intranasal administration and use thereof

United States Patent:  6,391,318

Assignee:  West Pharmaceutical Services Drug Delivery & Clinical Research Centre (Nottingham, GB)

Filed:  June 1, 1998

Foreign Application Priority Data:  Dec 07, 1995[GB] (9525083)

A variety of different types of nasal vaccine systems have been described including cholera toxin, microspheres, nanoparticles, liposomes, attenuated virus, and outer membrane proteins (proteosomes). The present invention is directed toward a novel nasal vaccine composition that utilizes the cationic polysaccharide, chitosan, as a delivery system. Chitosan is a polysaccharide comprising copolymers of glucosamine and N-acetylglucosamine. The term chitosan encompasses a series of chitosan polymers with different molecular weights (50 kDa-2,000 kDa) and degree of acetylation (40%-98%). Several vaccine animal studies were carried out employing influenza or pertussis antigens in combination with chitosan. Nasal administration of chitosan-antigen nasal vaccines induced significant serum IgG responses and secretory IgA levels. Animals vaccinated via the nasal route with various chitosan-antigen vaccines were also found to be protected against the appropriate challenge.

DETAILED DESCRIPTION OF THE INVENTION

It has now been found that, upon intranasal co-administration, chitosan enhances the immune response of antigens and thus provides an adjuvant effect.

Accordingly, in a first aspect of the invention, there is provided a vaccine composition adapted for intranasal administration, which composition includes antigen and an effective adjuvant amount of a chitosan (hereinafter referred to as "the compositions according to the invention").

The term "effective adjuvant amount" will be well understood by those skilled in the art, and includes an amount of a chitosan which is capable is of stimulating the immune response to nasally administered antigens, i.e. an amount that increases the immune response of a nasally administered antigen composition, as measured in terms of the IgA levels in the nasal washings. Suitably effective increases in IgA levels include by more than 5%, preferably by more than 25%, and in particular by more than 50%, as compared to the same antigen composition without any adjuvant.

Preferred concentrations of the chitosan in the compositions according to the invention are in the range 0.02 to 10%, more preferably 0.1 to 5% and particularly 0.25% to 2%.

It has now been found that, by administration of an antigen together with a particular chitosan derivative in an intranasal composition, it is possible to achieve an immune (e.g. IgG and IgA) response. It has now been found that, if a chitosan is incorporated into intranasal vaccine compositions containing an antigen, good systemic and local immune responses are produced. In particular, it has been found that the intranasal administration of the compositions according to the invention enhances both a protective IgA mucosal immune response and an IgG systemic immune response.

Thus, the invention further provides a method of enhancing a protective IgA mucosal immune response and an IgG systemic immune response by administering intranasally to a mammal a vaccine composition including an antigen and an effective adjuvant amount of a chitosan.

The antigen may be provided as a sub-unit of a cell wall protein or polysaccharide, or as DNA which produces the antigen in the cells after introduction of the DNA (e.g. by transfection). Strictly speaking, the DNA is not itself an "antigen" but it encodes the antigen and is termed antigen herein.

The antigen may further be provided in a purified or an unpurified form. However, the antigen preferably is provided in a purified form.

Antigens of the compositions and methods disclosed herein may include proteins from pathogens, recombinant proteins, peptides, polysaccharides, glycoproteins, lipopolysaccharides and DNA molecules (polynucleotides).

The following list of antigens is provided by means of illustration and is not meant to be exclusive: influenza virus antigens (such as haemagglutinin and neuraminidase antigens), Bordetella pertussis antigens (such as pertussis toxin, filamentous haemagglutinin, pertactin), human papilloma virus (HPV) antigens, Helicobacter pylori antigens, rabies antigens, tick-borne encephalitis (TBE) antigens, meningococcal antigens (such as capsular polysaccharides of serogroup A, B, C, Y and W-135), tetanus antigens (such as tetanus toxoid), diphtheria antigens (such as diphtheria toxoid), pneumococcal antigens (such as Streptococcus pneumoniae type 3 capsular polysaccharide), tuberculosis antigens, human immunodeficiency virus (HIV) antigens (such as GP-120, GP-160), cholera antigens (such as cholera toxin B subunit), staphylococcal antigen (such as staphylococcal enterotoxin B), shigella antigens (such as shigella polysaccharides), vesicular stomatitis virus antigen (such as vesicular stomatitis virus glycoprotein), cytomegalovirus (CMV) antigens, hepatitis antigens (such as hepatitis A (HAV), B (HBV), C (HCV), D (HDV) and G (HGV) virus antigens), respiratory syncytial virus (RSV) antigens, herpes simplex antigens, or combinations thereof (e.g. combinations of diphtheria, pertussis and tetanus (DPT)). Suitable antigens also include those delivered for induction of tolerance, such as retinal antigens.

Preferred antigens include Bordetella pertussis antigens, meningococcal antigens, tetanus antigens, diphtheria antigens, pneumococcal antigens, tuberculosis antigens and RSV antigens.

According to a further aspect of the invention, the antigen preferably is not an influenza virus antigen.

Preferably, the chitosan is water-soluble, and may advantageously be produced from chitin by deacetylation to a degree of greater than 40%, preferably between 50% and 90%, and more preferably between 70% and 95%, deacetylation.

Particular deacetylated chitosans which may be mentioned include the SEA CURE.TM. chitosan glutamate available from Protan Biopolymer A/S, Drammen, Norway.

The molecular weight of the chitosan may be between 10 kD and 500 kD, preferably between 50 kD and 300 kD and more preferably between 100 kD and 300 kD.

The compositions according to the invention may be used in the immunisation of a host against diseases, for example as described in the tests below.

According to a further aspect of the invention, there is provided a method of immunising a host against infection by disease, which method comprises administering intranasally to the host a vaccine composition comprising antigen together with an effective adjuvant amount of a chitosan as hereinbefore defined.

Moreover, according to a further aspect of the invention, there is provided a method of enhancing the immune response of an intranasally administered antigen, which method comprises co-administration of said antigen and a chitosan as hereinbefore defined.

The intranasal compositions according to the invention can be formulated as liquids or dry powders, for administration as aerosols, drops or insufflations.

Preferably, the compositions according to the invention are formulated as dry powders or in the form of microspheres.

Compositions for administration as nasal drops may contain one or more excipients of the type usually included in such compositions, for example preservatives, viscosity adjusting agents, tonicity adjusting agents, buffering agents and the like.

In order to ensure that the chitosan remains soluble in an aqueous medium, and to ensure also that the antigen is not adversely affected by too acidic a pH, a solution for intranasal administration preferably has a pH in the range 5.5 to 6.5, most preferably approximately pH 6.

Also provided is a means for dispensing the intranasal compositions of purified surface antigen and chitosan. A dispensing device may, for example, take the form of an aerosol delivery system, and may be arranged to dispense only a single dose, or a multiplicity of doses.

The vaccine should be administered to the patient in an amount effective to stimulate a protective immune response in the patient. For example, the vaccine may be administered to humans in one or more doses, each dose containing 1-250 micrograms and more preferably 2-50 micrograms of protein or polysaccharide antigen prepared from each viral or bacterial strain. For example, where haemagglutinin and neuraminidase preparations are prepared from three virus strains, e.g. 2.times.Influenza A and 1.times.Influenza B, a total dose of viral protein administered may be in the range 15-150 micrograms. Where Bordetella pertussis antigens are employed, a total dose of bacterial protein administered as FHA, pertussis toxin (toxoid) or pertactin, either individually or in combination may be in the range 5-150 micrograms.

Claim 1 of 17 Claims

We claim:

1. A vaccine composition for intranasal administration, wherein the composition comprises antigen and an effective adjuvant amount of a chitosan,

wherein the chitosan is produced from chitin by deacetylation to a degree of greater than 40% deacetylation and has a molecular weight between 10 kD and 500 kD.

____________________________________________
If you want to learn more about this patent, please go directly to the U.S. Patent and Trademark Office Web site to access the full patent.