Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K39/00—Medicinal preparations containing antigens or antibodies
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07H—SUGARS; DERIVATIVES THEREOF; NUCLEOSIDES; NUCLEOTIDES; NUCLEIC ACIDS
  • C07H3/00—Compounds containing only hydrogen atoms and saccharide radicals having only carbon, hydrogen, and oxygen atoms
  • C07H3/06—Oligosaccharides, i.e. having three to five saccharide radicals attached to each other by glycosidic linkages
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K39/00—Medicinal preparations containing antigens or antibodies
  • A61K39/02—Bacterial antigens
  • A61K39/09—Lactobacillales, e.g. aerococcus, enterococcus, lactobacillus, lactococcus, streptococcus
  • A61K39/092—Streptococcus
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K39/00—Medicinal preparations containing antigens or antibodies
  • A61K39/385—Haptens or antigens, bound to carriers
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K39/00—Medicinal preparations containing antigens or antibodies
  • A61K39/39—Medicinal preparations containing antigens or antibodies characterised by the immunostimulating additives, e.g. chemical adjuvants
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K47/00—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient
  • A61K47/50—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates
  • A61K47/51—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent
  • A61K47/62—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent the modifying agent being a protein, peptide or polyamino acid
  • A61K47/64—Drug-peptide, drug-protein or drug-polyamino acid conjugates, i.e. the modifying agent being a peptide, protein or polyamino acid which is covalently bonded or complexed to a therapeutically active agent
  • A61K47/646—Drug-peptide, drug-protein or drug-polyamino acid conjugates, i.e. the modifying agent being a peptide, protein or polyamino acid which is covalently bonded or complexed to a therapeutically active agent the entire peptide or protein drug conjugate elicits an immune response, e.g. conjugate vaccines
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P31/00—Antiinfectives, i.e. antibiotics, antiseptics, chemotherapeutics
  • A61P31/04—Antibacterial agents
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K39/00—Medicinal preparations containing antigens or antibodies
  • A61K2039/555—Medicinal preparations containing antigens or antibodies characterised by a specific combination antigen/adjuvant
  • A61K2039/55511—Organic adjuvants
  • A61K2039/55583—Polysaccharides
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K39/00—Medicinal preparations containing antigens or antibodies
  • A61K2039/60—Medicinal preparations containing antigens or antibodies characteristics by the carrier linked to the antigen
  • A61K2039/6031—Proteins
  • A61K2039/6037—Bacterial toxins, e.g. diphteria toxoid [DT], tetanus toxoid [TT]
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K39/00—Medicinal preparations containing antigens or antibodies
  • A61K2039/64—Medicinal preparations containing antigens or antibodies characterised by the architecture of the carrier-antigen complex, e.g. repetition of carrier-antigen units
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
  • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
  • Y02A50/30—Against vector-borne diseases, e.g. mosquito-borne, fly-borne, tick-borne or waterborne diseases whose impact is exacerbated by climate change

Definitions

• the immunogenic compositions comprise oligosaccharides covalently coupled to a carrier, wherein the resultant conjugate elicits an immunoprotective response.
• Immunostimulatory compositions comprise S. pneumococcus serotype 8 oligosaccharides covalently coupled to a carrier or as an admixture in a formulation.
• Fattom, A., Lue, C Szu, S. C, Mestecky, J., Schiffman, G., Brylar, D., Vann., W. F., Watson, D. , Kimzey, L. M., Robbins, J.B. and Schneerson, R., Infect, and Immun. 58: 2309, 1990. Fattom, A., Vann, W. F., Szu, S. C, Schneerson, R., Robbins, J. B. ,
• Bacterial capsular polysaccharides are cell surface antigens composed of identical repeat units which form extended saccharide chains. Polysaccharide structures are present on pathogenic bacteria and have been identified on Escherichia coli, Neisseria meningitidis, Haemophilus influenzae, Group A and Group B Streptococcus, Streptococcus pneumoniae and other species. (Kenne and Lindberg 1983).
• glycans consist of only a few monosaccharides (Hakomori and Kannagi 1986).
• the glycan structures by themselves are usually not antigenic, but constitute haptens in conjunction with protein or glycoprotein matrices.
• a general feature of saccharide antigens is their inability to elicit significant levels of IgG antibody classes (IgG isotypes) or memory responses, they are considered thymus-independent (TI) antigens.
• Conjunction of polysaccharide antigens or of immunologically inert carbohydrate haptens to thymus dependent (TD) antigens enhances their immunogenicity.
• the protein stimulates carrier-specific T-helper cells which play a role in the induction of anti-carbohydrate antibody synthesis (Bixler and Pillai 1989).
• TI antigens generally elicit low affinity antibodies of restricted class and do not produce immunologic memory. Adjuvants have little effect on response to TI antigens. In contrast, TD antigens elicit heterogeneous and high affinity antibodies with immunization and produce immunologic memory. Adjuvants enhance response to TD antigens. Secondary responses to TD antigens shows an increase in the IgG to IgM ratio, while for TI antigens the secondary response IgG to IgM ratio is one-to-one, similar to that of a primary response (Stein et al., 1982; Stein, 1992 and 1994).
• TD antigens In mice and humans, TD antigens elicit predominantly IgG, isotypes, with some amounts of IgG 2 and IgG 3 isotypes. TI responses to polysaccharides are restricted to IgG 3 of the IgG isotypes (Perlmutter et al., 1978; Slack et al., 1980).
• Pneumococci are currently divided into 84 serotypes based on their capsular polysaccharides. Although there is some variability of commonly occurring serotypes with geographic location, generally serotypes 1, 3, 4, 7, 8 and 12 are more prevalent in the adult population. Serotypes 1, 3, 4, 6, 9, 14, 18, 19 and 23 often cause pneumonia in children (Mandell, 1990; Connelly and Starke, 1991; Lee et al., 1991 ; Sorensen, 1993; Nielsen and Henricksen, 1993).
• the most widely used anti-pneumococcal vaccine is composed of purified capsular polysaccharides from 23 strains of pneumococci (Pneumovax ® 23, Merck Sharp & Dohme).
• the pneumococcal capsular types included in Pneumovax ® 23 are 1, 2, 3, 4, 5, 6B, 7F, 8, 9N, 9V, 10A, 11A, 12F, 14, 15B, 17F, 18C, 19F, 19A, 20, 22F, 23F, 33F (Danish nomenclature). These serotypes are said to be responsible for 90 percent of serious pneumococcal disease in the world.
• Avery and Goebel were the first to prepare vaccines against bacterial infections (Avery and Goebel 1929; Goebel and Avery 1929). More recently, several protein carrier conjugates have been developed which elicit thymus dependent responses to a variety of bacterial polysaccharides. To date, the development of conjugate vaccines to Hemophilus i ⁇ fluenzae type b (Hib) has received the most attention. Schneerson et al. (1980) have covalently coupled Hib polysaccharides (polyribitol-phosphate) to diphtheria toxoid.
• This group has also developed a Hib vaccine by derivatizing the polysaccharide with an adipic acid dihydrazide spacer and coupling this material to tetanus toxoid with carbodiimide (Schneerson et al., 1986).
• a similar procedure was used to produce conjugates containing diphtheria toxoid as the carrier (Gordon, 1986 and 1987).
• a bifunctional spacer was utilized to couple the outer membrane protein of group B Neisseria meningitidis to Hib polysaccharides (Marburg et al. , 1986, 1987 and 1989).
• conjugate vaccines have been developed by Jennings et al. (1985 and 1989), who utilized periodate activation to couple polysaccharides of Neisseria meningitidis to tetanus or diphtheria toxoid carriers. Porro (1987) defined methods to couple esterified -V. meningitidis oligosaccharides to carrier proteins. Conjugate vaccines containing polysaccharides of Pseudomonas aeruginosa coupled by the periodate procedure to detoxified protein from the same organism (Tsay and Collins, 1987) have been developed. Cryz and Furer (1988) used adipic acid dihydrazide as a spacer arm to produce conjugate vaccines against P. aeruginosa.
• Polysaccharides of specific serotypes of S. pneumoniae have also been coupled to classical carrier proteins such as tetanus or diphtheria toxoids (Schneerson et al., 1984; Fattom et al., 1988 and 1990; Schneerson et al., 1992), to N. meningitidis membrane protein (Marburg et al., 1987; Giebink et al., 1993) and to a pneumolysin mutant carrier (Paton et al., 1991; Lock et al., 1992; Lee et al., 1994).
• Technology for coupling S. pneumoniae oligosaccharides to CRM 197 protein has been developed (Porro, 1990).
• conjugate vaccines have variable or as yet undetermined immunopotentiation properties. Reproducibility of these coupling technologies with the maintenance of immunogenic epitopes is currently the greatest problem in developing effective S. pneumoniae gly co-conjugate vaccines.
• the optimal immunogenic oligosaccharide size appears to vary dependent on the serotype, indicating a conformational aspect of certain immunogenic epitopes (Eby et al., 1994; Steinhoff et al., 1994).
• Vaccines to DTP, tuberculosis, polio, measles, hepatitis, Hib and pneumonia which induce long lasting protection are needed.
• a multi-hapten protein conjugate containing a high level of oligosaccharides of optimal immunogenic size for each " serotype is desired.
• Figure 1 illustrates the repeat unit structures of the polysaccharides used in the Examples of the invention.
• Figure 2 shows the separation profile of Streptococcus pneumoniae serotype 8 capsular polysaccharides through a BioGel P-10 column after acid hydrolysis (0.5 M trifluoroacetic acid, 100 * C, 20 minutes) resulting in discernible oligosaccharides of one to eight repeat units.
• Figure 3 shows the relative size of the repeat units in peaks 1, 2, 3 and 4 of hydrolyzed Streptococcus pneumoniae serotype 8 capsular polysaccharides, as measured by HPLC analysis.
• Figure 4 shows the HPLC retention times of the glucose, M-3 maltotriose, M-7 maltoheptose, and M-10 malto-oligosaccharide standards used to determine the relative size of various oligosaccharide repeat units.
• Figure 5 is an example of the retention times of ribitol, rhamnose, galactose, fucose and mannose monosaccharide standards used to determine carbohydrate content of the hydrolysed repeat unit.
• Figure 6 shows the separation profile of S. pneumoniae serotype 6B polysaccharide hydrofluoric acid hydroly sates passed over a P-10 BioGel column.
• Figure 7 shows the separation profile of S. pneumoniae serotype 6B polysaccharide TFA hydroly sates passed over a P-60 BioGel column.
• Figure 8 shows the separation profile of S. pneumoniae serotype 14 polysaccharide TFA hydrolysates passed over a P-30 BioGel column.
• Figure 9 shows a separation profile of S. pneumoniae serotype 19F polysaccharide acetic acid hydrolysates acetic acid passed over a P-10 BioGel column.
• Figure 10 shows the separation profile of S. pneumoniae serotype 23F polysaccharide TFA hydrolysates passed over a P-10 BioGel column.
• Figure 11 shows the separation profile of S. pneumoniae serotype 8 polysaccharide cleaved by cellulase passed over a P-10 Bio Gel column.
• Figure 12 shows the separation profile of pneumococcal C-substance polysaccharide hydrofluoric acid hydrolysates passed over a P-10 Bio Gel column.
• Figure 13 shows the inhibition ELISA results using a mouse antiserum to Streptococcus pneumoniae serotype 8 oligosaccharide protein carrier conjugate.
• Figure 14 illustrates the acidification of oligosaccharides for carbodiimide coupling.
• Figure 15 shows the separation of reduced and periodate fractions of a polysaccharide (23 valent polysaccharide vaccine-Pneumovax ® 23, Merck, Sharp and Dohme).
• Figure 16 demonstrates separation of reduced and periodate fractions of oligosaccharides of serotype 6B of Streptococcus pneumoniae.
• Figure 17 demonstrates separation of reduced and periodate fractions of oligosaccharides of serotype 19F of Streptococcus pneumoniae.
• Figure 18 depicts the periodate and EDC coupling chemistry reactions.
• Figure 19 shows how a mono-hapten 8-oligosaccharide tetanus toxoid conjugate inhibited anti-8 serum binding to a 8 polysaccharide coated ELISA plate.
• Figure 20 depicts the IgG antibody isotypes elicited by S. pneumoniae serotype 8 polysaccharide following immunization with an 8: 14 di-hapten- oligosaccharide-TT conjugate.
• Figure 21 shows an increased level of IgG, antibody isotype elicited by polysaccharide following immunization with an 8: 14 di-hapten-oligosaccharide- conjugate, typical of a TD response.
• Figures 22A and 22B show IgG isotypes elicited from groups of mice immunized with 14-polysaccharide and oligosaccharide conjugates with and without adjuvant.
• compositions comprising: a) a size- separated carbohydrate hapten comprising at least one immunogenic epitope; and b) a carrier, wherein said hapten is covalently coupled to said carrier and wherein said hapten-carrier conjugate is protectively immunogenic.
• the invention provides methods of making conjugate compositions comprising: a) cleaving a bacterial polysaccharide into oligosaccharides so as to preserve immunogenic epitopes on the resulting oligosaccharides; b) separating the resulting oligosaccharides based on size; c) selecting those oligosaccharides which contain immunogenic epitopes based on inhibition ELISA; d) activating the oligosaccharides selected in step c); and e) coupling the activated oligosaccharides to a purified carrier, wherein the resulting composition contains immunogenic epitopes and is protectively immunogenic.
• the invention provides methods of providing protective immunization against a bacterial pathogen comprising administering to a mammal in need of such treatment an effective amount of the vaccine composition described above.
• the invention provides compositions useful for stimulating an immune response to an antigen, said immunostimulatory composition comprising an oligosaccharide of S. pneumoniae serotype 8 which contains an immunogenic epitope as determined by inhibition ELISA and a suitable pharmaceutical excipient, wherein said oligosaccharide provides an immunostimulatory effect.
• the invention provides methods of providing protective immunization against a bacterial pathogen comprising administering to a mammal in need of such treatment an effective amount of the composition of the serotype 8 composition described above.
• a still further yet aspect of the invention provides methods of augmenting an immunogenic response to an antigen comprising administering an oligosaccharide of S. pneumoniae serotype 8 which contains an immunogenic epitope as determined by inhibition ELISA along with said antigen.
• the invention provides methods of making the immunostimulatory compositions described above, comprising: a) cleaving S.
• the conjugate product may be composed of various haptens or carriers. Mono, di, and multi-hapten conjugates may be prepared. Methods to determine the presence of immunogenic epitopes on the hapten or carrier of the resultant conjugate are described. Such conjugates have utility as vaccines, therapeutic and prophylactic agents, immunomodulators diagnostic agents, development and research tools.
• This invention is particularly suited for developing conjugates as vaccines to such bacterial pathogens including, but not limited to Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influenzae B, Group B Streptococcus, Group A Streptococcus, Bordetella pertussis, Escherichia coli, Streptococcus mutans, Staphylococcus aureus, Salmonella typhi, Cryptococcus neoformans, Pseudomonas aeruginosa and Klebsiella pneumoniae.
• Conjugates of this invention convert weakly or non-immunogenic molecules to molecules which elicit specific immunoprotective antibody or cellular responses.
• thymus independent antigens thymus dependent antigens
• TI thymus dependent antigens
• Integrity of critical immunogenic epitopes and inconsistency of covalent linkage between the carbohydrate and protein are major limitations with these conjugate vaccines.
• the present invention is drawn to the discovery of coupling technology which gives good reproducibility with respect to the carbohydrate to carrier ratio of conjugates. This invention also provides methods to verify the presence of immunogenic epitopes on oligosaccharide haptens and hapten-carrier conjugates.
• Polysaccharide conjugates elicit non-boostable IgM antibody responses, typical of TI antigens.
• the antiserum produced in response to these polysaccharide conjugates does not have opsonic activity.
• oligosaccharides prepared by cleavage of polysaccharides from various bacterial strains are size separated and used to produce mono-hapten conjugates. These conjugates elicit IgG antibody isotypes with immunoprotective, opsonization ability. This antibody response is elicited without the use of any adjuvant.
• the methods of the inventions are ideally suited for producing immunogenic oligosaccharide hapten-carrier conjugates which utilize weakly or non-immunogenic polysaccharides of various strains.
• the presence of immunogenic epitopes on these oligosaccharides was found to be critical for eliciting an immunoprotective response.
• the goal of many researchers is to develop vaccines which elicit protection to the predominant bacterial serotypes which cause acute lower respiratory infection, otitis media and bacteremia in infants, without inducing carrier suppression.
• the methods of the invention can be utilized to produce multi-hapten conjugates with optimal immunogenic epitopes to each bacterial serotype. These conjugates, which contain lower carrier protein amounts than traditional conjugates, reduce the occurrence of the carrier suppression phenomenon. The reduced antigen load possible using these conjugates minimizes the antigenic competition observed with traditional conjugates.
• S- layers crystalline bacterial cell surface layers
• S-layer glycoproteins which elicit non-cross reactive antibody and cellular responses.
• Vaccines to a variety of diseases can be developed using S-layers isolated from various bacterial strains, thereby avoiding carrier suppression observed with tetanus and diphtheria toxoids.
• S-layers are difficult to isolate and purify, as well as costly to produce, making them impractical for wide usage as vaccine carriers.
• the present invention describes methods to prepare mono, di and multi-hapten oligosaccharide conjugates which reduce the amount of carrier necessary to elicit specific responses, thereby decreasing the risk of carrier induced epitope suppression, even when tetanus or diphtheria toxoid is used as the carrier.
• One specific application of the technology of the invention is for the development of effective vaccines for the prevention of pediatric pneumoniae infections.
• Another application of the invention is to develop vaccines for protection to strains of Group B Streptococcus, Group A Streptococcus, Haemophilus influenzae B, Streptococcus pneumoniae and N. meningitidis prevalent in infant disease, in the elderly or the immunosuppressed.
• Other applications include development of conjugates for eliciting protection to various bacterial or virus pathogens.
• oligosaccharide size and conformation is important to maximize immunogenicity of conjugate preparation.
• Different oligosaccharide sizes are separated from hydrolyzed polysaccharide mixtures and isolated by size fraction. The monosaccharide content and the relative size of separated oligosaccharides is measured by, for example, HPLC analysis. Different size repeat units are tested using inhibition ELISA. We have found that ELISA inhibition is directly proportional to the immunogenicity of the oligosaccharide preparation and the resultant conjugate.
• oligosaccharides prepared from cleavage of polysaccharides of S. pneumococcus strains 3, 6B, 8, 14, 19F and 23; pneumococcal C- substance; and N. meningitidis C-polysaccharide have been used in our laboratory.
• Preferred repeat units (R.U.) for oligosaccharides are as follows for some S. pneumococcus serotypes and pneumococcal C-substance: Serotype 3: 4-8 R.U. 6B: 4-10 R.U.
• R.U. 14 4-6 R.U. 19F: 4-10 R.U.
• C-substance 6-10 R.U.
• Preferred repeat units for N. meningitidis C-polysaccharide is 6-10 R.U.
• Creating charged groups on saccharide haptens has been discovered to facilitate the coupling of the haptens to the carrier.
• Use of cation or anion exchange columns is effective in allowing coupling of oligosaccharide to carrier at a higher sugar to carrier ratio. This provides more hapten per carrier, and reduces the carrier suppression phenomenon. Reduced fractions of carbohydrate are used for coupling to carrier.
• Carriers are generally purified using size exclusion column chromatography, although any standard method which removes impurities and aggregate may be used.
• the coupling reaction time and the amount of oligosaccharide, coupling reagent and carrier are critical for obtaining an ideal carbohydrate to carrier conjugate ratio.
• the use of effective blocking reagents which stop the coupling reaction but do not mask the immunogenic groups is important to create effective conjugate compositions.
• conjugates which still maintain their immunogenic epitopes.
• Conjugates with various oligosaccharide sequences and/or sizes can be produced.
• conjugates comprising oligosaccharide and polysaccharide combinations may be synthesized. Such conjugates are able to reduce or eliminate antigenic competition.
• conjugate design provides the ability to reduce carrier induced epitope suppression.
• Keys in this regard are the identification and use of immunogenic oligosaccharide epitopes and more effective coupling of sugar to protein. Binding a larger number of immunogenic epitopes per protein molecule means that less carrier is needed to provide protective immunization.
• Oligosaccharide means a carbohydrate compound made up of a small number of monosaccharide units.
• oligosaccharides may be formed by cleaving polysaccharides.
• Polysaccharide means a carbohydrate compound containing a large number of saccharide groups. Polysaccharides found on the outer surface of bacteria or viruses are particularly useful in the present invention.
• Carrier means a substance which elicits a thymus dependent immune response which can be coupled to a hapten or antigen to form a conjugate.
• various protein, glycoprotein, carbohydrate or sub-unit carriers can be used, including but not limited to, tetanus toxoid/toxin, diphtheria toxoid/toxin, bacteria outer membrane proteins, crystalline bacterial cell surface layers, serum albumin, gamma globulin or keyhole limpet hemocyanin.
• Immunogenic means causing an immune response.
• An immunogenic epitope means that portion of a molecule which is recognized by the immune system to cause an immunogenic response.
• Hapten means an antigen, including an incomplete or partial antigen which may not be capable, alone, of causing the production of antibodies.
• Di- and multi-hapten for purposes of this application, refer to compositions including two (di) or more (multi) oligosaccharide haptens conjugated to carrier.
• Protectively immunogenic or immunoprotective means stimulating an immune response which prevents infection by pathogen.
• Immunostimulatory means stimulating or enhancing an immune response to weakly immunogenic haptens or antigens. Neonate means a newborn animal, including an infant.
• Polysaccharides available through American Type Culture Collection, Rockville, Maryland or by isolation procedures known in the art, were cleaved into oligosaccharide units using appropriate concentrations of chemicals. These chemicals include, but are not limited to trifluoroacetic acid, acetic acid, hydrofluoric acid, hydrochloric acid, sodium hydroxide and sodium acetate. Different time periods and temperatures may be used depending on the particular chemistry and concentration and on the resulting oligosaccharide desired.
• enzymes e.g., cellulase and ⁇ -galactosidase
• isolated bacteriophage-associated endoglycans known in the art or prepared by art recognized methods can also be used to prepare oligosaccharides from polysaccharides.
• Figure 1 shows the repeat unit structures of the polysaccharides used in the Examples of the invention.
• Other bacterial and viral polysaccharide are known to those of skill in the art, and may be used in the methods and compositions of the present invention.
• Various polysaccharides can be cleaved including, but not limited to, pneumococcal group antigen (C-substance) and capsular polysaccharides of serotypes of Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influenzae, Group A Streptococcus and Group B Streptococcus.
• C-substance pneumococcal group antigen
• capsular polysaccharides of serotypes of Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influenzae, Group A Streptococcus and Group B Streptococcus.
• the resulting oligosaccharide mixtures are separated by size using P-10 (fractionation range 1,500 - 20,000 molecular weight), P-30 (2,500 - 40,000 molecular weight) and P-60 (3,000 - 60,000 molecular weight) BioGel columns.
• P-10 fractionation range 1,500 - 20,000 molecular weight
• P-30 2, - 40,000 molecular weight
• P-60 3,000 - 60,000 molecular weight
• the presence of carbohydrates in the various column fractions is determined using phenol-sulphuric or sialic acid assays and thin layer chromatography (TLC). Carbohydrate-containing column fractions are then analyzed by HPLC.
• cleavage procedures may be modified by changing enzymes or chemicals, molarity, reaction time or temperature in order to produce immunogenic epitopes.
• the oligosaccharide or polysaccharide to be used for coupling to carrier is acidified or reduced in preparation for EDC or periodate oxidation coupling.
• the oligosaccharide preparation may be reduced using a RexynTM 101 (H) organic acid cation exchange column to acidify the sugar for EDC coupling.
• sugars may be reduced using standard methods for periodate oxidation coupling.
• each oligosaccharide is activated individually for EDC or periodate conjugation.
• Preferred di-hapten oligosaccharide conjugates include: 3:8-TT, 6:8-TT, 6:14-TT, 8.14-TT, 8: 19-TT, 8:23-TT and 14: 19-TT.
• tetanus toxoid/toxin diphtheria toxoid/toxin
• bacteria outer membrane proteins crystalline bacterial cell surface layers
• serum albumin gamma globulin* or keyhole limpet hemocyanin.
• gamma globulin* keyhole limpet hemocyanin.
• tetanus toxoid was used as the carrier.
• Tetanus toxoid preparations routinely contain aggregates and low molecular weight impurities. Purity of carrier is essential for obtaining consistency with coupling reactions. Size exclusion chromatography is used to obtain a purified carrier preparation.
• the ELISA inhibition assay is used to determine the potential immunogenicity of various conjugates produced by our conjugation procedures.
• conjugates which demonstrate inhibition in this assay at least about a 25 % reduction and preferably about a 50% reduction in O.D. 405 at 6.25 ⁇ g concentration) using the methods set forth in the Examples, provide protective immunogenicity when used as a vaccine in mammals.
• this assay is used to screen for useful conjugate compositions.
• mice are immunized on day 0 (1 * -primary immunization) day 7
• Antigens were diluted to various doses in 0.9% NaCl and mice injected with 0.9% NaCl were used as negative controls. Mice were bled 7-10 days post -2 * and 3 * immunization to collect serum to assay immunoprotective antibody responses.
• a typical immunization schedule is shown in Table 1 for S. Pneumoniae serotype 3 polysaccharide and oligosaccharide-tetanus toxoid conjugates prepared using EDC coupling.
• the conjugates of this invention may be used as classical vaccines, as immunogens which elicit specific antibody production or stimulate specific cell mediated immunity responses. They may also be utilized as therapeutic modalities, for example, to stimulate the immune system to recognize tumor- associated antigens; as immunomodulators, for example, to stimulate lymphokine/cytokine production by activating specific cell receptors; as prophylactic agents, for example, to block receptors on cell membrane preventing cell adhesion; as diagnostic agents, for example, to identify specific cells; and as development and/or research tools, for example, to stimulate cells for monoclonal antibody production.
• the response to a polysaccharide (TI) antigen is usually composed of a one-to-one ratio of IgM and IgG.
• IgG isotypes are restricted, with IgG 3 being over-expressed in anti-poly saccharide serum.
• IgA isotypes may also be present.
• TI antigens elicit antibodies with low affinity and immunologic memory is not produced.
• TD antigens With TD antigens, increased secondary IgG antibody responses (an anamnestic response) are found, with a higher IgG to IgM ratio. Marked levels of IgA are usually not present.
• the TD antigen elicits a heterogeneous IgG isotype response, the predominant isotype being IgG,, IgG 2 . and 2b isotypes can be expressed, while the IgG 3 isotype level is usually relatively low.
• TD antigens elicit immunologic memory and antibody affinity increases with immunizations. Thus, analysis of the immunoglobulin isotypes produced in response to conjugate administration enables one to determine whether or not a conjugate will be protectively immunogenic.
• conjugates of the present invention induce a response typical of TD, rather than TI antigens, as measured by direct and isotyping ELISA bactericidal and opsonization assay.
• Conjugates prepared using our EDC coupling methods elicited better antibody responses than conjugates prepared by periodate activation. Doses of 1 ⁇ g were most immunogenic. Oligosaccharide-conjugates prepared with diphtheria toxoid carriers elicited antibody responses similar to the responses elicited with the oligosaccharide-tetanus toxoid conjugate.
• Protein carriers elicit and augment the immune response to haptens, but in the case of CPS-protein conjugates, the CPS portion is a relatively large TI antigen.
• the immune system may not recognize the CPS-protein as a conjugate, but simply as two distinct entities, resulting in a thymus-independent response to the CPS and a thymus-dependent response to the carrier.
• the immune system recognizes the polysaccharide of our polysaccharide-tetanus toxoid (TT) conjugate as a TI antigen.
• TT polysaccharide-tetanus toxoid
• the potential TD inducing capability of the carrier with respect to antibodies to the polysaccharide is not observed.
• the immunogenic epitopes of the carbohydrate haptens (oligosaccharides) must be in close proximity to the TD inducing epitopes of the carrier in order to convert a TI response to a TD response.
• immunization regimes convert an anti-polysaccharide TI response to a TD response can be designed using the conjugates of the present invention. Economical initial exposure to polysaccharide (e.g., using Pneumovax 23) followed by a single administration of a conjugate of the present invention would induce IgG antibody levels (an anamnestic response). Such an immunization regime would not induce carrier suppression. In such cases, the immune system initially educated to various carbohydrate epitopes and antigens (a TI response) would be induced by multi-hapten conjugates to elicit stronger immunogenic responses to pathogens frequently causing disease in specific population groups (e.g., serotypes 1, 3, 4, 6, 9, 14, 18, 19 and 23 in infants).
• specific population groups e.g., serotypes 1, 3, 4, 6, 9, 14, 18, 19 and 23 in infants.
• conjugates of the invention may be administered by various delivery methods including intraperitoneally, intramuscularly, intradermally, subcutaneously, orally or nasally.
• the formulation of the compositions of the present invention may include suitable pharmaceutical carriers.
• the conjugates of the invention are immunogenic without adjuvant, however adjuvants may increase immunoprotective antibody titers or cell mediated immunity response.
• adjuvants could include, but are not limited to, Freunds complete adjuvant, Freunds incomplete adjuvant, aluminium hydroxide, dimethyldioctadecyl- ammonium bromide, Adjuvax (Alpha-Beta Technology), Inject Alum (Pierce), Monophosphoryl Lipid A (Ribi Immunochem Research), MPL+TDM (Ribi Immunochem Research), Titermax (CytRx), toxins, toxoids, glycoproteins, lipids, glycolipids, bacterial cell walls, sub units (bacterial or viral), carbohydrate moieties (mono-, di-, tri- tetra-, oligo- and polysaccharide), various liposome formulations or saponins. Combinations of various adjuvants may be
• Exact formulation of the compositions will depend on the particular conjugate, the species to be immunized and the route of administration.
• compositions are useful for immunizing any animal susceptible to bacterial or viral infection, such as bovine, ovine, caprine, equine, leporine, porcine, canine, feline and avian species. Both domestic and wild animals may be immunized. Humans may also be immunized with these conjugate compositions.
• the route of administration may be any convenient route, and may vary depending on the bacteria or virus, the animal to be immunized, and other factors.
• Parenteral administration such as subcutaneous, intramuscular, or intravenous administration, is preferred.
• Subcutaneous administration is most preferred.
• Oral administration may also be used, including oral dosage forms which are enteric coated.
• the schedule of administration may vary depending on the bacteria or virus pathogen and the animal to be immunized. Animals may receive a single dose, or may receive a booster dose or doses. Annual boosters may be used for continued protection. In particular, three doses at days 0, 7 and 28 are prefened to initially elicit antibody response.
• Figure 2 shows the separation profile of Streptococcus pneumoniae serotype 8 capsular polysaccharides through a BioGel P-10 column after acid hydrolysis (0.5 M trifluoroacetic acid, 100'C, 20 minutes) resulting in discernible oligosaccharides of one to eight repeat units. Numbers one to eight correspond to the number of repeat units found in each peak, peak nine contains oligosaccharides of greater than eight repeat units. Oligosaccharides derived from hyaluronic acid were used to standardize the chromatographic system. The relative size of the repeat units in peaks 1 , 2, 3 and 4 were measured by HPLC analysis (Figure 3).
• the chemical structure of one serotype 8 repeat unit was determine to be ⁇ -glucose (1 ⁇ 4) ⁇ -glucose (l -» 4) ⁇ -galactose (1 -* 4) ⁇ glucuronic acid (1 ⁇ 4) by GC-MS and NMR analysis. This conesponds to the repeating unit structure cited in the literature (Jones and Perry 1957).
• Figures 6 - 10 are examples of separation profiles of S. pneumoniae serotypes 6B, 14, 19F and 23F polysaccharide hydrolysates (TFA, acetic acid or hydrofluoric acid) passed over P-10, P-30 or P-60 BioGel columns.
• TFA polysaccharide hydrolysates
• Figure 11 shows the separation of an enzyme cleaved polysaccharide (serotype 8 cleaved by cellulase). The separation of C-substance oligosaccharides is shown in Figure 12.
• Figure 13 shows the inhibition ELISA results using a mouse antiserum to Streptococcus pneumoniae serotype 8 oligosaccharide protein carrier conjugate (2-4 repeat units coupled using EDC to tetanus toxoid). Inhibition was tested with type 8 oligosaccharides (0.5 M TFA, 100 , 20 minute preparation) of 1, 2, 3, 4, 6, & 8+ repeat units, and with type 8 polysaccharides. From these results, it can be seen that the 1 repeat unit (a 4 monosaccharide chain) does not contain an immunogenic epitope. The 2 repeat unit (8 monosaccharide chain) was capable of inhibiting antibody binding to the ELISA plate, indicating that it contains an immunogenic epitope.
• type 8 oligosaccharides 0.5 M TFA, 100 , 20 minute preparation
• the molecular weight of repeat unit 2 was determined to be 1365 by FAB-MS analysis. This conelates well with the theoretical molecular weight of 8 saccharides. Repeat units of 3, 4, 6, 8+ and the whole polysaccharide also inhibited antibody binding to the ELISA plate, again indicating that immunogenic epitopes were present in these oligo/poly saccharides .
• Table 3 demonstrates similar results found using a rabbit anti-S. pneumoniae serotype 8 specific serum (Statems Seruminstitut). Repeat unit 1 did not markedly inhibit binding; repeat units 2, 3, 4, 5, 6, 7, 8+ and whole polysaccharide inhibited binding.
• Inhibition ELISA was also used to determine the presence of immunogenic epitopes on oligosaccharides prepared using different hydrolysis procedures on various polysaccharides.
• Table 4 shows results with methods used by the prior art, for example, Pono Canadian Patent No. 2 052 323 to hydrolyse S. pneumoniae serotype 6 polysaccharide (0.01 M acetic acid, 100'C, 30 hours).
• Whole polysaccharide blocked binding at low antigen concentration (effective at 0.39 ⁇ g concentration) while the acetic acid hydrolysate did not. Note that we could not size separate the hydrolyzed preparation because it was "caramelized.”
• TFA hydrolysing agent
• Table 5 shows that different hydrolysing agents (e.g., TFA) and reduced time and temperature produced oligosaccharides with more immunogenic epitopes, as shown in Table 5.
• Tables 6 and 7 also illustrate the effect of time for preparing 6B oligosaccharides with or without immunogenic epitopes.
• a 2 hour acetic acid preparation blocked antibody binding (at 3.13 ⁇ g concentration), the 24 and 48 hour preparations did not.
• a 1.5 hour TFA preparation more effectively blocked binding than a 3 hour preparation.
• TFA hydrolysis of S. pneumoniae serotype 14 at 70 * C for 7 hours is not prefened.
• Reduced molar concentrations of TFA e.g., 0.1 M is better for preparing immunogenic 14 oligosaccharides.
• Table 9 illustrates the importance of selecting oligosaccharides which contain immunogenic epitopes for coupling to carrier.
• the 3 repeat unit structure of serotype 14 oligosaccharide could not inhibit antibody binding, the 4 and 8 repeats, however, contain the immunogenic epitopes and effectively blocked antibody binding.
• Table 10 shows the effect of hydrolysate concentration and reaction time for preparing 14 oligosaccharides containing immunogenic epitopes. Immunogenic epitopes were conserved by a TFA 7 hour hydrolysis, but destroyed when hydrolysed for 24 hours. Table 11 illustrates the importance of using optimal heat conditions for producing 19F oligosaccharides containing immunogenic epitopes. Immunogenic epitopes were destroyed by HCl hydrolysis at room temperature, but maintained when hydrolysis was performed at 70 * C.
• Table 12 shows poor inhibition of antibody binding was observed with 0.25 M TFA, 70 * C, 3 hr hydrolysates of 23F polysaccharides, (Pono, Canadian Patent 2 052 323).
• Table 13 demonstrates the effect of time on the generation of immunogenic 23- oligosaccharides. Oligosaccharides produced by 0.1 M TFA hydrolysis, 70 * C for 3 hours inhibited antibody binding, oligosaccharides prepared by hydrolysis for 5 hours did not inhibit.
• Table 14 demonstrates the presence of immunogenic oligosaccharides after 0.5 M TFA hydrolysis at 70 "C for 15 minutes or with 5 M acetic acid at 70 * C for 5 hours. These hydrolysates effectively inhibited to 0.78 ⁇ g concentration.
• Table 15 demonstrates the utility of the inhibition ELISA to recognize immunogenic oligosaccharides of Neisseria meningitidis serotype C.
• FIG. 14 depicts a TFA cleavage between jS-D-Glcp (1 -* 4) ⁇ -D-Gal of an oligosaccharide structure resulting in the formation of an aldehyde and hydroxyl group. Further oxidation of the aldehyde results in a carboxyl group. When this material is passed through a cation exchange column, a COO " group results.
• the resultant conjugate was dialysed against d H 2 0 overnight using 50,000 molecular weight cut off (MWCO) dialysis tubing.
• MWCO molecular weight cut off
• Conjugates were lyophilized and then assayed by Lowry protein, phenol- sulfuric acid, sialic acid and phosphorous assays for composition (methods described below). Typically, conjugates prepared with this coupling methods have a carbohydrate to canier ratio of 1:2.
• Phenol-Sulfuric Acid Assay for Quantification of Carbohydrates Reagent: 5% phenol solution (5.5 mL liquid phenol (90%) added to 94.5 mL distilled water). Standard: Glucose 1 mg/ml stock solution. Prepare 2 to 60 ⁇ g/200 ⁇ l sample buffer for standard curve.
• Reagents a. 2.5 % ammonium molybdate; b. 10% ascorbic acid; c. 70% perchloric acid; and d. 1 mM sodium phosphate standard. Procedure: (Adapted from: Rouser, G. , Siakotos, A. N. and Fleischer, S. 1966. Lipids 1:85-86)
• Figure 15 shows the separation of a reduced polysaccharide (23 valent polysaccharide vaccine-Pneumovax ® 23, Merck, Sharp and Dohme) fraction.
• Figures 16 and 17 demonstrate separation of reduced oligosaccharides of serotypes 6B and 19F of Streptococcus pneumoniae, respectively.
• conjugate prepared using this coupling method have carbohydrate to carrier ratios of 1:5 to 1: 10.
• Figure 18 depicts the periodate and EDC coupling chemistry reactions.
• Example 4 describes methods used to produce immunogenic oligosaccharide/polysaccharide conjugates from weakly or non-immunogenic polysaccharides.
• Tetanus toxoid was purified for use as a carrier by column chromatography.
• This purified toxoid elicited high levels of IgM (e.g., 50 ⁇ g/ml mouse serum) and IgG isotypes (e.g., IgG, 100 ⁇ g/ml of serum; IgG ⁇ , 38 ⁇ g/ml of serum; IgG 2b , 68 ⁇ g/ml of serum; and IgG 3 , 105 ⁇ g/ml of serum).
• IgM e.g., 50 ⁇ g/ml mouse serum
• IgG isotypes e.g., IgG, 100 ⁇ g/ml of serum; IgG ⁇ , 38 ⁇ g/ml of serum; IgG 2b , 68 ⁇ g/ml of serum; and IgG 3 , 105 ⁇ g/ml of serum.
• the inhibition ELISA as described in Example 2 was used.
• the presence of immunogenic epitopes on a mono-hapten 8-oligosaccharide tetanus toxoid conjugate was confirmed by inhibition ELISA.
• This conjugate inhibited anti-8 serum binding to a 8 polysaccharide coated ELISA plate ( Figure 19). Free tetanus toxoid did not inhibit binding.
• the presence of immunogenic 8 oligosaccharide on di-hapten 6:8; 14:8 and 19:8 conjugates was also shown. This figure illustrates the reproducibility of our coupling procedures, as the 8- mono-hapten and di-hapten conjugates equally blocked antibody binding, indicating that each conjugate contained equivalent amounts of 8 oligosaccharide.
• Table 16 shows results of inhibition ELISA when 6B polysaccharide, 6B oligosaccharides, a 6B:8 di-hapten-oligosaccharide tetanus toxoid conjugate or tetanus toxoid alone was used as inhibiting antigens. Tetanus toxoid did not inhibit binding of anti-6B serum to a 6B-polysaccharide coated ELISA plate. Free 6B-oligosaccharide or polysaccharide did inhibit binding. The 6B:8 di- hapten-oligosaccharide-TT conjugate also inhibited binding. This confirms the presence of immunogenic 6B epitopes on the 6B:8 di-hapten-TT conjugate.
• N. meningitidis oligosaccharides were similarly maintained when coupled to tetanus toxoid (see Table 19).
• the basic procedure to measure antibody isotype levels is as follows to quantify IgM, IgG and IgA isotypes elicited by various conjugates: 1. Coat EIA plates (NUNC, IMMUNOSORB) with 1 ⁇ g/well of Ag in 0.05 M sodium carbonate/sodium bicarbonate buffer pH-9.5, 100 ⁇ l/well. 2. Incubate at 4 * C overnight. 3. Next day, block plates with 100 ⁇ l well of blocking buffer (1 x PBS + 1 % BSA). Incubate at room temperature for approximately 1 hour.
• wash plates 3 x with washing buffer 1 x PBS + 0.05% Tween). Flick off excess liquid by tapping the plates on the bench top.
• Table 2 shows the antibody elicited in mice when immunized with S. Pneumoniae serotype 8 oligosaccharide and polysaccharide conjugates. Only the 8 oligosaccharide-conjugate elicited IgG antibodies of all isotypes, the unconjugated oligosaccharide was not immunogenic, the polysaccharide and the polysaccharide-conjugate elicited antibody isotypes typical of TI responses (mainly IgM, IgA, and IgG 3 isotypes). Adjuvant was not necessary to elicit the IgG isotypes with our oligosaccharide-tetanus toxoid conjugate. Conjugates comprising relatively small oligosaccharides, haptens of 2 - 4 repeat units (8 - 16 saccharides), elicited the best antibody responses as measured by direct ELISA.
• test antibody diluted in PBS - .01% Tween. Incubate for 90 minutes at room temperature.
• Microelisa Auto Reader (405 nm) at approximate 30 minutes intervals.
• results in Table 20, show a comparison of IgG** and lgG 3 levels in mice immunized with 8-conjugate at 3 weeks of age or at 8 weeks of age.
• Significant IgG-, levels were elicited by the 8-oligosaccharide-TT-conjugate in mice immunized at 3 weeks old (0.273 ⁇ g/ml) and at 8 weeks old (0.700 ⁇ g/ml).
• an adjuvant e.g., FCA
• FCA increased specific IgG, (1.22 ⁇ g/ml).
• FCA an adjuvant
• the 8-polysaccharide induced over-expression of IgG 3 and low IgG,, typical of a polysaccharide TI response.
• the 8-polysaccharide-TT conjugate considered a "TD antigen", induced only low levels of IgG,, with overexpression of IgG 3 , characteristic of TI polysaccharide antigens. Also, adjuvant in combination with the 8-polysaccharide-TT conjugate did not enhance IgG, levels, but did increase IgG 3 antibody (Tl-like response). Some polysaccharide-conjugates are known to elicit combinations of TI and TD antibody response profiles (Stein, 1992; Stein, 1994).
• Figure 20 depicts the IgG antibody isotypes elicited by a 8: 14 di-hapten- oligosaccharide-TT conjugate to 8 polysaccharide. Like the 8-mono-hapten conjugate, this di-hapten conjugate could induce much higher levels of specific IgG, antibody (a TD response) than a 8-polysaccharide-conjugate or 8- polysaccharide alone. Overexpression of the IgG 3 isotype to polysaccharide immunogen is shown. Control mice were injected with tetanus toxoid alone.
• results obtained with serotype 14-oligosaccharide conjugates are shown in Table 21.
• Oligosaccharide-TT conjugates prepared using carbohydrate fractions of separation peaks 7 and 8 of a 0.5 M TFA hydrolysate elicited lower levels of IgG isotypes.
• the 14- polysaccharide-TT conjugate elicited relatively high levels of IgG, isotypes.
• serum from mice injected with this polysaccharide conjugate was not immunoprotective (as will be shown in Example 8, Table 24).
• the uncoupled 14 polysaccharide, tetanus toxoid alone, or 0.9 % NaCl negative control serum all displayed low levels of all isotypes, equivalent to normal mouse serum (NMS) levels.
• Figure 21 shows an increased level of IgG, antibody isotype to 14- polysaccharide elicited by a 8: 14 di-hapten-oligosaccharide-conjugate, typical of a TD response.
• mice displayed variable responsiveness to oligosaccharide- and polysaccharide-conjugates.
• variations in the different IgG antibody isotype levels were observed.
• TD antibody responses than polysaccharide-conjugates was not limited to S. pneumoniae immunogens. " Oligosaccharide-conjugates of Neisseria meningitidis Group C elicited greater levels of IgG, isotype antibody (7.01 ⁇ g/ml) than the polysaccharide-conjugate (3.60 ⁇ g/ml) or polysaccharide alone (0.162 ⁇ g/ml).
• Step # 5 and # 6 are done in triplicate
• I.V. inject 100 ⁇ l of sterile heparin into tail of each mouse (5 - 10 mice). After 10 minutes, bleed mice retro-orbitally into a sterile tube. 5. Measure O.D. of bacteria at 420 nm wavelength. Use THB+YE media as blank. (Use spectrophotometer 4040 to measure O.D.)
• Serum from mice immunized with a S. pneumoniae type 8 oligosaccharide conjugate was found to be immunoprotective as measured by the opsonization assay. Opsonization of S. pneumoniae bacteria mediated by specific anti-capsular antibodies is essential for host defense (Saunders, et al. , 1993). This assay is generally considered a reliable indication of immunoprotective capability in vivo. Results from assays show that antibodies to the 8 oligo-conjugate greatly reduce growth of colony forming units of S. pneumoniae serotype 8 on blood agar plates (Table 22). This reduction was specific, as colony growth of serotypes 3 and 6B (used as specificity controls) were not inhibited.
• the 8-oligo conjugate could elicit an immunoprotective antibody response in mice previously administered the whole polysaccharide alone.
• Mice injected with 2 doses of 8-polysaccharide followed by a tertiary oligo-conjugate injection had immunoprotective antibodies in their serum (70% colony reduction in opsonization assay).
• mice receiving 3 injections of polysaccharide elicited no significant amount of protective antibody.
• Oligosaccharide of specific serotypes coupled to a carrier protein may be beneficial as a booster to augment the immunoprotection of high risk groups, non-responsive or only marginally responsive to the current 23-valent polysaccharide vaccine.
• the mono-hapten 3 oligo-tetanus toxoid conjugate used in this study was not prepared with oligosaccharides that had been determined to have immunogenic epitopes by inhibition ELISA and was not capable of eliciting an immunoprotective response.
• the mechanism which allows the immune system to response to epitopes on the 3 oligosaccharide in the di- hapten form is, of course, speculative.
• the 8 oligosaccharides stimulate clones of cell (i.e. accessory or helper cells) which can augment the response to the epitopes on the serotype 3 oligosaccharide.
• the 8 oligosaccharide structure has adjuvant or adjuvant "like" activity.
• the relatively simple repeating unit structure of the 8- oligosaccharide (3-glucose (1 ⁇ 4) 3-Glucose (1 ⁇ 4) ⁇ -galactose (1 ⁇ 4) gluconic acid) may specifically or non-specifically stimulate/activate immune cells or induce receptors or factors to enhance a humoral/cellular response to non-immunogenic or weakly immunogenic polysaccharides/oligosaccharides.
• Serotype 8 oligosaccharides has adjuvant activity in conjugate form or as an admixture to the vaccine formulation.
• Opsonization results of a 14-oligosaccharide-TT conjugate show good bacterial colony reduction of the 14 serotype (76%).
• the 14-oligo-TT 0.5 M TFA preparation elicited less immunoprotective antibody (54% reduction).
• the serums from the polysaccharide-TT conjugate , the polysaccharide alone and the tetanus toxoid injected mice showed greatly reduced inhibition capacity (18, 2 and 15% respectively).
• Serum from control mice (0.9 NaCL injected and NMS) showed no reductive capacity.
• Di-hapten-oligosaccharide conjugates also elicited antibody with opsonic activity.
• a serum to a 8: 14-oligo-TT conjugate reduced serotype 14 colony forming units by 65% (Table 25).
• Example 9 Example 9:
• the unit mass of carbohydrate antigen of our mono- and multi-hapten conjugates will be equivalent (i.e., 1 :2 CHO:protein ratio for EDC conjugates).
• the design of our multi-hapten conjugates using reduced antigen load will minimize the potential for developing antigenic competition.
• Schedules B and E will determine if a primary injection with the conjugate is sufficient to educate the immune system to elicit a T dependent response when boosted with uncoupled polysaccharide(s).
• Schedules C and F will establish the capability of our conjugates to enhance immunoprotective antibody responses in mice previously primed with polysaccharide(s) alone. If so, a multi-hapten pneumoniae vaccine containing oligosaccharides of 3 to 4 serotypes may be very useful to augment the response to Pneumovax ® 23 in high risk patients.
• mice Groups of mice will be injected by 3 doses (1 * . 2' , 3°) of tetanus toxoid
• conjugates will be administered orally and by subcutaneous injection.
• the conjugates of the present invention will stimulate immune responses in infants, in children with immature immune systems and in the immunosuppressed.
• we will determine the immunopotentiating efficacy of our conjugates in young mice, in SCID and nude mice. As described above, these mice will also be pre-sensitized with tetanus toxoid prior to multi-conjugate inoculation to study the carrier suppression phenomenon.
• PSC-TT (A-123) is Polysaccharide- Tetanus Toxoid Conjugate (Lot # A 123).
• OSC-TT (A-124) is Oligosaccharide (4-8 repeat units)-Tetanus Toxoid Conjugate (Lot # A-124).
• PSC (A-123) is Polysaccharide (Lot # A-123).
• OSC (A- 124) is Oligosaccharide (4-8 repeat units) (Lot # A- 124).
• TT is Tetanus Toxoid.

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