title: Salmonella typhi O-polysaccharide--tetanus toxoid conjugated vaccine.
abstract: A Salmonella typhi conjugated vaccine was prepared by covalently linking the antigenic O-polysaccharide, selectively activated by periodate oxidation, to tetanus toxoid via reductive amination. The immunogenicity of the conjugate (O-TT) was examined by injecting Balb/c mice with 5 micrograms of the conjugate and Alhydrogel as adjuvant, boosting 14 and 28 days after the primary immunization, and quantification of the development of anti-polysaccharide and anti-tetanus toxoid antibodies by enzyme-linked immunosorbent assay. Mean anti-O-chain titres after the first and second boost were 129 and 502, respectively, while anti-tetanus toxoid titres were 159 and 1000, respectively. Anti-O-polysaccharide antibodies exhibited complement-mediated bactericidal activity against S. typhi. Immunized mice were fully protected against challenge with 10 LD50 of S. typhi Ty2 (p < 0.001) and partially protected against challenge with 100 LD50 of S. typhi Ty2 (p < 0.04).
authors.affiliation: Bacterial Products Division, Bureau of Biologics, Tunney's Pasture, Ottawa, Ontario, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Saxena
authors.forename: J L
authors.initials: JL
authors.lastname: Di Fabio
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology; D001428:Bacterial Vaccines / Q000276:immunology*; D002240:Carbohydrate Sequence; D005260:Female; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D019081:O Antigens; D011135:Polysaccharides, Bacterial / Q000276:immunology*; D012485:Salmonella typhi / Q000276:immunology*; D013745:Tetanus Toxoid / Q000276:immunology*; D018074:Vaccines, Conjugate / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines; D019081:O Antigens; D011135:Polysaccharides, Bacterial; D013745:Tetanus Toxoid; D018074:Vaccines, Conjugate