title: Synthesis and physicochemical and immunological characterization of pneumococcus type 12F polysaccharide-diphtheria toxoid conjugates.
abstract: A scheme for the synthesis and purification of conjugates, composed of the type 12F capsular polysaccharide of Streptococcus pneumoniae (Pn12F) and diphtheria toxoid, is described. The scheme is a modification of that described previously for the Vi capsular polysaccharide of Salmonella typhi, a linear homopolymer of N-acetylgalactoseaminouronic acid (S. C. Szu, A. L. Stone, J. D. Robbins, R. Schneerson, and J. B. Robbins, J. Exp. Med. 166:1510-1524, 1986). Pn12F is a branched-chain copolymer composed of a hexasaccharide repeating unit containing an aminouronic acid, N-acetylmannoseaminouronic acid (K. Leontein, B. Lindberg, and J. Lonngren, Can. J. Chem. 59:2081-2085, 1981). Sulfhydryl groups were introduced into Pn12F by forming an amide bond between cystamine and carboxyl groups of N-acetylmannoseaminouronic acid in the presence of a carbodiimide. The disulfide moiety of cystamine was reduced to form the cysteamine derivative of Pn12F which was, in turn, covalently bound to diphtheria toxoid by using the heterobifunctional linker N-succinimidyl-3-(2-pyridylthio)propionate. Unbound, high-molecular-weight Pn12F was removed from the conjugate by hydrophobic interaction chromatography through octyl Sepharose by using n-octyl-beta-D-glucopyranoside as the eluent. In young outbred mice, Pn12F did not elicit detectable serum antibodies. Pn12F-diphtheria toxoid, in contrast, elicited antibodies after two injections and had T-cell-dependent properties as evidenced by a response to priming and by its ability to elicit booster responses. This scheme seems applicable to the synthesis of conjugates with other capsular polysaccharides containing aminouronic acids. Clinical evaluation of Pn12F-diphtheria toxoid conjugates in healthy and in immunocompromised hosts is planned.
authors.affiliation: Laboratory of Developmental and Molecular Immunity, National Institute of Child Health and Human Development, Bethesda, Maryland 20892.
authors.forename: A
authors.initials: A
authors.lastname: Fattom
authors.forename: W F
authors.initials: WF
authors.lastname: Vann
authors.forename: S C
authors.initials: SC
authors.lastname: Szu
authors.forename: A
authors.initials: A
authors.lastname: Sutton
authors.forename: X
authors.initials: X
authors.lastname: Li
authors.forename: D
authors.initials: D
authors.lastname: Bryla
authors.forename: G
authors.initials: G
authors.lastname: Schiffman
authors.forename: J B
authors.initials: JB
authors.lastname: Robbins
authors.forename: R
authors.initials: R
authors.lastname: Schneerson
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000096:biosynthesis*; D001428:Bacterial Vaccines / Q000008:administration & dosage / Q000138:chemical synthesis* / Q000276:immunology; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002851:Chromatography, High Pressure Liquid; D004168:Diphtheria Toxoid / Q000008:administration & dosage / Q000276:immunology; D004220:Disulfides; D005260:Female; D007117:Immunization, Secondary; D051379:Mice; D011135:Polysaccharides, Bacterial / Q000008:administration & dosage / Q000276:immunology; D013296:Streptococcus pneumoniae / Q000276:immunology*; D013438:Sulfhydryl Compounds
chemical_list: D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines; D004168:Diphtheria Toxoid; D004220:Disulfides; D011135:Polysaccharides, Bacterial; C064834:Streptococcus pneumoniae type 12F polysaccharide; D013438:Sulfhydryl Compounds