IMMUNOLOGICAL AND BIOCHEMICAL STUDIES OF MENINGOCOCCAL C POLYSACCHARIDES ISOLATED BY DIETHYLAMINOETHYL CHROMATOGRAPHY

Meningococcal C polysaccharides [used in vaccines effective in adults but poorly immunogenic in children] isolated from the broth supernatant of [Neisseria meningitidis] C1+ and C1- strains by joint Sepharose 4B and DEAE-52 chromatography are antigenically identical to the group C antigen isolated by the Cetavlon procedure. Immunizations result in the induction of precipitating, hemagglutinating and bactericidal antibodies in rabbits and sheep and hemagglutinating and bactericidal antibodies in gerbils. Selective destruction of C1- polysaccharides with neuraminidase demonstrated that these antibodies are directed against the C polysaccharide. Neuraminidase digestions of the C1- polysaccharides resulted in release of up to 84% of the antigen as N-acetylneuraminic acid. C1+ polysaccharides were more resistant to neuraminidase, requiring greater concentrations of enzyme and longer intervals of exposure for digestion. Chemical analysis of the C1+ and C1- polysaccharides indicated that the contain < 0.5% protein and < 0.5% nucleic acid.