title: Polysaccharide nature of O antigen in protective ribosomal preparations from Shigella: experimental evidence and implications for the ribosomal vaccine concept.
abstract: Shigella ribosomal vaccine (SRV) was previously shown to be highly active in induction of mucosal and systemic O-antibody response and protection against Shigella infection in guinea pigs and monkeys. In this study, the O-specific component (OSC) was isolated from the SRV by affinity chromatography using rabbit O antibodies coupled to CNBr-Sepharose. The results of the reaction with carbocyanine dye as well as chemical data show that ribosomal OSC is devoid of lipid A and KDO, which are characteristic of classical LPS. The comparison of OSC with various LPS-related substances led to the conclusion that ribosomal OSC is similar to and probably identical with cytoplasmic O polysaccharide (L hapten), an O-side-chain polymer which accumulates in cytoplasm. It is hypothesized that the extremely high immunogenicity of SRV depends on a cooperative action of OSC, representing an epitope-specific part of the vaccine, and a ribosomal particle which serves as a vector, providing amplification of the immunogenic effect. The data obtained indicate the presence of a non-covalent link between the two components of the ribosomal vaccine.
authors.affiliation: Department of Bacterial Vaccines, Gabrichevsky Research Institute of Epidemiology and Microbiology, Moscow.
authors.forename: V I
authors.initials: VI
authors.lastname: Levenson
authors.forename: T P
authors.initials: TP
authors.lastname: Egorova
mesh_terms: D000942:Antigens, Bacterial / Q000032:analysis*; D001428:Bacterial Vaccines / Q000032:analysis*; D002499:Centrifugation, Density Gradient; D004405:Dysentery, Bacillary / Q000517:prevention & control*; D006241:Haptens; D006801:Humans; D066298:In Vitro Techniques; D019081:O Antigens; D011134:Polysaccharides; D012270:Ribosomes / Q000276:immunology*; D012760:Shigella / Q000276:immunology*
chemical_list: D000942:Antigens, Bacterial; D001428:Bacterial Vaccines; D006241:Haptens; D019081:O Antigens; D011134:Polysaccharides