title: O antigen as virulence factor in mouse typhoid: effect of B-cell suppression.
abstract: Immunosuppression by cyclophosphamide was used to make mice incapable of B-lymphocyte responses; they could not make an antibody response to NIP-Ficoll. These mice, as well as untreated mice, were challenged intraperitoneally with graded doses of isogenic O-4,12 or O-6,7 Salmonella typhimurium derivatives. The 50% lethal dose of the O-6,7 strains was 35- to 70-fold higher than that of the O-4,12 strains, both in the normal and the immunosuppressed animals, although the latter were approximately 1,000-fold more susceptible to the infection by either challenge organism. We conclude that the O-antigen-dependent difference in the mouse virulence of these sister strains is not mediated through differences in their capacity to evoke B-lymphocyte-mediated immune responses.
mesh_terms: D000818:Animals; D000917:Antibody Formation; D000942:Antigens, Bacterial; D001402:B-Lymphocytes / Q000187:drug effects*; D003520:Cyclophosphamide / Q000494:pharmacology*; D004195:Disease Models, Animal; D005362:Ficoll / Q000031:analogs & derivatives / Q000276:immunology; D006824:Hybridization, Genetic; D007165:Immunosuppression Therapy; D051379:Mice; D012475:Salmonella / Q000276:immunology; D012480:Salmonella Infections / Q000276:immunology*; D012486:Salmonella typhimurium / Q000472:pathogenicity*; D014774:Virulence
chemical_list: D000942:Antigens, Bacterial; D005362:Ficoll; D003520:Cyclophosphamide