title: Mouse-protective effect of rabbit anti-R-protein antibodies against group B streptococci type II carrying R-protein. Lack of effect on type III carrying R-protein.
abstract: R-proteins was isolated by affinity chromatography from an alkaline extract of group B streptococci, type III. the identity of the protein was demonstrated by pepsin- and trypsin-treatment and in double diffusion-in-gel with antisera from other laboratories. A monospecific rabbit antiserum against the R-protein was studied in mouse-protection tests, using three type II strains with R-protein and three without, and six type III strains, of which four carried R-protein. the serum protected animals from infection by type II strains carrying R-protein, but not against any of the other strains. The capacity of anti-R-protein serum to opsonize type II strains carrying R-protein was also demonstrated in phagocytosis experiments with mouse peritoneal macrophages. Studies with radio-labelled protein A and anti-R-protein antibodies showed that R-protein was localized on the surface of both type II and type III groups B streptococci. Taken together, the results suggest that type II group B streptococci should be divided into two subtypes, II, R+ and II, R-.
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology*; D000942:Antigens, Bacterial / Q000276:immunology*; D000954:Antigens, Surface / Q000276:immunology; D001426:Bacterial Proteins / Q000276:immunology* / Q000302:isolation & purification; D008264:Macrophages / Q000276:immunology; D051379:Mice; D009895:Opsonin Proteins; D010587:Phagocytosis; D012703:Serotyping; D013290:Streptococcal Infections / Q000517:prevention & control; D013297:Streptococcus pyogenes / Q000145:classification / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D000954:Antigens, Surface; D001426:Bacterial Proteins; D009895:Opsonin Proteins