title: Antigens of Streptococcus sanguis.
abstract: An antigenic analysis of the alpha-hemolytic streptococci isolated from dental plaque was performed by use of antisera against a strain of Streptococcus sanguis (M-5) which was isolated from dental plaque. Immunoelectrophoretic and Ouchterlony tests of Rantz and Randall extracts of 45 strains gave positive reactions with the M-5 antisera. These strains represented 60% of the strains tested. The number of antigens which could be identified in these extracts varied from one to five and were designated a to e. The a antigen was found in 36 of the strains tested, including reference strains of S. sanguis and the group H streptococci. The strains reacting with the M-5 antisera were divided into two majors types: type I consisted of 23 strains in which the a antigen was found alone or with one or more of the c, d, and e antigens; type II consisted of 13 strains in which both the a and b antigens were found with or without one or more of the c, d, and e antigens. The remaining strains contained, either singly or in combination, the b, c, d, and e antigens but not the a antigen. Biochemical tests of representatives of each serotype and reference strains indicated that strains reacting with M-5 antisera were S. sanguis. These findings suggest that S. sanguis strains share common physiological and serological properties.
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000032:analysis*; D003773:Dental Plaque / Q000276:immunology / Q000382:microbiology*; D006801:Humans; D007106:Immune Sera; D005779:Immunodiffusion; D007122:Immunoelectrophoresis; D011817:Rabbits / Q000276:immunology; D013291:Streptococcus / Q000276:immunology*
chemical_list: D000942:Antigens, Bacterial; D007106:Immune Sera