title: Antigens of Streptococcus sanguis: purification and characterization of the b antigen.
abstract: The antigen defining Streptococcus sanguis serotype 2 has been designated the b antigen. This antigen can be detected in extracts, obtained from whole cells by autoclaving (Rantz and Randall extraction), as a single precipitin band using a reference antiserum (M-5). However, the extract can also be shown to contain a teichoic acid using anti-polyglycerol phosphate serum. This teichoic acid does not contain the antigenic determinant for group H specificity. Studies of the b antigen have been hampered because of the difficulty in separating the b antigen from the teichoic acid using ion-exchange and molecular sieve chromatography. However, a relatively pure preparation has been obtained by affinity chromatography using anti-polyglycerol phosphate serum coupled to Sepharose. The isolated b antigen is a typical streptococcal cell wall polysaccharide composed of glucose, rhamnose, and N-acetylglucosamine in a molar ratio of 2.5:1.0:0.1. The antigen appears to have a single antigenic determinant closely related to isomaltose (glucose alpha-1,6-glucoside) based upon hapten inhibition studies.
mesh_terms: D000942:Antigens, Bacterial / Q000302:isolation & purification*; D003773:Dental Plaque / Q000382:microbiology*; D011135:Polysaccharides, Bacterial / Q000032:analysis / Q000276:immunology; D013298:Streptococcus sanguis / Q000276:immunology*
chemical_list: D000942:Antigens, Bacterial; D011135:Polysaccharides, Bacterial