title: Immunological and chemical studies of the streptococcal group O protein type antigens.
abstract: Two antigens present in group O streptococci have been described and are designated as type antigens. No other antigens are present in extracts of group O cells in significant quantity. Antigen I is a cell wall protein, and II is a nucleoprotein of undetermined cell location. The immunological specificity of the latter resides only in the protein. Both antigens have been extracted from the cell with water or 0.2 n HCl (pH 2) at 100 C, and antigen I can be removed by trypsin. After purification, pH 2 was found to destroy the serological activity of each antigen. Antgens I and II and also the O polysaccharide antigen can be distinguished on a single agar-gel diffusion plate with group O whole-cell antiserum. N- and C-terminal amino acid analyses and total amino acid composition prove that I and II are separate molecular species. Each possesses properties which separate them from the streptococcal M, R, and T proteins. Antigen I separated into three fractions, each possessing serological specificity, on a diethylaminoethyl-Sephadex column at pH 8.6 during an increase in buffer molarity. The protein is considered to possess a multiple unit structure. The results indicate that the O streptococci are limited to two serological types. Group O whole-cell antisera, after adsorption with a strain not containing the O polysaccharide, can now be prepared for the positive identification of the types of group O streptococci.
mesh_terms: D000469:Alkaline Phosphatase / Q000494:pharmacology; D000596:Amino Acids / Q000032:analysis; D000942:Antigens, Bacterial / Q000032:analysis* / Q000302:isolation & purification; D002473:Cell Wall / Q000276:immunology; D002855:Chromatography, Thin Layer; D003851:Deoxyribonucleases / Q000494:pharmacology; D000939:Epitopes / Q000032:analysis; D005959:Glucosidases / Q000494:pharmacology; D006386:Hemagglutination Tests; D005779:Immunodiffusion; D007122:Immunoelectrophoresis; D008970:Molecular Weight; D009698:Nucleoproteins / Q000032:analysis; D010429:Pentoses / Q000032:analysis; D010443:Peptide Chain Termination, Translational; D010758:Phosphorus / Q000032:analysis; D011233:Precipitin Tests; D012260:Ribonucleases / Q000494:pharmacology; D013291:Streptococcus / Q000145:classification / Q000276:immunology*; D014357:Trypsin / Q000494:pharmacology
chemical_list: D000596:Amino Acids; D000942:Antigens, Bacterial; D000939:Epitopes; D009698:Nucleoproteins; D010429:Pentoses; D010758:Phosphorus; D003851:Deoxyribonucleases; D012260:Ribonucleases; D000469:Alkaline Phosphatase; D005959:Glucosidases; D014357:Trypsin