title: The role of M protein in phagocytosis. II. Opsonization of Streptococcus pyogenes in vitro.
abstract: Opsonization of two different streptococcal group A type 12 strains was investigated. The strains differed only in M protein presence. It was observed that after the treatment of bacteria with fresh normal rabbit serum M positive strains bind to their surface IgG only whereas M negative strains solely some complement components. These results may suggest that streptococci lacking M protein are able to activate complement by alternate pathway.
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology*; D001666:Binding Sites, Antibody; D003165:Complement System Proteins / Q000276:immunology; D007106:Immune Sera; D007074:Immunoglobulin G / Q000276:immunology; D009154:Mutation; D010587:Phagocytosis; D011817:Rabbits / Q000276:immunology; D013297:Streptococcus pyogenes / Q000235:genetics / Q000276:immunology*
chemical_list: D001426:Bacterial Proteins; D007106:Immune Sera; D007074:Immunoglobulin G; D003165:Complement System Proteins