title: Human monoclonal antibodies reactive with antigens of the group A Streptococcus and human heart.
abstract: Human mAb were produced from tonsillar or PBL of normal individuals or patients infected with group A streptococci. Lymphocytes were purified on Ficoll-Hypaque gradients and stimulated in vitro with purified group A streptococcal membranes or M protein extracts. The mAb were selected for study based on their reaction with group A streptococci, pep M5 protein, and/or M6 Escherichia coli protein. Further analysis by Western immunoblot or competitive inhibition ELISA revealed that there were two types of antibodies: one type that reacted with myosin and DNA and the other type that reacted with myosin, keratin, and/or actin. The specificities of these human mAb are similar to specificities observed in our previous studies of murine mAb reactive with group A streptococci and heart Ag. For comparison, anti-myosin antibodies were affinity purified from the sera of infected or acute rheumatic fever patients and were shown to react with myosin and DNA as well as with group A streptococci and M protein. To affinity purify these antibodies from normal sera, five times the amount of sera was required to obtain detectable quantities. These data suggest that the human mAb reactive with group A streptococci and myosin reflect the antibodies seen in sera from infected patients or acute rheumatics and that the B lymphocyte clones capable of producing these cross-reactive antibodies are also present in normal individuals.
mesh_terms: D000907:Antibodies, Bacterial / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000937:Antigen-Antibody Reactions; D000942:Antigens, Bacterial / Q000276:immunology*; D001323:Autoantibodies / Q000096:biosynthesis / Q000276:immunology; D001324:Autoantigens / Q000276:immunology*; D001426:Bacterial Proteins / Q000276:immunology; D003429:Cross Reactions; D029968:Escherichia coli Proteins; D006801:Humans; D006825:Hybridomas / Q000378:metabolism; D009206:Myocardium / Q000276:immunology*; D009218:Myosins / Q000276:immunology; D013290:Streptococcal Infections / Q000097:blood; D013297:Streptococcus pyogenes / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial; D001323:Autoantibodies; D001324:Autoantigens; D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; C052378:polypeptide M5, E coli; D009218:Myosins