Protective and autoimmune epitopes of streptococcal M proteins.

Several rheumatogenic serotypes of streptococcal M protein have been shown to contain both protective and cardiac tissue crossreactive epitopes. By synthesizing peptides copying different regions of M protein polypeptides, we were able to localize the protective and heart crossreactive epitopes. Some epitopes are only opsonic, some are only crossreactive, whereas others are both opsonic and tissue crossreactive. Multivalency of vaccines can be obtained by synthesizing protective peptides of one M serotype in tandem with protective peptides of other M serotypes. Such hybrid peptides evoke protective immune responses against the related streptococci without evoking tissue crossreactive immunity.