Figure 5.

Reaction of lymphocytes infiltrating hearts in cardiac myosin-induced myocarditis and valvulitis proliferated to group A streptococcal M5 peptides. Lymphocytes from the myocardial infiltrate proliferated to four M5 peptides including M5 peptides B1A, B1B, and B1B2 with stimulation indices of >2.0. Also with elevated stimulation indices were two peptides in the C repeat region, C1C2 and C3. These data provide evidence that streptococcal M protein cross-reacts with myosin sensitized T cells in hearts developing inflammatory heart disease.