MOLECULAR MIMICRY BETWEEN CARDIAC MYOSIN AND TRYPANOSOMA-CRUZI ANTIGEN B13 - IDENTIFICATION OF A B13-DRIVEN HUMAN T-CELL CLONE THAT RECOGNIZES CARDIAC MYOSIN

Previous reports from our group have demonstrated the association of m olecular mimicry between cardiac myosin and the immunodominant Trypano soma cruzi protein B13 with chronic Chagas' disease cardiomyopathy at both the antibody and heart-infiltrating T cell level. At the peripher al blood level, we observed no difference in primary proliferative res ponses to T. cruzi B13 protein between chronic Chagas' cardiopathy pat ients, asymptomatic chagasics and normal individuals. In the present s tudy, we investigated whether T cells sensitized by T. cruzi B13 prote in respond to cardiac myosin. T cell clones generated from a B13-stimu lated T cell line obtained from peripheral blood of a B13-responsive n ormal donor were tested for proliferation against B13 protein and huma n cardiac myosin. The results showed that one clone responded to B13 p rotein alone and the clone FA46, displaying the highest stimulation in dex to B13 protein (SI = 25.7), also recognized cardiac myosin. These data show that B13 and cardiac myosin share epitopes at the T cell lev el and that sensitization of a T cell with B13 protein results in resp onse to cardiac myosin, It can be hypothesized that this also occurs i n vivo during T. cruzi infection which results in heart tissue damage in chronic Chagas' disease cardiomyopathy.