Experimental giant cell myocarditis induced by cardiac myosin immunization.

To identify a cardiac protein that could cause a serious autoimmune myocarditis, membranous proteins and myosin as antigens were investigated. In mice immunized with membranous proteins, the lesions induced were limited on the histological level. On the other hand, in Lewis rats immunized with cardiac myosin, serious myocarditis was induced. Every rat showed evidence of heart failure which was fatal in a few. Histology disclosed extensive cell infiltrates and myocardial necrosis. Among those lesions, giant cells were present. This myocarditis could be also transferred adoptively by lectin-activated spleen cells, T-lymphocytes, but not by IgG fraction. Thus, cardiac myosin can induce autoimmune giant cell myocarditis in Lewis rats.