CD4 and myocarditis: In this report, we describe the generation of T cell receptor (TCR) transgenic mice on a C57BL/6 genetic background specific to cardiac myosin heavy chain (Myhc)-α 334–352 and make the following observations: First, we verified that Myhc-α 334–352 was immunogenic in wild-type C57BL/6 mice and induced antigen-specific CD4 T cell responses despite being a poor binder of IAb; however, the immunized animals developed only mild myocarditis.