Immunohistochemical study of the myocardium in murine Coxsackie B3 virus myocarditis using monoclonal antibodies--significance of Lyt 1 antigen-bearing lymphocytes in cell-mediated immunity.

This light- and electron-microscopic study using monoclonal antibodies provides an immunohistochemical demonstration of lymphocytes in situ in the myocardium in murine coxsackie B3 virus myocarditis. On the 7th and 9th days after virus inoculation, we observed many necrotic cardiocyte foci infiltrated with numerous inflammatory cells including macrophages and T lymphocytes. There were only a few Lyt 1-bearing lymphocytes in this phase of inoculation. On the 14th day there were many Lyt 1-bearing cells among the T cells in the foci. By immuno-electron microscopy, some Lyt 1-bearing T lymphocytes were seen in close contact with macrophages and/or other lymphocytes. These Lyt 1-bearing lymphocytes appeared to represent helper T cells, although Lyt 2.3+ lymphocytes were not examined. It is well known that activation of helper T cells leads to stimulation of B cells and cytotoxic T cells. It is assumed, therefore, that Lyt 1-bearing T lymphocytes that infiltrated into the myocardial foci play an important role in immune responsiveness at this stage of viral myocarditis.