Hormonal Regulation of CD4(+) T-Cell Responses in Coxsackievirus B3-Induced Myocarditis in Mice

Coxsackievirus B3 infection causes significant cardiac inflammation in male, but not female, B1.Tg.Eα mice. This gender difference in disease susceptibility correlates with selective induction of CD4(+) Th1 (gamma interferon-positive) cell responses in animals with testosterone, whereas estradiol promotes preferential CD4(+) Th2 (interleukin-4 positive [IL-4(+)]) cell responses. Differences in immune deviation of CD4(+) T cells cannot be explained by variation in B7-1 or B7-2 expression. Infection significantly upregulated both molecules, but no differences were detected between estradiol- and testosterone-treated groups. Significantly increased numbers of activated (CD69(+)) T cells expressing the γδ T-cell receptor were found in male and testosterone-treated male and female mice. In vivo depletion of γδ(+) cells by using monoclonal antibodies inhibited myocarditis and resulted in a shift from a Th1 to Th2 response phenotype. Taken together, our results indicate that testosterone promotes a CD4(+) Th1 cell response and myocarditis by promoting increased γδ(+) cell activation.