It was previously demonstrated that perforin+ and IFNγ+ CD8+ T-cells play antagonistic roles in the heart tissue of T. cruzi-infected mice [5]; therefore, we examined whether rAdVax immunization influenced the number of cytotoxic (Pfn+) and inflammatory (IFNγ+) cells composing the chronic T. cruzi-induced myocarditis. This evidence concerns the gene CD8A and myocarditis.