During T. cruzi infection CD8+ T cells play a critical role in the immune response, as mice depleted of CD8+ T cells using antibodies (Tarleton, 1990; Tarleton et al., 1994), as well as mice lacking functional MHC class I molecules (β2-microglobulin-depleted, Tarleton et al., 1992) or CD8 knockout mice (Rottenberg et al., 1993), show higher susceptibility to infection and higher parasite burden. Here, CD8A is linked to infection.