In our earlier studies, a lack of Th1 to Th2 shift, as well as T cytotoxic 1(TC1) to TC2 cytokine shift in CD4+ and CD8+ T cells, respectively, in cells isolated from the intestine, peripheral blood, bone marrow, and axillary lymph node (LN) at 21 days post-SIV infection were detected when compared to the pre-infection phase [3,4]. Here, CD4 is linked to infection.