CD28 and infection: Furthermore, in consideration of the potential inflammation induced by Rev-Ind Nef ̄SIV in Group 3 monkeys, we also measured the relative representation of total CD4+ T cells, CD4+CD45RA-CCR5+, CD45RA-CCR7+ memory and CD4+ CD28+ CD95+ central memory cells before and 2 weeks after post-infection (Group 7).