CD8A and infection: Thus, Group M animals mounted Nef and Vif epitope-specific CD8+ T-cell responses in the chronic phase of infection, whereas such broadening of CD8+ T-cell responses was unclear and Gag epitope-specific CD8+ T cells were maintained in Group N. In particular, in three of six Group N macaques, R07-008, R09-009, and R09-010, comparison between 4 months and 2 years post-challenge showed no change in CD8+ T-cell target epitopes.