CD4 and infection: We tested the hypothesis that HIV-specific CD8+ T cells from HIV controllers, a very small proportion of the HIV-infected population who manage to spontaneously control viral replication and maintain stable CD4+ T cell counts without the need for antiretroviral therapy (Carrington and Walker, 2012, Deeks and Walker, 2007, Walker and Yu, 2013), could recognize and kill non-activated, infected CD4+ T cells due to the recognition of processed viral proteins following viral entry, without requiring productive infection.