CD8A and infection: In particular, (1) the appearance of CD8+ T-cell responses in the blood is correlated with a decline in viremia [16,19,20,21,22]; (2) the rate of disease progression of HIV-infected individuals is strongly dependent on MHC-I locus combinations [23,24,25]; (3) HIV escapes recognition from multiple CD8+ T-cell responses during the infection [16,26].