CD8A and infection: Sequence variation and the accumulation of mutations over course of infection are known to affect epitope recognition, specificity of the T cell receptor binding and recognition by HLA (Goulder et al., 1997; Nixon et al., 1988).Next, we evaluated whether the low magnitude of responses noted in HLA-B*57/5801 compared to high HLA-Cw*07-restricted CD8+ T cell responses was due to the sequence variation in the CD8+ T cell epitopes.