Third, the levels of Gag-CM9-specific CD8+ T cell responses in RBs at day 14 post infection also correlated strongly with the frequency of tat-SL8 escape mutants in RBs (Figure 4F; Spearman's correlation, r = 0.6731, p = 0.0164), but not PBMCs (data not shown) at day 28 post infection. Here, CD8A is linked to infection.