Fig. 5.

SIV infection is associated with higher levels of SIVGag-specific CD8⁺ T-cell responses in blood and CCR5⁺DR⁺CD4⁺ in rectal mucosa, and a low day 7 viral load is correlated with activated CCR5⁺CD4⁺ T cells in rectal mucosa. (A and B) Comparison of the percent of SIVGag peptide-responsive (A) or CD107a-expressing (B) CD8⁺ T cells in PBMCs before challenge in immunized RMs that remained uninfected (circles) or that acquired SIV infection (squares). Responsive cells are considered to be cytokine producing and/or CD107a expressing after background subtraction. (C and D) Comparison of the percent of CCR5⁺Ki-67⁺ (C) and CCR5⁺HLA-DR⁺ (D) CD4⁺ T cells in rectal mucosa before challenge in immunized RMs that remained uninfected (circles) and those that acquired SIV infection (squares). (E and F) The percentage of total CCR5⁺Ki-67⁺ (E) and effector memory (EM) CCR5⁺Ki-67⁺ (F) CD4⁺ T cells in rectal mucosa before challenge is plotted against the day 7 viral load in immunized RMs experiencing infection. The Mann–Whitney u test was used to determine differences between uninfected and infected groups. *P < 0.05; **P < 0.01 (Spearman’s correlation).