Similar levels of CCR5 are expressed on the surfaces of CD8⁺ T cells from natural and nonnatural hosts of SIV. (A) Representative contour plots showing CD8 and CCR5 staining of peripheral blood–derived T cells of healthy humans, RMs, PTMs, cynomolgus macaques, baboons, SMs, Caribbean AGMs, mandrills, sun-tailed monkeys, and chimpanzees. (B) Representative contour plots showing CD8 and CCR5 staining of T cells isolated from the LNs of RMs, baboons, SMs, AGMs, and mandrills. (C) Summary of CCR5 expression on peripheral blood–derived CD8⁺ T cells of the primate species listed in panel A. One-way nonparametric ANOVA (Kruskal-Wallis) followed by the Dunn multiple comparison test found no statistically significant differences (P > .05) in CCR5 expression on CD8⁺ T cells obtained from natural and nonnatural hosts of SIV. The only exception was SMs with lower levels of CD8⁺CCR5⁺ T cells than RMs (P < .05).