SIV infection of CD4⁺ T-cell subsets in LNs of RMs and SMs. Naive (CD28^dull,CCR7⁺CD95⁻), T_CM (CCR7⁺CD95⁺), T_EM (CCR7⁻CD95⁺), and T_FH (CCR7⁻PD-1⁺ICOS⁺CTLA-4⁺CD95⁺) CD4⁺ T cells were flow cytometrically sorted from LNs of SIVsmmE543-infected RMs (■), SIVmac239-infected RMs (□), and SIVsmm-infected SMs (●), and infection levels of individual subsets were determined by quantitative PCR. Infection frequencies of individual subsets are compared between RMs and SMs (A). Infection frequencies of different subsets are compared within RMs (B) and SMs (C). Numbers of CD4⁺ T cells in each subset containing viral DNA per 1000 total LNMCs. Horizontal lines represent the median. P values are based on the Mann-Whitney test (A,D) or the Wilcoxon matched pairs test (B-C).