Phenotype of LN-resident CD4⁺ T-cell subsets of RMs and SMs. Frequencies of T_FH (CCR7⁻PD-1⁺ICOS⁺CTLA-4⁺CD95⁺) CD4⁺ T cells among memory (CD28^brightCD95⁺) T cells was determined in SIV-uninfected RMs (▵), SIVsmmE543-infected RMs (■), SIVmac239-infected RMs (□), SIV-uninfected SMs (○), and SIVsmm-infected SMs (●) by flow cytometry (A). Expression of Ki-67 (B) and CCR5 (C) by subsets of LN CD4⁺ T cells. Horizontal lines represent the median. P values are based on the Mann-Whitney test.