Figure 3.

CD32-expressing CD3⁺CD4⁺ cells differ in their expression of immune checkpoint receptors, the activation marker HLA-DR and HIV co-receptors, as well as their memory phenotype. Representative gating of CD32-expressing populations on CD4 T cells from an HIV⁺ individual is shown (top panel) in panel (A), relative to isotype control (bottom panel). CD32⁻, CD32^low, and CD32^highCD3⁺CD4⁺ T cell populations were compared with regards to their expression of programmed death receptor-1 (PD-1) (B), Tim-3 (C), TIGIT [(D); all n = 20], and HLA-DR [(F), n = 19]. For panel (F), four samples were excluded from the analysis of the CD32^high population because there were five or fewer events. These same populations were compared with regards to their memory phenotype. The percentage of each population composed of naïve (CD45RA⁺CCR7⁺), central memory (T_CM; CD45RA⁻CCR7⁺), transitional memory (T_TM; CD45RA⁻CCR7⁻CD27⁺), effector memory (T_EM; CD45RA⁻CCR7⁻CD27⁻), and T_EMRA cells (CD45RA⁺CCR7⁻) was quantified by flow cytometry and is shown in panel (E) (n = 20). The comparisons are all shown in HIV⁺ individuals at 1 year following the initiation of antiretroviral therapy. The expression of HIV co-entry receptors CCR5 [(G); n = 6] and CXCR4 [(H); n = 5] was compared between CD32⁻, CD32^low, and CD32^highCD3⁺CD4⁺ T cell populations in healthy individuals. Throughout, a Kruskal–Wallis test was used to compare all three groups; pairwise comparisons were performed on all combinations of groups only if the overall test p-value was < 0.05; ****p < 0.0001, ***p = 0.0001–0.001, **p = 0.001–0.01, *p = 0.01–0.05; for ease of interpretation if p ≥ 0.05 for any comparison this is not shown on these plots.