FIG 1.

CD161⁺ CD4⁺ T cells are highly permissive for HIV-1 infection. (A) Percentage of CD161-positive subsets among CD4⁺ T cells in blood or lymph node. HIV-1⁻, results for samples from 15 HIV-seronegative donors; HIV-1⁺ W/O ART, results for samples from 18 viremic patients not on ART; HIV-1⁺ W/ ART, results for samples from 16 HIV-1-infected subjects with an undetectable plasma viral load on ART and CD4 cell counts above 450 per μl; LN HIV-1⁻, lymph node tissue samples from 6 HIV-1-negative individuals. (B) Percentage of CD161-positive subsets in CD4⁺ T cells from the beginning of ART to 12 months after the start of treatment (n = 13). (C) Expression level of CD161 on sorted CD161-positive or -negative CD4⁺ T cells from healthy donors (n = 4) under different treatment conditions for 12 days. (D) Frequency of cells expressing CXCR4 (left) and CCR5 (right) within CD161-positive and negative CD4⁺ T cell subsets. (E and F) Infectivity of X4- or R5-tropic HIV-1 for bulk, CD161⁺, or CD161⁻ CD4⁺ T cells. Subsets from HIV-negative subjects were sorted and then exposed directly (without prestimulation) to R5-tropic NL4-3 (BaL env) (n = 6) or X4-tropic NL4-3 (n = 11) or were first prestimulated via anti-CD3/CD28 for 3 days and then exposed to NL4-3 (BaL env) (n = 4) or NL4-3 (n = 6). Intracellular HIV-1 p24 levels were quantified by FACS (E) at the indicated time points postinfection (F). FSC-A, forward scatter area. Significant intergroup differences were determined using the rank Kruskal-Wallis test incorporating Dunn’s tests for multiple comparisons. The Mann-Whitney U test or Student's t test was used to compare the statistical significance between cell subsets. P values less than 0.05 were considered significant. *, P < 0.05; **, P < 0.01; ***, P < 0.001.