FIG 1.

Functional composition of Env-specific CD4⁺ T and pTfh cell responses present in the periphery of chronically HIV-1-infected untreated individuals. (a) Gating strategy used to determine functions of memory CD4⁺ T cells and pTfh cells. (b and c) Frequencies of CD45RO⁺ CD4⁺ T cells (b) and CD45RO⁺ CXCR5⁺ CD4⁺ T cells (c) producing CD40L, IFN-γ, IL-4/13, or IL-21 in response to overlapping peptides spanning the Env protein. The frequencies are expressed as a percentage of the parent population. Asterisks indicate the level of significance according to Friedman’s test with Dunn’s post hoc test for multiple comparisons. (d) Pie charts demonstrate the composition of Env-responding pTfh and CD4⁺ T cells based on the cosecretion of the four measured proteins. Each slice represents a distinct subset, while arcs surrounding the pie chart indicate which subsets express a certain protein. Differences between the pie charts were assessed by the permutation test. (e) Shown is the mean frequency of subsets based on (co)expression of CD40L, IFN-γ, IL-4/13, and IL-21 in the two cell populations; Env-specific pTfh cells and Env-specific memory CD4⁺ T cells. The frequency is expressed as a percentage of all cells responding to the Env protein. Statistical significance was assessed by the Wilcoxon rank sum test. Shown is the average of eight independent experiments.