In vitro HIV infection of pathogen-specific CD4 T cells in PBMCs. (A,C) Representative flow cytometric plots are shown for intracellular p24 expression in CFSE_low population of CD3⁺CD4 T cells in antigen-stimulated PBMCs with (top) or without (bottom) infection by R5-HIV (A) or X4-HIV (C). Only live CD14-19⁻CD3⁺CD8⁻ T cells were gated for analysis. The data are expressed as a proportion of intracellular p24⁺ cells in the CFSE_low population. (B,D) Comparison of the proportion of p24⁺CFSE_low cells between CMV-, TT-, and C albicans–specific CD4 T cells from multiple subjects are shown as a box and Whisker plots in B (R5 HIV) and D (X4 HIV). (E-F) Relative quantification of infectious R5 HIV (E) or X4 HIV (F) viruses produced by pathogen-specific CD4 T cells in supernatants. Quantification was based on infection of TZM-bl cells and the data are expressed as relative light units (RLU). A total of 6 donors and at least 6 independent experiments were performed. Statistical analysis was performed using the Mann-Whitney test. *** P < .005; **P < .01; *P < .05.