CD38⁺ CD4⁺ T cells are poor producers of IFN-γ following <i>in vitro</i> stimulation.

<p><b>(A-C)</b> Peripheral blood was collected prior to and seven days post-infection and CD38^- (black) and CD38⁺ (red) CD4⁺ T cells isolated using cell sorting. Intracellular IFN-γ production after brief mitogenic stimulation with PMA and Ionomycin was measured at the protein level using flow cytometry. <b>(D-E)</b> Peripheral blood was collected from healthy uninfected volunteers and <b>(D)</b> IFN-γ and <b>(E)</b> IL-2, TNF, IL-4, IL-10 and IL-17 gene expression after brief mitogenic stimulation with PMA and Ionomycin was measured by RT-qPCR. Gene expression was normalized to reference gene RPL13A. Graphs show combined data from (A-C) four to seven volunteers from one cohort and (D-E) 12 healthy volunteers; statistical differences between CD38⁺ and CD38^- CD4⁺ T cells and between prior to and seven days post infection were determined using the non-parametric Wilcoxon test; box and whisker plots indicate median, interquartile range and min-max; *, <i>p</i> < 0.05, **, <i>p</i> < 0.01; ***, <i>p</i> < 0.001; ****, <i>p</i> < 0.0001.