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

(A-C) 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. (D-E) Peripheral blood was collected from healthy uninfected volunteers and (D) IFN-γ and (E) 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; *, p < 0.05, **, p < 0.01; ***, p < 0.001; ****, p < 0.0001.