Figure 1.

Cytokine production by CD4⁺ and CD8⁺ T cells after polyclonal anti-CD3 stimulation. A, B, Frequency of functional memory CD4⁺ (A) and CD8⁺ (B) T cells from human immunodeficiency virus (HIV)–infected and HIV-uninfected participants that respond directly to anti-CD3 stimulation by simultaneously producing 2 antiviral cytokines, interferon (IFN) γ and tumor necrosis factor (TNF) α, as determined by intracellular cytokine staining and flow cytometry. The mean frequency of responsive T cells is plotted, with error bars representing 95% confidence intervals. C, D, Proportions of anti-CD3-responsive CD4⁺ (C) and CD8⁺ (D) T cells that produce both IFN-γ and TNF-α (IFN-γ ⁺TNF-α ⁺) or that produce only IFN-γ (IFN-γ ⁺TNF-α ⁻) or only TNF-α (IFN-γ ⁻TNF-α ⁺) after direct ex vivo stimulation with anti-CD3. All values are background subtracted (medium alone), and P values were determined by means of Wilcoxon signed rank test.