p110δ inhibitors block proliferation and cytokine production by naive and effector/memory CD4⁺ T cells. CD4⁺CD45RA⁺ (left column) and CD4⁺CD45RO⁺ (right column) T cells were stimulated with anti-CD3 in the presence of DMSO alone, IC, or LY. At 48 hours, CD69 expression (A-B), proliferation (C-D), IFN-γ (E-F), and IL-17 (G-H) production were measured. (A-B) Data are representative of one of 3 donors. (C-H) Each dot represents an individual donor. To calculate P values, Student t test was used to compare DMSO alone with LY, and 1-way repeated measures analysis of variance was used to compare DMSO alone with IC. *.01 < P < .05; **.001 < P < .01; ***P < .001. Percentage inhibition was calculated for each donor to determine the range of sensitivity in the population, and median values are shown below the graph. (I-F) T cells were stimulated for 16 hours with anti-CD3 and anti-CD28 in the presence of DMSO alone, IC, or LY, and IL-2 (I) or IFN-γ (J) production was measured. Data are mean ± SEM of triplicate readings and are representative of 1 of 3 donors.