HSV-pDCs and IL-3–pDCs induce granzymes and perforin in CD4⁺ T cells in a partially IL-10–dependent manner. Naive CD4⁺ T cells were stimulated with allogeneic HSV-pDCs or IL-3–pDCs for 8 days in the presence of isotype-matched control mAb, anti-IFN-α/β receptor mAb, or anti-IL-10 mAb. Alternatively, T cells were stimulated with allogeneic GM-CSF–mDCs for comparison. Activated T cells were gated based on the expression of CD25, and expression of intracellular granzyme A, granzyme B, and perforin was analyzed by flow cytometry. (A) Histograms. Open histograms represent cells stained with isotype-matched control mAbs. (B) Percentages of cells expressing the 3 molecules, indicated with markers in panel A. The data shown are representative of 3 experiments.