IL-4 production from non-αβ T cells in the absence of WASp. (A) Left panel shows intracellular staining for IL-4 from CD4⁻Gr1⁻FcϵR1α⁺ cells in peripheral blood after 6 hours of ionomycin stimulation, with brefeldin added for the final 4 hours of culture. Cells were gated on negative staining for CD19, CD4, and GR-1 from red cell–depleted peripheral blood. Representative plots are from 3 independent experiments. Numbers in quadrants equal the percentage of gated (isotype control for IL-4, 0.0048%). Right panel shows frequency of IL-4 producers within the FcϵR1α⁺ compartment. Mean ± SEM from 3 independent experiments. (B) Frequency and total number (×10⁴ per mouse) of IL-4 producers within the γδ T-cell compartment from LNs by intracellular staining after 6 hours of PMA/ionomycin stimulation as in panel A. Symbols represent individual mice from 2 independent experiments; P value by Mann-Whitney. Mean isotype control staining of activated cells is 1.460%. (C) Total serum IgE from 6- to 8-week-old mice was measured by ELISA. Symbols represent individual mice from 2 independent experiments. P values by Mann-Whitney. (D) Frequency and number of IL-4–producing γδ T cells from WAS^−/− TCR-Cα^−/− and WAS^+/+ TCR-Cα^−/− mice analyzed as in panel B. Symbols represent individual mice from 2 to 3 independent experiments.