CD4+ T cells from WT and H1-4RKO mice were activated with anti-CD3 and anti-CD28 mAbs in the presence or absence of picrotoxin and (A) IL-2, (B) IFN-γ, and (C) IL-4 production 72 h post stimulation was determined by ELISA and shown as mean ± SEM of n = 5 per strain. In (A, B, and C), significance of differences in cytokine production was determined by two-way ANOVA followed by Bonferroni post-hoc multiple comparison test (**, p<0.01; ****, p<0.0001).