H-ras and N-ras deficiency impair TCR-induced IFN-γ expression in CD4⁺ T cells. (A) Splenic T cells from mice of the indicated genotype were stimulated without or with anti-CD3 or anti-CD3 plus anti-CD28 mAb during 48 hours for analysis of intracellular IFN-γ and IL-4 expression in gated CD4⁺ T cells. Numbers within dot plots indicate percentage of cells in the gated regions. (B) Splenic T cells from mice of the indicated genotype were stimulated for 48 hours with anti-CD3 plus anti-CD28 in the absence or presence of either IL-12 (1 ng/mL), CpG-ODN (25 μg/mL), or IL-4 (100 ng/mL) plus anti–IFN-γ antibody (3 μg/mL) and analyzed for intracellular IFN-γ and IL-4 expression in gated CD4⁺ T cells by flow cytometry. Numbers within dot plots indicate percentage of cells in the gated regions.