IL-12/Stat4 signals are differentially regulated in CD8 and CD4 T cells. (A) Western blotting for Stat4 activation in CD4 and CD8 T cells. BALB/c CD4 and CD8 T cells were stimulated with IL-12 for 15 minutes, without anti-CD3 plus anti-CD28 mAb stimulation, or stimulated with IL-12 in combination with anti-CD3 plus anti-CD28 mAbs for 3 hours or 24 hours. (B) Real-time RT-PCR for IL-12Rβ2 expression. CD4 or CD8 T cells were stimulated with anti-CD3 plus anti-CD28 mAbs, with or without IL-12 or IFNγ for 3 or 24 hours. Data shown are one representative of 3 independent experiments; standard errors of PCR triplicates are shown.