The effect of in vivo IL-4C pretreatment on DC ability to induce NKT cell cytokine productions. DCs prepared from the splenocytes of IL-4C-pretreated or untreated mice (IL-4C DCs or cont. DCs) were mixed with DC-depleted splenocytes (SP) derived from IL-4C-pretreated or untreated mice (IL-4C SP or cont. SP). The mixed cells were stimulated with various concentrations of α-GalCer. IFN-γ and IL-4 production in the culture was measured by ELISA. Each column represents the mean ± SE of triplicate wells. The analysis was repeated twice with similar results. • indicates cont. SP + cont. DC; ▴, cont. SP + IL-4C DC; ▪, cont. SP; and ♦, cont. DC. ○ indicates IL-4C SP + cont. DC; ▵, IL-4C SP + IL-4C DC; □, IL-4C SP; and ⋄, IL-4C DC.