Figure 1

Synergistic effect of IL-12 and IL-18 on IFN-γ production by peripheral blood mononuclear cells (PBMCs) from healthy donors and its modulation by IL-18-binding protein (IL-18BP). PBMCs (1 × 10⁶/ml in RPMI 1640 medium with 10% fetal calf serum) were cultured in triplicate for IFN-γ production with or without IL-12, IL-18, the combination of IL-12 and IL-18, or the combination of IL-12, IL-18, and IL-18BP. (a) PBMCs were cultured for 7 days with 1 ng/ml of IL-12, and various concentrations of IL-18. (b) PBMCs were cultured for 7 days with the combination of IL-12 and IL-18. (c) PBMCs were cultured for 7 days with 1 ng/ml of IL-12 and 5 ng/ml of IL-18, with or without various concentrations of IL-18BP. (d) PBMCs were cultured for 3 days (white bars), 5 days (gray bars), or 7 days (black bars) with or without IL-12 (1 ng/ml) or IL-12 (1 ng/ml) + IL-18 (5 ng/ml). Bars show mean values ± SEM of triplicate cultures.