Role of IL-12p70 (IL-12p35/IL-12p40) and IL-23 (p19/IL-12p40) in the Th1-driving ability of LPS-treated DCs.

Addition of 20 μg/mL neutralizing anti–IL-12p35 or anti–IL-12p40 mAb reduces substantially the ability of LPS-treated DCs to generate IFN-γ⁺ CD4⁺ T cells when a mixed population of naive and memory responder T cells was used in 3d-MLR. The partial Th1-inducing potential of control and anti-CD40–treated DCs was also reduced by anti–IL-12p35 or anti–IL-12p40 mAb treatment (not shown). Irrel indicates irrelevant. (B) Detection of IFN-γ, IL-4, and IL-10 in highly purified (C3H) splenic CD4⁺CD62L⁺CD44^low naive T cells (i) after in vitro stimulation with γ-irradiated allogeneic (B10) CD86⁺ control DCs (ii-iv) or LPS-treated DCs (v-vii) in a 3d-MLR. Anti-CD40–treated DCs showed similar results to control DCs (not shown). As controls, (C3H) naive T cells maintained for 3 to 4 days in low-dose rIL-2 (2 U/mL) were included (viii-x). After 3d MLR, the T cells were harvested and restimulated with anti-CD3ε + anti-CD28 mAbs in the presence of brefeldin A. Cells were labeled with Cy-Cychrome anti-CD3, FITC anti-CD4, and PE anti–IFN-γ, anti–IL-4, or anti–IL-10 mAbs. DCs were gated out according to their lack of expression of CD3. Figures in quadrants denote percentages. Data are representative of 3 separate experiments.