Figure 2.

Endogenously produced IL-12 and CD40/CD40L interaction during coculture of DCs and NKT cells is essential for NKT cell activation by α-GalCer. Purified NKT cells were cocultured with DCs in the presence of α-GalCer for 36 h. The IFN-γ levels in culture supernatants were then determined by ELISA. (A) The ability of anti–IL-12 mAb to block NKT cell activation by α-GalCer. Anti-CD8 mAb was used as control rat IgG Ab. (B) The ability of anti-CD40 mAb and anti-CD40L mAb to block NKT cell activation by α-GalCer. As a control, rat anti-CD8 IgG mAb was added to the culture. (C) IL-12 production by DCs cultured with α-GalCer and NKT cells. DCs (5 × 10⁵) were activated with 50 ng/ml of α-GalCer for 8 h in the presence or absence of NK1.1⁺TCR-α/β⁻ NK cells (10⁵) or NK1.1⁺TCR-α/β⁺ NKT cells (10⁵). The bars represent mean ± SE of triplicate samples.