Figure 7.

CD 40 promotes early and late production of TNF-α and IFN- γ by lung leukocytes in mice with persistent cryptococcal lung infection. Lung leukocytes isolated from CD40^+/+ mice and CD40^−/− mice at 2 and 5 weeks postintratracheal infection with 10⁴ C. neoformans were cultured overnight in vitro at 5 × 10⁶ cells/ml without additional stimulus. Culture supernatants were analyzed for TNF-α (A), IFN- γ (B), IL-4 (C), or IL-5 (D) by ELISA as described in Materials and Methods. Data were pooled from two separate matched experiments and are expressed as the mean cytokine concentration (nanograms per milliliter) ± SEM; n = 8–9 mice per strain at each time point; *P < 0.05 for comparison between CD40^+/+ mice (black bars) versus CD40^−/− mice (gray bars).