FIG. 3.

Detection of IFN-γ and IL-4 in lymph node cells of gld TNF^−/− mice 6 weeks after infection with L. major. Cells were isolated from popliteal lymph nodes of gld TNF^−/− mice 6 weeks after infection with 3 × 10⁶ stationary-phase L. major promastigotes. As controls, cells were taken from the popliteal lymph nodes of similarly infected C57BL/6, gld, TNF^−/−, and BALB/c mice. (A) Cells (5 × 10⁵) from mice in each group (six mice per group) were pooled and stimulated in vitro with (Lm) or without (0) 10⁶ UV-irradiated L. major promastigotes for 72 h. IFN-γ production was evaluated in the supernatant as described in Materials and Methods. The data are representative of three different experiments; means and standard deviations of triplicate measurements are given. (B) Frequencies of IFN-γ⁺ CD4⁺ popliteal lymph node T cells 6 weeks after infection with L. major. gld TNF^−/−, TNF^−/−, gld, and C57BL/6 mice were infected subcutaneously with 3 × 10⁶ stationary-phase L. major promastigotes. After 6 weeks, the draining popliteal lymph nodes from each group of mice were removed and pooled, and cell suspensions were prepared. Intracellular staining of CD4⁺ T cells was performed as described in Materials and Methods. The data are representative of three independent experiments.