FIG. 6.

NO production by macrophages. Macrophages were infected with stationary-phase L. major promastigotes for 24 h. Cells were then washed and incubated for 48 h further with the compounds in the absence or presence of IFN-γ or LPS. Thereafter, the culture supernatants were collected for determination of the nitrite concentrations. (Upper panel) Micromolar concentrations of NO₂⁻ in the supernatants of noninfected macrophages cultured in the presence of compound 13b (40 μM) or compound 13e (40 μM), in the absence or presence of IFN-γ (100 U ml⁻¹) or LPS (15 μg ml⁻¹). (Lower panel) Change (n-fold) (infected/noninfected) of NO levels in supernatants of infected macrophages cultured in the presence of compound 13b or compound 13e, in the absence or presence of IFN-γ or LPS. The horizontal lines indicate changes in NO production induced by IFN-γ or LPS alone. A ratio of 1 means no change. Indicated comparisons 1 and 2, P < 0.005; indicated comparisons 3 and 4, P < 0.05.