Cytokine regulation of macrophage-mediated L. pifanoi killing. Shown are the results of macrophage-Leishmania killing assays. Isolated T cells from either P. acnes-vaccinated or P-4 plus P. acnes-vaccinated BALB/c mice were incubated together with L. pifanoi-infected peritoneal exudate macrophages. Antibodies (anti-IFN-γ, anti-TNF-α/LT, and/or anti-MIF) were added to the cultures, as indicated, to a final concentration of 10 μg/ml for each antibody. After 72 h, macrophages were washed, dried, fixed with methanol, and stained with 4′,6′-diamidino-2-phenylindole. The number of parasites per 100 macrophages and the percentage of infected macrophages were determined microscopically. Results are the averaged values of three independent experiments. Student t test: **, P ≤ 0.01; *, P ≤ 0.05 (compared to T cells from P-4-vaccinated mice); in A, P = 0.5, and in B, P = 0.1, when adjuvant control is compared with combination of anti-IFN-γ, anti-TNF-α/LT, and anti-MIF.