Effects of cytokines in the activation of peritoneal macrophages from mice infected with Toxoplasma gondii.

The present study was undertaken to assess the role of cytokines in the activation of peritoneal macrophages from Toxoplasma-infected mice. Peritoneal macrophages from Toxoplasma-infected mice (10 cysts of Beverley strain/mouse) were harvested 8 weeks after infection, and incubated with the mitogen-induced lymphokine, recombinant mouse interferon-gamma (IFN-gamma), recombinant mouse tumor necrosis factor-alpha (TNF-alpha) alone or in combination with IFN-gamma (IFN-gamma/TNF-alpha) for 24 hr at 37 degrees C, 5% CO2. Macrophage activation was measured by the amount of H2O2 and NO2- production, and anti-Toxoplasma activities of macrophages. IFN-gamma or IFN-gamma/TNF-alpha-treated macrophages from Toxoplasma-infected mice revealed significantly higher H2O2 production than resident macrophages from Toxoplasma-infected mice. The production of NO2- by TNF-alpha-, IFN-gamma- or IFN-gamma/TNF-alpha-treated macrophages from Toxoplasma-infected mice were significantly higher than that by resident macrophages, whereas lymphokine-treated group produced similar amount as that produced by resident macrophages. Anti-Toxoplasma activities of cytokine-treated macrophages from Toxoplasma-infected mice were significantly higher than those of resident macrophages. IFN-gamma-treated macrophages were significantly increased production of H2O2 and NO2-, and anti-Toxoplasma activities of macrophages between normal and Toxoplasma-infected mice, whereas the other cytokine-treated groups were not significant differences between them. These data suggested that IFN-gamma was the only one of cytokines capable of significantly activating the peritoneal macrophages from Toxoplasma-infected mice.