TABLE 2.

Effect of NMMA on cytokine inhibition of T. gondii growth in murine astrocytes

Treatment	Inhibition of T. gondii growth (% of control)a
	Medium only	Cytokines + NMMA
IFN-γ, IL-1	22.4 ± 3.1	24.7 ± 1.1
IFN-γ, IL-6	20.4 ± 2.3	21.0 ± 0.8
IFN-γ, IL-1, IL-6	18.2 ± 1.5	15.2 ± 4.1
IFN-γ, TNF-α	23.3 ± 3.7	16.6 ± 2.5
IFN-γ, TNF-α, IL-6	14.3 ± 2.9	16.8 ± 2.5

^aMean ± standard deviation of three separate experiments for astrocyte cultures treated with IFN-γ (100 U/ml), IL-1 (1 ng/ml), IL-6 (100 U/ml), and TNF-α (100 U/ml), in the presence or absence of NMMA (400 μM), and for control cultures incubated in medium alone. Cells were incubated with cytokines for 72 h prior to infection, and NMMA was added at the time of cytokine addition; [³H]uracil (2.5 μCi/ml) was added 2 h after infection, and cells were harvested 48 h later. No endotoxin contamination was detected in any of the cultures.