FIG. 4.

Expression of IFN-γ mRNA in brains of T. gondii-infected, sulfadiazine-treated IFN-γ^−/− and nude mice after adoptive transfer of immune spleen cells. Mice were infected with 10 cysts of the ME49 strain perorally and treated with sulfadiazine for 3 weeks beginning 4 days (IFN-γ^−/−) or 7 days (nude) after infection. Nine and 2 days before discontinuation of sulfadiazine treatment, mice received an intravenous injection of 2 × 10⁷ immune spleen cells from infected, control BALB/c mice (see Materials and Methods). At 5 days after discontinuation of sulfadiazine, the brains were analyzed for amounts of β-actin and IFN-γ mRNAs (see Materials and Methods). NC, negative control; PC, positive control. There were four mice in each experimental group.