FIG 6.

iNOS inhibitor prevents GRA15-dependent production of NO and reduction of IDO1 proteins. (A to C) THP-1 cells were infected with Pru T. gondii. The infected THP-1 cells were cocultured with Huh7 cells and then left untreated or treated with IFN-γ and/or aminoguanidine. (A) The levels of NO₂ released into the culture supernatant were measured by ELISA. (B) Expression of indicated proteins in the cell lysates was detected by Western blotting. (C) The parasite survival rates were measured by luciferase assay. (D and E) WT or IDO1-KO Huh7 cells were left untreated or treated with the indicated cytokines and/or aminoguanidine and infected with Pru T. gondii. (D) Levels of NO₂ released into the culture supernatant were measured by ELISA. (E) The parasite survival rates were measured by luciferase assay. The Western blot image is representative of three independent experiments (B). Indicated values represent means ± SD (three biological replicates per group from three independent experiments) (A, C, D, and E). ***, P < 0.001; **, P < 0.01; N.S., not significant (Student's t test).