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. 2018 Sep 19;9:2073. doi: 10.3389/fimmu.2018.02073

Figure 2.

Figure 2

IDO1 but not IDO2 has a critical role in anti-T. gondii response in HAP1 cells. (A) WT, IDO1-KO, IDO2-KO, or IDO1/IDO2-DKO HAP1 cells were stimulated with IFN-γ for 24 h, and then lysates were detected by Western blot. (B) Quantitative RT-PCR analysis of IDO2 mRNA level in IDO1-KO, IDO2-KO, or IDO1/IDO2-DKO HAP1 cells that were untreated or treated with IFN-γ for 24 h was performed. (C) WT, IDO1-KO, IDO2-KO, or IDO1/IDO2-DKO HAP1 cells were untreated or treated with IFN-γ for 24 h, and then infected with T. gondii. The parasite survival rate after 24 h post infection was measured by luciferase assay. (D) WT, IDO1-KO, IDO1-KO+empty, or IDO1-KO+IDO1 HAP1 cells were untreated or treated with IFN-γ for 24 h, and then infected with T. gondii. The parasite survival rate after 24 h post infection was measured by luciferase assay. (E) Fluorescence confocal microscopy of WT and IDO1-KO HAP1 cells stimulated by IFN-γ for 24 h, subsequently infected with T. gondii for 3 or 24 h, and immunostained for ACTIN (red) and T. gondii GAP45 (green). The nucleus was stained with DAPI (blue). Arrow heads show vacuoles containing 2 or more parasites. Scale bars correspond to 5 μm. (F,G) WT or IDO1-KO HAP1 cells were stimulated with IFN-γ for 24 h, and then infected with T. gondii. The parasite number per vacuole after 24 h post infection (F) or the parasite infection rate after 3 or 24 h post infection (G) was measured by IFA. Western blot and immunofluorescence images are representative of three independent experiments (A,E). Indicated values are means of ± s.d. (three biological replicates per group from three independent experiments) (B,C,D,F,G). ***p < 0.001, **p < 0.01; N.S., not significant; (Student's t-test). N.D., not detected.