Fig. 3

IDO1 suppresses the CD8⁺ T cell response in subcutaneous tumor tissue. a Immunohistochemical staining for IDO1, CD8 and NCR1 in sections of mouse tumor tissues from the pLenti-IDO1 group and the pLenti-Vector group. Top, representative pictures; bottom, quantitative data. Data represent the relative percentage of IDO1⁺, CD8⁺ and NCR1⁺ cells in the pLenti-IDO1 group to that in the pLenti-Vector group. Scale bars: 20 μm. b Representative pictures of immunofluorescent staining for IDO1 expression tumor cells and infiltrating CD8⁺ lymphocytes in sections of mouse tumor tissues from the pLenti-IDO1 group and the pLenti-Vector group. Blue, DAPI staining; red, IDO1 staining; green, CD8 staining. Scale bars: 20 μm. c FACS analysis of CD8⁺ T cells and CD4⁺ T cells in CD45⁺ cells of mice tumor tissues in the pLenti-IDO1 group and pLenti-Vector group. Left, representative pictures; right, quantitative data. a Mean ± SEM; c mean ± SD. a-c n = 5. a, c Two-tailed Student’s t-test was performed for statistical analysis; *P < 0.05, ***P < 0.001, NS: not significant