Figure 3.

IDO1 can inhibit MSLN-CAR-T cell function via its metabolite kynurenine. (A, B) MSLN-CAR-T cells were cultured in the absence or presence of KYN (50 μM) with IL-2 (50 U/mL) for 24 h. TIM3, PD-1, IFN-γ, and IL-2 were then detected via flow cytometry. (C) CAR-T cells treated with different concentrations of KYN were cocultured with tumor cells, to test CAR-T-mediated killing of tumor cells. Tumor cell apoptosis was determined via annexin V/PI staining. (D) CAR-T cell CD107 expression was detected via staining with anti‐CD107a antibody or isotype control antibody, and was analyzed using flow cytometry. *P < 0.05, **P < 0.01, ***P < 0.001 (repeated-measures one-way ANOVA or Student’s t-test).