Fig. 2

PD-1 knockdown did not enhance the cytotoxicity of CAR-T cells, but instead impaired it. a A549–19 and Raji cells both stimulated the expression of IFN-γ in CAR-T cells, and the expression of IFN-γ was impaired by PD-1 knockdown. b SCR-CART19 cells presented a higher positive rate of TCIIR induced CD107a expression. High expression of PD-L1 almost completely inhibited the CD107a expression. c PD-1 blockade promoted the secretion of IL-2 but not the other tested cytokines, however, better resistance to PD-L1-mediated immunosuppression was clearly indicated. d-f Lysis of Raji-luc cells (d), IFN-γ stimulated A549–19luc cells (e) and A549–19luc cells (f) at different E:T ratios were measured by luminescence. PD-1 knockdown impaired the lysis ability on Raji cells at low E:T ratios. **P < 0.01. Statistical significance was determined using the ANOVA method for multiple comparisons. Data represent the mean ± SEM of triplicates and are representative of at least 3 independent experiments or are plotted as individual points