Fig. 4.

Anti-PD-1 enhances cytotoxicity of T cells from tumour-bearing mice. Spleen cells from CT26 tumour-bearing mice were co-cultured with CTV-labelled CT26 tumour cells at the indicated E:T ratios for 24 h in the presence or absence of anti-PD-1. a Cell death was measured by 7-AAD staining and flow cytometry, gating on CTV⁺ cells. b IFN-γ and TNF concentrations in co-culture supernatants were quantified by ELISA. **P < 0.01, ***P < 0.001 by ANOVA. n = 4 mice per group