Mice treated with combined Trabectedin and α-PD-1 mAb developed a tumor antigen-specific CTL response. a Mice (6 mice per group) inoculated i.p. with 1 × 106 ID8 cells 10 day earlier were treated as described in Fig. 1a. Two weeks after treatment commencement, splenocytes from treated mice were cultured in the presence or absence of H-2Db-restricted mesothelin-derived peptides or control HPV-E7-derived peptide for 3 days and IFN-γ production in the supernatants were assayed by ELISA. b, c Splenocytes (5 × 106) from treated mice were incubated with 5 × 105 UV-irradiated ID8 cells for 4 days prior to subjected to analysis of antigen-specific CTL activity by CytoTox 96 Non-radioactive cytotoxicity assay using EL4 cells pulsed with H-2Db-restricted mesothelin (b) or HPV-E7 peptide (c) as target cells. d The killing activity of restimulated splenocytes from combination-treated mice was also evaluated in the presence of α-CD4, α-CD8 or control antibody. Data are expressed as M ± SEM of triplicate wells. *P < 0.05, **P < 0.01, ***P < 0.001.