Fig. 3
Polyepitope E0771 neoantigen DNA vaccines combined with anti-PD-L1 immunotherapy suppressed tumor growth in vivo. a Scheduling of DNA vaccination and anti-PD-L1 treatment. Wildtype female C57BL/6 mice (n = 15 per group) were vaccinated by gene gun on days − 4, − 1, and 2 and challenged with 106 E0771 cells on day 0. Anti-PD-L1 or control antibodies were administered every 3–4 days. b Tumors were measured with electronic calipers of the longest (L) and perpendicular (W) diagonals. Tumor sizes (mean ± SEM) were calculated as (L × W2)/2. Results from one of the three independent experiments were shown. c In a parallel experiment, tumors were harvested and dissociated to prepare single cell suspension on day 14. TILs were analyzed by Lrrc27/Db dextramer staining and flow cytometry. P = 0.0381, one-way ANOVA. d Tumor-draining lymph nodes (LN) were harvested on day 14. LN cells were used in an IFN-γ ELISpot assay and stimulated with selected MT peptides (8- to 10-mer). e Spleen cells were harvested from treated tumor-bearing mice on day 26 and used in an IFN-γ ELISpot assay. The studies were repeated once and similar results were obtained. Error bars, SEM. *P < 0.05, **P < 0.01, ***P < 0.001, t-test