Addition of anti-PD-1 Ab to Lm-LLO-E7 enhances antigen-specific immune responses and increases the level of tumor-infiltrated CD8 T cell. C57BL/6 mice (n = 5 per group) were treated as on Figure 2A, except on day 21 after tumor implantation mice were sacrificed. A. IFNγ production in the presence or absence of E7 peptide was analyzed in single-cell suspension obtained from spleens. Values represent number of spots from E7-re-stimulated culture minus that from irrelevant antigen re-stimulated culture ± SD. B. The absolute numbers of infiltrated CD45+CD8+ T cells were standardized per 10e6 of total tumor cells and presented as mean values ± SD. *P < 0.05, **P < 0.01 and ***P < 0.001. Similar results were obtained from two independent experiments.