Figure 4.

Programmed death ligand‐1 (PD‐L1) blockade augments ARNAX‐induced antigen‐specific CTL expansion in the priming phase. A, B, Tumor‐free mice were s.c. given ovalbumin (OVA) or 60 μg ARNAX‐140 + OVA on day 0. Isotype control or anti‐PD‐L1 Ab was given ip on days 0, 2, 4 and 6. On day 7, spleens were harvested. A, OVA‐specific CD8⁺ T‐cell proliferation in the spleen was evaluated with the tetramer assay. Student's t test was carried out to analyze statistical significance between ARNAX + OVA_Isotype group and ARNAX + OVA_anti‐PD‐L1 Ab group; *P < .05. B, Splenocytes were cultured in the presence of 100 nmol/L SL8 peptide for 3 d. Interferon (IFN)‐γ concentrations in the culture media were measured using the Cytometric Bead Array. Error bars indicate means ± SD; n = 2‐3 per group. Student's t test was carried out to analyze statistical significance between the ARNAX + OVA_Isotype and ARNAX + OVA_anti‐PD‐L1 Ab groups