Figure 6. Administration of anti-PD-L1 antibody significantly improves the therapeutic efficacy of vaccination plus IR.

(A) Scheme of the design of treatments strategies. IR: tumor-bearing mice received the first dose of local IR (20 Gy) when the tumor was established (Day 0), and the second dose of IR (15 Gy) on Day 7. Vacc: tumor-bearing mice received vaccination of 2 × 10⁶ MC57-SIY cells on the same day of IR (first dose). Subsequently, mice received 2 subcutaneous doses of boosted vaccine (10 μg SIY peptide plus 20 μg poly I: C for each dose) on Day 7 and Day 21. For PD-L1 blockade, mice received 200 μg/mice anti-PD-L1 antibody i.p. twice a week till Day 21. (B) Tumor growth curve of Panc02-SIY fragment tumors which were untreated or received indicated treatments. Error bars are mean ± S.E.M. **P < 0.01, compared with each of other four groups (Two-way ANOVA). (C) Overall survival analysis of Panc02-SIY fragment tumor-bearing mice receiving indicated treatments. *P < 0.05, **P < 0.01, Mantel-Cox test. (D) Panc02-SIY fragment-bearing mice received indicated treatments. 14 days post first dose of local IR, mice were sacrificed for flow cytometric analysis of IFNγ-producing CD8⁺ cells.