Expansion and function of MiHA-specific CTL RP1 is augmented by PD-L knockdown DCs. Two days after electroporation with PD-L1 and/or PD-L2 siRNA, mature HLA-B7⁺ DCs were loaded with or without 10μM LRH-1 peptide and cocultured with MiHA-specific CTL RP1 at a stimulation ratio of 1:1. PD-L knockdown resulted in < 20% PD-L1⁺ and/or < 1% PD-L2⁺ DC. (A) After 4 days, proliferation was determined following overnight [³H]-thymidine incorporation. Data of 1 of 2 independent experiments are shown, and bars are depicted as mean ± SD. CPM = counts per minute. (B) IFN-γ and (C) granzyme B levels were measured in CTL RP1 supernatant obtained at day 1 of coculture. Statistical analysis was performed using one-way ANOVA, followed by a Bonferroni post-hoc test. *P < .05, ***P < .001.