PD-L knockdown DCs boost the proliferative capacity and function of MiHA-specific CD8⁺ memory T cells. Two days after electroporation with PD-L1 and/or PD-L2 siRNA, mature HLA-B7⁺LRH-1⁻ DCs were loaded with or without 5μM LRH-1 peptide. PD-L knockdown resulted in < 5% PD-L1⁺ and/or < 2% PD-L2⁺ DCs. (A) PBMCs of patient UPN389, consecutively stimulated with PD-L knockdown DCs at a ratio of 1:0.1, were weekly screened for tetramer⁺ CD8⁺ T cells using flow cytometry. The numbers in the FACS plots represent the percentage of LRH-1–specific CD8⁺ T cells in the total CD3⁺CD8⁺ T-cell population. Data are representative for 2 independent experiments. (B) Cumulative numbers of LRH-1–specific CD8⁺ T cells of patient UPN389 obtained after 3 consecutive stimulations with PD-L knockdown DCs loaded with or without LRH-1 peptide. (C) Percentage of LRH-1–specific CD8⁺ T cells in PBMCs of patient UPN543. PBMCs were consecutively stimulated with PD-L knockdown DCs at a ratio of 1:0.1 and weekly screened for tetramer⁺ CD8⁺ T cells using flow cytometry. (D) Cumulative numbers of LRH-1–specific CD8⁺ T cells of patient UPN543 obtained after 2 consecutive stimulations with PD-L knockdown DCs loaded with or without LRH-1 peptide. (E) Degranulation of LRH-1–specific CD8⁺ T cells of patient UPN389, stimulated for 2 weeks with LRH-1 peptide-loaded PD-L knockdown DC, was measured by staining for CD107a during overnight stimulation with different target cells. PBMCs were cultured 1:1 with LRH-1⁻ donor EBV-LCL, LRH-1 peptide-loaded donor EBV-LCL, LRH-1⁺ recipient EBV-LCL, or in medium. ND indicates not determined.