Figure 3.

PD-1 inhibition enhances antitumor efficiency and proliferation capacity of BCMA CAR-T cells. (A) In vitro cytotoxicity of BCMA CAR-T or PD-1^KD BCMA CAR-T cells against 8226 cells, MM.1S cells (B), BCMA overexpressing K562 cells (C) and PD-L1/BCMA overexpressing K562 cells (D) was determined by a luciferase-based cytotoxicity assay. E/T ratio, effector/target ratio (n=3 independent healthy donors). (E) Cytokines in the supernatant after coculture with PD-L1/BCMA overexpressing K562 cells for 24 hours. GSEA of the genes associated with (F) the positive regulation of cytokines is listed in online supplemental table 1, and (G) the genes related to the proliferation of T cells are listed in online supplemental table 2. The genes from the left to the right of the rank-ordered list are enriched in PD-1^KD BCMA CAR-T cells and BCMA CAR-T cells. (H) Cell proliferation was compared among non-CAR T cells, PD-1^KD BCMA CAR-T cells and BCMA CAR-T cells on stimulation with one dose of antigen. (I) Analysis of apoptotic PD-1^KD BCMA CAR-T cells and BCMA CAR-T cells on day 5 after one dose of antigen stimulation. BCMA, B cell maturation antigen; FDR, false discovery rate; GSEA, gene set enrichment analysis; NES, normalized enrichment score.