LAG-3 expression is reduced on Blimp-1 KO anti-BCMA CAR T cells. (A) Schematic of cell culture protocol for production of Mock and Blimp-1 KO CAR T cells. (B-C) Blimp-1 deletion efficiency in KO CAR T cells when electroporated with 1 of 2 different Prdm1-targeting guide RNAs (sgRNA1 or sgRNA2). Displayed as Inference of CRISPR Edits analysis to calculate percentage of cells containing Blimp-1 indels (B) and abundance of Blimp-1 protein as measured by western blotting (C). (D) CAR T-cell growth from day 1 after CD3/CD28-mediated stimulation, based on daily cell counts and displayed as the cumulative number of population doublings (n = 6). Arrow indicates day of electroporation. (E-G) Expression of inhibitory receptors lymphocyte activation gene-3 (LAG-3), programmed cell death protein-1 (PD-1), T cell immunoreceptor with Ig and ITIM domains (TIGIT) and T cell immunoglobulin and mucin-domain containing-3 (TIM-3) (E), killer cell lectin-like receptor subfamily G member-1 (KLRG-1) (F), or activation markers CD25 and CD71 (G) on CD8⁺ CAR⁺ Mock and Blimp-1 KO CAR T cells, representative of 4 (F) or 7 (E,G) experiments. Graphs show means ± standard deviation (SD).