Blimp-1 KO CAR T cells display a memory-like phenotype. (A-B) Surface expression of CD127 (IL-7 receptor α-chain [IL-7Rα]) and CCR7 (A) or intracellular expression of TCF-7 (B) in CAR⁺ Mock and Blimp-1 KO CAR T cells. Representative histograms (left). Median fluorescence intensity (MFI) quantification (right). Fluorescence minus one (FMO) control in panel B shows Mock cells stained with all antibodies except TCF-7. (C) UT cells or Mock or Blimp-1 KO CAR T cells were cocultured with luciferase-expressing ARP-1 cells for 24 hours at effector-to-target (E:T) ratios ranging from 1:1 to 0.125:1. Displayed is the ARP-1 cell survival, as determined by bioluminescence, compared with ARP-1 cells cultured alone (n = 9). (D-G) Mock and Blimp-1 KO CAR T cells were cocultured with ARP-1 cells for 6 hours and production of effector molecules in CAR⁺ cells was assessed by flow cytometry. (D) Granzyme B expression in CD8⁺ cells, evaluated without (basal) and with (+ARP-1) ARP-1 cell stimulation. Representative histograms (left). Summary data showing fold change of MFI compared with basal Mock (right). FMO control represents Mock cells stained with all antibodies except granzyme B. (E) Production of TNF-α and IFN-γ in CD8⁺ cells. (F) Production of IL-2 in CD4⁺ and CD8⁺ cells. (G) Proportion of cells producing none (negative), 1 (single), 2 (double), or all 3 (triple) of the analyzed cytokines. Graphs show means ± SD for the panels A-B,D-G or mean ± standard error of the mean (SEM) for the panel C.