Fig. 5

Cytotoxic capacity of CAR-NK cells co-expressing IL-21. A Cytotoxicity of NT, CAR, CAR-15 and CAR-21 NK cells against CD19⁺ Raji and CD19⁻ K562 targets expressing firefly luciferase at different effector-to-target (E: T) ratio, as measured by luciferase-based cytotoxicity assay (n = 4 donors). The bars represent mean values with standard error. B The schematic of the repetitive tumor stimulation experiment. C Testing for killing effect on Raji-GL cells in repetitive co-culturing experiment by flow cytometric cytotoxicity assay (n = 3 donors). D The PD-1, Tim-3, and LAG-3 expression of NT, CAR, CAR-15 and CAR-21 NK cells after three rounds of co-culturing with Raji cells in the absence of IL-2 was measured by flow cytometry (n = 4 donors).