Fig. 3

Effect of IL-15 cytokine stimulation on CD70-CAR NK cell functionality. A Percentage viable CD70⁺ target cells after a 4 h co-culture with unstimulated CD70-CAR NK cells or stimulated overnight with IL-2, IL-7, IL-12, IL-15, or IL-18 cytokines (n = 4). B Percentage viable CD70⁺ target cells after a 4 h co-culture with CD70-CAR NK cells stimulated overnight with IL-2 or IL-15 (n = 4). C Percentage viable LIM2099 cells after a 4 h co-culture with unstimulated MOCK or CD70-CAR NK cells or stimulated overnight with IL-15 (n = 5). D Quantification of CD27⁺ cells and intensity of CD27 expression (ΔMFI), 24 h after electroporation on CD70-CAR NK cells or MOCK cells cultured overnight with or without IL-15 (n = 5). E Structural design of CD70-CAR and CD70-CAR-IL-15 constructs. F Representative histograms and quantification of surface CD27 expression on MOCK NK cells (black), CD70-CAR NK cells (blue) and CD70-CAR-IL-15 NK cells (orange) 24 h after electroporation (n = 8). G Secreted IL-15 in the supernatant of MOCK, CD70-CAR NK cells, or CD70-CAR-IL-15 NK cells after electroporation (n = 3). H Percentage viable Raji cells after a 4 h co-culture with CD70-CAR NK cells, CD70-CAR-IL-15 NK cells or MOCK cells in the presence of 100 μg/mL anti-CD27 blocking antibody or isotype control (n = 4). I Secreted IFN-γ, and TNF-α in the supernatant of MOCK, CD70-CAR NK cells, or CD70-CAR-IL-15 NK cells after electroporation (n = 6). Error bars represent mean ± standard error of mean. J Percentage viable target cells after a 4 h co-culture with CD70-CAR NK cells, CD70-CAR-IL-15 NK cells or MOCK cells (n = 6). K Simple linear regression and Spearman Correlation analysis of CD70 ΔMFI and CD70-CAR-IL-15 target cell lysis. Linear mixed models with either Dunnett’s or Tukey’s correction for multiple comparison was applied to compare means. ns = p > 0.05; *p < 0.05, **p < 0.01, ***p < 0.001 and ****p < 0.0001