Fig. 2

CD70-CAR NK cell development and validation. A Schematic representation of CD70-CAR NK cell generation and structural composition of the CD70-CAR construct. B CD70-CAR expression was detected by measuring CD27 expression on the cell surface using flow cytometry. Representative histograms of CD27 expression on NK-92 cells 4 h, 24 h, 48 h and 72 h after electroporation without (MOCK; white) or with CAR-encoding mRNA (CD70-CAR; blue). C Quantification of the amount CD27⁺ cells and the intensity of CD27 expression, depicted as mean fluorescence intensity minus isotype control (ΔMFI), 24 h post-electroporation (n = 6). D Percentage of viable Raji cells after a 4 h co-culture with CD70-CAR NK cells or MOCK control cells in the presence of 10 μg/mL anti-CD27 blocking antibody (CD27-block; red) or corresponding isotype control (Isotype; black; n = 4). E Representative flow cytometry histograms of CD70 expression on tumor cell lines (Raji, PANC-1, and LIM2099). F-G Quantification of percentage CD70⁺ cells and intensity of CD70 expression (ΔMFI) for Raji, PANC-1, and LIM2099 tumor cell lines, respectively. H Percentage of viable CD70⁺ tumor cells (Raji, PANC-1 and LIM2099) after a 4 h co-culture with CD70-CAR NK cells or MOCK control cells (n = 5). I Simple linear regression analysis of CD70-CAR NK cell target lysis and density of CD70 expression (ΔMFI) on target cells. Spearman’s correlation was used to analyze the correlation between the CD70 expression and target lysis. Linear mixed models were used to compare means of the lysis of the different tumor targets. ns = p > 0.05; *p < 0.05, **p < 0.01 and ****p < 0.0001