Figure 6.

The target selectivity of dual CAR-NK cells is not affected by HLA-DR-expressing surrounding cells

(A) Flow cytometric analysis of KG-1 cells stained with PE-conjugated antibodies against CD19 and HLA-DR, separately. Isotype antibodies were used as the negative control. Images are representative of three independent experiments with similar results. (B) ELISA analysis of IFN-γ production by single CAR-NK cells against KG-1 cells or K562-CD19 cells after a 4-h incubation. Data are shown as mean ± SEM of three independent experiments. (C and D) Comparison of the activation levels of single and dual CAR-NK cells against K562-CD19 cells (C) or K562-CD19-HLA-DR cells (D) in the presence or absence of KG-1 cells. CAR-NK cells, target cells, and surrounding KG-1 cells were cocultured at the indicated E:T:S ratios. After a 4-h incubation, cell culture supernatants were collected to assess for IFN-γ secretion by ELISA. Data are shown as mean ± SEM of three independent experiments. Statistical significance is calculated by unpaired two-tailed Student's t test. ∗∗∗∗p < 0.0001, ∗∗∗p < 0.001, ∗∗p < 0.01; n.s., not significant.