Fig. 4.

CD33 deletion protects CD34⁺ cells from CART33 cytotoxicity in vitro. (A) Schematic of CART33 construct. (B) Contour plot showing CAR expression in human primary T cells after lentiviral transduction with control (black) or CART33 (green or blue) virus. Percentage transduction in each group is specified next to the plots. CD4⁺ and CD8⁺ cells were transduced independently and comixed 1:1 before experiment. (C–F) Cytotoxicity assays. (C) CART33 cells or control T were incubated with HL-60 or CD34⁺CD33^WT or CD34⁺CD33^Del and cytotoxicity assessed by flow cytometry. (D–F) Triple culture cytotoxicity assay. CART33 cells or control T cells were coincubated with (D) HL-60 and CD34⁺CD33^WT or (E) with HL-60 and CD34⁺CD33^Del or (F) with CD34⁺CD33^WT and CD34⁺CD33^Del cells (four independent experiments).