CD33 and acute myeloid leukemia: Functional studies were performed to assess the in vitro cytotoxicity of BE-CAR7 T cells against Kasumi-3 cells, whilst BE-CAR33 and BE-CARCLL-1 T cells were tested against HL-60, MOLM-14 and U-937 cells and primary human AML samples expressing CD33 and CLL-1 (Fig. S3A, B).