CD33 and acute myeloid leukemia: To confirm expression levels of the target antigens on the three AML cell lines Kasumi-1, endogenously expressing CD33 and CD117, HL-60, and MOLM14, both expressing CD33 and transduced to display the extracellular domain of CD117 and sorted based on its expression level [23], we stained them with CD33 or CD117 Db-FM and detected the antigen-bound Db-FM with an APC-conjugated anti-FITC antibody (Fig. 2A, C, E).