Figure 5.

Membrane-proximal CD33-targeting chimeric antigen receptor (CAR) T cells decrease tumor burden in patient-derived acute myeloid leukemia (AML) xenograft model. (A) Flow cytometry histograms of CD33 expression on AML60B patient sample detected with isotype control or fluorescently labeled CD33-spcific antibody. (B) Quantitative geometric mean fluorescence intensity (MFI) of CD33 expression on AML60B patient sample detected with either isotype control or fluorescently labeled CD33-specific antibody. (C) Schematic diagram of experimental setup of a patient-derived xenograft model. NCG mice were inoculated with patient-derived AML blasts and treated with allogeneic CAR T cells. Bone marrow aspirates were analyzed 28 days post tumor inoculation. (D) Quantification of flow cytometric analysis demonstrating decreased tumor burden in mice treated with membrane-proximal CD33-targeting CAR T cells (n=6; *p<0.05 by unpaired t-test). (E) Survival of NCG mice-bearing AML60B patient-derived tumor and treated with membrane-distal or membrane-proximal CAR T cells (n=6; **p<0.01; *p<0.05). P values for survival determined by log-rank Mantel-Cox test, with 95% CI.