Extended Data Fig. 5: CSF1R is highly expressed on primary AML blasts.

(a) Representative histograms of CSF1R expression on AML cell lines after freeze and thaw cycles. (b, c) Schematic of culture methods used to cultivate primary AML samples throughout the course of the study. (d) Expression of CSF1R on primary AML samples after 24 to 48 hours of culture in cytokine rich medium. Left: Percentage positive cells gated to isotype. Each dot represents different primary AML samples. Right: Representative flow cytometric images from three different AML samples. Data are mean ± s.e.m. from six different donors. (e) Gating strategy to identify CD34⁺ CD38^± malignant HSPC. (f, g) Expression of target antigens (CSF1R, f; CD86, g) on malignant HPC (top) and HSC (bottom). (h) Expression of CSF1R on PDX-388 sample at indicated time points after thawing. (i) IHC staining of human CSF1R in the bone marrow of control-treated PDX-388-bearing mice. Shown are two representative pictures (right, left) in two different magnifications (top 10x, bottom 20x). (j) CD33 CART used for i.v. injection into PDX-388-bearing mice (Fig. 5k–m) were cocultured ex vivo with luciferase⁺ Mv4-11 tumor cells for 48 hours at indicated E:T ratios. Specific lysis was quantified by BLI. Shown is mean ± s.e.m. of three biological replicates. Experiment was carried out twice. (k) Representative flow cytometric image of percentage of CD3⁺ T cells (left) and percentage of CAR (c-myc)⁺ T cells (right) in the blood of PDX-388-bearing mice. (l, m) Ex vivo CD33 expression on PDX-388 AML blasts in the bone marrow after treatment with CD33 CART or CTRL-transduced T cells (CD19 CART) measured by flow cytometry. Depicted are representative histograms (l) or the change of CD33-PE-Cy5 MFI in CD33 CART treated mice compared to CTRL-transduced treated mice (m). (m) Data are mean ± s.e.m. from n = 3 mice injected with CD33 CART compared to CTRL-transduced mouse. (k–m) n = 3 mice injected with CD33 CART), n = 1 mouse injected with CTRL-transuced T cells.