Fig. 3

DSP107 mediated PMN trogocytosis of B cell lymphoma cell lines. A) Gating strategy for the PMN-mediated trogocytosis assay. PMNs are gated on forward-sideward scatter (left). Percentage of CD11b-APC labeled granulocytes positive for CFSE dye from cancer cells, calculated from the scatter (right), represents the level of phagocytic uptake. B) PMN-mediated trogocytosis with increasing concentrations of DSP107 (red) and combined with 1 μg/ml RTX (blue), parametric paired t-test was used with respect to control sample versus each dose of DSP107, C) PMN trogocytosis of nine B cell-lines without treatment (red) or with 10 nM DSP107 (blue). Each line represents a single experiment with an individual donor, parametric paired t-test, as described in B, was used, D) Comparison of PMN-mediated trogocytosis of nine B cell-lines between RTX (red) and combination treatment of RTX and DSP107 (blue). Analyzed as in B, E) PMN-mediated trogocytosis of Daudi cells with DSP107 and RTX or isotype control for RTX F) Comparison of 10 nM DSP107, comprising trimeric SIRPα (left) and 10 nM monomeric SIRPα (right) as prophagocytic agents. Analyzed as in B, G) Comparison of DSP107, CD47 mAb and SIRPα:Fc,. trogocytosis activity on SUDHL2 cells. DSP107, CD47 mAb or SIRPα:Fc for monotherapy (red) or combination treatment with RTX (blue) are used at an equal concentration of 10 nM. Trogocytosis results were normalized to the highest trogocytosis percentage of the same donor to compare the effect between drugs, parametric paired t-test was used with respect to control sample versus each drug. H) Trogocytosis of primary patient-derived malignant B cells by autologous PMNs from two donors I) AnnexinV staining of remaining cancer cells after trogocytosis assay, upon DSP107 stimuli or DSP107 with RTX (DSP107 bars) comparing to untreated cells or treatment with RTX alone (red bars), parametric paired t-test was used with respect to control sample versus treatment with DSP107. Across the figure, t-test values: * = p < 0.05, ** = p < 0.01, *** = p < 0.001, all error bars in the figure represent SD