FIGURE 6.

High affinity Velcro-CD47 variant enhances mAb ADCP. A–C, phagocytosis of GFP⁺ Raji lymphoma (A), SKBR3 breast cancer (B), and DLD-1 colon cancer (C) cells by donor-derived human macrophages with or without 10 μg/ml respective tumor-specific mAbs in the presence of PBS (blue), WT CD47 (maroon), N3612 (gray), and CV1 (green). D and E, phagocytosis of GFP⁺ SKBR3 breast cancer (D) and DLD-1 colon cancer (E) cells with titrating amounts of respective tumor-specific mAbs in the presence of the same protein treatments as in A–C. The proteins were used at 1 μm. A–E, all phagocytosis was performed with human macrophages derived from a minimum of two independent blood donors; data are representative of at least two independent experiments. Data represent the percentage of phagocytosis normalized to the maximal response by each donor for each cell line ± S.E. of duplicate wells. ns, not significant; **, p < 0.01; ***, p < 0.001, by one-way analysis of variance test.