Fig. 3.

CD23-mediated ADCP by wild type U937 cells and IgE. a Two-color flow cytometric dot plots detected ADCP of IGROV1 cells by U937 cells and MOv18 IgE after 1 and 2.5 h in culture. Left panels: CFSE-labeled IGROV1 (x axis, lower right) and U937 cells labeled with CD89-PE mAb (y axis, upper left). IGROV1 cells phagocytosed by U937 cells (CFSE⁺/PE⁺, upper right). Right panels: CFSE-labeled dead IGROV1 cells, labeled with Propidium Iodide (PI) (y axis, upper left) (CFSE⁺/PI⁺, upper right). b Quantitation of MOv18 IgE-mediated IGROV1 tumor cell killing by ADCC and ADCP after 1 and 2.5 h using unstimulated (top panel) and IL-4-treated (bottom panel) U937 cells. Cytotoxicity: black bars; phagocytosis: gray bars. Results are mean ± SD of six independent experiments. c ADCC and ADCP of IGROV1 tumor cells by unstimulated (top left) and IL-4 sitmulated (bottom left) U937 cells and after incubation of U937 cells with IDEC-152 Fab (top and bottom right panels) blocked tumor cell ADCP. Results are mean ± SD of six independent experiments. Significance of values compared to samples given MOv18 IgE by the Student’s t-test: ^n/s P > 0.05, *P < 0.05, **P < 0.005, ***P < 0.0005