Figure 3

Antibody binding to sialoadhesin, but not CD163, downregulates phagocytosis. Flow cytometric analysis of the effect of Sn- or CD163-specific antibodies on macrophage phagocytosis. The effect of the Sn-specific mAb 41D3 (Black circle), the CD163-specific mAb 2A10 (Dark grey circle) or an isotype-matched control mAb 13D12 (Light grey circle) on phagocytosis of beads by viable macrophages, expressed as the percentage of viable cells that have beads associated with them (A) or the MFI per viable cell (B), which is a measure for the amount of beads per cell. PAM were incubated with the indicated amount of mAb for 1 h, after which a phagocytosis assay was performed. As a control, non-treated PAM were included in the study. In addition, a phagocytosis assay was performed at 4°C (dotted line) with non-treated cells, to assess the percentage of macrophages that have beads bound to their surface and their MFI. Data represent the mean ± SEM of 3 independent experiments. *p < 0.05; **p < 0.01; ***p < 0.001.