Characterization of the Effects of Cross-Linking of Macrophage CD44 Associated with Increased Phagocytosis of Apoptotic PMN
Figure 1
CD44 cross-linking promotes human macrophage phagocytosis of apoptotic human PMN.
A) Monocyte-derived macrophages were incubated with CD44 mAb 5A4 Fab′ fragments (squares) or control Fab′ (triangles) for 30 min prior to addition of F(ab′)2 goat anti-mouse immunoglobulins (black symbols, solid line) or PBS control (gray symbols, dashed lines). Macrophages were then co-incubated with apoptotic targets at 37°C for the times indicated prior to assessment of phagocytosis by microscopy. Results shown are mean ± SEM for n = 5 separate experiments. ** indicates significant difference between cross-linking versus non-cross-linked (p<0.01). B) Monocyte-derived macrophages were incubated with CD44 mAb for 30 min to allow saturation of binding prior to addition of CMFDA-labelled apoptotic targets at 37°C for the times indicated. Assessment of phagocytosis was made by flow cytometry (white bars = untreated; gray bars (CD44-treated). Data shown are mean percentage phagocytosis ± SEM for 3 independent experiments. At all time points examined except 5 min, CD44-treated cells exhibit significant augmentation of phagocytosis (p<0.05).