MFG-E8 was regards as an opsonin that bridge apoptotic cells, which with surface phoshatidylserine exposure, and phagocyte bearing αvβ3 and αvβ5 integrins. Hanayana et. al. showed that thioglycollate-elicited macrophages produced and secreted MFG-E8. MFG-E8 significantly bound to apoptotic cells by recognizing aminophospholipids such as phosphatidylserine and bound to macrophages via its RGD motif, particularly strongly to αvβ3 integrin. Transfected NIH3T3 cell with high αvβ5 expression can engulf apoptotic cell in the presence of MFG-E8. The MFG-E8 dominant negative mutant that carries a point mutation in the RGD motif inhibited phagocytosis of apoptotic cells by peritoneal macrophages in vivo and in vitro. Borisenko et. al. estimated that MFG-E8 bind 2~8 fold stronger to oxidized PS than to native PS. And they also proposed MFG-E8 might bind to another cofactor, annexin I, on apoptotic cells, thus increase protein-membrane interaction.