This invention provides an antibody having antigen binding activity and which has a heavy chain constant region into which has been introduced an RGDS amino acid sequence giving the antibody affinity for cells, including macrophages. The antibody exhibits artificial cell adhesive activity which is the newly expressed activity that results from insertion of the RGDS amino acid sequence. This antibody having artificial cell adhesive activity can accelerate the phagocytosis of macrophages, and can activate other effector cells. Therefore, this antibody contributes to the self-defense mechanism.
