Mechanisms of action of mAbs. (A) CDC. C1q binds to the antibody and triggers the complement cascade leading to the formation of the MAC on the surface of the myeloma cell. (B) ADCC. FcγR (CD16) on NK cells or other immune effector cells bind to the Fc region of the antibody leading to cell lysis. (C) ADCP. Fc receptors on macrophages bind to antibody and induce phagocytosis of cell. (D) FcγR-mediated crosslinking of bound antibody on the cell surface leading to apoptosis. MAC, membrane attack complex. Adapted from van de Donk et al³²  with permission.