Immunoglobulin gamma Fc region receptor III (FcγRIII (also commonly called CD16))

Immunoglobulin gamma Fc region receptor III (FcγRIII, CD16) is a low-affinity Fc receptor for immunoglobulin G (IgG) found on natural killer (NK) cells, macrophages, monocytes, and neutrophils[1][2][5][8]. It exists in two forms, encoded by *FCGR3A* (CD16a, transmembrane) and *FCGR3B* (CD16b, GPI-anchored)[1][7][8]. FcγRIII mediates key immune effector functions, including antibody-dependent cell-mediated cytotoxicity (ADCC), phagocytosis, cytokine secretion, and degranulation, underpinning its role in linking humoral and cellular immunity[1][3][5]. Clinically, it is crucial for the mechanism of action of numerous therapeutic monoclonal antibodies and has roles in infection defense, inflammation, cancer immunotherapy, and autoimmunity[2][3][5]. Variations in FCGR3A and FCGR3B genes influence individual responses to antibody-based therapies and susceptibility to autoimmune diseases[9].

Other names

FcγRIIICD16Fc gamma receptor IIIFc gamma RIIIlow affinity immunoglobulin gamma Fc region receptor IIICD16a (for FcγRIIIa)CD16b (for FcγRIIIb)

Engagement of FcγRIII by an antibody Fc region induces immune effector functions such as ADCC and phagocytosis - Triggering of immune cell signaling cascades via ITAM (immunoreceptor tyrosine-based activation motif)