Low affinity immunoglobulin gamma Fc receptor III (FcγRIII)

Low affinity immunoglobulin gamma Fc receptor III, commonly known as CD16, is a cluster of differentiation molecule found on the surface of various immune effector cells, including natural killer (NK) cells, macrophages, monocytes, and neutrophils [14, 24]. It exists in two primary isoforms: FcγRIIIa (CD16a), a transmembrane protein found on NK cells and macrophages, and FcγRIIIb (CD16b), a GPI-anchored protein expressed on neutrophils [16, 24]. As a low-affinity receptor for the Fc region of immunoglobulin G (IgG), it serves as a critical bridge between the adaptive and innate immune systems by recognizing antibody-coated targets [4, 17]. Upon engagement, FcγRIIIa triggers antibody-dependent cellular cytotoxicity (ADCC), leading to the release of cytotoxic granules and the destruction of malignant or infected cells [4, 14]. This mechanism is a cornerstone of modern oncology, as many therapeutic monoclonal antibodies, such as rituximab and trastuzumab, utilize FcγRIII to recruit effector cells against tumors [14, 22]. Additionally, genetic variations such as the FCGR3A V158F polymorphism significantly influence the receptor's binding affinity and the clinical efficacy of antibody-based therapies [2, 11, 13].

Other names

CD16FCGR3Fc gamma receptor IIICD16aCD16bFCGR3AFCGR3BLow affinity immunoglobulin gamma Fc region receptor III-ALow affinity immunoglobulin gamma Fc region receptor III-B

Binding of the Fc region of IgG antibodies to FcγRIII on immune effector cells (such as NK cells and macrophages) triggers antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP) against target cells.