Fc gamma receptor IIIa (CD16a) (CD16a (sometimes CD16))

Fc gamma receptor IIIa (CD16a) is a low-affinity Fc receptor for IgG expressed on the surface of most peripheral blood natural killer (NK) cells; it is the main driver of antibody-dependent cell-mediated cytotoxicity (ADCC), a key mechanism for immune destruction of antibody-coated tumor or infected cells[1][2][4][5][6][7]. Upon binding the Fc portion of IgG on target cells, CD16a transmits activation signals via ITAM-bearing adaptor proteins (such as CD3ζ), resulting in release of cytotoxic mediators (perforin, granzymes) and pro-inflammatory cytokines (IFN-γ, TNF)[4][5][7]. CD16a is also expressed, to a lesser extent, on some monocytes and macrophages. The receptor is a prime target for immunotherapy, as many therapeutic antibodies against tumors depend on NK-mediated ADCC for efficacy[1][6]. Surface CD16 can be downregulated or shed upon NK cell activation, particularly via the metalloprotease ADAM17, which has implications for both therapeutic efficacy and immune regulation[2]. CD16 has two main isoforms in humans: CD16a (Fc gamma receptor IIIa, FCGR3A) on NK cells, and CD16b (FCGR3B) on neutrophils; only CD16a is considered an NK cell canonical surface antigen for therapeutic purposes[4][2][3][7].

Other names

CD16FcγRIIIFCGR3AFc gamma receptor IIIaFcgammaRIIIa

Antibody-dependent cell-mediated cytotoxicity (ADCC), Direct lysis of antibody-coated target cells, Cytokine secretion induction