Fc gamma receptor I (CD64), Fc gamma receptor II (CD32), Fc gamma receptor III (CD16) (FcγRI (CD64), FcγRII (CD32), FcγRIII (CD16))

Fc gamma receptors (FcγRs) are a family of cell surface receptors that bind to the Fc region of immunoglobulin G (IgG) antibodies and play a central role in linking humoral and cellular immunity. The three main classes on antigen-presenting cells (APCs) are Fc gamma receptor I (FcγRI, CD64), Fc gamma receptor II (FcγRII, CD32), and Fc gamma receptor III (FcγRIII, CD16). They differ in their structure, affinity for IgG subclasses, and their intracellular signaling motifs, which can be activating (ITAM) or inhibitory (ITIM). These receptors mediate key immune functions such as phagocytosis, antigen presentation, ADCC, and regulation of cytokine secretion, and are implicated in both host defense and in the pathology of autoimmune and inflammatory diseases. Their genetic diversity and expression levels can affect susceptibility to disease and response to antibody therapies[1][2][5][7][9].

Other names

Fcγ receptorsFcγRCD64 (FcγRI)CD32 (FcγRII)CD16 (FcγRIII)Immunoglobulin gamma Fc receptor

Triggering phagocytosis via ITAM-mediated signaling Inducing ADCC via NK cell activation Modulating cytokine production and degranulation Inhibiting immune activation (for FcγRIIB via ITIM motif) Altering antibody effector function through Fc engineering