Fc-gamma receptor II (FcγRII)

Fc-gamma receptor II (FcγRII, CD32) is a family of low-affinity cell surface receptors for the Fc region of immunoglobulin G (IgG), consisting primarily of three isoforms: FcγRIIa, FcγRIIb, and FcγRIIc, encoded by the FCGR2A, FCGR2B, and FCGR2C genes, respectively. They are widely expressed on immune cells such as B cells, dendritic cells, neutrophils, monocytes, platelets, and natural killer cells. FcγRII receptors have two Ig-like extracellular domains and cytoplasmic tails containing either an immunoreceptor tyrosine-based activation motif (ITAM, in FcγRIIa/c) or an immunoreceptor tyrosine inhibitory motif (ITIM, in FcγRIIb). This structure allows FcγRII to play both activating and inhibitory roles in immune cell signaling. Their primary functions are clearance of IgG-coated pathogens (phagocytosis), regulation of antibody-mediated effector activity, and modulation of inflammation. Genetically determined polymorphisms are relevant to individual variation in disease susceptibility and response to antibody-based therapies.

Other names

CD32Fc gamma receptor IIa (FcγRIIa)Fc gamma receptor IIb (FcγRIIb)Fc gamma receptor IIc (FcγRIIc)FCGR2A (gene symbol)FCGR2B (gene symbol)FCGR2C (gene symbol)

Engagement by the Fc portion of IgG in immune complexes can trigger intracellular signaling via ITAM (activating, FcγRIIa/c) or ITIM (inhibitory, FcγRIIb) motifs. Activates or suppresses effector functions such as phagocytosis, cytokine release, or inhibition of cell activation based on subtype. Modifies the efficacy and safety profile of IgG1/IgG3 therapeutic antibodies by modulating effector cell recruitment and function.