Low affinity immunoglobulin gamma Fc region receptor II (FcγRII) (FcγRII)

Type II Fc gamma receptors (FcγRII), also known as CD32, are a family of cell-surface glycoproteins that bind the Fc portion of immunoglobulin G (IgG) with low affinity (UniProt P12318, P31994). This group consists of three distinct isoforms: the activating receptors FcγRIIa and FcγRIIc, and the inhibitory receptor FcγRIIb. FcγRIIa and FcγRIIc signal through immunoreceptor tyrosine-based activation motifs (ITAMs) to promote phagocytosis and pro-inflammatory responses, while FcγRIIb utilizes an immunoreceptor tyrosine-based inhibitory motif (ITIM) to dampen immune activation, particularly in B cells (PubMed PMID: 25311635). These receptors are essential for maintaining immune homeostasis and are expressed across a wide range of leukocytes, including myeloid cells and B lymphocytes. In clinical settings, FcγRIIb is a target for overcoming resistance to monoclonal antibody therapies in B-cell malignancies, while polymorphisms in FcγRIIa are known to influence the efficacy of various therapeutic antibodies (PubMed PMID: 29038208). Drugs targeting these receptors aim to either enhance effector cell recruitment or suppress pathological immune responses in autoimmune and inflammatory diseases.

Other names

CD32Fc-gamma RIIFCGR2FcRIICD32 receptor

Modulation of immune cell activity through the binding of IgG Fc domains, leading to either the activation of effector functions like phagocytosis and ADCC (via FcγRIIa/c) or the inhibition of B-cell receptor-mediated signaling and antibody production (via FcγRIIb) (StatPearls NBK545220).