Low affinity immunoglobulin gamma Fc region receptor II and III (FcγRII/III)

Fc gamma receptor II (CD32) and III (CD16) are members of the immunoglobulin superfamily that serve as low-affinity receptors for the Fc region of IgG antibodies (UniProt P12318, P08637). These receptors are expressed on a wide variety of immune cells, including natural killer (NK) cells, macrophages, neutrophils, and B cells, where they play a pivotal role in bridging the humoral and cellular immune responses (PubMed: 25614319). FcγRII includes activating (IIA, IIC) and inhibitory (IIB) isoforms, while FcγRIII (IIIA, IIIB) primarily mediates activating signals such as antibody-dependent cellular cytotoxicity (ADCC) and phagocytosis (PubMed: 21934666). In oncology, many therapeutic monoclonal antibodies, such as Rituximab and Margetuximab, are designed to interact with FcγRIIIA to enhance tumor cell killing (PubMed: 31515461). Conversely, the inhibitory FcγRIIB is a target in autoimmune diseases and B-cell malignancies, where its blockade can restore immune activation or induce apoptosis (PubMed: 28438887). Safety concerns associated with targeting these receptors include cytokine release syndrome and infusion-related reactions due to systemic immune activation (PubMed: 30232150).

Other names

CD32CD16FCGR2FCGR3Fc-gamma RIIFc-gamma RIIILow affinity immunoglobulin gamma Fc region receptor IILow affinity immunoglobulin gamma Fc region receptor III

Modulation of immune cell activation and effector functions through binding of the Fc portion of IgG antibodies to trigger ADCC, phagocytosis, or inhibitory signaling (PubMed: 25614319, 28438887).