Low affinity immunoglobulin gamma Fc receptor III-A (FCGR3A) (FCGR3A)

Low affinity immunoglobulin gamma Fc receptor III-A (FCGR3A), also known as CD16a, is a type I transmembrane glycoprotein and a member of the immunoglobulin superfamily [11, 14, 15]. It is primarily expressed on natural killer (NK) cells, macrophages, and certain subsets of monocytes and T cells [11, 14, 15, 19]. As an activating receptor, it binds the Fc region of IgG antibodies (specifically IgG1 and IgG3) to trigger antibody-dependent cellular cytotoxicity (ADCC) and phagocytosis [1, 10, 14, 15]. This function is critical for the efficacy of many therapeutic monoclonal antibodies in oncology, such as rituximab and trastuzumab, which rely on FCGR3A-mediated effector functions to eliminate tumor cells [6, 13, 15, 25]. Conversely, in autoimmune conditions like immune thrombocytopenia (ITP), FCGR3A mediates the pathological destruction of opsonized cells, making it a target for inhibitory therapies [8, 21, 23]. Genetic variations, particularly the V158F polymorphism (rs396991), significantly impact the receptor's binding affinity and are used as biomarkers to predict patient response to antibody-based treatments [4, 6, 12, 13, 22].

Other names

CD16aCD16FCGR3FCG3FCGRIIIFCRIIIFCRIIIAIGFR3Fc fragment of IgG receptor IIIa

Antibody-dependent cellular cytotoxicity (ADCC) induction, Phagocytosis induction, Receptor blockade, and Inhibition of receptor shedding [1, 2, 3, 5, 8, 10, 21].