High-affinity immunoglobulin epsilon receptor I (FcεRI)

The **high-affinity immunoglobulin epsilon receptor I (FcεRI)** is the primary cell surface receptor for immunoglobulin E (IgE), an antibody isotype crucial for allergic reactions and parasite immunity[1][5]. This tetrameric receptor is mainly expressed on mast cells and basophils, consisting of one alpha (binding IgE), one beta (amplifying signal), and two gamma subunits (initiating downstream signaling via ITAM motifs)[1][9]. Engagement of FcεRI by allergen-bound IgE leads to receptor cross-linking, triggering rapid release of preformed mediators such as histamine and cytokines, which drive the symptoms of allergic inflammation[1][5][2]. FcεRI also plays a role in immune surveillance and defense against parasites, as well as modulating antigen presentation and the production of pro-inflammatory mediators. Therapeutic blockade of its interaction with IgE, as with the monoclonal antibody omalizumab, is used to treat allergic diseases by dampening receptor-mediated cell activation[1]. High surface expression levels serve as biomarkers for allergic predisposition and response to therapy, but targeting this receptor carries risks of immunosuppression or, paradoxically, hypersensitivity reactions if not carefully controlled[1][5].

Other names

Fc epsilon RIHigh-affinity IgE receptorFcεRIImmunoglobulin E receptorFCER1

Inhibition of IgE binding to FcεRI (prevents receptor cross-linking, reduces immune cell activation)