Immunoglobulin E antibody and high-affinity immunoglobulin E receptor complex (IgE–FcεRI)

Immunoglobulin E (IgE) is a class of antibody produced mainly by plasma cells in mucosal tissues, especially in the respiratory and gastrointestinal tracts[5][1]. IgE has a unique structural composition with four constant domains (Cε1–Cε4) and no hinge region, conferring distinctive flexibility and effector properties[1][6]. IgE’s main biological role is binding with high affinity to the cell-surface receptor FcεRI on mast cells and basophils, priming them for rapid degranulation upon subsequent allergen exposure. FcεRI is a multimeric transmembrane receptor complex composed of one alpha (α) chain (for IgE binding), one beta (β) chain, and a gamma (γ) chain dimer mediating intracellular signal transduction[2][4][6][8]. Engagement of allergen-bound IgE with FcεRI triggers release of inflammatory mediators (such as histamine), resulting in type I hypersensitivity (immediate allergic) reactions and playing a central role in allergic diseases and anti-parasite responses. Therapeutically, interruption of the IgE–FcεRI interaction is an established strategy for treating severe allergic disease, with anti-IgE monoclonal antibodies such as omalizumab representing key approved interventions[7].

Other names

IgEFc epsilon receptor IHigh-affinity IgE receptorFcεRIFcεRIαFcεRIβFcRγFcεRIγ

Omalizumab/ligelizumab bind circulating IgE, preventing IgE from binding FcεRI and downregulating receptor expression on effector cells. Anti-FcεRI agents directly block IgE binding or induce receptor internalization. Inhibition of IgE–FcεRI interaction to prevent mast cell/basophil activation and mediator release.