High-affinity immunoglobulin E receptor (FcεRI) bound to immunoglobulin E (FcεRI–IgE complex)

The **high-affinity immunoglobulin E receptor (FcεRI)** is a multimeric cell-surface protein primarily expressed on mast cells and basophils. It binds circulating **immunoglobulin E (IgE)** with high affinity. When an allergen cross-links multiple IgEs already bound to these receptors on effector cells, it triggers cellular activation—leading to degranulation and release of histamine and other pro-inflammatory mediators that drive immediate allergic responses[2][3][5]. The structure consists typically of one α subunit that binds the Fc region of IgE, one β subunit, and two γ subunits involved in signal transduction[2]. This interaction underlies type I hypersensitivity reactions such as those seen in allergies and asthma. Therapeutically targeting this axis—most notably by preventing IgE from binding its high-affinity receptor—is a validated strategy for treating severe allergic diseases[3][5]. **Note:** The submitted target name refers not to a single molecule but rather a functional ligand-receptor complex central to allergy biology. The canonical therapeutic target is usually considered either "Immunoglobulin E" itself or the "High-affinity immunoglobulin E receptor" (FcεRI), rather than their combined state as a named entity.

Other names

Fc epsilon RI–IgE complexFcεRI–IgEHigh-affinity IgE receptor–IgE complex

Inhibition of IgE binding to FcεRI prevents cross-linking and activation of mast cells/basophils, thereby blocking degranulation and release of inflammatory mediators[3].