IgEreseptorin

IgEreseptorin, commonly referred to in English as the IgE receptor, denotes receptors that bind immunoglobulin E (IgE). The best characterized member is FcεRI, a high-affinity receptor expressed on mast cells and basophils, and present at lower levels on dendritic cells, eosinophils, monocytes, and Langerhans cells. A separate low-affinity receptor, FcεRII (CD23), is found on B cells and some other cell types. In humans, FcεRI is a tetramer consisting of one α-chain that binds IgE, a β-chain, and two γ-chains responsible for signaling.

Binding of IgE to FcεRI is relatively long-lived until IgE dissociates. Cross-linking of receptor-bound IgE by multivalent allergen causes receptor aggregation and activation of the cell, leading to degranulation and release of histamine, proteases, and newly synthesized mediators such as leukotrienes and cytokines. This initiates immediate hypersensitivity reactions and, with continued allergen exposure, late-phase inflammatory responses.

Expression of FcεRI is upregulated in response to IL-4 and other Th2-type signals, increasing sensitivity to allergens. Removal of circulating IgE or blockade of IgE binding reduces receptor occupancy and dampens cellular activation; clinically, this is exploited by anti-IgE therapies (e.g., omalizumab).

Beyond allergy, FcεRI on dendritic cells and other antigen-presenting cells can influence antigen presentation and T cell polarization, linking IgE responses to adaptive immunity. Ongoing research investigates receptor regulation, non-mast cell roles, and therapeutic strategies targeting the IgE–FcεRI axis.