Immunoglobulin heavy constant epsilon (IGHE) (IgE)

Immunoglobulin E (IgE) is a specialized antibody isotype that plays a central role in the pathogenesis of allergic diseases and the host defense against parasitic infections [1, 4]. The Cε3 domain of the IgE heavy chain is a critical structural region that mediates binding to the high-affinity IgE receptor (FcεRI) on mast cells and basophils, as well as the low-affinity receptor (FcεRII/CD23) [3, 4]. When allergen-specific IgE binds to FcεRI, subsequent exposure to the allergen triggers the cross-linking of these receptors, leading to the degranulation of effector cells and the release of inflammatory mediators like histamine and leukotrienes [4]. Therapeutic agents such as omalizumab are designed to specifically target the Cε3 domain of free, circulating IgE [2, 3]. By binding to this domain, these drugs prevent IgE from interacting with its receptors, thereby inhibiting the allergic cascade and reducing the density of FcεRI on the surface of inflammatory cells [2, 5]. This specific targeting of the free form is essential to avoid cross-linking receptor-bound IgE, which would otherwise trigger the very allergic response the treatment aims to prevent [3].

Other names

Immunoglobulin EIgEIGHEImmunoglobulin heavy constant epsilonEpsilon heavy chain

Monoclonal antibodies bind to the Cε3 domain of circulating (free) IgE, sterically hindering its interaction with the high-affinity FcεRI receptor on mast cells and basophils, which prevents the allergic inflammatory cascade and downregulates receptor expression [2, 3, 5].