Immunoglobulin E (IgE) and Immunoglobulin G (IgG) (IgE/IgG)

Polyclonal allergen-specific IgE and IgG are the primary immunoglobulins mediating the type I hypersensitivity response and its clinical regulation [1]. IgE antibodies bind to high-affinity FcεRI receptors on the surface of mast cells and basophils; subsequent allergen-induced cross-linking of these bound antibodies triggers the explosive release of inflammatory mediators like histamine and leukotrienes [1, 3]. Conversely, allergen-specific IgG, particularly the IgG4 subclass, serves a protective role by acting as a "blocking antibody" that competes with IgE for allergen binding and signals through the inhibitory receptor FcγRIIb [2]. Therapeutic strategies targeting this system include monoclonal antibodies like Omalizumab, which sequester free IgE to prevent its interaction with effector cells and lead to the downregulation of surface FcεRI [4]. Allergen immunotherapy (AIT) further modulates this axis by promoting the production of allergen-specific IgG4 and inducing long-term immune tolerance [2]. Monitoring the levels and ratios of these polyclonal antibodies is a standard clinical practice for diagnosing allergic diseases and assessing the efficacy of desensitization treatments.

Other names

Allergen-specific antibodiesReaginic antibodiesBlocking antibodiessIgEsIgG4mIgEMembrane-bound IgE

Anti-IgE monoclonal antibodies bind to the Cε3 domain of free IgE, preventing its interaction with high-affinity FcεRI receptors on mast cells and basophils [1, 4]. Allergen immunotherapy (AIT) induces a shift from IgE production to allergen-specific IgG4, which acts as a competitive inhibitor for allergen binding and recruits inhibitory FcγRIIb signaling to suppress effector cell activation [2].