Immunoglobulin E antibody (IgE)

Immunoglobulin E (IgE) antibodies are a class of glycoprotein immunoglobulins produced by plasma cells and present in mammals at very low concentrations in circulation. IgE is defined by the epsilon (ε) heavy chain, which confers unique structural features: four constant domains (Cε1–Cε4), no hinge region, and substantial carbohydrate content[2][1][5]. It plays a central role in allergic immune responses by binding with high affinity to FcεRI receptors on mast cells and basophils, triggering immediate hypersensitivity reactions, and with lower affinity to CD23/FcεRII on B cells and other cells—which regulates IgE synthesis and presentation[3][4][5]. Physiologically, IgE contributes to defense against helminth and protozoan parasites and responds to environmental antigens at body surfaces, but its potent expulsive and inflammatory action poses risks of host tissue damage, underlying numerous allergic disorders—including asthma, food allergies, and anaphylaxis[5][2][4]. Several anti-IgE biologic drugs (notably omalizumab) are approved for diseases characterized by excessive IgE activity; these neutralize IgE and prevent its interaction with FcεRI, lowering allergic inflammatory responses[3][4]. Monitoring total and allergen-specific IgE serves as biomarker for diagnosis and management. Therapeutic manipulation of IgE poses safety concerns, especially risk for severe allergic reactions and impaired parasitic defense[4][5][2].

Other names

IgEImmunoglobulin EHuman IgEEpsilon immunoglobulin

Neutralization of circulating IgE by monoclonal antibody (e.g., omalizumab binds free IgE and prevents interaction with FcεRI); Prevention of FcεRI and CD23 receptor binding (drug-dependent inhibition; some antibodies selectively inhibit either receptor)