Human Immunoglobulin E specific for Fel d 1 (Fel d 1-specific IgE)

Human Immunoglobulin E (IgE) specific for Fel d 1 is the primary immunological mediator of cat allergy, a prevalent condition characterized by hypersensitivity to the major cat allergen, Fel d 1 (Grönlund et al., 2010, PMID: 20394811). Fel d 1 is a secretoglobin protein found in cat dander, saliva, and skin, which becomes airborne and easily inhaled. In sensitized individuals, these specific IgE antibodies are produced by B cells and subsequently bind to the high-affinity IgE receptor (FcεRI) on the surface of mast cells and basophils (Gould & Sutton, 2008, PMID: 18219310). Upon re-exposure to the allergen, Fel d 1 cross-links the IgE-FcεRI complexes, triggering the immediate release of inflammatory mediators like histamine and leukotrienes, which cause symptoms ranging from allergic rhinitis to severe asthma (Bonnet et al., 2018, PMID: 29304427). Therapeutic strategies targeting this molecule include the use of monoclonal antibodies like Omalizumab, which sequester circulating IgE and prevent its interaction with receptors (DrugBank DB00043), and allergen-specific immunotherapy (AIT), which aims to modify the immune response to reduce the levels or activity of Fel d 1-specific IgE. Monitoring levels of these antibodies is crucial for diagnosing cat allergy and assessing the efficacy of immunotherapy.

Other names

Anti-Fel d 1 IgECat allergen-specific IgEFel d 1 sIgEFelis domesticus allergen 1-specific IgE

Anti-IgE monoclonal antibodies bind to the Cε3 domain of circulating IgE, preventing its binding to the high-affinity receptor FcεRI on mast cells and basophils, thereby inhibiting the allergic cascade. Allergen-specific immunotherapy (AIT) utilizes Fel d 1 extracts to induce regulatory T cells and promote the production of allergen-specific IgG4 antibodies, which act as blocking antibodies to prevent Fel d 1 from cross-linking IgE on effector cells.