Allergen protein

Allergen proteins are a diverse class of proteins derived from sources such as pollen, house dust mites, animal dander, and various foods that trigger Type I hypersensitivity reactions in genetically predisposed individuals. These proteins often possess specific structural features or biochemical activities—such as protease activity or lipid-binding capabilities—that facilitate their penetration of mucosal surfaces and the subsequent induction of a Th2-skewed immune response and IgE production. In clinical pharmacology, allergen proteins are not generally the targets of inhibition by small molecules; rather, they serve as the active pharmaceutical ingredients in allergen immunotherapy (AIT). AIT involves the repeated administration of specific allergen proteins to induce peripheral immune tolerance, characterized by the expansion of regulatory T cells (Tregs), a shift from Th2 to Th1 responses, and the production of IgG4 'blocking' antibodies. While AIT is unique as a disease-modifying treatment for allergies, the use of these proteins carries a therapeutic challenge due to the risk of inducing systemic allergic reactions or anaphylaxis during treatment.

Other names

AntigenImmunogenAtopy-inducing proteinAllergenic substanceAllergen extract

Induction of peripheral immune tolerance through repeated, controlled exposure to the allergen protein. This process promotes the differentiation of allergen-specific regulatory T cells (Tregs) and regulatory B cells (Bregs), leading to the secretion of IL-10 and TGF-beta. These cytokines suppress Th2-mediated inflammation and induce a switch in antibody production from IgE to 'blocking' IgG4 and IgA antibodies, which competitively inhibit allergen binding to mast cell-bound IgE, thereby preventing degranulation.