Peanut allergens Ara h 1, Ara h 2, and Ara h 3 (Ara h 1/2/3)

Ara h 1, Ara h 2, and Ara h 3 are the primary seed storage proteins in peanuts (Arachis hypogaea) and are the most significant allergens involved in peanut-mediated hypersensitivity (UniProt P43238, Q6PSU2, O82580). Ara h 1 is a 7S globulin (vicilin), Ara h 2 is a 2S albumin, and Ara h 3 is an 11S globulin (glycinin); Ara h 2 is often cited as the most potent of the three (PubMed: 25599442). These proteins are highly stable and resistant to heat and digestion, which preserves their allergenic epitopes during food processing (PubMed: 11486335). In sensitized patients, these allergens cross-link IgE on mast cells and basophils, triggering the release of inflammatory mediators that cause symptoms from mild skin reactions to fatal anaphylaxis (StatPearls: Peanut Allergy). They are the therapeutic targets for FDA-approved treatments like Palforzia (Peanut allergen powder-dnfp), which utilizes these proteins to induce desensitization through oral immunotherapy (FDA: Palforzia Prescribing Information).

Other names

Arachis hypogaea allergen 1Arachis hypogaea allergen 2Arachis hypogaea allergen 3Major peanut allergensVicilin-like proteinConglutin-like proteinGlycinin

Allergen-specific immunotherapy (AIT) induces clinical desensitization by gradually increasing the threshold for allergic reaction through the modulation of T-cell responses and the production of blocking antibodies like IgG4 (PubMed: 30213461).