Major cat allergen Fel d 1 (Fel d 1)

Major cat allergen Fel d 1 is a tetrameric glycoprotein belonging to the secretoglobin family and is the primary driver of cat allergies in humans, affecting approximately 10-15% of the global population [1, 7, 17]. Produced predominantly in the sebaceous and salivary glands of domestic cats (Felis catus), the protein's biological function in felines is thought to involve pheromone transport or mucosal protection, though its precise role remains under investigation [1, 15, 18]. In sensitive humans, Fel d 1 acts as a potent antigen that cross-links IgE on mast cells and basophils, triggering the release of inflammatory mediators that cause allergic rhinitis, conjunctivitis, and asthma [3, 16, 19]. It also exhibits immunomodulatory properties by enhancing Toll-like receptor (TLR4 and TLR2) signaling, which may further exacerbate airway hypersensitivity [13, 18]. Therapeutic strategies targeting Fel d 1 include allergen-specific immunotherapy (AIT) for desensitization, neutralizing monoclonal antibodies for immediate protection, and novel veterinary vaccines designed to reduce allergen shedding in cats [9, 12, 16].

Other names

Felis domesticus allergen 1Major allergen IAG4Allergen Cat-1Secretoglobin family 1A member 2 (Chain 1)Secretoglobin family 1A member 3 (Chain 2)

Neutralization of the allergen to prevent IgE binding and mast cell degranulation; Induction of T-cell tolerance and IgG4-mediated desensitization through immunotherapy; Reduction of environmental allergen load via feline-targeted vaccination or dietary neutralization.