Walnut allergens (Jug r) (Jug r)

Walnut allergens, primarily from the English walnut (Juglans regia), consist of several protein families including 2S albumins (Jug r 1), 7S globulins (Jug r 2), lipid transfer proteins (Jug r 3), and 11S globulins (Jug r 4) (Source: allergen.org). These proteins serve biological roles in the plant as seed storage components or defense mechanisms but act as potent allergens in humans by inducing IgE-mediated hypersensitivity (Source: PMID: 21542931). Cross-reactivity is a significant clinical feature, particularly with other members of the Juglandaceae family like pecans, and to a lesser extent with hazelnut (Cor a 9, Cor a 14) and other tree nuts due to the structural homology of conserved seed storage proteins (Source: PMID: 25535934). In sensitized individuals, exposure can lead to symptoms ranging from oral allergy syndrome to life-threatening anaphylaxis. While not therapeutic targets in the traditional sense, these allergens are the focus of diagnostic testing and allergen-specific immunotherapy (AIT) aimed at inducing clinical desensitization (Source: PMID: 30340672).

Other names

Juglans regia allergensTree nut allergensJug r allergensSeed storage proteins

Allergens act as antigens that cross-link allergen-specific IgE antibodies bound to FcεRI receptors on the surface of mast cells and basophils, triggering the release of inflammatory mediators such as histamine and leukotrienes.