Bet v 1 (Major birch pollen allergen) (Bet v 1)

Bet v 1 is the primary allergen found in birch (Betula verrucosa) pollen and serves as the prototype for the PR-10 (pathogenesis-related protein family 10) class of allergens [1, 3]. It is a 17.5 kDa protein characterized by a large hydrophobic pocket that binds various physiological ligands, including plant hormones, flavonoids, and fatty acids [4, 8]. In sensitized individuals, Bet v 1 triggers an IgE-mediated immune response, leading to seasonal allergic rhinitis, conjunctivitis, and allergic asthma [1, 6]. Due to its high structural homology with proteins in other Fagales trees—such as alder (Aln g 1), hazel (Cor a 1), and oak (Que a 1)—it is the main driver of cross-reactive tree pollen allergies [3, 9]. Furthermore, Bet v 1 is responsible for pollen-food allergy syndrome, where patients react to homologous proteins in fruits and vegetables like apples (Mal d 1) and hazelnuts (Cor a 1.04) [10, 12]. Therapeutic interventions primarily involve allergen-specific immunotherapy (AIT), which uses standardized birch pollen extracts or recombinant Bet v 1 to induce immune tolerance [2, 16]. This process shifts the immune profile from a Th2-dominated allergic response to a Th1 or regulatory T-cell (Treg) profile and stimulates the production of blocking IgG4 antibodies [15, 18]. These IgG4 antibodies compete with IgE for allergen binding, thereby preventing the degranulation of mast cells and basophils [15].

Other names

PR-10 proteinsBetula verrucosa allergen 1Major birch pollen allergenBet v 1-like proteinsFagales tree pollen allergensPathogenesis-related protein family 10

Allergen-specific immunotherapy (AIT) inducing immune tolerance through a shift from Th2 to Th1/Treg immune responses and the production of allergen-specific blocking IgG4 antibodies that inhibit IgE-mediated mast cell and basophil activation [2, 15, 18].