Bet v 1aF1 + Bet v 1aF2

Bet v 1aF1 + Bet v 1aF2 is a combination immunotherapy consisting of two recombinant fragments of the major birch pollen allergen, Bet v 1a. Fragment 1 (F1) corresponds to amino acid residues 1–74, while Fragment 2 (F2) corresponds to residues 75–160. This fragment-based vaccine strategy is designed to be 'hypoallergenic'; by splitting the native protein into fragments, the three-dimensional conformational epitopes required for IgE binding are disrupted, significantly reducing the risk of IgE-mediated allergic reactions (anaphylaxis) during administration. Despite the loss of IgE binding, the fragments retain the full complement of T-cell epitopes found in the parent allergen. The vaccine works by inducing immunological tolerance through the modulation of allergen-specific T-cell responses, shifting the immune profile from a Th2 (allergic) phenotype toward a Th1 or regulatory T-cell (Treg) phenotype. It was primarily developed by researchers at the Medical University of Vienna in collaboration with Biomay AG for the treatment of birch pollen-induced allergic rhinitis and asthma.

Other names

Bet v 1 fragmentsRecombinant Bet v 1a fragments F1 and F2rBet v 1a F1+F2Birch pollen allergen fragments