Genetic engineering of a hypoallergenic trimer of the major birch pollen allergen, Bet v 1

An estimated 100 million individuals suffer from birch pollen allergy. Spec ific immunotherapy, the only curative allergy treatment, can cause life-thr eatening anaphylactic side effects. Here, we report the genetic engineering of a recombinant trimer consisting of three covalently linked copies of th e major birch pollen allergen, Bet v 1. The trimer exhibited profoundly red uced allergenic activity but contained similar secondary structures such as Bet v 1 wild type, Bet v 1-specific B cell and T-cell epitopes, and induce d Th1 cytokine release. As immunogen, rBet v 1 trimer induced IgG antibodie s, which blocked patients' IgE binding to Bet v 1 and related allergens. Th us, rBet v 1 trimer represents a novel hypoallergenic vaccine prototype for treatment of one of the most frequent allergy forms.