Mucosal tolerance induction with hypoallergenic molecules in a murine model of allergic asthma

Type I allergy, frequently elicited by airborne allergens, has constantly i ncreased within recent years. Birch pollen and its major allergen Bet v 1 r epresent a major source of type I allergens. By genetic engineering hypoall ergenic Bet v 1 fragments were produced, which lost the IgE binding capacit y but retained the T cell epitopes. We have established a murine model of a erosol sensitization to birch pollen and its major allergen Bet v 1, leadin g to type I allergic immune responses and airway hyperresponsiveness. In th e present study we demonstrate that mucosal administration of recombinant B et v 1 prior to sensitization led to allergen-specific suppression of B and T cell responses in vivo and in vitro, reduction of eosinophilic infiltrat ion in the lungs and inhibition of airway hyperresponsiveness. Intranasal p retreatment with the nonanaphylactic fragments of Bet v 1 prevented allergi c immune responses and airway inflammation to the same degree as the pretre atment with the complete molecule. We conclude from our studies that mucosa l tolerance induction with hypoallergenic molecules could provide a safe an d convenient treatment strategy against type I allergies. Copyright (C) 200 1 S. Karger AG, Basel.