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

SPECIFIC AIMSOur aim was to obtain by genetic engineering a recombinant allergen derivative with profoundly reduced allergenic activity but that would preserve structural features, B cell as well as T cell epitopes of the wild-type allergen. A recombinant trimer consisting of three covalently linked copies of one of the most frequent environmental allergens, the major birch pollen allergen, Bet v 1 was expressed in Escherichia coli and analyzed for secondary structure content by circular dichroism (CD). The presence of immunoglobulin E (IgE) epitopes was investigated by IgE binding/competition assays; allergenic activity was analyzed by basophil histamine release and skin testing in allergic patients. T cell epitopes and the cytokine release profile were studied using cultured T cells from sensitized patients. We also investigated whether rBet v 1 trimer induces IgG antibodies in vivo that block patient’s IgE binding to Bet v 1 and related allergens.PRINCIPAL FINDINGS1. Recombinant Bet v 1 trimer contains...