Specificities of IgE and IgG antibodies in patients with birch pollen allergy

58 sera from patients with established birch pollen allergy showed characteristic antibody-binding patterns in immunoblotting experiments. Regarding IgE, 56/58 patients recognized a protein of molecular weight (MW) 17 kilodaltons (kD), previously defined as Bet v I. 23/58 patients in addition reacted with a variety of 11 minor allergens with MWs ranging from 13 to 68 kD. A 13-kD protein was proved to represent an independent minor allergen. IgG binding in patients and healthy individuals was more pronounced on the minor allergens than on Bet v I. 3 different allergens were not detected by IgG of healthy individuals. In two-dimensional electrophoresis/immunoblot, a monoclonal antibody and human IgE (in both cases directed against Bet v I) detected a very similar cluster of spots, probably representing isoallergens of Bet v I.