Characterization of soybean allergens causing sensitization of occupationally exposed bakers.

Fourteen bakers suffering from workplace-related respiratory symptoms and sensitized to soybean were studied. Twelve of them were also allergic to wheat flour, 10 to rye flour, and five to alpha-amylase of Aspergillus oryzae (Asp o 2). IgE estimation by RAST strongly indicated that the trypsin inhibitor and lipoxidase are major allergens of soybean. Various allergenic components could be characterized by immunoblotting after two-dimensional electrophoresis. Our RAST and immunoblotting results show an interindividually different allergic response to inhalative soybean constituents, and that the trypsin inhibitor (20 kDa, pI approximately 4.5) is an important inhalative soybean allergen recognized by IgE antibodies in the sera of 86% of the examined sensitized bakers.