IDENTIFICATION OF PEANUT AGGLUTININ AND SOYBEAN TRYPSIN-INHIBITOR AS MINOR LEGUME ALLERGENS

Peanuts and soybeans are frequent causes of food hypersensitivity reac tions in children. Sera from 12 patients with atopic dermatitis and a positive double-blind placebo-controlled food challenge to peanut and sera from 5 patients with atopic dermatitis and a positive double-blin d placebo-controlled food challenge to soybean were used to identify a nd characterize specific legume allergens. Identification of a minor a llergen from peanut and a minor allergen from soybean was accomplished using various physicochemical techniques. The peanut fraction, peanut agglutinin, isolated by anion-exchange chromatography and electroluti on and confirmed by amino acid sequencing, bound IgE in only 50% of th e peanut challenge positive patients. The soybean fraction, soybean tr ypsin inhibitor, identified by gel filtration and electroelution and c onfirmed by amino acid sequencing, bound IgE in only 20% of the soy ch allenge positive patients. The identification of these two known legum e proteins as minor allergens should allow further immunologic and str uctural investigations to compare the major and minor legume allergens .