PURIFICATION AND CHARACTERIZATION OF THE MAJOR ALLERGEN FROM APPLE AND ITS ALLERGENIC CROSS-REACTIVITY WITH BET-V-1

The major allergen from apple extract was concentrated by anion exchange chromatography and further purified by reverse-phase HPLC. A distinct peak with a high degree of homogeneity was obtained. The isolated protein has a MW of 18 kD and specific IgE-binding capacity (immunoblotting, IgE-binding inhibition). N-terminal amino acid analyses of the allergen allowed 37 cleavages and showed 67.6% identity to Bet v 1, the major allergen of birch pollen. Enzyme immunoassay inhibition studies with serum of birch/apple-allergic patients showed that besides cross-reacting structures to Bet v 1, apple-specific IgE antibodies could exist. Monoclonal antibodies (mAbs) were raised against the 18-kD allergen from apple and characterized by means of immunoblotting and ELISA. Only three of the eight studied mAbs reacted with Bet v 1.