IDENTIFICATION AND CHARACTERIZATION OF ALLERGENS RELATED TO BET-V-I, THE MAJOR BIRCH POLLEN ALLERGEN, IN APPLE, CHERRY, CELERY AND CARROT BY 2-DIMENSIONAL IMMUNOBLOTTING AND N-TERMINAL MICROSEQUENCING

Low temperature extracts taken from Granny Smith and Braeburn apples, cherries, celery and carrots were separated by two-dimensional electro phoresis. Bet nu I, the major birch pollen allergen, related allergens in apple, cherry, celery and carrot extracts were detected by means o f two-dimensional immunoblotting with patients' sera containing IgE an tibodies specific to Bet nu I, a rabbit polyclonal antiserum raised ag ainst Bet nu I, and two Bet nu I specific mouse monoclonal antibodies. The major cross-reacting allergen spots were observed with molecular weights/isoelectric points of 18.0 kDa/pI 5.5 for apple (Granny Smith and Braeburn) and 18.0 kDa/pI 5.8 for cherry, 15.5 kDa/pI 4.4-4.6 for celery and 16.0 kDa/pI 4.4 for carrot extract. Additional antibody rea ctivities with certain isoprotein spots were observed, which may indic ate the presence of Bet nu I-related epitopes on these proteins. Based on the first 15 N-terminal amino acid residues, the major allergen sp ots revealed 53% sequence identity between Bet nu I and the Granny Smi th apple allergen, 50% between Braeburn apple allergen and Bet nu I, 6 7% between Bet nu I and the cherry allergen, and 40 and 28% for celery and carrot, respectively. Furthermore, the N-terminal sequences showe d identities ranging from 40% (apple/cherry) to 66%(celery) with PcPR l-l, a pathogenesis-related protein in parsley.