title: Identification of allergens in fruits and vegetables: IgE cross-reactivities with the important birch pollen allergens Bet v 1 and Bet v 2 (birch profilin).
abstract: BACKGROUND
  In this study serum samples collected from 20 patients with birch pollen allergy were investigated. All patients had experienced allergic symptoms after contact with or ingestion of particular fresh fruits and vegetables known as birch pollen-related foods.
  
  
  METHODS
  Serum samples were tested by means of immunoblotting for IgE reactivities with proteins in extracts of birch pollen, apple, pear, celery, carrot, and potato. Anti-Bet v 1 and anti-Bet v 2 antibodies were used to investigate cross-reactivity. Inhibition studies were performed by preincubation of sera with recombinant Bet v 1 and Bet v 2.
  
  
  RESULTS
  IgE binding to proteins, corresponding to the major birch pollen allergen Bet v 1 and to Bet v 2 (birch pollen profilin) could be observed. An allergen homologous to Bet v 1 could be detected in apple, pear, and celery when a Bet v 1-specific monoclonal antibody was used. Testing a polyclonal rabbit anti-Bet v 2 antibody with extracts of the respective plants revealed the presence of profilins in every source tested. Inhibition with recombinant Bet v 1 and Bet v 2 led to complete blocking or marked reduction of IgE binding to proteins of comparable molecular weights in the respective food extracts, indicating IgE cross-reactivity.
  
  
  CONCLUSIONS
  Our results indicate that many plant-derived food agents contain proteins with high homology to the birch pollen allergens Bet v 1 and Bet v 2 and must therefore be considered as potentially threatening for patients with tree pollen allergy.
authors.affiliation: Institute of General and Experimental Pathology, University of Vienna, Austria.
authors.forename: C
authors.initials: C
authors.lastname: Ebner
authors.forename: R
authors.initials: R
authors.lastname: Hirschwehr
authors.forename: L
authors.initials: L
authors.lastname: Bauer
authors.forename: H
authors.initials: H
authors.lastname: Breiteneder
authors.forename: R
authors.initials: R
authors.lastname: Valenta
authors.forename: H
authors.initials: H
authors.lastname: Ebner
authors.forename: D
authors.initials: D
authors.lastname: Kraft
authors.forename: O
authors.initials: O
authors.lastname: Scheiner
mesh_terms: D000485:Allergens / Q000276:immunology*; D052179:Antigens, Plant; D003285:Contractile Proteins; D003429:Cross Reactions; D005638:Fruit / Q000276:immunology; D006801:Humans; D006967:Hypersensitivity / Q000209:etiology / Q000276:immunology*; D015151:Immunoblotting; D007073:Immunoglobulin E / Q000276:immunology; D008840:Microfilament Proteins / Q000276:immunology*; D010940:Plant Proteins / Q000276:immunology*; D010944:Plants / Q000276:immunology*; D011058:Pollen / Q000276:immunology; D051304:Profilins; D014197:Trees / Q000276:immunology; D014675:Vegetables / Q000276:immunology
chemical_list: D000485:Allergens; D052179:Antigens, Plant; D003285:Contractile Proteins; D008840:Microfilament Proteins; D010940:Plant Proteins; D051304:Profilins; C061312:Bet v 1 allergen, Betula; D007073:Immunoglobulin E