Identification of B-cell epitopes of Bet v 1 involved in cross-reactivity with food allergens

Allergy. 2009 Apr;64(4):647-51. doi: 10.1111/j.1398-9995.2008.01844.x. Epub 2009 Jan 9.


Background: The pollen-food syndrome (PFS) is an association of food allergies to fruits, nuts, and vegetables in patients with pollen allergy. Mal d 1, the major apple allergen, is one of the most commonly associated food allergens for birch pollen-allergic patients suffering from PFS. Although the reactions are due to cross-reactive IgE antibodies originally raised against pollen Bet v 1, not every Bet v 1-allergic patient develops clinical reactions towards apple.

Aim of the study: We speculate that distinct IgE epitopes are responsible for the clinical manifestation of PFS. To test this hypothesis we grafted five Mal d 1 stretches onto Bet v 1. The grafted regions were 7- or 8-amino acids long encompassing amino acids residues previously shown to be crucial for IgE recognition of Bet v 1.

Methods: A Bet v 1-Mal d 1 chimeric protein designated BMC was expressed in Escherichia coli and purified to homogeneity. IgE reactivity of BMC was tested with patients' sera originating from (i) Bet v 1-allergic patients displaying no clinical symptoms upon ingestion of apples; and (ii) Bet v 1-allergic patients displaying allergic symptoms upon ingestion of apples and other Bet v 1-related foods.

Results and conclusion: Compared to birch pollen-allergic individuals, patients suffering from PFS showed significantly higher IgE reactivity with BMC (chimeric protein). The results suggest that the Mal d 1 regions grafted onto the Bet v 1 sequence comprise important IgE epitopes recognized by Bet v 1-allergic patients suffering from allergy to apples.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Allergens / immunology*
  • Antigens, Plant
  • Betula / immunology
  • Blotting, Western
  • Cross Reactions
  • Enzyme-Linked Immunosorbent Assay
  • Epitopes, B-Lymphocyte / immunology*
  • Food Hypersensitivity / immunology*
  • Humans
  • Malus / adverse effects
  • Malus / immunology
  • Plant Proteins / immunology*
  • Pollen / immunology
  • Polymerase Chain Reaction
  • Recombinant Proteins / immunology


  • Allergens
  • Antigens, Plant
  • Epitopes, B-Lymphocyte
  • MALD1 protein, Malus domestica
  • Plant Proteins
  • Recombinant Proteins
  • Bet v 1 allergen, Betula