title: Characterization of the T cell response to the major hazelnut allergen, Cor a 1.04: evidence for a relevant T cell epitope not cross-reactive with homologous pollen allergens.
abstract: BACKGROUND
  IgE antibodies specific for the major birch-pollen allergen, Bet v 1, cross-react with homologous allergens in particular foods, e.g. apples, carrots and hazelnuts. In a high number of tree pollen-allergic individuals, this cross-reactivity causes clinical symptoms, commonly known as the 'birch-fruit-syndrome'.
  
  
  OBJECTIVE
  To characterize the T cell response to the Bet v 1-related major allergen in hazelnuts, Cor a 1.04, and its cellular cross-reactivity with Bet v 1 and the homologous hazel pollen allergen, Cor a 1.
  
  
  METHODS
  Using recombinant Cor a 1.04, T cell lines (TCL) and T cell clones (TCC) were established from peripheral blood mononuclear cells of tree pollen-allergic patients with associated food allergy. T cell epitopes were determined using overlapping synthetic peptides in Cor a 1.04-reactive TCL and TCC. In parallel, reactivity to Bet v 1 and Cor a 1 was tested.
  
  
  RESULTS
  In total, 20 distinct T cell epitopes on the hazelnut allergen were identified. Several Cor a 1.04-specific TCL and TCC reacted with pollen allergens albeit less pronounced than with the hazelnut allergen. Several Cor a 1.04-specific TCC did not react with pollen allergens. Interestingly, these clones were found to react with the Bet v 1-related major allergen in carrots, Dau c 1. The cellular cross-reactivity between both food allergens could be associated with the most frequently recognized T cell epitope of Cor a 1.04, Cor a 1.04(142-153).
  
  
  CONCLUSIONS
  The major hazelnut allergen cross-reacts with the major allergens of birch and hazel pollen but apparently contains a relevant T cell epitope not shared with pollen allergens. Our finding may have important implications for the specific immunotherapy of tree pollen-allergic patients suffering from concomitant hazelnut allergy.
authors.affiliation: Department of Pathophysiology, Center of Physiology and Pathophysiology, Medical University of Vienna, Vienna, Austria. barbara.bohle@meduniwien.ac.at
authors.forename: B
authors.initials: B
authors.lastname: Bohle
authors.forename: A
authors.initials: A
authors.lastname: Radakovics
authors.forename: D
authors.initials: D
authors.lastname: Lüttkopf
authors.forename: B
authors.initials: B
authors.lastname: Jahn-Schmid
authors.forename: S
authors.initials: S
authors.lastname: Vieths
authors.forename: C
authors.initials: C
authors.lastname: Ebner
mesh_terms: D000485:Allergens / Q000276:immunology*; D052179:Antigens, Plant; D002460:Cell Line; D049109:Cell Proliferation; D031211:Corylus / Q000276:immunology; D003429:Cross Reactions / Q000276:immunology; D018604:Epitope Mapping; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology; D021184:Nut Hypersensitivity / Q000276:immunology; D010446:Peptide Fragments / Q000276:immunology; D010940:Plant Proteins / Q000276:immunology*; D011058:Pollen / Q000276:immunology; D011994:Recombinant Proteins / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000485:Allergens; D052179:Antigens, Plant; C061277:Cor a I protein, hazel; C119925:Dau c 1 protein, Daucus carota; D018984:Epitopes, T-Lymphocyte; D010446:Peptide Fragments; D010940:Plant Proteins; D011994:Recombinant Proteins