title: Identification of a Dau c PRPlike protein (Dau c 1.03) as a new allergenic isoform in carrots (cultivar Rodelika).
abstract: BACKGROUND
  Up to 25% of food allergic subjects in central Europe suffer from carrot allergy. Until now, two isoforms of the major carrot (Daucus carota) allergen Dau c 1 have been described: Dau c 1.01, comprising five variants (Dau c 1.0101-Dau c 1.0105) and Dau c 1.02.
  
  
  OBJECTIVE
  To investigate potential allergenic properties of a Dau c PRPlike protein, a novel isoform of the PR-10 protein family in carrot.
  
  
  METHODS
  Dau c PRPlike cDNA from carrot roots (cv Rodelika) was cloned after RT-PCR and 5'RACE. Dau c PRPlike protein was expressed in E. coli, purified under native conditions by Ni-NTA chromatography and analysed by CD spectroscopy. Immuno-reactivity of the rDau c PRPlike protein was compared with rDau c 1.0104 and rDau c 1.0201 in terms of IgE binding (immunoblotting, ImmunoCAP), IgE cross-reactivity (ELISA inhibition) and in vitro mediator release with sera from carrot allergic patients. mRNA expression of Dau c PRPlike protein in wild-type and transgenic carrot roots was analysed by qRT-PCR.
  
  
  RESULTS
  The Dau c PRPlike protein was identified as a new allergenic isoform, Dau c 1.03, in carrot roots. 68% of carrot allergic patients were sensitized to rDau c 1.03. The IgE-reactivity of rDau c 1.03 strongly correlated with reactivity to rDau c 1.0104, but not to rDau c 1.0201. The extent of IgE cross-reactivity and allergenic potency of Dau c 1 isoforms varied between the individual sera tested. Dau c 1.03 mRNA transcripts were up-regulated in Dau c 1.01 and Dau c 1.02 gene-silenced carrot roots.
  
  
  CONCLUSIONS
  Dau c 1 isoforms display distinct IgE epitope heterogeneity. Dau c 1.03 appears to contribute to the allergenicity of carrots and the manifestation of carrot allergy. The epitope diversity of different Dau c 1 isoforms should be considered for component-resolved diagnosis and gene silencing of carrot allergens.
authors.affiliation: Division of Allergology, Paul-Ehrlich-Institut, Langen, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Wangorsch
authors.forename: D
authors.initials: D
authors.lastname: Weigand
authors.forename: S
authors.initials: S
authors.lastname: Peters
authors.forename: V
authors.initials: V
authors.lastname: Mahler
authors.forename: K
authors.initials: K
authors.lastname: Fötisch
authors.forename: A
authors.initials: A
authors.lastname: Reuter
authors.forename: J
authors.initials: J
authors.lastname: Imani
authors.forename: A M
authors.initials: AM
authors.lastname: Dewitt
authors.forename: K-H
authors.initials: KH
authors.lastname: Kogel
authors.forename: J
authors.initials: J
authors.lastname: Lidholm
authors.forename: S
authors.initials: S
authors.lastname: Vieths
authors.forename: S
authors.initials: S
authors.lastname: Scheurer
mesh_terms: D000485:Allergens / Q000737:chemistry / Q000276:immunology; D052179:Antigens, Plant / Q000737:chemistry* / Q000276:immunology; D002942:Circular Dichroism; D018552:Daucus carota / Q000009:adverse effects / Q000276:immunology*; D000939:Epitopes; D005260:Female; D005512:Food Hypersensitivity / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D008297:Male; D010940:Plant Proteins / Q000737:chemistry* / Q000276:immunology; D020033:Protein Isoforms / Q000737:chemistry / Q000276:immunology*; D017422:Sequence Analysis, DNA; D012882:Skin Tests
chemical_list: D000485:Allergens; D052179:Antigens, Plant; C119925:Dau c 1 protein, Daucus carota; D000939:Epitopes; D010940:Plant Proteins; D020033:Protein Isoforms; D007073:Immunoglobulin E