title: Immunoproteomic tools are used to identify masked allergens: Ole e 12, an allergenic isoflavone reductase from olive (Olea europaea) pollen.
abstract: Proteins performing important biochemical activities in the olive tree (Olea europaea) pollen have been identified as allergens. One novel 37-kDa protein seems to be associated to the IgE-binding profile of a group of patients suffering allergy to peach and olive pollen. Three previously described olive pollen allergens exhibit very similar molecular mass. Our objective was to identify this allergen by using immunoproteomic approaches. After 2D-electrophoresis and mass spectrometry, peptide sequences from several IgE-binding spots, allowed identifying this new allergen, as well as cloning and DNA sequencing of the corresponding gene. The allergen, named Ole e 12, is a polymorphic isoflavone reductase-like protein of 308 amino acids showing 80% and 74% identity with birch and pear allergens, Bet v 6 and Pyr c 5, respectively. A prevalence of 33% in the selected population is in contrast to 4%-10% in groups of subjects suffering from pollinosis. Recombinant allergen was produced in Escherichia coli, and deeply characterised. Immunoblotting and ELISA detection as well as inhibition experiments were performed with polyclonal antisera and allergic patients' sera. The recombinant allergen retains the IgE reactivity of its natural counterpart. Close structural and immunological relationships between members of this protein family were supported by their IgG recognition in vegetable species. In summary, Ole e 12 is a minor olive pollen allergen, which gains relevance in patients allergic to peach with olive pollinosis. Proteomic approaches used to analyse this allergen provide useful tools to identify hidden allergens, relevant for several allergic populations and thus complete allergenic panels.
authors.affiliation: Dpto. Bioquímica y Biología Molecular I, Universidad Complutense, Madrid, Spain.
authors.forename: Lourdes
authors.initials: L
authors.lastname: Castro
authors.affiliation: Servicio de Alergia, Instituto de Investigación Hospital 12 de Octubre (i+12), Madrid, Spain.
authors.forename: Jesús F
authors.initials: JF
authors.lastname: Crespo
authors.affiliation: Servicio de Alergia, Instituto de Investigación Hospital 12 de Octubre (i+12), Madrid, Spain.
authors.forename: Julia
authors.initials: J
authors.lastname: Rodríguez
authors.affiliation: Dpto. Bioquímica y Biología Molecular I, Universidad Complutense, Madrid, Spain.
authors.forename: Rosalía
authors.initials: R
authors.lastname: Rodríguez
authors.affiliation: Dpto. Bioquímica y Biología Molecular I, Universidad Complutense, Madrid, Spain. Electronic address: mayte@bbm1.ucm.es.
authors.forename: Mayte
authors.initials: M
authors.lastname: Villalba
mesh_terms: D000485:Allergens / Q000737:chemistry* / Q000276:immunology; D000595:Amino Acid Sequence; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D008969:Molecular Sequence Data; D031658:Olea / Q000737:chemistry*; D011058:Pollen / Q000737:chemistry*; D040901:Proteomics; D017386:Sequence Homology, Amino Acid
chemical_list: D000485:Allergens; D007073:Immunoglobulin E
keywords: 2-DE; Allergen; Isoflavone reductase-like; Olea europaea pollen; Peach allergy; Proteomics