title: IgE recognition of chimeric isoforms of the honeybee (Apis mellifera) venom allergen Api m 10 evaluated by protein array technology.
abstract: Api m 10 has recently been established as novel major allergen that is recognized by more than 60% of honeybee venom (HBV) allergic patients. Previous studies suggest Api m 10 protein heterogeneity which may have implications for diagnosis and immunotherapy of HBV allergy. In the present study, RT-PCR revealed the expression of at least nine additional Api m 10 transcript isoforms by the venom glands. Two distinct mechanisms are responsible for the generation of these isoforms: while the previously known variant 2 is produced by an alternative splicing event, novel identified isoforms are intragenic chimeric transcripts. To the best of our knowledge, this is the first report of the identification of chimeric transcripts generated by the honeybee. By a retrospective proteomic analysis we found evidence for the presence of several of these isoforms in the venom proteome. Additionally, we analyzed IgE reactivity to different isoforms by protein array technology using sera from HBV allergic patients, which revealed that IgE recognition of Api m 10 is both isoform- and patient-specific. While it was previously demonstrated that the majority of HBV allergic patients display IgE reactivity to variant 2, our study also shows that some patients lacking IgE antibodies for variant 2 display IgE reactivity to two of the novel identified Api m 10 variants, i.e. variants 3 and 4.
authors.affiliation: Laboratory of Molecular Entomology and Bee Pathology, Ghent University, Krijgslaan 281 S2, B-9000 Ghent, Belgium.
authors.forename: Matthias
authors.initials: M
authors.lastname: Van Vaerenbergh
authors.affiliation: Laboratory of Molecular Entomology and Bee Pathology, Ghent University, Krijgslaan 281 S2, B-9000 Ghent, Belgium.
authors.forename: Lina
authors.initials: L
authors.lastname: De Smet
authors.affiliation: Allergy Research Group, Department of Dermatology, University Medical Center Freiburg, Hauptstrasse 7, D-79104 Freiburg, Germany.
authors.forename: David
authors.initials: D
authors.lastname: Rafei-Shamsabadi
authors.affiliation: Center of Allergy and Environment (ZAUM), Technical University and Helmholtz Center Munich, Ingolstädter Landstraße 1, D-85764 Munich, Germany.
authors.forename: Simon
authors.initials: S
authors.lastname: Blank
authors.affiliation: Department of Engineering, Aarhus University, Gustav Wieds Vej 10, DK-8000 Aarhus C, Denmark.
authors.forename: Edzard
authors.initials: E
authors.lastname: Spillner
authors.affiliation: Department of Immunology, Allergology, and Rheumatology, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp, Belgium.
authors.forename: Didier G
authors.initials: DG
authors.lastname: Ebo
authors.affiliation: Laboratory of Protein Biochemistry and Biomolecular Engineering, Ghent University, K.L. Ledeganckstraat 35, B-9000 Ghent, Belgium.
authors.forename: Bart
authors.initials: B
authors.lastname: Devreese
authors.affiliation: Allergy Research Group, Department of Dermatology, University Medical Center Freiburg, Hauptstrasse 7, D-79104 Freiburg, Germany.
authors.forename: Thilo
authors.initials: T
authors.lastname: Jakob
authors.affiliation: Laboratory of Molecular Entomology and Bee Pathology, Ghent University, Krijgslaan 281 S2, B-9000 Ghent, Belgium. Electronic address: Dirk.deGraaf@UGent.be.
authors.forename: Dirk C
authors.initials: DC
authors.lastname: de Graaf
mesh_terms: D000485:Allergens / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D000595:Amino Acid Sequence; D000818:Animals; D001514:Bee Venoms / Q000276:immunology*; D001516:Bees / Q000276:immunology*; D005091:Exons / Q000235:genetics; D005786:Gene Expression Regulation; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology*; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D040081:Protein Array Analysis / Q000379:methods*; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D040901:Proteomics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D000485:Allergens; D001514:Bee Venoms; D019476:Insect Proteins; D020033:Protein Isoforms; D012333:RNA, Messenger; D007073:Immunoglobulin E
keywords: Allergy; Chimeric transcripts; Honeybee; Protein array; Venom