title: Api m 10, a genuine A. mellifera venom allergen, is clinically relevant but underrepresented in therapeutic extracts.
abstract: BACKGROUND
  Generalized systemic reactions to stinging hymenoptera venom constitute a potentially fatal condition in venom-allergic individuals. Hence, the identification and characterization of all allergens is imperative for improvement of diagnosis and design of effective immunotherapeutic approaches. Our aim was the immunochemical characterization of the carbohydrate-rich protein Api m 10, an Apis mellifera venom component and putative allergen, with focus on the relevance of glycosylation. Furthermore, the presence of Api m 10 in honeybee venom (HBV) and licensed venom immunotherapy preparations was addressed.
  
  
  METHODS
  Api m 10 was produced as soluble, aglycosylated protein in Escherichia coli and as differentially glycosylated protein providing a varying degree of fucosylation in insect cells. IgE reactivity and basophil activation of allergic patients were analyzed. For detection of Api m 10 in different venom preparations, a monoclonal human IgE antibody was generated.
  
  
  RESULTS
  Both, the aglycosylated and the glycosylated variant of Api m 10 devoid of cross-reactive carbohydrate determinants (CCD), exhibited IgE reactivity with approximately 50% of HBV-sensitized patients. A corresponding reactivity could be documented for the activation of basophils. Although the detection of the native protein in crude HBV suggested content comparable to other relevant allergens, three therapeutical HBV extracts lacked detectable amounts of this component.
  
  
  CONCLUSIONS
  Api m 10 is a genuine allergen of A. mellifera venom with IgE sensitizing potential in a significant fraction of allergic patients independent of CCD reactivity. Thus, Api m 10 could become a key element for component-resolved diagnostic tests and improved immunotherapeutic approaches in hymenoptera venom allergy.
authors.affiliation: Institute of Biochemistry and Molecular Biology, University of Hamburg, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Blank
authors.forename: H
authors.initials: H
authors.lastname: Seismann
authors.forename: Y
authors.initials: Y
authors.lastname: Michel
authors.forename: M
authors.initials: M
authors.lastname: McIntyre
authors.forename: L
authors.initials: L
authors.lastname: Cifuentes
authors.forename: I
authors.initials: I
authors.lastname: Braren
authors.forename: T
authors.initials: T
authors.lastname: Grunwald
authors.forename: U
authors.initials: U
authors.lastname: Darsow
authors.forename: J
authors.initials: J
authors.lastname: Ring
authors.forename: R
authors.initials: R
authors.lastname: Bredehorst
authors.forename: M
authors.initials: M
authors.lastname: Ollert
authors.forename: E
authors.initials: E
authors.lastname: Spillner
mesh_terms: D000485:Allergens / Q000235:genetics / Q000276:immunology* / Q000627:therapeutic use; D000818:Animals; D001491:Basophils / Q000276:immunology; D001514:Bee Venoms / Q000235:genetics / Q000276:immunology* / Q000627:therapeutic use; D001516:Bees / Q000235:genetics / Q000276:immunology*; D003429:Cross Reactions / Q000276:immunology; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D007299:Insect Bites and Stings / Q000276:immunology / Q000628:therapy; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology / Q000627:therapeutic use
chemical_list: D000485:Allergens; C569170:Api m 10 allergen, Apis mellifera; D001514:Bee Venoms; D011994:Recombinant Proteins; D007073:Immunoglobulin E