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Api m 10, a genuine A. mellifera venom allergen, is clinically relevant but underrepresented in therapeutic extracts

Authors


  • Edited by: Reto Crameri

Edzard Spillner, Institute of Biochemistry and Molecular Biology, Department of Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany. Tel.: ++49 40 42838 6982 Fax: ++49 40 42838 7255 E-mail: spillner@chemie.uni-hamburg.de
Markus Ollert, Clinical Research Division of Molecular and Clinical Allergotoxicology, Department of Dermatology and Allergy, Biederstein TUM, Biedersteiner Str. 29, 80802 Munich, Germany Tel.: ++49 89 4140 3550 Fax: ++49 89 4140 3552 E-mail: ollert@lrz.tum.de

Abstract

To cite this article:  Blank S, Seismann H, Michel Y, McIntyre M, Cifuentes L, Braren I, Grunwald T, Darsow U, Ring J, Bredehorst R, Ollert M, Spillner E. Api m 10, a genuine A. mellifera venom allergen, is clinically relevant but underrepresented in therapeutic extracts. Allergy 2011; 66: 1322–1329.

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.

Conclusion:  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.

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