title: Glycoproteins are species-specific markers and major IgE reactants in grass pollens.
abstract: Grass pollen allergic patients are concomitantly exposed and sensitized to pollens from multiple Pooideae (i.e. common grass) species. As such, they are currently desensitized by allergen-specific immunotherapy using extracts made from mixes of pollens from Anthoxanthum odoratum, Dactylis glomerata, Lolium perenne, Phleum pratense and Poa pratensis. Herein, we demonstrate that species-specific glycoprotein patterns are documented by 1D and 2D electrophoresis and Western blotting analysis, which can be used as an identity test for such pollens. Most allergens are glycoproteins bearing complex N-glycans encompassing β1,2 xylose and α1,3 fucose glycoepitopes. Glycoepitope destruction using periodate oxidation has no impact on seric IgE reactivity in 75% atopic patients (n = 24). The latter have thus no significant IgE responses to carbohydrate-containing epitopes. In contrast, periodate treatment strongly impairs IgE recognition of glycoallergens in 25% of patients tested, demonstrating the presence of carbohydrate-specific IgE in those patients. While the clinical impact of carbohydrate-specific IgE is still a matter of controversy, the presence of these IgE in the serum of many allergic patients illustrates the need for cross-reacting carbohydrate epitope-free recombinant allergens to develop relevant diagnostic tests. These data also support the pertinence of mixing multiple grass pollens to desensitize atopic patients, with the aim to broaden the repertoire of glycoepitopes in the vaccine, thus mimicking natural exposure conditions.
authors.affiliation: 1ANGANY Genetics, Seine Biopolis, 70 route de Lyons, 76000 Rouen, France 2Stallergènes SA, 6 rue Alexis de Tocqueville, 92160 Antony, France.
authors.forename: Hélène
authors.initials: H
authors.lastname: Manduzio
authors.forename: Anne-Catherine
authors.initials: AC
authors.lastname: Fitchette
authors.forename: Maud
authors.initials: M
authors.lastname: Hrabina
authors.forename: Henri
authors.initials: H
authors.lastname: Chabre
authors.forename: Thierry
authors.initials: T
authors.lastname: Batard
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Nony
authors.forename: Loïc
authors.initials: L
authors.lastname: Faye
authors.forename: Philippe
authors.initials: P
authors.lastname: Moingeon
authors.forename: Véronique
authors.initials: V
authors.lastname: Gomord
mesh_terms: D000485:Allergens / Q000276:immunology*; D015415:Biomarkers; D003429:Cross Reactions; D015180:Electrophoresis, Gel, Two-Dimensional; D006023:Glycoproteins / Q000276:immunology*; D007073:Immunoglobulin E / Q000276:immunology*; D006109:Poaceae / Q000276:immunology*; D011058:Pollen / Q000276:immunology*; D013045:Species Specificity
chemical_list: D000485:Allergens; D015415:Biomarkers; D006023:Glycoproteins; D007073:Immunoglobulin E