Cross‐reactive N‐glycans of Api g 5, a high molecular weight glycoprotein allergen from celery, are required for immunoglobulin E binding and activation of effector cells from allergic patients

  title={Cross‐reactive N‐glycans of Api g 5, a high molecular weight glycoprotein allergen from celery, are required for immunoglobulin E binding and activation of effector cells from allergic patients},
  author={Merima Bublin and Christian Radauer and Iain B. H. Wilson and Dietrich Kraft and Otto Scheiner and Heimo Breiteneder and Karin Hoffmann‐Sommergruber},
  journal={The FASEB Journal},
Allergy diagnosis relying on the determination of specific IgE is frequently complicated by the presence of cross‐reacting IgE of unclear clinical relevance. Particularly, the anaphylactogenic activity of IgE directed to cross‐reactive carbohydrate moieties of glycoproteins from plants and invertebrates has been a matter of debate. In this study, we present the biochemical and immunological characterization of Api g 5, a glycoprotein allergen from celery with homology to FAD containing oxidases… 

Definition of immunogenic carbohydrate epitopes.

Various experiments have shown that fucosyltransferases from both fly and worm are responsible in vivo and in vitro for the synthesis of N-glycans which cross-react with anti-horseradish peroxidase, so these enzymes can be considered as useful tools in generating standard compounds for testing cross-reactive carbohydrate epitopes of allergenic interest.

Allergenic relevance of nonspecific lipid transfer proteins 2: Identification and characterization of Api g 6 from celery tuber as representative of a novel IgE-binding protein family.

Despite similar structural and physicochemical features as nsLTP1, immunological properties of Api g 6 are distinct which warrants its inclusion in molecule-based diagnosis of A. graveolens allergy.

Purification and structural analysis of the novel glycoprotein allergen Cyn d 24, a pathogenesis‐related protein PR‐1, from Bermuda grass pollen

This is the first study to identify any grass pollen allergen as a pathogenesis‐related protein’1, and the results of the sequence alignment indicate that this novelAllergen is a pathogen‐relatedprotein.

Human IgE Antibodies Against Cross-Reactive Carbohydrate Determinants

It is well-documented in allergology now that IgE antibodies may be directed also against carbohydrates attached to carrier proteins, namely β-arabinose-containing O-linked glycans in mugwort pollen allergy, and α-galactose (αGal) in allergic reactions to meat and certain biologicals.

Molecular characterization of Api g 2, a novel allergenic member of the lipid-transfer protein 1 family from celery stalks.

It can be anticipated that inclusion of recombinant Api g 2 in the current panel of allergens for molecule-based diagnosis will facilitate the evaluation of the clinical relevance of nsLTP sensitization in celery allergy and help clinicians in the management of food allergic patients.

Role of the polypeptide backbone and post-translational modifications in cross-reactivity of Art v 1, the major mugwort pollen allergen

It is concluded that Art v 1 is poorly involved in mugwort cross-reactivity to food allergens.

The Role of Protein Glycosylation in Allergy

  • F. Altmann
  • Biology
    International Archives of Allergy and Immunology
  • 2006
Low binding affinity between IgE and plant N-glycans now drops out as a plausible explanation for the benign nature of CCDs, which may result from blocking antibodies induced by an incidental ‘immune therapy’ exerted by everyday contact with plant materials.

Reduction of Cross-Reactive Carbohydrate Determinants in Plant Foodstuff: Elucidation of Clinical Relevance and Implications for Allergy Diagnosis

This proof-of-principle study demonstrates feasibility of CCD-reduced foodstuff in patients with carbohydrate-specific IgE to minimize ‘false-positive results’ in routine serum tests.

Carbohydrate epitopes currently recognized as targets for IgE antibodies

The features of the main glycan groups known to be involved in IgE recognition are revisited, and their characteristic structural, functional, and clinical features are discussed.



Involvement of Carbohydrate Epitopes in the IgE Response of Celery–Allergic Patients

The results demonstrate that IgE specific for CCD is common in celery–allergic patients, and can represent the major proportion of IgE against this food, and show that proteins carrying multiple glycan units can be biologically active in patients sensitized to CCD.

N- and O-linked oligosaccharides of allergenic glycoproteins

This review is focused on glycosidic epitopes of oligosaccharides linked to allergenic glycoproteins, showing that complex plant N-glycans containing α1,3 fucose and β1,2 xylose are most frequently involved in the structures of IgE epitopes.

Fucose alpha 1,3-linked to the core region of glycoprotein N-glycans creates an important epitope for IgE from honeybee venom allergic individuals.

It is concluded that alpha 1,3-fucosylation of the innermost N-acetylglucosamine residue of N-glycoproteins forms an IgE-reactive determinant.

Carbohydrate Epitopes and Their Relevance for the Diagnosis and Treatment of Allergic Diseases

  • R. Van Ree
  • Biology
    International Archives of Allergy and Immunology
  • 2002
Allergenicity of plant and invertebrate N-glycans has been shown to be caused by the presence of two typical nonmammalian substitutions, but cross-reactive IgE antibodies against these carbohydrate structures have never been convincingly shown to induce clinical food allergy.

Core alpha1,3-fucose is a key part of the epitope recognized by antibodies reacting against plant N-linked oligosaccharides and is present in a wide variety of plant extracts.

It is concluded that the alpha1, 3-fucose residue linked to the chitobiose core of plant glycoproteins is the most important residue in the epitope recognized by the two antibodies studied, but that the polyclonal anti-horseradish peroxidase antiserum also contains antibody populations that recognize the xyloselinked to the core mannose of many plant and gastropod N-linked oligosaccharides.

Specific IgE to cross-reactive carbohydrate determinants strongly affect the in vitro diagnosis of allergic diseases.

Clinical relevance of carbohydrate allergen epitopes

This topic is particularly relevant in relation to false-positive serology: IgE antibodies reactive to foods in the absence of overt food allergy (a longstanding issue in allergic serology).

Poor biologic activity of cross-reactive IgE directed to carbohydrate determinants of glycoproteins.