Definition of immunogenic carbohydrate epitopes.

Area of Science:

• Immunology
• Glycobiology
• Allergen research

Background:

• Carbohydrates are significant sources of immunological cross-reactivity in allergies.
• Major allergens like Api g 5 (celery) and Cup a 1 (cypress pollen) exhibit cross-reactivity.
• These allergens bind to IgE and react with anti-horseradish peroxidase (HRP).

Purpose of the Study:

• To investigate the structural basis of carbohydrate-mediated cross-reactivity in allergens.
• To explore the role of invertebrate enzymes in synthesizing cross-reactive carbohydrate epitopes.
• To assess the utility of invertebrate fucosyltransferases for generating standard allergenic compounds.

Main Methods:

• Mass spectrometric analysis of tryptic peptides and N-glycans from celery and cypress pollen allergens.
• Genetic and biochemical studies on fucosyltransferases in Drosophila melanogaster and Caenorhabditis elegans.
• In vivo and in vitro experiments to synthesize N-glycans using invertebrate fucosyltransferases.

Main Results:

• Oligosaccharides with xylose and core alpha1,3-fucose residues were identified in Api g 5 and Cup a 1 N-glycans.
• Invertebrates like fruit flies and worms possess core alpha1,3-fucosyltransferases.
• Fucosyltransferases from fruit flies and worms synthesized N-glycans that cross-reacted with anti-HRP.

Conclusions:

• Core alpha1,3-fucose residues are key structures in allergenic cross-reactivity.
• Invertebrate core alpha1,3-fucosyltransferases are responsible for synthesizing these cross-reactive N-glycans.
• These enzymes represent valuable tools for producing standard compounds for testing allergenic carbohydrate epitopes.