The Major Allergen from Hen's Egg White: Ovomucoid (Gal d 1)

Ovomucoid (OM) is the dominant allergen from hen's egg white. Frequency of sensitization to OM varies from 34-97% in egg allergic patients. The carbohydrate moieties of OM present up to 22-29%. It consists of 186 amino acids forming three tandem domains, each providing trypsin inhibitory activity. Effective isolation and purification of OM was attained by combined IEC / SEC and by automated fraction collection using capillary zone electrophoresis. Matrix-assisted laser desorption / ionisation time of flight (MALDI-TOF) mass spectrometry revealed an average Mr of 28.0 kDa. Immunoblot and RAST inhibition experiments of native and deglycosylated OM indicate that only peptide epitopes participate in IgEbinding structures of OM. All 3 domains exhibit IgEbinding potencies. At least 8 independent IgE binding regions using synthetic peptides of OM were identified. T-cell proliferative response in PBMC from egg allergic patients could be induced by all 3 domains, predominantly by the second and third domains. (Internet Symposium on Food Allergens 1999, 1(4):137-46) food allergy egg white ovomucoid posttranslational modifications B-cell epitopes T-cell proliferation SDS-PAGE IEC / SEC capillary electrophoresis MALDI-TOF