INFLUENCE OF FOOD-PROCESSING ON THE IMMUNOCHEMICAL STABILITY OF CELERY ALLERGENS

Celery roots were processed by microwave heating, cooking, drying, gam ma-irradiation, ultra high pressure treatment and high voltage impulse treatment. The immunochemical stabilities of the three known allergen ic structures of celery were tested with sera from patients who were s ensitised to celery. In addition, rabbit antisera were used to detect the allergens profilin and Api g 1 on celery immunoblots. The specific ity and reactivity of IgE from the patients' sera were investigated by immunoblotting, by an enzyme allergosorbent test (EAST) and by dose-r elated IgE inhibition experiments. The results of all three methods ag reed closely and indicated high antigenic and allergenic activity in n ative celery which was reduced by thermal processing. The heat-stabili ty of the known celery allergens decreased in the following order: car bohydrate epitopes > profilin > Api g l. In contrast, the allergenicit y was only mildly reduced by nonthermal processing. The results obtain ed with human IgE were confirmed by an in vitro mediator-release assay that is based on rat basophil leukemia cells (RBL cells) which were p assively sensitised with celery-specific murine IgE. With sera from mi ce that had been immunised with native celery, the native sample and n on-thermal celery preparations elicited the strongest mediator release , whereas a weak response was obtained with samples from heat-processe d celery. These results agreed closely with the data obtained in aller gic patients whose IgE antibodies were directed against the major prot ein allergen Api g l. Our results may be helpful in risk assessment an d in selecting food preparations which can be consumed without symptom s by a subgroup of celery-allergic patients with a known sensitisation pattern.