Immunoblot study of IgE binding allergens in celery roots

The purpose of this study was to characterize the IgE binding components of celery root by immunoblot analysis and to investigate the cross-reactive nature of the allergens.

Sensitization to celery is very common in patients hypersensitive to mugwort pollen and birch pollen, and is due to cross-reactions of allergen-specific IgE antibodies. Recently, the pan-allergen profilin has been identified as an important cross-reactive allergen in celery, birch pollen and mugwort pollen. Very few data, however, on additional celery allergens are available.

Sera of 38 patients with an isolated or combined sensitization to birch pollen, mugwort pollen, and celery were investigated by immunoblot and immunoblot inhibition techniques using celery extract and purified Bet v I, the major allergen from birch pollen. The selection of sera was based on serologic sensitization, independent of clinical manifestations. Celery profilin was affinity isolated and analyzed by immunoblotting with patients' sera as well as with rabbit polyclonal antiserum raised against celery profilin.

Only weak IgE binding occurred on celery immunoblots in the patient groups with a negative RAST to celery. Sera of 6/8 patients with a birch pollen/celery sensitization recognized a 16-kDa celery allergen that cross-reacted with Bet v I in immunoblot inhibition experiments. In the mugwort pollen/celery and birch pollen/mugwort pollen/celery patient groups, the sera of 6/16 patients contained IgE that bound to a 15 to 16-kDa double band identified as celery profilin. Furthermore, three sera of the birch pollen/mugwort pollen/celery group appeared to contain IgE antibodies against carbohydrate determinants.

The 16-kDa Bet v I-related celery protein appears to be an important allergen for patients sensitized to birch pollen and celery. In contrast IgE binding to celery profilin appears to be more important in patients with an additional sensitization to mugwort pollen.