Quantification of major peanut allergens Ara h 1 and Ara h 2 in the peanutvarieties Runner, Spanish, Virginia, and Valencia, bred in different partsof the world

Background: The serology of peanut allergy seems to be different in various parts of the world. We analyzed the composition of 13 samples of three var ieties of peanut in order to compare their allergenic nature. Methods: Peanut cultivars that are commonly processed in the West were anal yzed for protein content, protein composition, and Ara h 1 and Ara h 2 cont ent by biochemical methods. IgE-binding properties were analyzed by ELISA u sing serum from patients with documented peanut allergy. Results: Total protein contents were comparable for all tested samples (24- 29%), and proteins were extractable to the same extent. SDS-PAGE patterns d iffered slightly, but all major bands were visible in all samples (molecula r masses of approximately 14-100 kDa under reducing conditions). Ara h 1 an d Ara h 2 were quantified by SDS-PAGE densitometry and were expressed as pe rcentage of the total protein content. Ara h 1 was in the range 12-16%, whe reas Ara h 2 was 5.9-9.3%. In view of the analytic uncertainty of this dete rmination, the content of both Ara h 1 and Ara h 2 was not significantly di fferent between the tested samples. In an IgE-binding inhibition ELISA, the affinities of the peanut proteins for peanut-specific IgE were measured. M inor differences were observed between the tested samples, with the most po tent IgE-binding sample having a two times higher ability to bind IgE than the weakest IgE-binding sample. Conclusions: The results suggest that peanuts of different varieties and fr om different parts of the world contain similar proteins, including Ara h I and Ara h 2. Consequently, the IgE-binding properties are similar to a gre at extent. This indicates that differences in the serology of peanut allerg y may not originate from differences in the allergen composition of the pea nut.