Allergen analysis of buckwheat by the immunoblotting method

Inhalation or ingestion of very small amounts of buckwheat allergen can initiate severe symptoms including wheezing, rhinorrhea, urticaria, vomiting and anaphylactic shock in patients with hypersensitivity against buckwheat. However, few studies of the immunological properties of buckwheat allergen have been made. The aim of the present investigation was to analyze the allergen in buckwheat antigen using the immunoblotting method, radioallergosorbent test (RAST) and RAST inhibition assay. Buckwheat 24 kilodalton protein (BW24KD) was shown by immunoblotting analysis to be the most frequently recognized allergenic component, binding to IgE antibodies from 100% of the patients' sera. There was a significant positive correlation (p < 0.001) between % bindings for BW24KD and buckwheat. In the RAST inhibition assay using patients' sera which showed positive IgE antibodies to buckwheat and BW24KD, there was effective inhibition in a dose-dependent manner between inhibition in a dose-dependent manner between BW24KD and buckwheat. These data indicated that BW24KD was a major allergen in buckwheat antigens. The experiments of SDS-PAGE using digestion buffer with or without 2-mercaptoethanol suggested that BW24KD was a component of heterodimer and the paired components had different molecular weights.