Measurement of specific IgE to abalone(Haliotis discus hannai) and identification of IgE binding components

Abstract

Background : Abalone, which is a member of the shellfish family, can often induce severe allergic reactions in sensitized individuals, but there have beenonly a few studies ofn its allergenic components. A recent study has identified two major allergens with molecular weights of 38 and 49 kDa in South African abalone. Objectives : The aim of this study is to evaluate skin test prevalence and IgE sensitization to northern disk abalone (Haliotis discus hannai) which is one of the major abalones in this country, and to identify its allergenic components. Methods : Skin prick tests were performed with 62 home-made extracts of domestic foods including abalone, turban shell, triton shell, shrimp etc. in 1,738 patients with various allergic diseases. Serum specific IgE antibodies to abalone were determined by ELISA in 81 positive responders on skin prick tests to abalone extract and 40 non-atopic healthy controls. ELISA inhibition tests were performed to evaluate cross-allergenecity between abalone and other sea foods(turban shell, triton shell, shrimp and house dust mite). Allergenic components of Haliotis discus hannai were identified by SDS-PAGE and IgE-immunoblot analysis. Results : The positive response rate(A/H ratio≥2+) to abalone on skin prick test was 4.7% in patients with various allergic diseases. Serum spcecific IgE to abalone was detected in 23(34.5%) of 67 patients. Serum specific IgE levels to abalone tended to increase according to skin test reactivity without statistical significance(p〉0.05). ELISA inhibition tests showed significant dose-dependent inhibitions with addition of turban shell, triton shell and shrimp extracts IgE immunoblot analysis showed ten allergenic components (33, 37, 40, 60, 63, 71, 76, 86, 92, 111 kDa), of which seven allergens (40, 60, 63, 71, 76, 86, 92 kd) were bound to IgE in more than 50% of the sera tested. Conclusion : The sensitization rate to abalone was 4.7% in allergy patients. Serum specific IgE to abalone was detected by ELISA, and 7 major allergens within abalone were identified. Further studies will be needed to elucidate their clinical significances.