| Abstrakt: |
BACKGROUND: Pen al is a major allergen in shrimp. It is a 284 amino acid protein member of the tropomyosin family with a molecular weight of 36 kDa. Irradiation and heat treatments have been previously shown to reduce the immunoreactivity of Pen al, but since anaphylaxis is not induced by the whole protein but by epitopes within the protein, studying of the influence of these treatments on the epitopes of Pen al is helpful for understanding the sensitization mechanism. In this study, the immunoreactivity of the five epitopes of Pen al exposed to heat and irradiation treatments was detected by Ci-ELISA and western blot, using specific anti-sera generated from 5 synthesized epitope peptides of Pen al. We examined the function of each epitope in the sensitization process by analyzing the variations of their immunoreactivity following irradiation, heat treatment, or a combination of both. RESULTS: Pen al was treated by gamma irradiation, heat at 100°C or a combination of irradiation and heat. The IC50 value for each of the five epitopes was detected. The IC50 value of epitopes 1, 2, and 4 decreased under all treatments, especially epitope 4; its IC50 value decreased sharply from 15.88 to 0.11 following 7 kGy irradiation and to 0.03 - 0.04 under 10 kGy or 7 kGy irradiation and heat. The IC50 value of epitope 3 increased from 1.49 to 5.32 under 7 kGy irradiation and to 10.03 under 7kGy and heat, but mildly decreased after 10 kGy irradiation. In contrast, the IC50 value of epitope 5 hardly changed following any treatments. CONCLUSION: The variation in the IC50 values of epitope 3 was consistent with the IC50 values measured from the whole Pen al protein, while epitope 5 was stable following irradiation and heat treatments. Since the variation of immunoreactivity of epitope 3 was consistent with Pen al, this suggests that epitope 3 is the determinative epitope in the allergenicity of Pen al; epitope 5 was stable with all treatment conditions, suggesting that it could be used in immunoassay kits for the detection of treated shrimp. [ABSTRACT FROM AUTHOR] |
