Identification of the Major Allergen in the Shrimp (Metapenaeus Joynen): Effects of Heating and Digestive Enzymes

Abstract

Background: Shrimp is one of the major causative food allergens in this country. We reported IgE-prevalence and its IgE binding components of the home made shrimp (M. joyneri) extracts in allergy patients in this country. The Property of food allergens can be changed by heat or digestion enzymes. We observed the changes of IgE binding components of Metapenaeus joyneri with exposure to heat￢ing and digestive enzymes in ex vivo system. Method: IgE immunoblot was applied to analyze the changes of IgE binding components within the fresh and boiled shrimps in sera from five patients with allergy showing strong positive reactions (A/H ? 2+) to the skin prick test and high serum specific IgE (>_ 100 A.U) to the shrimp. To evaluate heating and enzyme effects, heating, SGF (gastric fluid, simulated) and SIF (intestinal fluid, simulated) were treated for 10, 30 and 90 minutes and SDS-PAGE and IgE-immunoblot were repeated. To identify the major allergens, 2-D electrophoresis and IgE-immunoblot were followed by amino acid sequence analysis using MALDI-TOF and FASTF program. Result: The 45 kDa band was resistant to heating in three of five patients. In the fresh shrimp, 36-45 kDa bands remained after SGF treatment, while minimal changes were noted after SIF treatment. The 2D-immunoblot of 45 kDa demonstrated two spots (pl 5.1, 4.75), and one (pI 5.1) was identified as an arginine kinase having 100% homology with European lobster by amino acid analysis. Conclusion: The major allergen of M. joyneri was identified as an arginine kinase which was resistant to heating and digestion enzymes. (Korean J Asthma, Allergy Clin Immunol 2004;24:211-216)