BACKGROUND: Krill, which morphologically resembles small shrimp, represents small ocean crustaceans and has been used for human consumption in Japan and some other countries. The major allergen in crustaceans has been reported to be tropomyosin, but the allergenicity of krill tropomyosin remains uncertain. METHODS: Amino acid sequences of tropomyosin in two species of krill (Euphausia superba and E. pacifica) were deduced. Recombinant krill tropomyosins were produced in Escherichia coli using a pCold IV vector system, and the cross-reactivity of shrimp allergy-related IgE to the recombinant tropomyosins and several animal protein extracts was assessed by immunoblotting. RESULTS: The deduced amino acid sequences of the E. superba and E. pacifica tropomyosins (designated as Eup s 1 and Eup p 1, respectively) were 284 residues and showed significant homology to those of shrimp, lobster and crab tropomyosins. Shrimp allergy-related IgE reacted to approximately 38-kDa protein bands in krill (E. superba), shrimp, lobster and crab protein extracts but did not react to protein extracts from either mollusks or vertebrates. Furthermore, the IgE recognized rEup s 1 and rEup p 1 as 38-kDa protein bands, and absorption of the IgE with rEup s 1 removed IgE reactivity to recombinant tropomyosins and protein extracts from krill and shrimp. CONCLUSIONS: Krill tropomyosins included highly homologous sequences to previously reported IgE-binding epitopes in Pen a 1 (tropomyosin of Penaeus aztecus). The cross-reactivity in shrimp allergy-related IgE binding among krill, shrimp, lobster and crab tropomyosins was revealed. These observations suggest the potential allergenicity of krill tropomyosin. 2007 S. Karger AG, Basel
BACKGROUND: Krill, which morphologically resembles small shrimp, represents small ocean crustaceans and has been used for human consumption in Japan and some other countries. The major allergen in crustaceans has been reported to be tropomyosin, but the allergenicity of krill tropomyosin remains uncertain. METHODS: Amino acid sequences of tropomyosin in two species of krill (Euphausia superba and E. pacifica) were deduced. Recombinant krill tropomyosins were produced in Escherichia coli using a pCold IV vector system, and the cross-reactivity of shrimp allergy-related IgE to the recombinant tropomyosins and several animal protein extracts was assessed by immunoblotting. RESULTS: The deduced amino acid sequences of the E. superba and E. pacifica tropomyosins (designated as Eup s 1 and Eup p 1, respectively) were 284 residues and showed significant homology to those of shrimp, lobster and crab tropomyosins. Shrimp allergy-related IgE reacted to approximately 38-kDa protein bands in krill (E. superba), shrimp, lobster and crab protein extracts but did not react to protein extracts from either mollusks or vertebrates. Furthermore, the IgE recognized rEup s 1 and rEup p 1 as 38-kDa protein bands, and absorption of the IgE with rEup s 1 removed IgE reactivity to recombinant tropomyosins and protein extracts from krill and shrimp. CONCLUSIONS: Krill tropomyosins included highly homologous sequences to previously reported IgE-binding epitopes in Pen a 1 (tropomyosin of Penaeus aztecus). The cross-reactivity in shrimp allergy-related IgE binding among krill, shrimp, lobster and crab tropomyosins was revealed. These observations suggest the potential allergenicity of krill tropomyosin. 2007 S. Karger AG, Basel
Authors: Nicki Y H Leung; Christine Y Y Wai; ShangAn Shu; Jinjun Wang; Thomas P Kenny; Ka Hou Chu; Patrick S C Leung Journal: Clin Rev Allergy Immunol Date: 2014-06 Impact factor: 8.667