BACKGROUND: Crab sensitivity is one of the most common seafood allergies. However, to date, there has been no report on the molecular characterization of crab allergens and no comparative analysis with other seafood allergens. OBJECTIVE: This study was undertaken to clone, identify, and determine the primary structure of a major IgE-reactive molecule in crab. METHODS: We constructed an expression cDNA library from a common crab, Charybdis feriatus. This library was then screened with the use of sera from subjects with a well-documented history of type I hypersensitivity reactions upon ingestion of crab. An IgE-reactive clone was chosen and subcloned into plasmids for nucleotide sequence determination and expression in Escherichia coli. RESULTS: We identified a 1-kb cDNA designated as Cha f 1. Expression of Cha f 1 produces a 34-kd recombinant protein reactive to the IgE antibodies from patients with crab allergies but not from control subjects. Cha f 1 has an opening reading frame of 264 amino acids and demonstrates marked homology to the shrimp tropomyosin Met e 1. Absorption of allergic sera with Cha f I removes IgE reactivity to crab extract. Moreover, absorption of allergic sera with recombinant shrimp Met e 1 tropomyosin removes IgE reactivity to Cha f 1. CONCLUSIONS: This 34-kd protein, designated as Cha f 1, is the first identified major allergen of crab. Nucleotide and amino acid comparison shows that this protein is the crab tropomyosin. The molecular basis of shrimp and crab allergy is readily demonstrated at the nucleotide and amino acid level.
BACKGROUND: Crab sensitivity is one of the most common seafood allergies. However, to date, there has been no report on the molecular characterization of crab allergens and no comparative analysis with other seafood allergens. OBJECTIVE: This study was undertaken to clone, identify, and determine the primary structure of a major IgE-reactive molecule in crab. METHODS: We constructed an expression cDNA library from a common crab, Charybdis feriatus. This library was then screened with the use of sera from subjects with a well-documented history of type I hypersensitivity reactions upon ingestion of crab. An IgE-reactive clone was chosen and subcloned into plasmids for nucleotide sequence determination and expression in Escherichia coli. RESULTS: We identified a 1-kb cDNA designated as Cha f 1. Expression of Cha f 1 produces a 34-kd recombinant protein reactive to the IgE antibodies from patients with crab allergies but not from control subjects. Cha f 1 has an opening reading frame of 264 amino acids and demonstrates marked homology to the shrimp tropomyosin Met e 1. Absorption of allergic sera with Cha f I removes IgE reactivity to crab extract. Moreover, absorption of allergic sera with recombinant shrimp Met e 1 tropomyosin removes IgE reactivity to Cha f 1. CONCLUSIONS: This 34-kd protein, designated as Cha f 1, is the first identified major allergen of crab. Nucleotide and amino acid comparison shows that this protein is the crab tropomyosin. The molecular basis of shrimp and crab allergy is readily demonstrated at the nucleotide and amino acid level.
Authors: Eugene V Ravkov; Igor Y Pavlov; Thomas B Martins; Gerald J Gleich; Lori A Wagner; Harry R Hill; Julio C Delgado Journal: Hum Immunol Date: 2013-08-28 Impact factor: 2.850
Authors: Roberto Romero; Juan Pedro Kusanovic; Hernan Muñoz; Ricardo Gomez; Ronald F Lamont; Lami Yeo Journal: J Matern Fetal Neonatal Med Date: 2010-04
Authors: Shuping Wang; Julio C Delgado; Eugene Ravkov; David D Eckels; Ann Georgelas; Igor Y Pavlov; Matthew Cusick; Kate Sebastian; Gerald J Gleich; Lori A Wagner Journal: Hum Immunol Date: 2011-12-28 Impact factor: 2.850
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