Structural and Immunological Characterization of Recombinant Pan b 1, a Major Allergen of Northern Shrimp, <b><i>Pandalus borealis</i></b>

• Published in: International Archives of Allergy and Immunology
• Main Authors: Myrset, Heidi R., Barletta, Bianca, Di Felice, Gabriella, Egaas, Eliann, Dooper, Maaike M.B.W.
• Format: Article in Journal/Newspaper
• Language: English
• Published: S. Karger AG 2012
• Subjects: Immunology; General Medicine; Immunology and Allergy; Norway; northern shrimp; Pandalus borealis
• Online Access: http://dx.doi.org/10.1159/000339740; https://www.karger.com/Article/Pdf/339740

<b><i>Background:</i></b> Shellfish allergy is one of the major causes of life-threatening allergic reactions to food. The shrimp species <i>Pandalus borealis</i> is the commercially most important coldwater shrimp species, and its protein extract is commonly used in shrimp allergy diagnostics. However, the DNA sequence of its major allergen, tropomyosin, designated Pan b 1, was not previously described. Our aim was to identify the cDNA sequence of Pan b 1 and to generate a recombinant protein with similar structure and allergenicity as the natural protein. <b><i>Methods:</i></b><i>P. borealis</i> shrimps were caught in the Oslofjord (Norway). cDNA from Pan b 1 was generated, an N-terminal histidine tag was added, and the protein was expressed in <i>Escherichia coli</i>. The recombinant Pan b 1 was characterized by structural and IgE-binding studies and investigated further with basophil activation tests (BATs) and skin prick tests (SPTs) on Norwegian shrimp-allergic individuals. <b><i>Results:</i></b> The open reading frame encoded 284 amino acids that shared 97–100% identity with other shrimp tropomyosins. Mass spectroscopy of natural Pan b 1 confirmed the protein’s molecular mass and indicated the absence of posttranslational modifications. Circular dichroism spectroscopy revealed virtually identical spectra between recombinant and natural Pan b 1, which together with native PAGE and size exclusion chromatography results indicated a similar structure. Furthermore, immunoblot and ELISA studies as well as BATs and SPTs showed equivalent results of recombinant and natural Pan b 1. <b><i>Conclusion:</i></b> A recombinant tropomyosin from <i>P. borealis</i> was generated that can be ...