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Novel sequences and epitopes of diagnostic value derived from the Anisakis simplex Ani s 7 major allergen *
Author(s) -
Rodríguez E.,
Anadón A. M.,
GarcíaBodas E.,
Romarís F.,
Iglesias R.,
Gárate T.,
Ubeira F. M.
Publication year - 2008
Publication title -
allergy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.363
H-Index - 173
eISSN - 1398-9995
pISSN - 0105-4538
DOI - 10.1111/j.1398-9995.2007.01564.x
Subject(s) - anisakis simplex , allergen , anisakis , epitope , simplex , immunology , value (mathematics) , biology , allergy , medicine , virology , mathematics , ecology , antibody , combinatorics , larva , statistics
Background: Anisakis simplex allergens may cause severe allergic reactions in infected patients. Human anisakiasis can be specifically diagnosed by detection of immunoglobulin E (IgE) antibodies against O ‐deglycosylated nAni s 7 allergen captured by monoclonal antibody (mAb) UA3 (UA3‐ELISA), although the nature of this important allergen is unknown. The aim of this study was to clone and characterize the Ani s 7 major allergen, and to obtain a recombinant fragment suitable for serodiagnosis. Methods: An Anisakis cDNA library was screened with mAb UA3 and a cDNA clone (rAni s 7) encoding a 1096‐amino acid fragment of Ani s 7 (GenBank: EF158010 ) was identified. Bioinformatic tools and immunological and biochemical techniques were used to characterize the allergen obtained. Results: The rAni s 7 fragment comprised 19 repeats of a novel C X 17−25 C X 9−22 C X 8 C X 6 tandem repeat motif not seen in any previously reported protein sequence. An internal 435 Met– 713 Arg fragment of the rAni s 7 (t‐Ani s 7) was expressed in Escherichia coli and evaluated for serodiagnostic utility. Indirect enzyme‐linked immunosorbent assay (ELISA) with t‐Ani s 7 identified as positive the same 60 sera as UA3‐ELISA. The sequence MCQCVQKYGTEFCKKRLA from rAni s 7 was identified as the epitope recognized by mAb UA3, and is the target for over 60% of human IgE antibodies that react with O ‐deglycosylated nAni s 7. Conclusions: In addition to their clear value for serodiagnosis of human anisakiasis, the nature of the novel sequences and epitopes identified in the Ani s 7 allergen are of interest for a better understanding of the mechanisms operating in Anisakis ‐induced allergy.