Novel sequences and epitopes of diagnostic value derived from the Anisakis simplex Ani s 7 major allergen.

Abstract

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 CX(17-25)CX(9-22)CX(8)CX(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.

• Authors: E Rodríguez, A M Anadón, E García-Bodas, F Romarís, R Iglesias, T Gárate, F M Ubeira
• Journal: Allergy (Allergy) Vol. 63 Issue 2 Pg. 219-25 (Feb 2008) ISSN: 1398-9995 [Electronic] Denmark
• PMID: 18186812 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Allergens
• Antibodies, Helminth
• Antigens, Helminth
• Epitopes
• Helminth Proteins

Topics

• Allergens (chemistry, genetics)
• Amino Acid Sequence
• Animals
• Anisakiasis (diagnosis, immunology)
• Anisakis (immunology)
• Antibodies, Helminth (blood)
• Antigens, Helminth (chemistry, genetics, immunology)
• Cloning, Molecular
• Epitope Mapping
• Epitopes (chemistry, immunology)
• Gene Library
• Helminth Proteins (chemistry, genetics)
• Humans
• Molecular Sequence Data