Epitopes described in "Identification and mutational analysis of the immunodominant IgE binding epitopes of the major peanut allergen Ara h 2."

Article Authors:J S Stanley; N King; A W Burks; S K Huang; H Sampson; G Cockrell; R M Helm; C M West; G A Bannon
Article Title:Identification and mutational analysis of the immunodominant IgE binding epitopes of the major peanut allergen Ara h 2.
Reference Detail
Reference ID:315210
Abstract:A major peanut allergen, Ara h 2, is recognized by serum IgE from > 90% of patients with peanut hypersensitivity. Biochemical characterization of this allergen indicates that it is a glycoprotein of approximately 17.5 kDa. Using N-terminal amino acid sequence data from purified Ara h 2, oligonucleotide primers were synthesized and used to identify a clone (741 bp) from a peanut cDNA library. This clone was capable of encoding a 17.5-kDa protein with homology to the conglutin family of seed storage proteins. The major linear immunoglobulin E (IgE)-binding epitopes of this allergen were mapped using overlapping peptides synthesized on an activated cellulose membrane and pooled serum IgE from 15 peanut-sensitive patients. Ten IgE-binding epitopes were identified, distributed throughout the length of the Ara h 2 protein. Sixty-three percent of the amino acids represented in the epitopes were either polar uncharged or apolar residues. In an effort to determine which, if any, of the 10 epitopes were recognized by the majority of patients with peanut hypersensitivity, each set of 10 peptides was probed individually with serum IgE from 10 different patients. All of the patient sera tested recognized multiple epitopes. Three epitopes (aa27-36, aa57-66, and aa65-74) were recognized by all patients tested. In addition, these three peptides bound more IgE than all the other epitopes combined, indicating that they are the immunodominant epitopes of the Ara h 2 protein. Mutational analysis of the Ara h 2 epitopes indicate that single amino acid changes result in loss of IgE binding. Two epitopes in region aa57-74 contained the amino acid sequence DPYSP that appears to be necessary for IgE binding. These results may allow for the design of improved diagnostic and therapeutic approaches to peanut hypersensitivity.
Affiliations:Department of Biochemistry & Molecular Biology, University of Arkansas for Medical Sciences, Arkansas Children's Hospital Research Institute, Little Rock 72205, USA.
Reference Type:Literature
PubMed ID:9186485
Journal:Arch Biochem Biophys
Journal Volume:342
Article Pages:244-53
Journal ISSN:1096-0384
Article Chemical List:2S Albumins, Plant;Allergens;Antigens, Plant;Ara h II protein, Arachis hypogaea;Epitopes;Glycoproteins;Immunodominant Epitopes;Peptide Fragments;Plant Proteins;Immunoglobulin E
Article MeSH List:2S Albumins, Plant; Adult; Allergens(chemistry; immunology); Amino Acid Sequence; Antigens, Plant; Arachis hypogaea(immunology); Base Sequence; Binding Sites, Antibody; Cloning, Molecular; DNA Mutational Analysis; Epitope Mapping; Epitopes(chemistry; immunology); Food Hypersensitivity(immunology); Glycoproteins(chemistry; immunology); Humans; Immunodominant Epitopes; Immunoglobulin E(immunology); Molecular Sequence Data; Peptide Fragments(chemical synthesis; chemistry; immunology); Plant Proteins; Sequence Homology, Amino Acid
Article Comments:Data originally imported from the Database of Functional Molecular Immunology, FIMM (http://sdmc.lit.org.sg:8080/fimm/)
Curation Last Updated:2014-10-03 19:44:10