Research

IgE versus IgG4 epitopes of the peanut allergen Ara h 1 in patients with severe allergy

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Abstract

Background: Development and maintenance of tolerance to food allergens appears to be associated with alterations in antigen specific IgE and IgG4 responses. Previous studies have focused only on comparing IgE and IgG4 linear epitope recognition patterns but take no account of conformational epitopes. Objective: The aim of this study was to compare Ara h 1-specific IgE and IgG4 epitope recognition patterns in patients with severe peanut allergy, applying a method allowing for identification of both linear and conformational epitopes. Methods: Polyclonal sera from three individual patients, suffering from severe allergic reaction to peanuts, including anaphylaxis, were used to analyse the IgE and IgG4 epitope recognition patterns of the major peanut allergen Ara h 1. Epitope identification was conducted by competitive immuno-screening of a phage-displayed random heptamer peptide library. Resulting epitope-mimicking sequences were aligned for identification of consensus sequences and localised on the surface of the Ara h 1 molecule by a computer-based algorithm. Results: All epitope-mimicking sequences identified were found to correspond to conformational epitopes. Each individual patient had his/her own distinct IgE as well as IgG4 epitope recognition profile, though some important IgE epitopes were common to all patients. In general the IgG4 epitope pattern was more heterogeneous than the IgE pattern, did not coincide with IgE epitopes and had a lower affinity than IgE. Conclusions: This study demonstrated the usefulness of the phage-display technology in distinguishing between the epitope pattern of IgE and IgG4, giving detailed information on fine specificity and affinity. Competitive immuno-screening of phage-display random peptide libraries could be a future valuable tool to study the balance and dynamics of the IgE and IgG4 epitope recognition repertoire and provide a diagnostic tool giving information on the associated allergic phenotype. (C) 2013 Elsevier Ltd. All rights reserved.

Amino Acid Sequence Antigens Plant Epitope Mapping Epitopes Glycoproteins Humans Immunoglobulin E Immunoglobulin G Molecular Mimicry Peanut Hypersensitivity Plant Proteins Sequence Alignment Ara h 1 protein Arachis hypogaea 37341-29-0 Immunoglobulin E peanut allergy Peanut Hypersensitivity (MeSH) immune system disease Primates Mammalia Vertebrata Chordata Animalia (Animals Chordates Humans Mammals Primates Vertebrates) - Hominidae [86215] human common IgE IgE epitope IgG4 IgG4 epitope peanut allergen Ara h 1 allergen 10006 Clinical biochemistry - General methods and applications 10064 Biochemistry studies - Proteins peptides and amino acids 13502 Food technology - General and methods 15002 Blood - Blood and lymph studies 15004 Blood - Blood cell studies 34502 Immunology - General and methods 34508 Immunology - Immunopathology tissue immunology 35500 Allergy Allied Medical Sciences Clinical Immunology Human Medicine Medical Sciences serum blood and lymphatics computer-based algorithm mathematical and computer techniques phage-display technology laboratory techniques genetic techniques Allergy Clinical Chemistry Foods BIOCHEMISTRY IMMUNOLOGY COWS MILK ALLERGY PEPTIDE MICROARRAY IMMUNOASSAY EFFECTOR CELL DEGRANULATION E-BINDING EPITOPES FOOD ALLERGY SEQUENTIAL EPITOPES ORAL IMMUNOTHERAPY IMMUNOGLOBULIN-E DOUBLE-BLIND SUBLINGUAL IMMUNOTHERAPY Peanut allergy Ara h 1 Phage-display epitope food allergen immunoglobulin E immunoglobulin G4 peanut allergen Ara h 1 unclassified drug amino acid composition amino acid sequence antibody affinity antibody response antigen purification antigen recognition article biopanning consensus sequence controlled study enzyme linked immunosorbent assay epitope mapping human human tissue peanut allergy peptide library phage display priority journal sequence alignment IMMUNOGLOBULIN E