title: Mapping of the IgE and IgG4 sequential epitopes of ovomucoid with a peptide microarray immunoassay.
abstract: BACKGROUND
  Ovomucoid (Gal d 1) has been demonstrated to be the most important allergen in IgE-mediated egg allergy. Peptide microarray analysis is a novel method that can provide useful information on the nature of specific allergens.
  
  
  METHODS
  A peptide microarray immunoassay was performed using a 15- and 20-amino acid (aa) library of overlapping peptides (3-offset) of the primary sequence of ovomucoid. Sera from 50 patients with IgE-mediated egg allergy and reactivity to ovomucoid, with more than 1 year of follow-up, and sera from 10 controls were tested. Peptides were considered major epitopes when the average weighted Z-score was greater than 3 and recognized by at least 20% of the patient's sera. Specific IgE epitopes were established on the basis of the IgE/IgG4 Z-score ratio.
  
  
  RESULTS
  The IgE and IgG4 recognition pattern was similar in both sets of peptides, but the signal intensity was generally higher in the 20-aa set. Thirty-four percent of the patients did not recognize any IgE sequential peptide and 20% of the patients recognized more than 10 sequential peptides. We identified 3 major IgE B-cell epitopes in domains I and II of ovomucoid. IgE/IgG4 ratio analysis showed that peptides 1-2 (aa 4-20) and peptides 29-31 (aa 91-104) were specific IgE epitopes.
  
  
  CONCLUSIONS
  By using peptide microarray immunoassay in egg-allergic patients, we established that 34% of the patients do not have any linear epitope recognized by IgE. Further studies are needed to determine the clinical relevance of this finding.
authors.affiliation: Servicio de Bioquímica-Investigación, Hospital Universitario Ramón y Cajal, IRYCIS, Madrid, España. javier.botas@hrc.es
authors.forename: Javier
authors.initials: J
authors.lastname: Martínez-Botas
authors.forename: Inmaculada
authors.initials: I
authors.lastname: Cerecedo
authors.forename: Javier
authors.initials: J
authors.lastname: Zamora
authors.forename: Cristina
authors.initials: C
authors.lastname: Vlaicu
authors.forename: Maria Carmen
authors.initials: MC
authors.lastname: Dieguez
authors.forename: Diego
authors.initials: D
authors.lastname: Gómez-Coronado
authors.forename: Verónica
authors.initials: V
authors.lastname: de Dios
authors.forename: Soledad
authors.initials: S
authors.lastname: Terrados
authors.forename: Belén
authors.initials: B
authors.lastname: de la Hoz
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D021181:Egg Hypersensitivity / Q000097:blood / Q000276:immunology*; D018604:Epitope Mapping / Q000379:methods; D000939:Epitopes / Q000737:chemistry / Q000276:immunology*; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000737:chemistry / Q000276:immunology*; D007074:Immunoglobulin G / Q000737:chemistry / Q000276:immunology*; D008297:Male; D010059:Ovomucin / Q000737:chemistry / Q000276:immunology*; D040081:Protein Array Analysis / Q000379:methods
chemical_list: D000939:Epitopes; D007074:Immunoglobulin G; D010059:Ovomucin; D007073:Immunoglobulin E