title: Usefulness of recombinant γ-gliadin 1 for identifying patients with celiac disease and monitoring adherence to a gluten-free diet.
abstract: BACKGROUND
  Celiac disease (CD) is an inflammatory disease of the small intestine caused by an immunologic hypersensitivity reaction to dietary wheat gluten.
  
  
  OBJECTIVE
  We sought to clone, express, and perform IgA epitope mapping of a CD-specific wheat antigen and to study its usefulness for identifying patients with CD and monitoring adherence to a gluten-free diet.
  
  
  METHODS
  A synthetic gene coding for γ-gliadin 1 (GG1) was expressed in Escherichia coli. Recombinant γ-gliadin 1 (rGG1) was purified and characterized biochemically, structurally, and immunologically by using sera from patients with CD and control subjects. Overlapping GG1 peptides were synthesized for IgA and IgG epitope mapping. GG1 and peptide-specific antibodies were raised for tracing GG1 in cereals and dietary wheat products and to study its resistance to digestion.
  
  
  RESULTS
  rGG1 was expressed and purified. rGG1-based IgA ELISAs performed in populations of patients with CD and control subjects showed a specificity of 92.9%, which was higher than that of gliadin extract (e). Furthermore, it allowed monitoring of adherence to a gluten-free diet in patients. A 26-amino-acid peptide from the proline-glutamine-rich repetitive N-terminal region was identified as the immunodominant IgA epitope. GG1-related antigens were found in rye, barley, and spelt but not in oat, rice, or maize. GG1 was detected in dietary wheat products after baking, and in particular, the major IgA epitope-containing region was resistant against digestion.
  
  
  CONCLUSIONS
  rGG1 and its epitope might be useful for identifying patients with CD, monitoring treatment, and studying the pathomechanisms of CD and development of preventive and therapeutic strategies.
authors.affiliation: Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Vienna, Austria.
authors.forename: Bharani
authors.initials: B
authors.lastname: Srinivasan
authors.affiliation: Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Vienna, Austria.
authors.forename: Margarete
authors.initials: M
authors.lastname: Focke-Tejkl
authors.affiliation: Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Vienna, Austria.
authors.forename: Milena
authors.initials: M
authors.lastname: Weber
authors.affiliation: Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Vienna, Austria.
authors.forename: Sandra
authors.initials: S
authors.lastname: Pahr
authors.affiliation: Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Vienna, Austria.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Baar
authors.affiliation: Medical Clinic 1, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany.
authors.forename: Raja
authors.initials: R
authors.lastname: Atreya
authors.affiliation: Medical Clinic 1, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany.
authors.forename: Markus F
authors.initials: MF
authors.lastname: Neurath
authors.affiliation: Department of Gastroenterology and Hepatology, Medical University of Vienna, Vienna, Austria.
authors.forename: Harald
authors.initials: H
authors.lastname: Vogelsang
authors.affiliation: Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria.
authors.forename: Wolf-Dietrich
authors.initials: WD
authors.lastname: Huber
authors.affiliation: Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Vienna, Austria. Electronic address: rudolf.valenta@meduniwien.ac.at.
authors.forename: Rudolf
authors.initials: R
authors.lastname: Valenta
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000595:Amino Acid Sequence; D002446:Celiac Disease / Q000175:diagnosis* / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D055050:Diet, Gluten-Free; D018604:Epitope Mapping; D004926:Escherichia coli / Q000235:genetics; D005260:Female; D005903:Gliadin / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D007070:Immunoglobulin A / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology; D007223:Infant; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D010349:Patient Compliance; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D055815:Young Adult
chemical_list: D007070:Immunoglobulin A; D007074:Immunoglobulin G; D011994:Recombinant Proteins; D005903:Gliadin
keywords: Celiac disease; cloning; epitope; recombinant gamma gliadin 1