31-43 amino acid sequence of the alpha-gliadin induces anti-endomysial antibody production during in vitro challenge

Background: Wheat gliadin is the culprit antigen of coeliac disease (CD). T wo short sequences of NH2-terminal portion of gliadin seem to be responsibl e for CD. Antiendomysial antibodies (EMA), highly sensitive and specific fo r CD, are detectable in the culture media from treated CD patients, after i n vitro challenge with peptic-tryptic (PT) digest of gliadin. In this study we detected EMA production after in vitro challenge with 31-43 peptide. We used 56-68 peptide, lacking toxic sequences, as a negative control. Method s: Duodenal samples from 11 treated CD patients and 9 control patients were cultured with 31-43 and 56-68 peptides and PT gliadin. Indirect immunofluo rescence analysis was used for EMA detection. Results: EMA were detected in culture media of 10 of 11 specimens challenged with PT-gliadin and in the media of all specimens challenged with 31-43 peptide. No EMA were detectabl e in any treated patients cultured with 56-68 peptide or with medium alone. No EMA were observed in cultures of control specimens. Discussion: The abi lity of the 31-43 sequence of the a-gliadin to induce EMA production sugges ts its involvement in the pathogenesis of CD. Furthermore, it may be a more useful antigenic substance than PT gliadin for both in vitro and in vivo s tudies of CD.