ANTI-ALPHA-GLIADIN ANTIBODIES (AGA) IN THE SERUM OF CELIAC CHILDREN AND CONTROLS RECOGNIZE AN IDENTICAL COLLECTION OF LINEAR EPITOPES OF ALPHA-GLIADIN

Anti-gliadin antibodies can be found in the serum of patients with ove rt and subclinical coeliac disease, but also in that of some controls. The aim of the present study was to identify the linear epitopes of t he alpha-gliadin molecule to which the humoral response is directed. T herefore, the IgG and IgA antibody reactivity against an overlapping s et of synthetic peptides covering the entire sequence of alpha-gliadin was measured in the sera from patients with coeliac disease, from con trols with elevated titres of anti-gliadin antibodies and from healthy children using an ELISA technique. The antibodies mainly recognize pe ptides derived from the N-terminal region of alpha-gliadin, containing the motif QPFXXQXPY. Reactivity was also detected against two other s ynthetic peptides, which do not contain this motif and represent a seq uence encoded further to the C-terminal region of alpha-gliadin. Anti- gliadin antibodies in sera from patients with coeliac disease and from controls recognize the same linear epitopes. Thus, serological invest igation of the specificity of these antibodies using a peptide ELISA d oes not allow discrimination between patients and controls.