Toxicity of different wheat gliadins in coeliac disease

To determine the toxic effect of different gliadins on coeliac patients, which has been variably assessed in the literature, wheat prolamines (gliadin) were separated into the main fractions alpha-, beta-, gamma-, and omega-gliadins by chromatography on Sulfopropyl Sephadex C-50. The chemical compositions of the gliands were characterized by polyacrylamide gel electrophoresis, amino-acid analysis, determination of amide nitrogen and peptide maps. The peptide fractions B2 and B3 were isolated from the gliadins by a peptic tryptic digestion, ultrafiltration and gel filtration on Sephadex G-50. The gliadins and the peptide fractions were examined for coeliac activity by immunological tests (LIF tests) and by organ-culture tests. The results show that the peptide fractions are generally more active than their respective gliadins. The peptide fractions of all gliadins have a coeliac-specific toxic effect; their activities correlate with the chemical composition of the gliadins.