Toxicity of Wheat Flour Proteins and ProteinDerived Peptides for In VitroDeveloping Intestine

A peptic-tryptic-cotazym (PTC) digest of a crude wheat gliadin preparation was obtained under experimental conditions simulating in vivoprotein digestion and then fractionated into 10 peaks by ion-exchange chromatography. PTC-gliadin digest and one of its subfractions (coded as fraction 9 according to its elution pattern) were very active in inhibiting in vitrodevelopment and morphogenesis of small intestine from 17− and 18-day-old rat fetuses, whereas they were harmless for the culture of jejunum from 21-day-old fetuses. PTC-digest also induced extensive tissue degeneration and necrosis of in vitrocultured small intestinal mucosa from patients with active celiac disease (gluten-induced entheropathy), but did not cause any detectable effect on histolog-ically normal human small intestinal mucosa. Some wheat albumin and gliadin fractions were also tested on in vitrodeveloping small intestine from 17-day-old rat fetus. Among all the tested protein fractions, only one gliadin fraction (coded as αio-gliadin from its gel electrophoretic mobility) exhibited a toxic effect; morphologic alterations induced by αio-gliadin were similar to those induced by PTC-digest and fraction 9.