Re-evaluation of the techique of organ culture for studying gluten toxicity in coeliac disease

In vitro cytotoxicity of four different gluten fractions was tested in organ culture for up to 48 hours using flat intestinal biopsies from children with coeliac disease. The fractions were (1) a peptic-tryptic digest of gliadin containing a moderate amount of alpha-gliadin, (2) a peptic-tryptic digest of gluten (Frazer fraction III) froma strain of wheat with a high content of alpha-gliadin, (3) alpha-gliadin, and (4) alpha-GT-18,000, a tryptic fragment of alpha-gliadin. The latter three fractions were toxic to coeliac patients in vivo. In vitro, however, none of these fractions proved to be cytotoxic. When added to the culture medium they were not capable of inhibiting the regeneration of the surface epithelium as visualised by histology and electron microscopy. The only difference between cultures with and without gluten fractions was that the former produced slightly more mucus when maintained in vitro as observed in the dissecting microscope. Furthermore, for Frazer fraction III the absence of apparent toxicity was confirmed by the behaviour of brush border enzyme activities during culture. Our results are not in accordance with those reported in the literature. We believe that the criteria used at the present time for the assessment of gluten toxicity in vitro should be extended to include the process of enterocyte desquamation.