T lymphocyte stimulation of human small intestinal glycoprotein biosynthesis: effects of anti-CD3 antibody on normal and coeliac mucosa

The effects of mucosal T-cell activation on human small intestinal glycoprotein biosynthesis have been examined during short-term culture in vitro. The incorporation of 3H-glucosamine into tissue and secreted glycoproteins was determined. Activation of mucosal T lymphocytes of normal duodenal biopsies with the monoclonal anti-CD3 antibody significantly increased both the total glucosamine incorporation into glycoproteins (p less than 0.01) and the secretion of in vitro radiolabelled glycoproteins (p less than 0.001). This effect was inhibited by ciclosporin. Secretion of glycoproteins was also stimulated by culture with pokeweed mitogen. In patients with coeliac disease, culture of small intestinal biopsies with anti-CD3 antibody significantly increased (p less than 0.05) glycoprotein biosynthesis in treated patients, but had no stimulatory effect in untreated patients with villous atrophy. These results show that activation of mucosal T lymphocytes induces quantitative changes in intestinal glycoprotein synthesis and secretion and T lymphocytes therefore have an important role in non-specific intestinal defences. The results are consistent with the suggestion that increased glycoprotein synthesis and secretion in untreated coeliac mucosa result from T-cell activation.