HOMEOSTATIC REGULATION OF INTESTINAL EPITHELIA BY INTRAEPITHELIAL GAMMA-DELTA T-CELLS

Although T cells bearing gamma delta T-cell receptors have long been k nown to be present in the epithelial lining of many organs, their spec ificity and function remain elusive. In the present study, we examined the intestinal epithelia of T-cell-receptor mutant mice, which were d eficient in either gamma delta T cells or alpha beta T cells, and of n ormal littermates, The absence of gamma delta T cells was associated w ith a reduction in epithelial cell turnover and a downregulation of th e expression of major histocompatibility complex class II molecules. N o such effects were observed in alpha beta T-cen-deficient mice, These findings indicate that intraepithelial gamma delta T cells regulate t he generation and differentiation of intestinal epithelial cells.