A NOVEL ALKALINE PHOSPHATASE-BASED ISOLATION METHOD ALLOWS CHARACTERIZATION OF INTRAEPITHELIAL LYMPHOCYTES FROM VILLI TIP AND CRYPT REGIONSOF MURINE SMALL-INTESTINE

The isolation of intestinal intraepithelial lymphocytes (IEL) is a maj or prerequisite for the investigation of cellular and molecular cross- talk in the intestinal mucosa. Since intestinal epithelial cells exhib it distinct functional features at the villi tip and crypt levels, suc h differences could extend to IEL. We developed a mechanical procedure for isolation of IEL from these distinct epithelial sites to test our hypothesis. Cells isolated from the intestinal epithelium by sequenti al incubations under stirring were segregated based upon their alkalin e phosphatase (AP) activity since villi tip and crypt fractions expres sed high and low AP activity, respectively. IEL preparations obtained after a further purification step in Percoll gradient contained >90% I ntegrin alpha(IEL) chain(+), CD3(+) T cells, and no Igf cells. Villi t ip IEL preparations possessed increased numbers of low density IEL whe n compared to crypt IEL, suggesting that distinct IEL-epithelial cell interactions occur at the intestinal villi tip and crypt levels. (C) 1 997 Academic Press.