Improved isolation methods for mucosal leukocytes from small and large intestines in rats.

We optimized the isolation protocol for intraepithelial lymphocytes (IELs) and lamina propria lymphocytes (LPLs) from the rat small intestine, and LPLs from even the rat large intestine. The major population of IELs in the small intestine was considered to be from the villus epithelia. The cytotoxicity of mucosal leukocytes was comparable among isolated fractions from both the small and large intestines, regardless of the population differences. Further analyses of the cells collected from other lymphoid tissues demonstrated that CD161(+) cells selectively accumulated in the intestinal lamina propria and did not recirculate through the lymph ducts. Our modified isolation protocol enables the collection of mucosal immune cells from the rat intestines without any deterioration of cell function and could contribute to a better understanding of dietary influences on the mucosal immune system.