ANALYSIS OF NATURAL-KILLER EFFECTOR AND SUPPRESSOR ACTIVITY BY INTRAEPITHELIAL LYMPHOCYTES FROM MOUSE SMALL-INTESTINE

Abstract

Intraepithelial lymphocytes (IEL) are morphologically similar to NK [natural killer] cells in other tissues; the NK activity of IEL isolated from mouse small intestine was studied. In contrast to spleen NK cells, IEL showed little activity against mouse lymphoma YAC-1 over 4 h, but had high levels of NK activity when the assay was extended to 18 h. IEL from nude mice did not show the enhanced NK activity found in other tissues. IEL also suppressed the NK activity of spleen cells and this suppressor function was not mediated by T lymphocytes or macrophages. The intestinal epithelium apparently contains a population of potent NK cells which may represent a type of NK cell different to that found in other tissues. There are also cells capable of regulating NK cell function in the epithelial layer.