Mucosal lymphocytes in the rat small intestine: phenotypical characterization in situ.

Lymphocyte subpopulations in the intestinal mucosa of the rat were quantified in situ and compared with data obtained by other authors using enzymic or mechanical methods (Selby et al., 1984; Gibson et al., 1985) in order to assess any selective loss of cell types or contamination with lamina propria lymphocytes after these enzymic or mechanical isolation procedures. Intraepithelial lymphocytes (IEL) were predominantly of the suppressor/cytotoxic phenotype (MRC OX-8) and nearly all cells bore the pan T marker W3/13. About 10% of the IEL phenotypically belonged to the T-helper (W3/25) lineage. MRC OX-19, the rat equivalent of the mouse Lyt-1 antigen, was present on about 15% of the IEL. The main subpopulation of lamina propria T lymphocytes (T-LPL) showed a T-helper phenotype and a smaller subpopulation a suppressor/cytotoxic phenotype. Practically all T-LPL expressed the pan T marker W3/13, and half of these T cells were MRC OX-19+. The results proved to be in agreement with the data obtained after enzymic or mechanical isolation procedures and indicate that proportional contamination with LPL is not likely to occur with these methods.