T lymphocytes in the intestinal epithelium and lamina propria of mice.

Mesenteric lymphoblasts have a predilection to localize selectively in the murine small intestine within 24 hr after adoptive transfer. In this report, we quantify the localization and intraintestinal distribution of radiolabelled mesenteric lymph node (MLN) T and B blasts in relation to the in situ distribution of intestinal T and B cells which were detected immunohistochemically. Our results show that, within 24 hr after transfer, MLN T blasts localized predominantly in the intestinal epithelium and villus lamina propria, whereas B blasts were found mostly in the basal lamina propria of the gut. In the epithelium and villus lamina propria, 100% and 68%, respectively, of labelled were of thymic origin; this cell type comprised 54% of labelled cells in the basal lamina propria. This pattern of localization was the reverse of the distribution of T lymphocytes and B-cell derived plasmacytes residing in the intestinal wall. These results suggest that MLN T lymphocytes may be a component of common mucosal immunological system and may be integrated with peripheral immunity according to the immunological needs of the host.