LAMINA PROPRIA MACROPHAGES OF INTESTINE OF GUINEA-PIG - POSSIBLE ROLE IN PHAGOCYTOSIS OF MIGRATING CELLS

Abstract

Macrophages of lamina propria were commonly found in the small and large intestine of guinea pigs, mice, rats and in human duodenum. Frequency of macrophage occurrence was highest in the lamina propria of villous apices of the small intestine and beneath the lining epithelium of the large intestine. In cytoplasm of lamina propria macrophages localized in those regions, Feulgen-positive (DNA-containing) granules could be observed particularly in the guinea pig intestine. Autoradiography of the latter, 3-5 days after 3H thymidine injection, showed coincidence of occurrence of labeled Feulgen-positive granules in the macrophage cytoplasm with the appearance of labeled epithelial cells and sheath-fibroblasts in the region of lamina propria containing the highest accumulation of macrophages, i.e., at the apices of villi of the small intestine and beneath lining epithelium of the large intestine. Labeled nuclei of macrophages were observed scarcely and much less frequently than were labeled cytoplasmic granules. No labeled Feulgen-positive granules could be seen in macrophages 1/2 h, 1, 2 and 7 days after 3H thymidine injection. Lamina propria macrophages may play a role in phagocytosis of some migrating cells of the intestinal mucosa, most probably of sheath-fibroblasts and/or intraepithelial lymphocytes.