THE PASSAGE OF MACROPHAGES AND LYMPHOCYTES FROM THE INTERSTITIUM ACROSS THE LYMPHATIC ENDOTHELIUM OF RAT LACTEALS

The passage of cells across the lymphatic endothelium of rat lacteals in both normal and non-pathological experimental conditions (fasting, lymphatic stasis) was studied by means of serial thin sections and three-dimensional models. Two different pathways of transendothelial migration were observed: (1) macrophages enter the lymphatic lumen via the cytoplasm of endothelial cells, without involvement of intercellular junctions, whereas (2) lymphocytes migrate through "intraendothelial channels", dynamic structures organized by the lymphatic endothelium under physiological conditions. © 1990 Springer-Verlag.