Lrious factors secreted from Lymphology I 2 (1979) 9- I 0 rmus cells or other, by acti- The Migration of Lymphocytes across the Vascular Endothelium in Lymph Nodes: A Scanning Electron Microscopic Study : Fukumoto, Y. Nawa, M M. Nishi, N. Hamada, H. Nomura, M. Mastueda, T. Aiko L Era: The generation of 1ilic cells in the lymphoid ti ssues First Depart ment of Surgery, Kagoshima University School of Medicine, I with cell-free lymph. Aust. J. Kagoshima, Japan :ci. 53 (1975) 11- 26 : Fukumoto, M. Miyamoto: h humoral factor. Evidence for Summary Ob servations and Discussion ietic factor in rat thoracic duct Endothelial cell s of Postcapillary Venules (PCV) Most endothelial cells were 7 to 14 !J. major ogy 30 (1976) 349- 359 and the passage of lymphocytes through the wall : Fukumoto, M. Miyamoto: axis, 3 to 6 !J. in minor axis, and 5 to 8 !J. in of PCV were investiga ted with Scanning Electron height. They were high and swelled out into h humoral factor. Biological Microscope (SEM) in mesenteric lymph nodes of a lymphocytopoietic factor rats. Individual endothelial cells of PCV in the the tubular lumina at the center, and were ~ct lymph. Immunology, 32 lymph node did not have flat surface or were not lower with nearing the periphery (Fig. I). typica lly cubic, but swe lled at the central part : Fukumoto: Lymphocyte acti­ assuming a foot ball-like shape. Circulating lympho­ nd in rat thoracic duct lymph. cytes are considered to migrate into lymphatic 6 (1975) 245 - 249 (in Japa- tissues through the wall of PCV from the blood stream. Two hypotheses, inter-end othelial cell passage and intra-e nd othelial cell passage, have been proposed. The three-d irn ensional studies on lymphocytes passing the wa ll with SEM confirmed hool of Medicine, that migrating lymphocytes pushes their way through the interce llular space with pressing the adjoining en­ dothelial cell s from beginning to end, supporting the former hypothesis. Invasion of lymphocytes in to endothelial ce ll s were not observed. Thome first reported a light microscopic study on the PCV, though this anatomical Fig. J SEM pi cture of the luminal surface of PCV. Lymphocytes stick between neighboring endothelial term was first used by Schultze. Thereafter, cells. Noticeably 4 or 5 lymphocytes invade central many investigators have given attention to the one endothelial cell. Granular processes are found peculiar structures from the morphological, on the free surface of endothelial cell. x3800 immunological , and pathological point of view. PCV was characterized by the peculiar struc­ Wenk et a!. reconstructed the three-dimensional tures consisting of high endothelial cells which properties of high endothelial cells of PCV in were cubic in cross section and by the presence the lymph node through observation of serial of many lymphocytes in the lumina and endo­ sections with TEM. However, these can not thelium. In our study stress was placed on give all investigators satisfaction. The height the observation about the three-dimensional and shape of endothelial cells are not always structure of PCV and the passing mode of uniform. At the invasion of lymphocytes the circulating lymphocytes by SEM. endothelial cells continuous to them were de­ formed by their pressure. Endothelial cells Materials may restrict the loss of cytoplasm by adapting their external shape to the form of lymphocy­ Male Wistar rats weighing 250- 350 g were tes on the one hand, and assist the movement used. of lymphocytes on the other hand. Umetani 0024- 7766 1300- 0009 $ 02.00 © 1979 Georg Thieme Publishers Permission granted for single print for individual use. Reproduction not permitted without permission of Journal LYMPHOLOGY. I 0 M. Nishi , N. Hamada, H. Nomura, M. Mastucda, T. Aiko suggested that endothelial cells of PCV of passage of lymphocytes through endothelial rabbit tonsils had marginal processes which cells was obtained in observation of either might make the passage of lymphocytes surface or cracked section. A lymphocyte Observatil easy by constraction. However, bundle of first sticks in a furrow , then gradually invades microvilli corresponding to marginal pro­ into deeper part with change of its end into cesses were not found in our SEM study of wedge-shaped one as shown in Fig. 2, adheres Yoshihiro ~ Endothelial cells of rats mesenteric lymph to the neighboring cells, and moves on under First Departr nodes. pressing them. Another valid evidence ob­ University M tained from the present SEM study for the Marchesi and Gowans first investigated the intercellular migration hypothesis is that a state of lymphocytes passing through the Summary few lymphocytes adhered to an endothelial wall of PCV and reported that lympho­ cell very frequently. It is difficult to consider Hepatic superficial lymph flo• cytes first entered endothelial cells from jccting patent blue V solutior that a few lymphocytes can pass through the luminal surface, traversed the cytoplasm, peritoneoscopy. This procedu cytoplasm of an endothelial cell , even if one ob servations of the direction o and then got out to the basement membrane. lymphocyte could do so. m superficial lymphatic vessel In opposition to their hypothesis, some in­ lymph from these lymphatic ' vestigators insisted that lymphocytes might vessels of the ga llbladd er. Inc: observed in patients wi th incr move to lymphatic parenchyma from the Acknowledgement blood stream through intercellular spaces and lobular distortion. The authors arc grateful to Prof. M. Murakami of and that it was impossible to consider the the Second Department of Anatomy, Faculty of intracellular passage of lymphocytes. In the Medicine, Kurumc University for kindly valuable In 1965 my colleague Hal present SEM study the surface of the inner advice and Dr. T. Shimada for his support and in observing lymph flow a spaces could be observed extensively the spe­ encouragement. hilus by injecting patent b cial relationship between lymphocytes and into the liver. l have appli endothelial cell~ in the spaces which have References examine the superficial ly1 been impossible to obtain with TEM could be taken in one view . Almost all lymphocytes Farr, A. G. , P.P.H. DeBruyn: The mode of human liver under periton in PCV existed in wide furrows between endo­ lymphocyte migration through postcapillary ve­ paper, the procedure and I nule endothelium in lymph node. Amer. J. Anal. in several liver diseases are thelial cells and no evidence suggesting the 14 3 (19 75) 59- 92 2 Hamada, N.: Scanning electron-microscopic studies on postcapillary venules and lymphocyte Materials and Methods migration into endothelium in rat mesenteri c lymph Materials: Fig. I illustrate~ nodes. Acta Medica Univ. Kagoshirna 20 (1978) 77 - 92 3 March esi, V. T., J.L. Gowans: The migration of The 20 em needle was esp lymphocytes through the endothelium of venulcs dye solution injection into in lymph nodes: an electron microscope study. diameter of the needle wa: Proc. R. Soc. London, B. Bioi. Sci. , 159 (1964) inner diameter of the canr 283 - 290 4 Schultze, W. : Untersuchungen tiber die capillaren which was used in the Vir und postcapill li ren Venen lymphatischer Organe. technique. The nee dl e tip 1 Z. Ges. Anat., 76 (1925) 421 - 462 em in length. The needle t 5 Thome, R. : Endothclien als Phagocyten. Arch. be attached to the syringe. Mikr. Anal. 52 (1898) 820- 843 was 11 % patent blue V (pc 6 Umetani, Y. : Postcapillary venule in rabbit tonsil and entry of lymphocytes into its endothelium: Chroma Co. , Stuttgart) sto a scanningPermission and transmi grantedss ion e lforectron single mi printcrosc forope individual use. Methods: The dye-injectio1 Reproductionstudy. Arch. notHi s to!.permitted jap., 40 without (1977) permission 77 - 94 of Journal LYMPHOLOGY. fig. 2 Picture of PCV by Epoxy-resin cracking into the abdominal cavity method. The advanced tip of a lymphocyte be­ 7 Wenk, E.J., D. Orlic, E.J. Reith, J.A .G. Rhodin: comes thin and wedge-shaped and is entering into The ultrastructure of mouse lymph node venules in peritoneoscopy, piercin! a narrow gap by pushing the neighboring cells and the passage of lymphocytes across their walls. em in depth. Then, 0.5 ml xl I 000 J. Ultrastr. Res., 47 (1974) 214- 241 dye solution was injected . appeared on the liver surfa pattern. The network colle M. Nishi, First Dept. of Surgery, Kagoshima Uni versity School of Medicine, Kagoshima, Japan superficial lymphatic vesse 0024- 7766 1300- 0011 .