Intercellular contacts between migrating blood cells and cells of the sinusoidal wall of bone marrow. An ultrastructural study using tannic acid

Abstract

The migration of blood cells across the sinusoidal wall of murine bone marrow was studied following fixation with tannic acid-glutaraldehyde. Electron microscopic examination showed regions of close membrane apposition (referred to in this study as "intercellular contacts") between migrating blood cells and cells of the sinusoidal wall (adventitial and endothelial cells). Ultrastructurally the intercellular contacts are pentalaminar structures resembling gap junctions of other organs after tannic-acid fixation. The possibility that these contacts are regions of intercellular communication and/or sites of membrane attachment utilized for locomotion of the migrating blood cells is discussed.

Ultrastructural recognition of gap junctions between melanocytes in human vestibular organs by tannic acid containing fixative preparation and freeze-fracture technique

“…2a,b). The gap between the two outer leaflets of the gap junctions was permeable to the tannic acid, which spread into the intercellular space of the apposed plasma membranes of the gap junctions (Campbell, 1982). Therefore, the narrow gap of two outer leaflets of apposed plasma membranes, usually thin and with a low electron density by conventional TEM examination in which the fixative contains glutaraldehyde alone, showed relatively high electron-dense deposition.…”

Intercellular contacts of lymphocytes during migration across high‐endothelial venules of lymph nodes. An electron microscopic study

“…In marrow of mice, these contacts are observed between developing blood cells and fixed cells of the marrow (Campbell, 1980) and between migrating blood cells and cells of the sinusoidal wall (Campbell, 1982). In marrow of chickens, these contacts are observed between the intravascular erythroblasts and endothelial cells of the sinusoidal wall (Sorrel1 and Weiss, 1982).…”

“…Recent studies (Campbell, 1982) have demonstrated "intercellular contacts" resembling gap junctions between migrating blood cells and cells of the sinusoidal wall of bone marrow. In view of these findings, the present study was undertaken to determine whether similar intercellular contacts are present between migrating lymphocytes and cells of HEY Tannic acid-glutaraldehyde fixation was employed, because this fixative enhances membrane staining (van Deurs, 1975;Wagner, 1976) and preserves surface components of the membranes (Chew, 1980).…”

Gap junctions in cells of the immune system: structure, regulation and possible functional roles

“…Megakaryocytes present in normal bone marrow contain Cx43, but not Cx26 or Cx32 (38). During migration, gap junction-like structures have been identified between neutrophils or lymphocytes and cells of the sinusoidal wall (adventitial or endothelial cells) of the bone marrow (39).…”