Studies of erythrocyte sequestration. II. Liver homing

Liver phagocytosis in late stages of lethal canine endotoxin shock. A patho-morphological study

Liver phagocytosis was studied by means of electron microscopy in late stages of lethal canine endotoxin shock. A massive phagocytic activity was found within hepatic macrophages. The phagocytosed material found within Kupffer cells consisted of red cells, red-cell fragments, platelets, a fibrin-like material and damaged polymorphonuclear leukocytes. Red cells and red-cell fragments seemed to constitute the major part of the material involved.

Studies on intravascular phagocytosis in the lung

In this paper we have shown for the first time endocytosis by intravascular lung phagocytes. Glutaraldehyde-treated erythrocytes (discocytes) homed rapidly to the rat lung as measured by scintigraphic procedures. Transmission and scanning electron microscopy showed that the discocytes are phagocytosed by macrophages, blood monocytes and granulocytes as whole cells. This process could not be inhibited by silica treatment.

Analysis of lectin-dependent recognition of desialylated erythrocytes by Kupffer cells

Kupffer cells isolated from the rat liver are able to bind neuraminidase-treated rat erythrocytes via a D-galactose-specific receptor on the cell surface. Binding of desialylated erythrocytes was inhibited by several mono- and oligo-saccharides related to D-galactose, but not by unrelated sugars. However, after phosphorylation at position 6 D-glucose was as good an inhibitor as D-galactose. Two synthetic glycoproteins, D-galactosyl-albumin and, at a higher concentration, D-glucosyl-albumin, strongly inhibit cell contacts. Lectin-mediated binding of desialylated erythrocytes is dependent on the presence of Ca2'ons, but independent of ATP formation and cell motility. It is concluded that binding of desialylated erythrocytes by rat Kupffer cells is mediated by a Ca2-dependent D-galactosyl/D-glucosyl-recognition system.