The adhesion of liver cells

Abstract

The adhesion of cells in the intact rat liver, and the surface properties of isolated cells have been studied. The removal of divalent ions, probably calcium, from the liver results in a loosening of the intercellular bond so that it may then be broken by a suitable force, but does not allow the cells to separate spontaneously. Treatment by a number of proteolytic enzymes, including purified collagenase and elastase, lead to a breakdown or liver structure, largely through a spontaneous loosening of the cells from each other. Liver cells isolated from the organ following perfusion with a chelating agent are tough refractile bodies which appear morphologically intact although they can be shown biochemically to have leaked important cell constituents. Staining with aniline blue reveals a clear-cut surface layer. Following enzymic treatment this layer disappears and the cells become less refractile, more fragile and flatten on a surface, although still intact. It has been found that isolated liver cells and cells from other organs and from solid tumours will reaggregate quickly into firm masses if injected intraperitoncally into mice. Cells which have been treated with proteolytic enzymes do not do so, nor do the cells from ascites tumours. Suggestions are put forward concerning the mechanisms of cell adhesion and it is postulated that protein materials play an important part in the adhesion of adult liver cells. There is so far no evidence that a mucopolysaccharide is involved. These mechanisms of cell adhesion may Well differ between types of tissue, between adult and embryonic and between normal and malignant tissues.