Intercellular adhesion of rat hepatocytes. Identification of a cell surface glycoprotein involved in the initial adhesion process.

A cell surface molecule involved in intercellular adhesion between rat hepatocytes in vitro has been identified. Papain-solubilized plasma membrane components were fractionated; the ability of the solubilized components to neutralize the inhibition of cell aggregation, caused by multispecific antibodies directed against the cell surface, was used to follow the purification. The purified components were used to immunize rabbits. The resulting antibodies effectively inhibited hepatocyte aggregation, and this inhibitory effect could be neutralized by detergent-solubilized plasma membrane components having an apparent molecular weight of 105,000 in polyacrylamide gel electrophoresis. Also by immunoprecipitation, immunoblotting, and immunosorbent techniques it was demonstrated that the antibodies specifically reacted with a plasma membrane component having an apparent molecular weight of 105,000. This component was susceptible to digestion with papain and showed specific binding to the carbohydrate-binding lectin Lens culinaris hemagglutinin. It was thus concluded that a glycoprotein with a mass of about 105,000 daltons is involved in rat hepatocyte intercellular adhesion.