Galactose-specific receptors on liver cells. II. Characterization of the purified receptor from macrophages reveals no structural relationship to the hepatocyte receptor.

We have isolated a galactose-specific receptor protein from rat liver macrophages by three techniques, all using EDTA extraction and subsequent affinity chromatography. The purified receptor has an apparent molecular mass of 30 kDa and exhibits hemagglutinating activity. Monospecific receptor-antisera produce one precipitation line with the macrophage receptor in Ouchterlony double diffusion but show no cross-reaction with the hepatocyte receptor. Sinusoidal cells, but not hepatocytes, are stained with monoclonal antibodies to the macrophage receptor, whereas anti-hepatocyte receptor antibodies stain hepatocyte surfaces but not sinusoidal cells. We conclude that the galactose-specific receptor from liver macrophages is structurally different from the hepatocyte receptor, although the two lectins share a similar binding specificity.