Localization of Fc receptors on liver sinusoidal endothelium. A histological study by electron microscopy.

The localization of Fc receptors for IgG on mouse liver sinusoidal endothelium was studied in tissue sections by light and electron microscopy using peroxidase-antiperoxidase IgG complexes as ligands. Light microscopy revealed that Fc receptors were continuously present along the sinusoidal wall, but absent on the endothelium of the central vein and that of the portal area blood vessels. Electron microscopy revealed Fc receptors on both the luminal and basal aspects of the plasma membrane, far more being present on the former, on the walls of cytoplasmic fenestrae, and abundantly on the walls of coated pits and vesicles of sinusoidal endothelial cells. Fc receptors were found more frequently on sinusoidal endothelial cells than on Kupffer cells. Fat-storing cells lacked the receptors and hepatocytes showed an ambiguous result which was considered to be nonspecific.