BINDING-SITES FOR ENDOTOXIC LIPOPOLYSACCHARIDE ON THE PLASMA-MEMBRANE OF ISOLATED RABBIT HEPATOCYTES

  • 1 January 1979
    • journal article
    • research article
    • Vol. 26  (5) , 368-374
Abstract
In vivo fixation of bacterial lipopolysaccharide (LPS) on the plasma membrane of mechanically or enzymatically isolated hepatocytes from rabbits was studied by immunofluorescence. Antisera against LPS from Escherichia coli 026:B6 and 0111:B4 were induced in rabbits. Antibody [Ab] titers up to 1:1024 were determined by the passive hemagglutination test. There was no immunologic cross reactivity between the 2 antisera. Ig[immunoglobulin]G and IgM were prepared from anti-LPS and normal rabbit serum and conjugated with fluorescein isothiocyanate. Ab activity against LPS was localized in the IgM fraction. Hepatocytes were isolated by a perfusion technique without enzymes and with collagenase. LPS binding to the hepatocellular plasma membrane increased proportionally with LPS concentration in a range between 0.01 mg/ml. The fluorescence pattern of the membrane-fixed IgM anti-LPS-antibody at the surface of LPS-coated hepatocytes was coarse granular. The in vitro reaction of LPS with hepatocytes was not influenced by complement presence. Demonstration of binding sites for LPS on the hepatocellular plasma membrane indicates that Kupffer cells and parenchymal liver cells are involved in hepatic clearance activity for endotoxin.