Generation of a monoclonal human single chain antibody fragment to hepatic stellate cells - a potential mechanism for targeting liver anti-fibrotic therapeutics

Background/Aims: Hepatic stellate cells are pivotal to fibrogenesis in the liver and many potential anti-fibrotic therapeutics are required to act on targets within hepatic stellate cells. The aim of this study was to generate a human antibody fragment to hepatic stellate cells. Methods: Phage display was used to generate a human monoclonal antibody fragment to a peptide sequence present on an extracellular domain of synaptophysin, a protein expressed on the surface of hepatic stellate cells. Results: An antibody fragment was isolated (termed C1-3), expressed in bacteria and purified. Fluorescently-labelled C1-3 antibody associated with human hepatic stellate cells but not hepatocytes in culture. Binding of fluorescently labelled C1-3 to hepatic stellate cells was blocked by the extracellular synaptophysin peptide sequence and uptake of the antibody intracellularly was inhibited by monensin. The toxin tributyl tin-when conjugated to C1-3-retained the ability to kill hepatic stellate cells confirming that C1-3 is sequestered intracellularly. Conclusions: This antibody fragment may be an effective means to target therapeutics to human hepatic stellate cells. (C) 2005 European Association. for the Study of the Liver. Published by Elsevier B.V. All rights reserved.