GENE-TRANSFER INTO HEPATOCYTES AND HUMAN LIVER-TISSUE BY BACULOVIRUS VECTORS

Gene therapy of liver diseases requires the development of efficient v ectors for gene transfer in vivo, Retroviral and adenoviral vectors ha ve been shown to deliver genes efficiently into hepatocytes in vitro a nd in vivo, However, these vectors do not allow for exclusive infectio n of the liver which would be highly advantageous for in vivo gene the rapy strategies, We have recently demonstrated that genetically modifi ed baculoviruses (Autographa californica nuclear polyhedrosis virus) e fficiently deliver genes into cultured cells and have a strong prefere nce for hepatocytes of different origin, Baculoviral gene transduction efficiency into human hepatocytes was determined to approach 100% and expression levels are high, provided that gene expression is controll ed by mammalian promoters, In this report, we present further properti es of baculoviruses regarding their use for hepatocyte gene transfer, Baculovirus-mediated gene expression declines rapidly in the hepatocel lular carcinoma cell line Huh7 and more slowly in primary cultures of mouse hepatocytes. Direct application of baculoviruses for gene delive ry to the liver in vivo is hampered by serum components, presumably by complement, However, we demonstrate here that baculoviral gene transf er is feasible in ex vivo perfused human liver tissue, This result sug gests the development of a strategy using baculoviral vectors for live r-directed gene therapy.