The application of a lentiviral vector for gene transfer in fetal human hepatocytes.

BACKGROUND: The applications of traditional retroviral vectors are limited because proviral integrations into the host genome require DNA synthesis. Lentiviruses are considered to be advantageous because of their ability to infect non-dividing cells.
METHODS: To demonstrate the potential of lentiviral vectors, we used a human immunodeficiency virus (HIV)-1 virus encoding the green fluorescence protein (GFP) to infect fetal human hepatocytes. GFP-expressing cells were transplanted into the liver of Balb/C SCID mice via intrasplenic injection.
RESULTS: Primary fetal hepatocytes incorporated the GFP reporter with high (30-40%) efficiency. A cell line derived from human fetal liver (HFL) exhibited similar transduction efficiency to the lentiviral vector. To demonstrate the relationship between lentiviral gene transfer and cell proliferation, cells were subjected to gamma-irradiation, which attenuated the replication of primary fetal hepatocytes. However, lentiviral gene transfer was unaffected by this decrease in cell proliferation. GFP expression in transduced cells was preserved during multiple passages in cell culture. When GFP-expressing cells were transplanted into the liver of Balb/C SCID mice via intrasplenic injection, GFP expression was observed throughout the 3 week duration of the study.
CONCLUSION: These studies establish that human hepatocytes are amenable to lentiviral gene transfer with sustained transgene expression. Incorporation of lentiviral vectors will be helpful in testing strategies for hepatic gene therapy.