Efficient liver-directed gene transfer by in situ generation of retroviral vector from adenoviral templates.

To improve liver-directed retroviral-mediated gene transfer, we injected C57/BL10 mice intravenously with three adenoviral vectors encoding retroviral vector genome and structural components: AdGagPol expressing the respective structural genes of Moloney murine leukaemia virus, Ad10AlEnv expressing the 10Al envelope protein of 10Al-MuLV, and AdLEIN, encoding the LEIN retrovirus genome, expressing green fluorescence protein (eGFP) and the neomycin resistance gene. Materials and Methods: The extent of eGFP expression was determined after I and 15 weeks by fluorescence microscopy and FACS analysis. Proviral integration was determined by a novel PCR-based technique. Results: Hepatocytes infected with all three Ad vectors generated LEIN retrovirus after one week and in situ transduction of neighbouring cells resulted in stable proviral integration associated with eGFP expression ranging front 4.3% to 20.5% in different liver cell populations 15 weeks post-infection. Conclusion: Hybrid adeno-retro viral vectors can be efficiently used to improve the efficiency of retroviral-mediated gene transfer to the liver.