ADENOVIRUS-MEDIATED TRANSFER OF THE AMPHOTROPIC RETROVIRUS RECEPTOR CDNA INCREASES RETROVIRAL TRANSDUCTION IN CULTURED-CELLS

The presence of functional amphotropic receptors on the cell surface i s necessary for amphotropic retrovirus-mediated gene transfer. A recom binant adenoviral vector that expresses the receptor for amphotropic r etrovirus (RAM) was constructed and used to express the receptor cDNA in different cell types in culture. Transfer of the RAM cDNA increased amphotropic retroviral-mediated transfer from 0 to 60% in Chinese ham ster ovary cells. RAM expression increased retroviral transduction fou r- to eight-fold from 2-4% to 18%-35% in HeLa, Namalva, and X63 cells, but had no effect on 208F and HepG2 cells which have high baseline re troviral transduction rates of about 50%. For the purpose of applicati on to ex vivo gene therapy, primary mouse hepatocytes were studied in a similar manner. Hepatocytes had a baseline transduction efficiency o f about 40% and did not have increased rates of retroviral-mediated ge ne transfer with expression of recombinant RAM. This recombinant adeno viral vector conferred infection of amphotropic retrovirus into cells that were relatively resistant to infection, thus offering a rapid and easy method to stably introduce genes into these cell lines.