An experimental system for the analysis of targeted retrovirus transduction

Recombinant retroviruses have frequently been used to transfer genes to cells in ex vivo human gene therapy protocols. Retroviruses have rarely been used for in vivo gene transfer protocols, however, because of the likelihood that innocent bystander cells, adjacent to the diseased cells that are the target of the therapy, would be inadvertently modified. This has limited the use of retroviruses for many important gene therapy applications such as those for the brain, heart and lungs. To overcome this limitation, retroviruses have been constructed that bind to receptors that are expressed only on the cell type of interest. In general, the efficiency with which these targeted retroviruses are able to transfer genes to cells has been far too low to be of any practical use in human gene transfer. We hypothesize that the low efficiency of gene transfer of targeted retroviruses is due in part to unfavorable trafficking of the viruses within the targeted cells, and that the pathways that these viruses are trafficked within these cells are largely dictated by the receptors to which they bind. In this study, we have established an experimental framework with which to test our hypothesis and to examine the kinetics and intracellular trafficking of retroviruses.