EFFICIENCY OF IN-VIVO GENE-TRANSFER USING MURINE RETROVIRAL VECTORS IS STRAIN-DEPENDENT IN MICE

Retroviral vectors can be used to transduce cultured cells at high fre quencies, but efficient transduction of target cells in vivo has prove d difficult and little is known about the factors that influence the e fficiency of retroviral infection. Many commonly used mouse strains ha rbor endogenous C-type proviruses, some of which are expressed and hav e circulating antibodies against the viral envelope glycoproteins that cross-react with the Moloney strain of murine leukemia virus (MoMLV), from which most current retroviral vectors are derived. We have inves tigated the relative efficiency of retroviral-mediated gene transfer i nto regenerating skeletal muscle of a variety of mouse strains using a MoMLV-based vector. Humoral immune competence and interference betwee n endogenous MLVs and exogenous recombinant MoMLV were observed to aff ect the efficiency of retroviral-mediated transfection in vivo. Our re sults indicate that the mouse genetic background and immune status nee d to be considered when choosing a preclinical model for in vivo retro viral-mediated gene transfer.