A GENERAL-METHOD FOR THE GENERATION OF HIGH-TITER, PANTROPIC RETROVIRAL VECTORS - HIGHLY EFFICIENT INFECTION OF PRIMARY HEPATOCYTES

Retroviral vectors have been central components in many studies leadin g to human gene therapy. However, the generally low titers and ineffic ient infectivity of retroviral vectors in human cells have limited the ir use. We previously reported that the G protein of vesicular stomati tis virus can serve as the exclusive envelope protein component for on e specific retroviral vector, LGRNL, that expresses vesicular stomatit is virus G. We now report a more useful general transient transfection scheme for producing very high-titer vesicular stomatitis virus G-env eloped pseudotypes from any Moloney murine leukemia-based retroviral v ector without having to rely on the expression of the cytotoxic G prot ein from the retroviral vector itself. We also demonstrate very high e fficiency of infection with a pseudotyped lacZ vector in primary mouse hepatocytes. We suggest that pseudotyped retroviral vectors carrying reporter genes will permit genetic studies in many previously inaccess ible vertebrate and invertebrate systems. Furthermore, because these v ectors represent retroviral vectors of sufficiently high titer to allo w efficient direct retroviral-mediated in vivo gene transfer, we also suggest that pseudotyped vectors carrying potentially therapeutic gene s will become useful to test the potential for in vivo gene therapy.