EFFICIENT TRANSDUCTION OF MAMMALIAN-CELLS BY A RECOMBINANT BACULOVIRUS HAVING THE VESICULAR STOMATITIS-VIRUS-G GLYCOPROTEIN

Baculovirus vectors recently have been shown to be capable of efficien t transduction of human hepatoma cells and primary hepatocytes in cult ure, This paper describes the generation of a novel recombinant baculo virus (VGZ3) in which the vesicular stomatitis virus glycoprotein G (V SV G) is present in the viral envelope, The gene encoding VSV G was in serted into the baculovirus genome under the control of the polyhedrin promoter such that it was expressed at very high levels in infected i nsect cells but not in mammalian cells, Expression of the lacZ reporte r gene was driven by a promoter that is functional in mammalian cells (the Rous sarcoma virus long terminal repeat), We show by Western anal ysis that VSV G protein was present in purified baculovirus preparatio ns, A VSV G monoclonal antibody blocked transduction of mammalian cell s by VGZ3. This virus was morphologically distinct from baculovirus la cking VSV G, with virions adopting an oval rather than rod-shaped morp hology, VGZ3 transduced human hepatoma cells in vitro at an efficiency roughly 10-fold greater than baculovirus lacking VSV G (the virus Z4) , VGZ3 was also capable of transducing cell lines that could not be tr ansduced efficiently by 24, We provide evidence that VSV G protein may enhance transduction by increasing the efficiency of escape of baculo virus from intracellular vesicles rather than by increasing cell bindi ng or uptake of the virus, The possible use of this and related baculo viruses in gene therapy is discussed.