A packaging cell line for lentivirus vectors

Lentivirus vectors can transduce dividing and nondividing cells. Using thre e-plasmid transient transfections, high-titer (>109 IU/ml) recombinant lent ivirus vectors pseudotyped with vesicular stomatitis virus G (VSV-G) protei n can be generated (T. Kafri et al., Nat. Genet, 17:314-317, 1997; H, Miyos hi et al,, Proc. Natl, Acad, Sci, USA 94:10319-10323, 1997; L, Naldini et a l,, Science 272:263-267, 1996), The recombinant lentiviruses can efficientl y infect brain, liver, muscle, and retinal tissue in vivo. Furthermore, the transduced tissues demonstrated long-term expression of reporter genes in immunocompetent rodents. We now report the generation of a tetracycline-ind ucible VSV-G pseudotyped lentivirus packaging cell line which can generate virus particles at titers greater than 106 IU/ml for at least 3 to 4 days. The vector produced by the inducible cell line can be concentrated to titer s of 109 IU/ml and can efficiently transduce nondividing cells in vitro and in vivo. The availability of a lentivirus packaging cell line will signifi cantly facilitate the production of high-titer lentivirus vectors for gene therapy and study of human immunodeficiency virus biology.