ENHANCED IN-VITRO AND IN-VIVO GENE DELIVERY USING CATIONIC AGENT COMPLEXED RETROVIRUS VECTORS

Retroviruses are, at present, the most efficient integrative vectors a vailable for gene delivery. However, these viruses are still limited b y relatively low titres. Although several protocols exist to improve v irus titre most of them are time-consuming and unable to provide suffi cient virus for in vivo applications virus titre can be enhanced by po lybrene and other cationic agents. By investigating a broad range of c ationic agents for their ability to enhance virus infectivity we found that both ecotropic and amphotropic retrovirus infection could be inc reased. In particular, the lipopoly-amine dioctadecylamidoglycylspermi ne (DOGS) gave up to one order of magnitude enhancement above polybren e-mediated infection without cytotoxicity. To increase virus infectivi ty further we combined the enhancing effect of DOGS on virus infectivi ty with concentration of virus particles by ultrafiltration to reach t itres of 1 x 10(9) IU/ml. The in vivo transduction of regenerating rat liver by an amphotropic retrovirus was increased approximately five-f old by the addition of DOGS compared with virus alone. There was no an imal toxicity observed following the administration of DOGS. The impro ved transduction efficiency seen both in vitro and in vivo following t he co-administration of DOGS/virus complexes may be useful for future gene therapy applications.