1. ¹Research Institute for Virology and Biomedicine, University of Veterinary Medicine, Vienna, Austria
2. ²Institute of Medical Chemistry, University of Veterinary Medicine, Vienna, Austria
3. ³Department of Histology and Embryology, Faculty of Medicine Pilsen, Charles University Prague, Pilsen, Czech Republic
4. ⁴Austrianova Biotechnology GmbH, Vienna, Austria

Correspondence: Dr M Renner, Austrianova Biotechnology GmbH, Veterinaerplatz 1, A-1210 Vienna, Austria. E-mail: renner@austrianova.com

⁵Current address: German Institute of Human Nutrition, Nuthetal, Germany

Received 20 June 2006; Revised 4 April 2007; Accepted 10 May 2007; Published online 5 July 2007.

Abstract

Lentiviral vectors have proven to be promising tools for transduction of brain cells in vivo and in vitro. In this study, we have examined the central nervous system (CNS) transduction efficiencies and patterns of a self-inactivating simian immunodeficiency virus (SIVmac)-derived lentiviral vector pseudotyped with glycoproteins from the vesicular stomatitis virus (VSV-G), the amphotropic murine leukemia virus (MLV4070Aenv), the lymphocytic choriomeningitis virus (LCMV-GP), the Ross River virus (RRV-GP) and the rabies virus (RV-G). All glycoproteins were efficiently incorporated into SIV virions, allowing efficient transduction of neuronal cell lines as well as of primary dissociated mouse brain cell cultures. After injection of highly concentrated vector stocks into the striatum of adult mice, quantitative analyses revealed high transduction efficiency with VSV-G pseudotypes, while LCMV-GP and RV-G pseudotypes exhibited moderate transduction efficiencies. MLV4070Aenv and RRV-GP pseudotypes, however, showed only weak levels of transduction after stereotactic injection into the brain. Regarding cell tropism in vivo, VSV-G-pseudotyped SIV vectors transduced neuronal as well as glial cells, whereas all other pseudotypes preferentially transduced neuroglial cells. In addition, we analyzed the influence of the central polypurine tract (cPPT) in context of the VSV-G-pseudotyped SIV transfer vector for infection of brain cells. Deletion of the cPPT sequence from the transfer vector decreased the in vivo transduction efficiency by fourfold, and, more importantly, this modification changed the transduction pattern, since these vectors were no longer able to infect neuronal cells in vivo. Vector injection into the brain did elicit a humoral immune response in the injected hemisphere; however, no gross signs of inflammation could be detected. Analysis of the biodistribution of the vector revealed that, besides the injected brain region, no vector-specific sequences could be detected in any of the organs evaluated. These data indicate SIV vectors as efficient gene delivery vehicles for the treatment of neurodegenerative diseases.