1. ¹Department of Biotechnology and Molecular Medicine, AI Virtanen Institute for Molecular Sciences, University of Kuopio, Kuopio, Finland
2. ²Ark Therapeutics Oyj, Microkatu, Kuopio, Finland
3. ³Gene Therapy Unit, Kuopio University Hospital, Kuopio, Finland
4. ⁴Biomedical Imaging Unit, AI Virtanen Institute for Molecular Sciences, University of Kuopio, Kuopio, Finland
5. ⁵Department of Neurology, AI Virtanen Institute for Molecular Sciences, University of Kuopio, Kuopio, Finland
6. ⁶Department of Medicine, AI Virtanen Institute for Molecular Sciences, University of Kuopio, Kuopio, Finland

Correspondence: Professor S Ylä-Herttuala, Department of Biotechnology and Molecular Medicine, AI Virtanen Institute for Molecular Sciences, University of Kuopio, PO Box 1627, FIN-70211, Kuopio, Finland. E-mail: Seppo.Ylaherttuala@uku.fi

⁷These authors contributed equally to this work.

Received 31 January 2009; Revised 31 March 2009; Accepted 1 April 2009; Published online 14 May 2009.

Abstract

Lentiviruses have shown great promise for human gene therapy. However, no optimal strategies are yet available for noninvasive imaging of virus biodistribution and subsequent transduction in vivo. We have developed a dual-imaging strategy based on avidin–biotin system allowing easy exchange of the surface ligand on HIV-derived lentivirus envelope. This was achieved by displaying avidin or streptavidin fused to the transmembrane anchor of vesicular stomatitis virus G protein on gp64-pseudotyped envelopes. Avidin and streptavidin were efficiently incorporated on virus particles, which consequently showed binding to biotin in ELISA. These vectors, conjugated to biotinylated radionuclides and engineered to express a ferritin transgene, enabled for the first-time dual imaging of virus biodistribution and transduction pattern by single-photon emission computed tomography and magnetic resonance imaging after stereotactic injection into rat brain. In addition, vector retargeting to cancer cells overexpressing CD46, epidermal growth factor and transferrin receptors using biotinylated ligands and antibodies was demonstrated in vitro. In conclusion, we have generated novel lentivirus vectors for noninvasive imaging and targeting of lentivirus-mediated gene delivery. This study suggests that these novel vectors could be applicable for the treatment of central nervous system disorders and cancer.