1. ¹Department of Haematological and Molecular Medicine, Guy's, King's and St Thomas' School of Medicine, The Rayne Institute, King's College London, 123 Coldharbour Lane, London SE5 9NU, UK
2. ²Cambridge Unit for Bioscience Engineering, Department of Chemical Engineering, University of Cambridge, New Museums Site, Pembroke Street, Cambridge CB2 3RA, UK
3. ³Centre for Ultrastructural Imaging, King's College London, New Hunts House, Guy's Campus, London Bridge, London SE1 1UL, UK

Correspondence: Farzin Farzaneh, Fax: +44 20 7733 3877. E-mail: farzin.farzaneh@kcl.ac.uk

Received 11 April 2005; Revised 7 September 2005; Accepted 13 September 2005.

Abstract

Nonviral, host-derived proteins on lentiviral vector surfaces can have a profound effect on the vector's biology as they can both promote infection and provide resistance to complement inactivation. We have exploited this to engineer a specific posttranslational modification of a "nonenvelope," virally associated protein. The bacterial biotin ligase (BirA) and a modified human LNGFR have been introduced into HEK293T cells and their protein products directed to the lumen of the endoplasmic reticulum. The BirA then couples biotin to an acceptor peptide that has been fused to the LNGFR. This results in the covalent linkage of biotin to the extracellular domain of the LNGFR expressed on the cell surface. Lentiviral vectors from these cells are metabolically labeled with biotin in the presence of free biotin. These biotinylated lentiviral vectors have a high affinity for streptavidin paramagnetic particles and, once captured, are easily manipulated in vitro. This is illustrated by the concentration of lentiviral vectors pseudotyped with either the VSV-G or an amphotropic envelope in excess of 4500-fold. This new cell line has the potential for widespread application to envelope pseudotypes compatible with lentiviral vector production.