Efficient retroviral infection of human cells utilising an adenoviral vector expressing the ecotropic receptor.

Abstract

Murine leukemia viruses (MLV) are a vector of choice for gene delivery in current human clinical trials. The first step in retroviral infection is the binding of the viral particle to a receptor on the target cell1. Thus, the presence of the appropriate viral receptors on the surface of target cells is the major determinant of the susceptibility of mammalian cells to MLV. The phosphate transporter shared by primates, mice, and rats that acts as the viral receptor for amphotropic MLV2,3 is present on many different human cell types but is not ubiquitous or plentiful, placing a grave restriction on the infection efficiency of this retrovirus. In this study, we utilized an adenoviral vector to express transiently the receptor for the ecotropic murine leukemia virus in a panel of human cell lines. Ecotropic strains of MLV, such as Moloney, Rauscher, and Friend, attach to cells utilizing a common cationic amino acid transporter that is confined to mice and rats4. The cationic amino acid transporter was expressed in human cells by means of a recombinant adenovirus constructed with murine cDNA. Expression of the receptor made cells from human mesothelium, kidney, lung, and cervical epithelium highly permissive to infection with recombinant ecotropic retrovirus. This strategy offers a means of obtaining high levels of stable gene transfer in a wide range of human cells. The use of a dual vector system may overcome some of the present limitations to gene transfer.