Transduction of Human ES Cells by Lentiviral Vectors

This chapter focuses on the use of vectors derived from lentiviruses for stable gene delivery into human embryonic stem (hES) cells. The lentiviruses are a subgroup of retroviruses associated with slow chronic diseases in humans and animals. Vectors derived from lentiviruses have been developed over the last few years, and have been shown to efficiently transduce a variety of cell types, including primary cells. The key properties of lentiviral vectors include: efficient infection of both dividing and nondividing cells; integration into the host cell DNA, thus, allowing a stable expression and germ line transmission of the transgene; and lack of immunogenicity. The potential of modified lentiviral vectors pseudotyped with vesicular stomatitis virus glycoprotein (VSV-G) to promote efficient and stable gene delivery into hES cells was recently demonstrated. Several studies performed until now have established the use of HIV-1-derived vectors as efficient gene delivery tools into hES cells, which promote stable and high expression of the transgene. The lentiviral vectors could be designed to overexpress transcriptional factors that direct the differentiation of hES cells into a specific cell type. Constructing vectors containing lineage- or cell type-specific promoters driving the expression of selectable markers could promote the selection of either undifferentiated stem cells or differentiated cells of specific lineages. The ability to direct the differentiation of hES cells or to select a specific lineage may be highly valuable to the study of human embryogenesis, and could provide an unlimited supply of a pure population of various cell types for transplantation therapy.