Retroviral vectors promote efficient and stable gene transfer and expression in cultured cells, including primary cells from humans and other animals that are difficult to transfect using other techniques. Transferred genes are integrated at relatively random sites in the host cell genome with minimal alteration of host cell genomic DNA. These properties have resulted in the use of retroviral vectors as markers for cells transplanted into humans, with or without suicide genes to allow destruction of the transplanted cells when necessary, and for human gene therapy.

Retroviral vector is a powerful tool for delivering target genes into almost all types of dividing cells in vivo and in vitro. Retroviral vectors most attractive features as gene transfer tools contain the capacity for large genetic payload (up to 9 kb), high transducing efficiency in vivo and in vitro, minimal patient immune response, and the ability to permanently modify the genetic content of the target cell, sustaining a long-term expression of the delivered gene. However, the production of recombinant retroviral vector is challenging, especially when high-titer of recombinant retroviral vectors (>10⁷ transducing unit (TU)/ml) is required.