Lentivirus

Unlike other retrovirus, lentiviral vectors have the advantage of infecting both dividing and non-dividing cells. However, they retain stable and long-term expression which is heritable. Lentivirus can be pseudo-typed with ease to infect certain tissues and cell lines with greater efficiency. Made to accommodate expression cassettes of approximately 7 kb, these viral vectors elicit minimal immune responses in vivo.

FIV-based lentiviral vectors are available solely to University of Iowa researchers through an exclusive contract with the Chiron Corporation. Others may use these vectors if Material Transfer Agreements with Chiron are approved. The Feline Immunodeficiency virus has not been found to infect humans. The virus is produced through a triple transfection of a shuttle, a backbone, and an envelope vector. There are several reporter viruses available for purchase. The vectors can be concentrated to titers of 10⁹ TU/ml.

HIV-based lentiviral vectors are available to University of Iowa investigators, and outside users. These vectors are replication-incompetent.  The virus is produced through a quadruple transfection of a shuttle, two backbone plasmids and an envelope vector.  The vectors can be concentrated to titers between 10⁷ – 10⁸ TU/ml.

Retrovirus

Retrovirus based on Moloney Murine Leukemia Virus (MMuLV) allows for gene delivery to most dividing mammalian cell lines. These vectors are pseudo-typed with an ecotropic or amphotropic envelope. The ecotropic envelope is used to deliver genes to dividing murine or rat cells. The amphotropic envelope allows delivery of genes to most mammalian cells including human. These vectors have stable gene expression due to viral genome integration. It can accommodate inserts up to 6.5Kb.