Lentiviral vectors are widely used to efficiently transduce both dividing and quiescent cells, which makes them powerful tools for gene delivery. Most commercially available lentiviral packaging systems generate lentivirus that integrates efficiently into the target cell genome as a provirus. However, non-integrating lentivirus can be produced through the use of mutations in the integrase protein that minimize proviral integration. The resulting integrase-deficient lentivirus (IDLV) generates circular vector episomes in transduced target cells that are gradually lost by dilution in dividing cells (transient expression), but are stable in quiescent cells. Inherently, IDLVs have a greatly reduced risk of causing insertional mutagenesis compared to integrating lentiviruses.
The Lenti-X HTX Packaging System (Integrase Deficient) is the only 4th generation lentiviral packaging system for IDLV generation. The system contains a combination of five plasmids mixed in optimal proportions to provide the highest possible lentiviral titers when transfected into Lenti-X 293T cells. The Xfect Transfection Reagent and Tet System Approved FBS are required for the protocol, and are included in the system. Additionally, a sample of Lenti-X GoStix is provided to enable rapid qualitative determination of lentiviral titer.