Applications | High Titer Virus Production

Overview of Recombinant Lentivirus Particles and Infection of Target Cell. (1) Producer cells (e.g. 293T) are transfected with 3-4 plasmids encoding the gene of interest, vesicular stomatitis G protein (VSV-G) and essential virus proteins (e.g. gag, pol and rev). (2) Virus is assembled and released into the supernatant through budding with the producer cell plasma membrane resulting in an envelope decorated with VSV-G. The medium containing virus is filtered through a 0.45 µm filter to remove any cells. (3) Target cells are frequently transduced with recombinant lentivirus particles in the presence of a polycation to increase aggregation and uptake. The virus enters the cell and the capsid is uncoated revealing the RNA genome and viral enzymes. The viral RNA is reverse transcribed into DNA which is then integrated into the host genome. (4) Transcription and translation result in the production of the protein encoded by the gene of interest.

High Functional Titers with TransIT®-Lenti Transfection Reagent. Adherent 293T/17 cells were transfected in a 6-well plate with pLKO.1-puro-CMV-TurboGFP™ transfer vector and the Lentivirus Packaging Mix Powered by MISSION® Genomics (1:1 ratio, 2 µg/well) with the following reagents: TransIT®-Lenti (3:1, vol:wt), Lipofectamine® 2000 (3:1), Lipofectamine® 3000 (3:1:1), 25 kDa PEI (6:1), or CaPO4 precipitation (4 µg pDNA/well). The supernatant was harvested, filtered (0.45 µm), and titered using 293T/17 cells. Lentivirus transductions were performed in the presence of 8 µg/ml TransduceIT™ and GFP expression was measured 72 hours post-transduction using guava easyCyte™ 5HT Flow Cytometer. Error bars represent triplicate transfection complexes titered individually. Functional titers were calculated using virus dilutions with less than 20% GFP positive cells.

High Efficiency Transfection with TransIT®-Lenti Transfection Reagent. Adherent 293T/17 cells were transfected in a 6-well plate format using the pLKO.1-puro-CMV-TurboGFP™ transfer vector and the Lentivirus Packaging Mix Powered by MISSION® Genomics using the TransIT®-Lenti Transfection Reagent (3:1, vol:wt). GFP efficiency was measured at 48 hours post-transfection using guava easyCyte™ 5HT Flow Cytometer.  Error bars represent five transfection complexes. Images were captured at 48 hours post-transfection (10X objective) using a Zeiss Axiovert S100 inverted fluorescence microscope. The observed cell rounding and cell-cell fusion is due to high expression of the vesicular stomatitis virus G protein (VSV-G) for pseudotyping the recombinant lentivirus.

Lentivirus Production is Scalable. Adherent 293T/17 cells were transfected in a 12-well, 6-well or 100 mm plate format using the pLKO.1-puro-CMV-TurboGFP™ transfer vector and the Lentivirus Packaging Mix Powered by MISSION® Genomics at a 1:1 ratio, and the TransIT®-Lenti Transfection Reagent (3:1, vol:wt). The supernatant was harvested, filtered (0.45 µm), and titered using 293T/17 cells. Lentivirus transductions were performed in the presence of 8 µg/ml TransduceIT™ and GFP expression was measured 72 hours post-transduction using guava easyCyte™ 5HT Flow Cytometer. Error bars represent triplicate transfection complexes titered individually. Functional titers were calculated using virus dilutions with less than 20% GFP positive cells.

High Transduction Efficiency with Unconcentrated Lentivirus Using TransIT®-Lenti. (A) Lentivirus was produced with the TransIT®-Lenti Transfection Reagent (3:1, vol:wt) or Lipofectamine® 2000 using pLKO.1-puro-CMV-TurboGFP™ transfer vector and the Lentivirus Packaging Mix Powered by MISSION® Genomics). The supernatant was harvested, filtered (0.45 µm), and frozen. Lentivirus transductions were performed 5 days post-plating with iCell® Motor Neurons (Cellular Dynamics International). For bothTransIT-Lenti and Lipofectamine® 2000, one microliter of unconcentrated supernatant was added per well of a 96-well plate. GFP efficiency was measured 72 hours post-transduction using guava easyCyte™ 5HT Flow Cytometer. Error bars represent the SEM of duplicate wells. (B) iCell® Motor Neurons were plated in Ibidy 35mm dishes and transduced with lentivirus produced using the TransIT®-Lenti Transfection Reagent and MISSION® vectors. Images were captured at 72 hours post-transduction with a Zeiss Axiovert S100 inverted fluorescence microscope using a 63X objective under oil.