Citrine Lentivirus

The production of lentiviral vectors revolves around the use of cell lines, often called packaging cells, to produce viral vector particles. Large-scale production of the vector begins with the cultivation of sufficient numbers of packaging cells, such as derivatives of the HEK293T cell line. The packaging cells are expanded in culture for several days, and then these cells are transiently transfected with plasmid DNA encoding the proteins required for lentiviral vector production. These core packaging plasmids include envelope proteins (most commonly VSV-G), HIV-1 gag and pol gene products, and HIV accessory proteins, such as Rev. Co-transfection of these plasmids with the lentiviral vector genome containing the gene of interest provides the cell line with all the necessary components to produce functional vector particles. Over a period of several days, the packaging cells produce lentiviral vector particles that can be harvested from the culture medium. After flow filtration, the clarified vector is treated to remove contaminating DNA products, and the viral product is purified using various methods such as gradient purification or chromatography. After purification, the elution fraction is subjected to a series of filtration steps to achieve sterility and remove any remaining cellular debris. The purity of the product is critical. Packaging cell fragments are easily collected with the vector product, and these impurities may cause inflammatory responses in vitro and in vivo. After the vector stock solution is prepared, it is reported that it can remain stable for up to 9 years when stored at -80°C.