Lentivirusus have become a widely used gene delivery tool. Their advantages include convenience, high efficiency, broad cell range and stable integration. But as lentiviral vectors gain popularity as a research reagent, more education is needed on their safety.
What kinds of precautions are recommended? This short video will clarify this issue.
Lentivirusus are a subgroup of retroviruses with an envelope and a positive-strand RNA genome. They can infect human cells, and precautions should therefore be strictly followed when handling lentiviruses.
Research-grade lentiviruses are considered a biosafety level 2 material. Lab coats, gloves, and a tissue culture hood are required for all handling. All wastes should be bleached, and solid wastes should be autoclaved. More details can be found at the NIH’s BSL2 guidelines from the link above.
In the natural Lenti life cycle, the RNA genome is reverse transcribed, integrated, expressed into essential proteins, and ultimately assembled into viral particles for the next round of infection. Will this pose a health risk? Don’t worry; scientists have engineered reagent Lentiviruses for research use to stop viral replication.
One safety measure is splitting the essential elements into multiple vectors:
1). A shortened version of Lenti genome flanked by 2 LTRs carrying the gene of interest;
2). Other essential viral proteins are encoded by separate packaging plasmids.
Co-transfecting the above plasmids into HEK293 cells will produce pseudo viral particles, containing only the shortened Lenti vector. These pseudo viral particles are perfect for delivering the gene of interest into cells, yet they cannot propagate. In the 2nd generation of lentiviral system, 2 packaging plasmids are used. in the 3rd generation, 3 packaging plasmids are used, further improving its biosafety.
In addition, the 3rd generation lenti system employs a self-inactive (SIN) 3-prime LTR with a deletion in the U3 region, further impairing the chance of producing replication-competent viruses.
In summary, Lentiviruses are a biologically active agent and safe-handling guidelines should be strictly followed. But there is no need to worry; if you know how to handle routine cell culture, you know how to handle lentiviruses. To minimize your exposure to lentiviruses, OriGene offers ready-to-use lentiviral particles that you can simply pipet onto your cell culture. For details please visit OriGene website.