scFv(CD19)-CD28-41BB-CD3zeta CAR-T Lentivirus

Researchers have engineered the lentivirus for safety, distributing its genes across three plasmids: a packaging plasmid (which provides the viral core structural protein gag and reverse transcriptase pol), an envelope plasmid (which provides the envelope glycoprotein VSV-G for cell membrane penetration), and a shuttle plasmid carrying the target gene. Scientists also deleted the HIV-1 vif, vpr, vpu, and nef genes, as well as the U3 sequence in the 3'' LTR of the shuttle plasmid, rendering HIV-1 unable to replicate and produce new viral particles. Furthermore, the vesicular stomatitis virus (VSV-G) glycoprotein replaced the env-encoded envelope glycoprotein in the envelope plasmid to expand the range of cells infected by the lentivirus. With this reduced biosafety risk, the lentivirus has been used as a vector for gene delivery into mammalian cells. Due to its high efficiency and long-lasting expression, it is widely used in gene therapy, gene editing, and cell biology research.

Lentiviral vectors can efficiently deliver target genes (such as CAR genes) into immune cells and stably integrate them into the cell genome, enabling sustained expression of the CAR gene during cell division and proliferation. This efficient transfection capability is fundamental to the success of immune cell therapy. Compared to other viral vectors, lentiviruses have lower immunogenicity. Therefore, when lentiviral vectors are used to transduce immune cells, the patient''s immune system''s response to the virus is relatively weak. This helps minimize adverse reactions, especially during the long-term survival of the cells after infusion, by avoiding excessive immune rejection. In immune cell therapy, transfected effector cells are immune cells that, after transfection, express CARs and exert anti-tumor effects. Lentiviruses precisely deliver the CAR gene to these effector cells, enabling them to recognize and attack tumor target cells. Target cells are tumor cells that these immune cells recognize and kill. Through lentiviral transfection, immune cells can enhance their specific recognition and killing capabilities for tumor cells, thereby improving therapeutic efficacy.