EF1a-CD9-tdTomato Lentivirus

Lentiviral vectors (LVs) originate from the genus Lentivirus within the Retroviridae family, with the human immunodeficiency virus (HIV) as their prototype. To ensure their safe use in gene therapy, scientists have modified the HIV-1 genome. The HIV-1 genome is packaged in separate plasmids and co-transfected into cells to eliminate its ability to replicate, thereby constructing a lentiviral vector capable of only single infection. The lentiviral vector genome consists of single-stranded positive-sense RNA. After entering the cell, the genome is reverse-transcribed into DNA by its own reverse transcriptase in the cytoplasm, forming a pre-DNA integration complex. After entering the cell nucleus, the DNA integrates into the cellular genome. The integrated DNA is transcribed into mRNA, which then returns to the cytoplasm to express the target gene or fragment.

The widely used four-plasmid system, consisting of a packaging plasmid, an envelope plasmid, a transfer plasmid, and a helper plasmid, has greatly improved the safety and application range of lentiviral vectors. Its structural characteristics are as follows:

- Envelope protein (e.g., VSV-G): determines the range and efficiency of viral infection;

- Genome: carries the target gene (CAR sequence) and essential packaging components (e.g., LTR, Ψ packaging signal);

- Safety enhancement: Third-generation lentiviral vectors utilize a four-plasmid system (transfer plasmid + packaging plasmid + envelope plasmid + helper plasmid) to eliminate pathogenic genes, ensuring replication incompetence.