a) Advantages of lentivirus -mediated gene delivery
Lentivirus has been developed as an attractive candidate for creating viral vectors for gene therapy due to various advantages.
1) Customized cloning for any other gene ORF expression, shRNA/miRNA and CRISPR/Cas9.
2) No known immunogenic proteins generated.
3) High titer. 10⁸TU/ml or 10⁹TU/ml lentiviral titer for cell line transfection in medium or large scale.
4) With broad range of hosts. Mediate efficient transfection in both dividing and non-dividing cells.
5) Integration into host cell genome, mediating long-term and stable expression of exogenous genes.
6) Deliver complex genetic elements, such as intron-containing sequences.
7) Simple system for vector manipulation and production.

b) Drawbacks of lentivirus-mediated gene transfer
Although lentivirus benefits a great deal of disease therapies, it does present some drawbacks.
1) Based on HIV-1, recombinant lentivirus vectors require at least three HIV-1 genes (gag, pol, and rev) for production, which is still not safe enough for gene therapy. To date, the best solution for this drawback is to turn to adenovirus or AAV vectors, which may be safer than lentivirus vector.