Advantages and Drawbacks of Lentivirus Vector-mediated Gene Delivery

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.

Table 2. Comparison between Retrovirus, Lentivirus, Adenovirus and Adeno-associated virus (AAV) vectors.
Comparison Retrovirus Lentivirus Adenovirus AAV
Genome ss RNA ss RNA ds DNA ss DNA
Integration Yes Yes no no
Packaging Capacity 3kb 4kb 5.5kb 2kb
Time to peak expression 72h 72h 36h-72h cell: 7 days; animals: 2 weeks
Sustainable time about 3 weeks stable expression transient expression > 6 months
Cell Type most dividing/non-dividing Cells most dividing/non-dividing Cells most dividing/non-dividing Cells most dividing/non-dividing Cells
Titer 10^7 TU/ml 10^8 TU/ml 10^11 PFU/ml 10^12 vg/ml
Animal experiment suitable low efficiency lowest efficiency most suitable
Immune Response high medium medium mild