Lentiviral vectors essentials

Lentiviral vectors are gene transfer tools derived from viruses. They are used to deliver specific genes into target cells. All pathogenic and replicative properties of the viruses have been removed to only keep their gene transport capability.

Lentiviral vectors can integrate into dividing or non dividing cells. The integrated copy number is variable but can be managed by controlling the quantity of lentiviral vectors applied to the target cells. The integration into the host genome is stable and always random.

The unpredictability of the integration site can potentially lead to secondary phenotypes such as oncogenesis but the risk of adverse effects is very low when third generation lentiviral vectors are used.

Lentiviral vectors: the most versatile gene transfer tool

There are several tools available on the market to deliver genes into host cells. The most commonly used are transfection tools, adeno-associated viral vectors (AAV) and lentiviral vectors. Each one has advantages and disadvantages for particular applications, as shown below:

Examples DNA
transfection
AAV Lentiviral
vectors
Gene transfer into
immortalized cell lines
Check Check * Check
Gene transfer into
primary cells
Check ** Check * Check
Gene transfer into
stem cells
Cross Cross Check
Gene transfer in vivo Cross Check * Check

*Gene transfer using AAV is limited by pseudotypes and by the length of the sequence of interest.
**Cell toxicity induced by the use of this tool is an obstacle for the study of gene expression in primary cells.

From transfection to transduction

Advantages and disadvantages for each gene transfer tool depend on their technical characteristics such as expression, genome status or insert size.

  Transfection Adenoviral associated vectors Lentiviral vectors
WT Virus No viral sequences Linear single strand DNA Linear single strand RNA
Insert size No limite 4,5 kb 10 kb
Expression Transient
No dose effect
Transient/Stable
No dose effect
Stable
Dose effect
Genome status Episomal Episomal Integrated
Target cells Dividing Dividing and quiescent Dividing and quiescent
Applications Mostly in vitro immortalized cells             In vivo In vitro, In vivo Immortalized & primary cells

 

Natural advantages of lentiviral vectors

Compared to other viral vectors, lentiviral vectors feature strong advantages related to the natural effectiveness of lentiviruses. By nature, lentiviruses are the most effective infectious agents for performing gene transfer into their hosts. The natural advantages of lentiviral vectors are:   

  • Gene delivery into dividing and non-dividing cells.
  • Gene delivery from in vitro transduction to in vivo injection.
  • A stable expression of the gene of interest thanks to DNA integration into the host genome.

Additional benefits of lentiviral vectors from Vectalys

The patented production technology of Vectalys provides additional benefits to lentiviral vectors:

  • No toxicity to target cells: Vectalys’ purification processes prevent toxicity effect on cells. Transducing your target eukaryotic cells with our purified lentiviral vectors does not affect the viability of the cells, their capacity to proliferate  in vitro, or their ability to progress along a differentiation pathway.
  • 100% transduction efficiency: High concentration of lentiviral vectors allows transduction of any cells (immortalized, primary or stem cells) by simply increasing the multiplicity of infection (MOI). Even the most difficult target cells can be transduced.
  • Transient expression into Primary cells: Lentiflash, our new generation of lentiviral particles, overcomes the issues, for certain applications, related to DNA insertion into the host genome. Particularly, Lentiflash offers the possibility to transfer genes transiently, similarly to transfection tools, but with the efficiency of lentiviral vectors in transferring genes into any cell types.