Lentiviral Vectors

How are GEG Tech lentiviral vectors different from other viral vectors?

GEG Tech has a particular know-how in the field of lentiviral vector design and production stemming from more than fifteen years of research during which more than several thousands of lentiviral vectors have been produced. This experience has led us to set up optimized protocols and reach high quality standards, constantly improved. Hence, GEG Tech lentiviral vector productions show high efficiency, suited for either in vitroin vivo or transgenesis applications. Our expertise allows us to take on all challenges. Notably, we provide our clients with lentiviral vectors expressing particularly challenging transgenes, for instance, ones that directly interfere with the lentiviral cycle.

What kind of products does the catalog offer?

Our catalog only contains ready-to-use lentiviral vector particles. They are purified, highly concentrated, and titered.

The vectors displayed in the catalog present a variety of promoters and transgenes for a large diversity of application fields such as angiogenesis, apoptosis, neurology, ophthalmology, genome editors. Furthermore, these combinations are declined with GEG Tech specific features, including our collection of integrases and envelopes. GEG Tech products are also available with several packaging options: we propose small volumes, particularly suited for preliminary assays or small scale in vitro studies. Larger volumes are available to answer recurrent usages; high titer vectors are perfect for most in vitro applications, while very high titer vectors will allow to transduce most transduction-resistant cells in vitro and are particularly suited for your in vivo and transgenesis applications.

For what kind of applications can lentiviral vectors be used?

Our lentiviral vectors can be used in large array of purposes. Taking advantage of Lenti-ONE features can significantly enhance your research. Here are some examples of in vitro and in vivo applications:

  • Stable expression transgenes of interest in target cells.

  • Expression of reporter systems to characterize a given vector in particular contexts (promoter, envelope, type of cells, level of expression etc…) and then determine the optimal vector configuration in said particular context (envelope, integrase, promoter).

  • Transient expression of transgenes of interest in dividing cells (IPs factors, RNAi factors, genome editing tools)

  • Induction of long term expression in non-dividing cells (therapeutic factors, transcription factors) with reduced genotoxicity

  • Generation of cellular models, such as cell lines with recombination induced by transiently expressed genome editing tools (eg: ZFN)

  • Generation of animal models by zygote injection and transient expression of genome editing tools (KO animals).

  See Fields of application

Which cell type is transduced by Lenti-ONE™?

Lentiviral vectors are very flexible gene transfer tools and can transduce a large variety of cells. Lenti-ONE™ can mediate ubiquitous or cell specific expression depending on the envelope and the promoter selected for your vector. Indeed the envelope will determine the entry mechanism of the vector into the cell, and the promoter will define the mechanism of transcription of the transgene. For example, the VSV envelope allows entry in almost any mammalian cells and the CMV or PGK promoter induce ubiquitous expression of transgenes. Consequently, the combination of these elements generates ubiquitous transduction and transgene expression in a wide range of cell types. In contrast, Mokola envelope restricts vector entry into glial cells, in addition the GFAP promoter is expected to specifically drive expression in astrocytes. Consequently, the combined use of the Mokola envelope with a GFAP promoter will confer a high preference for astrocytes. Depending on the experimental context, it is thus possible to combine a specific envelope with a specific promoter to control the specificity of expression.

How are the vectors titered?

GEG Tech produces each batch of vector with great caution, routinely established protocols and regular quality controls all along the production process. The final step consists in determining the concentration of the produced vector.

Each vector particle contains 2 molecules of RNA genome. For each vector production, the concentration of RNA molecules is determined per microliter based on an optimized protocol of RNA extraction, reverse transcription and real time PCR. As RNA genomes are rapidly degraded when not protected into the vector capsid, the RNA content gives a relevant measurement of the vector efficiency, in contrast to the widely used p24 content. Indeed, the p24 capsid protein can be either free or associated to a particle containing no RNA genome, thus giving a falsly estimated efficiency. Plus, the RNA titer is entirely independant of the vector features such as envelopes, promoters, or transgenes, which means RNA titer allows you to compare vectors with each other, despite their design differences.

GEG Tech also provides for each vector production a TU equivalent titer, which is based on the RNA content compared with one of a standard CMV-GFP vector, for which TU titer has been determined on HEK293T cells. In other words, it gives an estimation of what the TU would be if the vector is used in optimal conditions (i.e. appropriate promoter and envelope for the cell type). However, if you wish to know the actual TU of your vector, you can ask for it as an Extra QC.

What are the storage and handling recommendations?

Upon receipt, the viral vectors must be stored at -80°C.

The vectors should be taken out from the -80°C freezer at the last moment and kept on ice for gentle thawing. Once thawed, they should be used for transduction as soon as possible to avoid degradation. It is essential to avoid heat shock of the viral vectors and cells. If the vectors should be diluted in medium, use a medium at room temperature to minimize the heat shock experienced by both vectors and cells.

We recommend not refreezing the viral vectors. In order to guarantee viral vectors titer, we recommend keeping freeze-thaw cycles to a minimum. In case that more than one freeze-thaw cycle is required according to your application, GEG Tech recommends applying a decrease of about 15% on the titer for each freeze-thaw cycle.

What are the safety issues when using GEG Tech lentiviral vectors?

GEG Tech vectors are biosafety level 2 products. The use of retroviral derived vectors implies laboratory biosafety procedures and practices in accordance with regulations applicable in your country. All lentiviral vectors provided by GEG Tech are produced through the transfection of three plasmids and are SIN lentiviral vectors. The viral vectors are not capable of producing replicative particles from transduced cells; however they maintain full transduction efficiency to a wide range of cells.

GEG Tech vectors are suited for research applications, either in vitro or in vivo, providing that you respect local laws regarding GMO class 2 storage and handling. All GEG Tech vectors are distributed for laboratory research use only and cannot under any circumstances be used for diagnostic or treatment applications. Please refer to the material safety datasheet for more information.

  See Safety and regulatory issues section