Retrovirus as Vaccine-vectors
Retrovirus vectors have been considered as promising tools to transfer therapeutic genes into patient cells because they can permanently integrate into host cellular genome. Improved gene delivery vectors are essential for the success of human gene therapy. Creative Biolabs has always focused on the development of viral vectors and has improved the efficiency and safety of these vectors by making multiple types of modifications. As a service provider, our goal is to provide the highest level of service, confidentiality and customer support.
Introduction of Retrovirus Structure
Retroviruses are members of a family of RNA viruses that replicate through a DNA intermediate in host cells. Knowledge about retroviral replication and virion assembly mechanisms provides the basis for the development of retroviral vectors. The simpler retroviruses (including murine leukemia virus, MLV) contain three genes common to all retroviruses: gag, pol and env. The gag coding region produces a matrix, capsid and nucleocapsid structural protein. The pol gene encodes proteases (PR), reverse transcriptase involved in genome processing and integrase. Finally, env encodes an Env glycoprotein comprising two subunits SU and TM that bind to the target cell receptor and mediate viral-cell membrane fusion, respectively. There is also a psi packaging signal and two LTRs (long terminal repeats) with regulatory functions within the virus.
Fig.1 The structure of retrovirus.
Retrovirus as Vaccine-vectors
Viruses are natural vehicles for genetic information because they are obligate cellular parasites. Retroviruses are an effective tool for gene transfer for a number of reasons. First and most importantly, they can stably integrate their genetic information into the host cell chromosome. Prior to this insertion, the RNA genome was converted to double-stranded DNA by reverse transcription. Second, target cell specificity can be easily altered by incorporating a heterologous envelope protein during vector production. Third, the production of hybrid vectors comprising different vector designs and incorporation of elements from various viruses is feasible. In principle, all retroviral genus can produce potential gene therapy vectors. So far, the research has focused mainly on three viruses, namely gammaretroviruses (murine leukemia virus, MLV), lentiviruses (human immunodeficiency virus, HIV), and spumaviruses (human foamy virus, HFV). In addition, alpha retroviral vectors have been developed because they exhibit a relatively neutral integration pattern.
The Design of Retrovirus Vectors
To generate a recombinant virus that only replicates in the packaging cell and not in the host cell, the viral gene is replaced by the DNA of the gene of interest; the viral LTR and the encapsidation (psi) signal used to incorporate the viral RNA into the particle are retained. When the viral genome containing the therapeutic gene is transfected into packaging cells (Gag, pol, and env are expressed in trans in packaging cells), all of the required components are put together to form recombinant retroviral particles. This virus can transfect target cells but does not form infectious particles because the gene encoding the viral protein is deleted in its genome. This is a safety device commonly used for viral vectors. The viral genes responsible for viral replication are separated from the rest of the genome, reducing the risk of infectious particle recombination, and thus retrovirus vector is a highly safe viral vector.
Fig.2 Production of recombinant viral vectors.
Recombinant retroviruses are commonly employed as gene delivery vehicles and are used in clinical trials of human gene therapy. Creative Biolabs is a world leader in recombinant viral technology, providing the most comprehensive services for AAV-, lenti-, adeno- and retro-viral vectors in ready-to-use formats. Our company's customized retroviral vectors enable efficient and stable expression of genes in a wide range of mammalian cells. Simply send us your gene and we will do the rest!
All of our products can only be used for research purposes. These vaccine ingredients CANNOT be used directly on humans or animals.
