Viral vectors are used for the delivery of genetical material into cells under in vivo and in vitro conditions. By now four main types of viral vectors have been developed: retroviruses, lentiviruses, adenoviruses and adeno-associated viruses. These viruses are extensively used in gene therapy – an innovative technique which allows modifying defective genes which might be a cause of a particular genetic disease. To treat such diseases scientists perform a transfer of the “correct” gene to the cell with a defective gene using viral vectors.
For the time being, gene therapy stands out as an advanced potential treatment of genetic or other irremediable diseases like malignancy or some viral infections. To perform gene therapy researchers have to extract patient’s samples, then transduce and modify them with the help of viral vectors and after that re-implant it in patients with the aim of correct the defective genetic information and treat a patient.
Due to the growing interest in the potential of gene therapy, the development and use of viral vectors is becoming more and more widespread all over the globe. There are two different methods for making viral vectors: scale-out of adherent-cell systems based on 2D planar technologies and scale-up of 3D suspension cell cultures in stirred-tank bioreactors. While manufacturing viral vectors scientists also have to generate and maintain cell lines and then perform cell transfection with plasmids to get viral vectors.
Researchers suggest that new viral vectors and possible ways of implementation of gene therapy will be discovered in years to come. What’s more, using such innovative technologies as massive parallel sequencing will help to enhance this process. However, there are some factors such as government regulations which may delay getting the approval of these products. Firstly, the manufactures of viral vectors have to undergo critical raw material control. The biggest regulators such as FDA, EMA, and PMDA have already published some regulatory guidelines for manufacturing of vectors. Moreover, all laboratory stages must be performed in compliance with good laboratory practice (GLP).