ReviewChallenges of up-scaling lentivirus production and processing

- Lentivirus production is challenging to up-scale due to lack of a suitable stable cell line.
- Technologies for up-scale of transient transfection have been developed.
- Large volumes of virus supernatant require sophisticated purification/concentration methods.
- Overcoming challenges of up-scaling lentivirus production will hasten gene/cell therapy trials.

Lentiviruses are becoming an increasingly popular choice of gene transfer vehicle for use in the treatment of a variety of genetic and acquired human diseases. As research progresses from basic studies into pre-clinical and clinical phases, there is a growing demand for large volumes of high purity, concentrated vector, and accordingly, the means to produce such quantities. Unlike other viral vectors, lentiviruses are difficult to produce using stable cell lines, therefore transient transfection of adherent cell lines is conventionally used, and this method has proven challenging to up-scale. Furthermore, with the required increases in the volume of vector needed for larger animal and human use, comes the need for more efficient and sophisticated supernatant purification and concentration techniques. This review presents the challenges of up-scaling lentivirus production and processing approaches, novel systems for overcoming these issues, and the quality assessments recommended for producing a clinical grade lentiviral gene therapy product.