A Fed-batch Process for the Production of Recombinant Adeno-Associated Virus (rAAV) Vectors Using the Sf9-Rhabdovirus-Negative Cell Line.

Background: Gene therapy has been effectively applied in many biological studies and for the treatment of many genetic or cancer diseases. Currently, Recombinant Adeno- Associated Viruses (rAAVs) are one of the main types of delivery vectors used for gene therapy. rAAV vectors produced via the Sf9 cells have the advantages of high rAAV yields, easy scaleup, and low cost.

Method: Here, we used Sf9 rhabdovirus-negative (Sf9-RVN) cells to validate and optimize the rAAV production process, and the fed-batch process increased the rAAV production titre.

Results: In the fed-batch procedure, the cell density reached 12.9×106 cells/mL, which was approximately twice as high as in the batch culture process. The rAAV titre was also approximately 8-fold higher in the fed-batch process, reaching 1.5×1012 VG/mL. The optimized process was validated by generating rAAVs with various serotypes and genes of interest (GOI), all of which gave production titres greater than 1×1012 VG/mL.

Conclusion: We used Sf9-RVN cells to develop a fed-batch rAAV production process that replaces Sf9 cells to meet regulatory standards. This process has good applicability, and the rAAV titre can reach at least 1×1012 VG/mL, which is higher than the level of 1011 VG/mL reported in the literature.