Pilot-scale process development for recombinant adeno-associated virus (rAAV) production based on high-density Sf9 cell culture

In recent years, gene therapy drugs have been widely marketed, and their effectiveness and potential have been confirmed. Thus, increasing their production on an industrial scale is critical. Recombinant adeno-associated viruses (rAAVs) are optimal vectors for gene therapy applications, and the baculovirus expression vector system (BEVS), which is based on Sf9 cell culture, is a common tool for rAAV production.

In this work, an Sf9 cell fed-batch process was developed using shake flasks. In the laboratory-scale bioreactor, four processes were selected as the key factors when carrying out the orthogonal experiment. On the basis of the equal P/V principle and considering the problem posed by air bubbles, a pilot-scale level bioreactor process was established.

Here, we describe a method in which a BEVS was used to produce rAAV vectors, with the cell density increasing to 22.8 × 10⁶ cells/mL and the rAAV titre increasing to 20 × 10¹¹ VG/mL upon adding feed material. By resolving the problems associated with high-density cell culture and air bubbles, this process was successfully scaled to a 50 L pilot-scale level.

This successful experiment not only provides a technological basis for further scale-up but also guarantees product capacity. We hope that this development process can provide reference data for studying cell culture-based drug production.