SARS-CoV-2 Production in a Scalable High Cell Density Bioreactor

Area of Science:

• Biotechnology
• Virology
• Vaccine Development

Background:

• The COVID-19 pandemic highlighted the need for robust vaccine production platforms.
• Whole virus vaccines require efficient and scalable virus manufacturing processes.

Purpose of the Study:

• To establish and optimize the production of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in a scalable packed-bed bioreactor.
• To evaluate the suitability of Vero (WHO) cells and animal component-free medium for large-scale SARS-CoV-2 manufacturing.

Main Methods:

• SARS-CoV-2 was cultured in CelCradle™ 500-AP bioreactors using Vero (WHO) cells and BioNOC™ II carriers in animal component-free medium.
• Optimization involved testing parameters such as harvest frequency and production temperature.
• Infection was performed at a multiplicity of infection of 0.006.

Main Results:

• The optimal conditions yielded a peak SARS-CoV-2 infectivity titer of 7.3 log₁₀ 50% tissue culture infectious dose (TCID₅₀)/mL at 72 hours post-infection.
• Two harvests per day and a production temperature of 33 °C maximized virus yield.
• A total of 10.5 log₁₀ TCID₅₀ of SARS-CoV-2 was produced in approximately 5 L, with six harvests achieving titers ≥6.5 log₁₀ TCID₅₀/mL.

Conclusions:

• Successful, scalable, animal component-free production of SARS-CoV-2 was achieved in Vero (WHO) cells within a packed-bed bioreactor.
• The established method provides a viable platform for large-scale manufacturing of SARS-CoV-2 for vaccine development.
• Addition of recombinant trypsin did not enhance virus yields under the tested conditions.