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

• Published in: Vaccines (Basel) Vol. 9; no. 7; p. 706
• Main Authors: Offersgaard, Anna, Duarte Hernandez, Carlos Rene, Pihl, Anne Finne, Costa, Rui, Venkatesan, Nandini Prabhakar, Lin, Xiangliang, Van Pham, Long, Feng, Shan, Fahnøe, Ulrik, Scheel, Troels Kasper Høyer, Ramirez, Santseharay, Reichl, Udo, Bukh, Jens, Genzel, Yvonne, Gottwein, Judith Margarete
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 29-06-2021; MDPI
• Subjects: Bioreactors; CelCradle; Cell culture; Cell density; Cell number; Coronaviruses; COVID-19; COVID-19 vaccines; Disease; Experiments; Glucose; Infections; Infectivity; Licenses; mRNA vaccines; Multiplicity of infection; packed-bed; Pandemics; Respiratory diseases; scalable bioreactor; Severe acute respiratory syndrome coronavirus 2; Tissue culture; Tropical diseases; Trypsin; Vaccines; Viral diseases; Viruses; whole virus vaccine; Denmark; Grand Island New York; United States > US; Germany
• ISSN: 2076-393X; 2076-393X
• DOI: 10.3390/vaccines9070706

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has demonstrated the value of pursuing different vaccine strategies. Vaccines based on whole viruses, a widely used vaccine technology, depend on efficient virus production. This study aimed to establish SARS-CoV-2 production in the scalable packed-bed CelCradleTM 500-AP bioreactor. CelCradleTM 500-AP bottles with 0.5 L working volume and 5.5 g BioNOC™ II carriers were seeded with 1.5 × 108 Vero (WHO) cells, approved for vaccine production, in animal component-free medium and infected at a multiplicity of infection of 0.006 at a total cell number of 2.2–2.5 × 109 cells/bottle seven days post cell seeding. Among several tested conditions, two harvests per day and a virus production temperature of 33 °C resulted in the highest virus yield with a peak SARS-CoV-2 infectivity titer of 7.3 log10 50% tissue culture infectious dose (TCID50)/mL at 72 h post-infection. Six harvests had titers of ≥6.5 log10 TCID50/mL, and a total of 10.5 log10 TCID50 were produced in ~5 L. While trypsin was reported to enhance virus spread in cell culture, addition of 0.5% recombinant trypsin after infection did not improve virus yields. Overall, we demonstrated successful animal component-free production of SARS-CoV-2 in well-characterized Vero (WHO) cells in a scalable packed-bed bioreactor.