Sars-Cov-2 Production In A Scalable High Cell Density Bioreactor

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 CelCradle (TM) 500-AP bioreactor. CelCradle (TM) 500-AP bottles with 0.5 L working volume and 5.5 g BioNOC (TM) II carriers were seeded with 1.5 x 10(8) 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 2.22.5 x 10(9) cells/bottle seven days post cell seeding. Among several tested conditions, two harvests per day and a virus production temperature of 33 degrees C resulted in the highest virus yield with a peak SARS-CoV-2 infectivity titer of 7.3 log(10) 50% tissue culture infectious dose (TCID50)/mL at 72 h post-infection. Six harvests had titers of >= 6.5 log(10) TCID50/mL, and a total of 10.5 log(10) TCID50 were produced in similar to 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.