Abstract
The Vero cell line is the most used continuous cell line in viral
vaccine manufacturing. This adherent cell culture platform requires the
use of surfaces to support cell growth, typically roller bottles or
microcarriers. We have recently compared the production of rVSV-ZEBOV on
Vero cells between microcarrier and fixed-bed bioreactors. However,
suspension cultures are considered superior with regards to process
scalability. Therefore, we further explore the Vero suspension system
for rVSV-vectored vaccine production. Previously, this suspension cell
line was only able to be cultivated in a proprietary medium. Here, we
expand the adaptation and bioreactor cultivation to a serum-free
commercial medium. Following small scale optimization and screening
studies, we demonstrate bioreactor productions of highly relevant
vaccines and vaccine candidates against Ebola virus disease, HIV and
COVID-19 in the Vero suspension system. rVSV-ZEBOV, rVSV-HIV and
rVSVInd-msp-SF-Gtc can replicate to high titers in the bioreactor,
reaching 3.87 × 107 TCID50/mL, 2.12 × 107 TCID50/mL and 3.59 × 109
TCID50/mL, respectively. Further, we compare cell specific
productivities, and the quality of the produced viruses by determining
the ratio of total viral particles to infectious viral particles