Optimization of VSV‐ΔG‐spike production process with the Ambr15 system for a SARS‐COV‐2 vaccine

Abstract

To face the coronavirus disease 2019 pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) virus, our institute has developed the rVSV‐ΔG‐spike vaccine, in which the glycoprotein of vesicular stomatitis virus (VSV) was replaced by the spike protein of SARS‐CoV‐2. Many process parameters can influence production yield. To maximize virus vaccine yield, each parameter should be tested independently and in combination with others. Here, we report the optimization of the production of the VSV‐ΔG‐spike vaccine in Vero cells using the Ambr15 system. This system facilitates high‐throughput screening of process parameters, as it contains 24 individually controlled, single‐use stirred‐tank minireactors. During optimization, critical parameters were tested. Those parameters included: cell densities; the multiplicity of infection; virus production temperature; medium addition and medium exchange; and supplementation of glucose in the virus production step. Virus production temperature, medium addition, and medium exchange were all found to significantly influence the yield. The optimized parameters were tested in the BioBLU 5p bioreactors production process and those that were found to contribute to the vaccine yield were integrated into the final process. The findings of this study demonstrate that an Ambr15 system is an effective tool for bioprocess optimization of vaccine production using macrocarriers and that the combination of production temperature, rate of medium addition, and medium exchange significantly improved virus yield.

Application of Ambr15 system for simulation of entire SARS‐CoV‐2 vaccine production process involving macrocarriers

“…These results clearly demonstrate the suitability of the Ambr15 system for simulating the virus production step. Establishment of the process simulation was a basic requirement for later experiments conducted for vaccine production process optimization with the system 15 . In addition, virus production kinetics in the Ambr15 system, using the same basic process parameters, was compared in Bioreactors.…”

“…This simulation was later served as a basis for vaccine production process optimization with the system. 15 Moreover, these capabilities of the Ambr15 system can be incorporated to other processes and can promote cell‐based vaccine production. Integration of macrocarriers expands the Ambr15 spectrum, which had been limited to suspension cells or microcarriers only.…”

“…A strong correlation between glucose consumption rate and number of cells was found to be of 40 pg/h/cell with R 2 = 0.959 process simulation was a basic requirement for later experiments conducted for vaccine production process optimization with the system. 15 In addition, virus production kinetics in the Ambr15 system, using the same basic process parameters, was compared in Bioreactors. The similar results that were achieved (Figure 6, blue) further demonstrate the Ambr15 ability to model processes in larger reactors.…”

“…The resulting titer vaccine virus confirmed the relevance of the Ambr15 system for process optimization studies. This relevance was proved by subsequent experiments with the adjusted Ambr15 system that were able to optimize the vaccine production process 15 …”

“…This relevance was proved by subsequent experiments with the adjusted Ambr15 system that were able to optimize the vaccine production process. 15 …”