Production process development of pseudorabies virus vaccine by using novel scale-down model of fixed-bed bioreactor

Abstract In this study, the novel tube-fixed-bed bioreactor which consist of TubeSpin bioreactor 50 tube and 0.44 g macrocarriers was developed as the scale-down model of fixed-bed bioreactor. The adherent Vero cell-based pseudorabies virus (PRV) production process was tested in this novel model. The Vero cells grow well in tube-fixed-bed bioreactor and the cell density reached 5.8 × 106 cells/mL after 7 days culture. The PRV production parameters (time of infection (TOI), multiplicity of infection (MOI) and harvest process) were optimized in tube-fixed-bed bioreactor. Then the optimized process (TOI=3 d, MOI=0.001 and multiple harvest process) was 25-fold scale-up to Xcell 1 L laboratory-scale fixed-bed bioreactor and 125-fold scale-up to Xcell 5 L fixed-bed bioreactor successfully. The total PRV virus harvest in Xcell 1 L bioreactor at 5 day post infection (dpi) was 10.25 log10 TCID50 which corresponds to 177,827 doses of vaccine. The total PRV virus harvest in Xcell 5 L bioreactor at 5 dpi was 11.13 log10 TCID50 which corresponded to 1,348,962 doses of vaccine. The growth curve, metabolism and PRV production profile of three scale bioreactors were comparable confirmed the feasibility and scalability of tube-fixed-bed bioreactor as scale-down model of fixed-bed bioreactor for virus production process development.