caa a22 4500 605503672 CHVBK 20210128100612.0 cr unu---uuuuu 210128e20150201xx s 000 0 eng 10.1007/s00253-014-6260-z doi (NATIONALLICENCE)springer-10.1007/s00253-014-6260-z Effect of the peak cell density of recombinant AcMNPV-infected Hi5 cells on baculovirus yields [Elektronische Daten] [Hoai Huynh, Trinh Tran, Leslie Chan, Lars Nielsen, Steven Reid] The phenomenon of the cell density effect is not readily explained by an obvious nutrient limitation, and a recent study has suggested that for recombinant Autographa californica multiple nucleopolyhedrovirus (rAcMNPV)-infected Sf9 cells, a drop in messenger RNA (mRNA) levels may be sufficient to explain the cell density effect for this system. The current study aims to investigate the response in cell-specific yields (viral DNA (vDNA), LacZ mRNA and β-galactosidase (β-Gal) protein) with increasing infection cell density (ICD) for rAcMNPV-infected Hi5 cells, where the rAcMNPV expresses the β-Gal gene under control of the polyhedral promoter. Hi5 cells in suspension culture of Express Five® medium were synchronously infected with a rAcMNPV at multiple ICDs between 0.5 and 6 × 106 cells/mL and a multiplicity of infection of 10 plaque-forming units (PFU)/cell either in the original or fresh medium conditions. There were negative correlations between the three key virus infection indicators (vDNA, mRNA and β-Gal) and the peak cell density (PCD). However, unlike infected Sf9 cells, the yield decline started at the lowest PCD investigated (0.6 × 106 cells/mL). Generally, the yield decline with increasing PCD was most pronounced for β-Gal followed by mRNA and was more moderate for vDNA. The decline was significantly reduced but not totally arrested when fresh medium replacement was used. The results suggest that the reduction in recombinant protein-specific yields at high PCDs is associated with limitations during the up-stream processes of replication and transcription rather than entirely caused by limitations during translation. In addition, low production rates at late infection stages of moderate to high ICDs are a probable cause of the cell density effect. Springer-Verlag Berlin Heidelberg, 2014 Baculovirus nationallicence Hi5 cells nationallicence Cell density effect nationallicence Viral DNA replication nationallicence mRNA expression nationallicence β-Gal nationallicence Huynh Hoai Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, 4072, St Lucia, QLD, Australia aut Tran Trinh Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, 4072, St Lucia, QLD, Australia aut Chan Leslie Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, 4072, St Lucia, QLD, Australia aut Nielsen Lars Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, 4072, St Lucia, QLD, Australia aut Reid Steven Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, 4072, St Lucia, QLD, Australia aut Applied Microbiology and Biotechnology Springer Berlin Heidelberg 99/4(2015-02-01), 1687-1700 0175-7598 99:4<1687 2015 99 253 https://doi.org/10.1007/s00253-014-6260-z text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00253-014-6260-z text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Huynh Hoai Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, 4072, St Lucia, QLD, Australia aut NATIONALLICENCE 700 1- Tran Trinh Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, 4072, St Lucia, QLD, Australia aut NATIONALLICENCE 700 1- Chan Leslie Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, 4072, St Lucia, QLD, Australia aut NATIONALLICENCE 700 1- Nielsen Lars Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, 4072, St Lucia, QLD, Australia aut NATIONALLICENCE 700 1- Reid Steven Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, 4072, St Lucia, QLD, Australia aut NATIONALLICENCE 773 0- Applied Microbiology and Biotechnology Springer Berlin Heidelberg 99/4(2015-02-01), 1687-1700 0175-7598 99:4<1687 2015 99 253