Significant increase in recombinant protein production of a virus-infected Sf-9 insect cell culture of low MOI under low dissolved oxygen conditions

• Published in: Journal of bioscience and bioengineering Vol. 94; no. 5; pp. 426 - 433
• Main Authors: Gotoh, Takeshi, Miyazaki, Yoshinori, Chiba, Kunihiro, Kikuchi, Ken-ichi
• Format: Journal Article
• Language: English
• Published: Amsterdarm Elsevier B.V 2002; Elsevier Science; Elsevier Limited
• Subjects: Animal cells; AUTOGRAPHA CALIFORNICA; BACULOVIRIDAE; baculovirus; Biological and medical sciences; Biotechnology; CELL CULTURE; DISSOLVED OXYGEN; Eukaryotic cell cultures; Fundamental and applied biological sciences. Psychology; INFECTION; insect cells; Methods. Procedures. Technologies; Miscellaneous; proteases; RECOMBINANT PROTEINS; Sf-9; SPODOPTERA FRUGIPERDA; β-galactosidase; dissolved oxygen; Sf-9; β-galactosidase; baculovirus; insect cells; proteases; Nucleopolyhedrovirus; Cell culture; Insecta; Baculoviridae; Enzymatic activity; Production; Recombinant protein; β-Galactosidase; Enzyme; Spodoptera frugiperda; Oxygen consumption; Virus; Infection; Lactates; Peptidases; Cell line; Animal; Arthropoda; Glycosidases; Lepidoptera; Concentration effect; Hydrolases; Noctuidae; Biological accumulation; Invertebrata; Dissolved oxygen; O-Glycosidases
• ISSN: 1389-1723; 1347-4421
• DOI: 10.1016/S1389-1723(02)80220-1

Spodoptera frugiperda Sf-9 insect cells were infected with recombinant Autographa californica nuclear polyhedrosis virus at a low multiplicity of infection (MOI) (0.1), and the effect of dissolved oxygen (DO) on the production of a polyhedrin promoter-driven recombinant protein (β-galactosidase), intrinsic proteases (carboxyl and cysteine proteases), and the virus was determined. The DO concentrations used in the present study were 45%, 25%, 5%, and 1.3% of air saturation. At 5% DO the cell growth following viral infection was greatest and β-galactosidase was about 5-fold increased in volumetric yield compared to that at 45% and 25% DO, whereas the growth at 1.3% DO was extremely poor. The virus titer in the medium at 4–8 d post-infection (dpi) was also highest at 5% DO, but the titer was significantly decreased by further increasing the culture time. This was in part attributed to the fact that baculovirus is susceptible to oxidative inactivation under aerobic conditions. The DO dependency of the specific oxygen consumption rate of virus-infected and uninfected Sf-9 cells was expressed by a Monod-type equation. A critical DO, above which the rate of oxygen utilization is not limited by DO, was estimated to be 3.5% of air saturation for virus-infected Sf-9 cells. These results indicated that for a baculovirus-infected Sf-9 insect cell culture of low MOI, the optimal DO was likely to be approximately 5% of air saturation, which is above the critical DO for the infected Sf-9 cells but sufficiently low to reduce the possibility of the oxidative inactivation of virus. For the production of carboxyl and cysteine proteases, the accumulation behavior and concentrations did not significantly vary with DO, except that a peak of cysteine protease activity was observed intracellularly only at 5% DO, coinciding with β-galactosidase production.