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Jawinski K, Hartmann M, Singh C, Kinnear E, Busse DC, Ciabattini A, Fiorino F, Medaglini D, Trombetta CM, Montomoli E, Contreras V, Le Grand R, Coiffier C, Primard C, Verrier B, Tregoning JS. Recombinant Haemagglutinin Derived From the Ciliated Protozoan Tetrahymena thermophila Is Protective Against Influenza Infection. Front Immunol 2019; 10:2661. [PMID: 31798589 PMCID: PMC6863932 DOI: 10.3389/fimmu.2019.02661] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 10/28/2019] [Indexed: 12/14/2022] Open
Abstract
Current influenza vaccines manufactured using eggs have considerable limitations, both in terms of scale up production and the potential impact passaging through eggs can have on the antigenicity of the vaccine virus strains. Alternative methods of manufacture are required, particularly in the context of an emerging pandemic strain. Here we explore the production of recombinant influenza haemagglutinin using the ciliated protozoan Tetrahymena thermophila. For the first time we were able to produce haemagglutinin from both seasonal influenza A and B strains. This ciliate derived material was immunogenic, inducing an antibody response in both mice and non-human primates. Mice immunized with ciliate derived haemagglutinin were protected against challenge with homologous influenza A or B viruses. The antigen could also be combined with submicron particles containing a Nod2 ligand, significantly boosting the immune response and reducing the dose of antigen required. Thus, we show that Tetrahymena can be used as a manufacturing platform for viral vaccine antigens.
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Affiliation(s)
| | | | - Charanjit Singh
- Department of Infectious Disease, St Mary's Campus, Imperial College London, London, United Kingdom
| | - Ekaterina Kinnear
- Department of Infectious Disease, St Mary's Campus, Imperial College London, London, United Kingdom
| | - David C Busse
- Department of Infectious Disease, St Mary's Campus, Imperial College London, London, United Kingdom
| | - Annalisa Ciabattini
- Laboratory of Molecular Microbiology and Biotechnology, Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Fabio Fiorino
- Laboratory of Molecular Microbiology and Biotechnology, Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Donata Medaglini
- Laboratory of Molecular Microbiology and Biotechnology, Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | | | - Emanuele Montomoli
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy.,VisMederi s.r.l., Siena, Italy
| | - Vanessa Contreras
- CEA-Université Paris Sud 11-INSERM U1184, Immunology of Viral Infections and Autoimmune Diseases, IDMIT Department, IBFJ, Le Kremlin-Bicêtre, France
| | - Roger Le Grand
- CEA-Université Paris Sud 11-INSERM U1184, Immunology of Viral Infections and Autoimmune Diseases, IDMIT Department, IBFJ, Le Kremlin-Bicêtre, France
| | - Celine Coiffier
- Laboratoire de Biologie Tissulaire et d'Ingénierie Thérapeutique, UMR 5305, Université Lyon 1, CNRS, IBCP, Lyon, France
| | | | | | - John S Tregoning
- Department of Infectious Disease, St Mary's Campus, Imperial College London, London, United Kingdom
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2
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Computational fluid dynamic analysis of hydrodynamic shear stress generated by different impeller combinations in stirred bioreactor. Biochem Eng J 2019. [DOI: 10.1016/j.bej.2019.107312] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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3
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Comprehensive study on Wave bioreactor system to scale up the cultivation of and recombinant protein expression in baculovirus-infected insect cells. Biochem Eng J 2019. [DOI: 10.1016/j.bej.2018.12.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Kaiser SC, Werner S, Jossen V, Blaschczok K, Eibl D. Power Input Measurements in Stirred Bioreactors at Laboratory Scale. J Vis Exp 2018. [PMID: 29863665 PMCID: PMC6101222 DOI: 10.3791/56078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The power input in stirred bioreactors is an important scaling-up parameter and can be measured through the torque that acts on the impeller shaft during rotation. However, the experimental determination of the power input in small-scale vessels is still challenging due to relatively high friction losses inside typically used bushings, bearings and/or shaft seals and the accuracy of commercially available torque meters. Thus, only limited data for small-scale bioreactors, in particular single-use systems, is available in the literature, making comparisons among different single-use systems and their conventional counterparts difficult. This manuscript provides a protocol on how to measure power inputs in benchtop scale bioreactors over a wide range of turbulence conditions, which can be described by the dimensionless Reynolds number (Re). The aforementioned friction losses are effectively reduced by the use of an air bearing. The procedure on how to set up, conduct and evaluate a torque-based power input measurement, with special focus on cell culture typical agitation conditions with low to moderate turbulence (100 < Re < 2·104), is described in detail. The power input of several multi-use and single-use bioreactors is provided by the dimensionless power number (also called Newton number, P0), which is determined to be in the range of P0 ≈ 0.3 and P0 ≈ 4.5 for the maximum Reynolds numbers in the different bioreactors.
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Affiliation(s)
| | - Sören Werner
- Institute of Chemistry and Biotechnology, Zurich University of Applied Sciences, School of Life Sciences and Facility Management
| | - Valentin Jossen
- Institute of Chemistry and Biotechnology, Zurich University of Applied Sciences, School of Life Sciences and Facility Management
| | - Katharina Blaschczok
- Institute of Chemistry and Biotechnology, Zurich University of Applied Sciences, School of Life Sciences and Facility Management
| | - Dieter Eibl
- Institute of Chemistry and Biotechnology, Zurich University of Applied Sciences, School of Life Sciences and Facility Management
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5
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Molina-Miras A, Sánchez-Mirón A, García-Camacho F, Molina-Grima E. CFD-aided optimization of a laboratory-scale centrifugation for a shear-sensitive insect cell line. FOOD AND BIOPRODUCTS PROCESSING 2018. [DOI: 10.1016/j.fbp.2017.11.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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6
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Kaiser SC, Werner S, Jossen V, Kraume M, Eibl D. Development of a method for reliable power input measurements in conventional and single-use stirred bioreactors at laboratory scale. Eng Life Sci 2017; 17:500-511. [PMID: 28579937 PMCID: PMC5434943 DOI: 10.1002/elsc.201600096] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 10/08/2016] [Accepted: 10/20/2016] [Indexed: 11/08/2022] Open
Abstract
Power input is an important engineering and scale-up/down criterion in stirred bioreactors. However, reliably measuring power input in laboratory-scale systems is still challenging. Even though torque measurements have proven to be suitable in pilot scale systems, sensor accuracy, resolution, and errors from relatively high levels of friction inside bearings can become limiting factors at smaller scales. An experimental setup for power input measurements was developed in this study by focusing on stainless steel and single-use bioreactors in the single-digit volume range. The friction losses inside the air bearings were effectively reduced to less than 0.5% of the measurement range of the torque meter. A comparison of dimensionless power numbers determined for a reference Rushton turbine stirrer (NP = 4.17 ± 0.14 for fully turbulent conditions) revealed good agreement with literature data. Hence, the power numbers of several reusable and single-use bioreactors could be determined over a wide range of Reynolds numbers between 100 and >104. Power numbers of between 0.3 and 4.5 (for Re = 104) were determined for the different systems. The rigid plastic vessels showed similar power characteristics to their reusable counterparts. Thus, it was demonstrated that the torque-based technique can be used to reliably measure power input in stirred reusable and single-use bioreactors at the laboratory scale.
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Affiliation(s)
| | - Sören Werner
- Institute of Chemistry and Biotechnology Zurich University of Applied Sciences Wädenswil Switzerland
| | - Valentin Jossen
- Institute of Chemistry and Biotechnology Zurich University of Applied Sciences Wädenswil Switzerland
| | - Matthias Kraume
- Technische Universität Berlin Fachgebiet Verfahrenstechnik Berlin Germany
| | - Dieter Eibl
- Institute of Chemistry and Biotechnology Zurich University of Applied Sciences Wädenswil Switzerland
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7
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Nestola P, Peixoto C, Villain L, Alves PM, Carrondo MJT, Mota JPB. Rational development of two flowthrough purification strategies for adenovirus type 5 and retro virus-like particles. J Chromatogr A 2015; 1426:91-101. [PMID: 26643723 DOI: 10.1016/j.chroma.2015.11.037] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2015] [Revised: 11/10/2015] [Accepted: 11/10/2015] [Indexed: 12/22/2022]
Abstract
We report on the rational design and implementation of flowthrough (FT) platforms for purification of virus vectors (VVs) and virus-like particles (VLPs), combining anion-exchange polyallylamine membranes (Sartobind STIC) and core-shell octylamine resins (CaptoCore 700). In one configuration, the VV bulk is concentrated and conditioned with appropriate buffer in a ultra/diafiltration (UF/DF) unit prior to injection into the STIC chromatography membrane. The FT pool and an intermediate cut of the elution pool of the STIC membrane are admixed and directed to a second UF/DF. Finally, the retentate is injected into a CC700 packed bed adsorber where the purified VVs are collected in the FT pool, whereas the residual amount of DNA and host cell protein (HCP) are discarded in the eluate. The experimental recovery achieved with this downstream processing (DSP) platform is close to 100%, the DNA clearance is roughly a 4-log reduction, and the HCP level is reduced by 5 logs. The platform developed for VLP purification is simpler than the previous one, as the STIC membrane adsorber and CC700 bed are connected in series with no UF/DF unit in between. Experimentally, the FT scheme for VLP purification gave a recovery yield of 45% in the chromatography train; the experimental log reduction of DNA and HCP were 2.0 and 3.5, respectively. These results are in line with other purification strategies in the specific field of enveloped VLPs. Both DSP platforms were successfully developed from an initial design space of the binding of the major contaminant (DNA) to the two ligands, determined by surface plasmon resonance, which was subsequently scaled up and confirmed experimentally.
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Affiliation(s)
- Piergiuseppe Nestola
- Instituto de Biologia Experimental e Tecnológica, Apartado 12, 2781-901 Oeiras, Portugal; Instituto de Tecnologia Química e Biológica, Universidade NOVA de Lisboa, 2780-157 Oeiras, Portugal
| | - Cristina Peixoto
- Instituto de Biologia Experimental e Tecnológica, Apartado 12, 2781-901 Oeiras, Portugal; Instituto de Tecnologia Química e Biológica, Universidade NOVA de Lisboa, 2780-157 Oeiras, Portugal
| | - Louis Villain
- Sartorius Stedim Biotech GmbH, Spindler-Strasse11, 37079 Gottingen, Germany
| | - Paula M Alves
- Instituto de Biologia Experimental e Tecnológica, Apartado 12, 2781-901 Oeiras, Portugal; Instituto de Tecnologia Química e Biológica, Universidade NOVA de Lisboa, 2780-157 Oeiras, Portugal
| | - Manuel J T Carrondo
- Instituto de Biologia Experimental e Tecnológica, Apartado 12, 2781-901 Oeiras, Portugal; Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
| | - José P B Mota
- LAQV-REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal; Instituto de Biologia Experimental e Tecnológica, Apartado 12, 2781-901 Oeiras, Portugal.
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Vidigal J, Dias MM, Fernandes F, Patrone M, Bispo C, Andrade C, Gardner R, Carrondo MJ, Alves PM, Teixeira AP. A cell sorting protocol for selecting high-producing sub-populations of Sf9 and High Five™ cells. J Biotechnol 2013; 168:436-9. [DOI: 10.1016/j.jbiotec.2013.10.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 10/10/2013] [Accepted: 10/15/2013] [Indexed: 10/26/2022]
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9
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Liu Y, Li F, Hu W, Wiltberger K, Ryll T. Effects of bubble-liquid two-phase turbulent hydrodynamics on cell damage in sparged bioreactor. Biotechnol Prog 2013; 30:48-58. [DOI: 10.1002/btpr.1790] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 06/08/2013] [Accepted: 07/18/2013] [Indexed: 11/11/2022]
Affiliation(s)
- Yang Liu
- Dept. of Chemical and Bimolecular Engineering; North Carolina State University; Raleigh NC
| | - Fanxing Li
- Dept. of Chemical and Bimolecular Engineering; North Carolina State University; Raleigh NC
| | - Weiwei Hu
- Dept. of Cell Culture Development; Biogen Idec Inc., Research Triangle Park; NC
| | - Kelly Wiltberger
- Dept. of Cell Culture Development; Biogen Idec Inc., Research Triangle Park; NC
| | - Thomas Ryll
- Dept. of Cell Culture Development; Biogen Idec Inc.; Cambridge MA
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10
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Negrete A, Pai A, Shiloach J. Use of hollow fiber tangential flow filtration for the recovery and concentration of HIV virus-like particles produced in insect cells. J Virol Methods 2013; 195:240-6. [PMID: 24157258 DOI: 10.1016/j.jviromet.2013.10.017] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 10/09/2013] [Accepted: 10/11/2013] [Indexed: 12/11/2022]
Abstract
Attenuated viruses, inactivated viruses and virus like particles (VLPs) are known to be efficient vaccines partially due to their particulate structure. A potential HIV vaccine candidate engineered as a VLP (HIV gag-VLP) and produced in insect cells is currently under preclinical trials demanding large amounts. Due to their extreme fragility and sensitivity to shear forces the recovery and concentration of these extracellular enveloped particles of approximately 120 nm in size is challenging. The current bench scale gradient ultracentrifugation and precipitation methods have been found unsuitable for larger scale processes. In this study a two-step tangential flow filtration (TFF) process using hollow fibers was developed for the clarification and concentration of HIV gag-VLPs. The first step is microfiltration for cell removal and the second step is ultrafiltration for concentrating the HIV gag-VLPs. The chosen parameters for the microfiltration step were hollow fiber membranes of 0.45 μm cut off 5000 s(-1) shear force and a flux of 10 LMH. The chosen parameters for the ultrafiltration step were a 500 kDa cut off membrane, 6000 s(-1) shear force and a trans-membrane pressure (TMP) of 1.25 bar. The utilization of these parameters provided with concentrated HIV-gag VLPs from 2L of starting cell suspension within 6h of processing time. These downstream processing conditions are extremely valuable for the further large-scale purification process development for HIV gag-VLPs and other particulate bioproducts.
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Affiliation(s)
- Alejandro Negrete
- Biotechnology Core Laboratory, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States.
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11
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Drugmand JC, Schneider YJ, Agathos SN. Insect cells as factories for biomanufacturing. Biotechnol Adv 2012; 30:1140-57. [DOI: 10.1016/j.biotechadv.2011.09.014] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Revised: 09/13/2011] [Accepted: 09/16/2011] [Indexed: 10/17/2022]
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12
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Barbosa MJ, Albrecht M, Wijffels RH. Hydrodynamic stress and lethal events in sparged microalgae cultures. Biotechnol Bioeng 2003; 83:112-20. [PMID: 12740938 DOI: 10.1002/bit.10657] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The effect of high superficial gas velocities in continuous and batch cultures of the strains Dunaliella tertiolecta, Chlamydomonas reinhardtii wild-type and cell wall-lacking mutant was studied in bubble columns. No cell damage was found for D. tertiolecta and C. reinhardtii (wild-type) up to superficial gas velocities of 0.076 and 0.085 m s(-1), respectively, suggesting that high superficial gas velocities alone cannot be responsible for cell death and, consequently, bubble bursting cannot be the sole cause for cell injury. A death rate of 0.46 +/- 0.08 h(-1) was found for C. reinhardtii (cell wall-lacking mutant) at a superficial gas velocity of 0.076 m s(-1), and increased to 1.01 +/- 0.29 h(-1) on increasing superficial gas velocity to 0.085 m s(-1). Shear sensitivity is thus strain-dependent and to some extent the cell wall plays a role in the protection against hydrodynamic shear. When studying the effect of bubble formation at the sparger in batch cultures of D. tertiolecta by varying the number of nozzles, a death rate of 0.047 +/- 0.016 h(-1) was obtained at high gas entrance velocities. D. tertiolecta was cultivated in a pilot-plant reactor under different superficial gas velocities of up to 0.026 m s(-1), with relatively low gas entrance velocities and no cell damage was observed. There is some indication that the main parameter causing cell death and damage was the gas entrance velocity at the sparger.
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Affiliation(s)
- Maria J Barbosa
- Food and Bioprocess Engineering Group, Wageningen University, P.O. Box 8129, 6700 EV Wageningen, The Netherlands.
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13
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Barbosa MJ, Wijffels RH. Overcoming shear stress of microalgae cultures in sparged photobioreactors. Biotechnol Bioeng 2003; 85:78-85. [PMID: 14705014 DOI: 10.1002/bit.10862] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
In the present work we identified and quantified the effect of hydrodynamic stress on two different microalgae strains, Dunaliella tertiolecta and D. salina, cultivated in bench-scale bubble columns. The cell death rate constant increased with increasing gas-entrance velocity at the sparger. Dunaliella salina was slightly more sensitive than D. tertiolecta. The critical gas-entrance velocities were approximately 50 and 30 m s(-1) for D. tertiolecta and D. salina, respectively. The effects of gas-flow rate, culture height, and nozzle diameter on the death rate constant were also studied. From these results it was concluded that bubble rising and bubble bursting are not responsible for cell death. Regarding nozzle diameter, small nozzles were more detrimental to cells. The bubble formation at the sparger was found to be the main event leading to cell death.
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Affiliation(s)
- Maria J Barbosa
- Food and Bioprocess Engineering Group, Wageningen University, PO Box 8129, 6700 EV Wageningen, The Netherlands.
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Maranga L, Cruz PE, Aunins JG, Carrondo MJT. Production of core and virus-like particles with baculovirus infected insect cells. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2002; 74:183-206. [PMID: 11991179 DOI: 10.1007/3-540-45736-4_9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
In this paper the fundamental aspects of process development for the production of core and virus-like particles with baculovirus infected insect cells are reviewed. The issues addressed include: particle formation and monomer composition, chemical and physical conditions for optimal cell growth, baculovirus replication and product expression, multiplicity of infection strategy, and scale-up of the process. Study of the differences in the metabolic requirements of infected and non-infected cells is necessary for high cell density processes. In the bioreactor, the specific oxygen uptake rate (OURsp) plays a central role in process scale-up, leading to the specification of the bioreactor operational parameters. Shear stress can also be an important variable for bioreactor operation due to its influence on cell growth and product expression. The determination of the critical variables in process development is discussed, showing the relevance of the mathematical models that have been developed for the insect cells/baculovirus system in process implementation and control.
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Affiliation(s)
- Luis Maranga
- Instituto de Biologia Experimental e Tecnológica/Instituto de Tecnologia Química e Biológica IBET/ITQB, Oeiras, Portugal
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15
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Altmann F, Staudacher E, Wilson IB, März L. Insect cells as hosts for the expression of recombinant glycoproteins. Glycoconj J 1999; 16:109-23. [PMID: 10612411 DOI: 10.1023/a:1026488408951] [Citation(s) in RCA: 241] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Baculovirus-mediated expression in insect cells has become well-established for the production of recombinant glycoproteins. Its frequent use arises from the relative ease and speed with which a heterologous protein can be expressed on the laboratory scale and the high chance of obtaining a biologically active protein. In addition to Spodoptera frugiperda Sf9 cells, which are probably the most widely used insect cell line, other mainly lepidopteran cell lines are exploited for protein expression. Recombinant baculovirus is the usual vector for the expression of foreign genes but stable transfection of - especially dipteran - insect cells presents an interesting alternative. Insect cells can be grown on serum free media which is an advantage in terms of costs as well as of biosafety. For large scale culture, conditions have been developed which meet the special requirements of insect cells. With regard to protein folding and post-translational processing, insect cells are second only to mammalian cell lines. Evidence is presented that many processing events known in mammalian systems do also occur in insects. In this review, emphasis is laid, however, on protein glycosylation, particularly N-glycosylation, which in insects differs in many respects from that in mammals. For instance, truncated oligosaccharides containing just three or even only two mannose residues and sometimes fucose have been found on expressed proteins. These small structures can be explained by post-synthetic trimming reactions. Indeed, cell lines having a low level of N-acetyl-beta-glucosaminidase, e.g. Estigmene acrea cells, produce N- glycans with non-reducing terminal N-acetylglucosamine residues. The Trichoplusia ni cell line TN-5B1-4 was even found to produce small amounts of galactose terminated N-glycans. However, there appears to be no significant sialylation of N-glycans in insect cells. Insect cells expressed glycoproteins may, though, be alpha1,3-fucosylated on the reducing-terminal GlcNAc residue. This type of fucosylation renders the N-glycans on one hand resistant to hydrolysis with PNGase F and on the other immunogenic. Even in the absence of alpha1,3-fucosylation, the truncated N-glycans of glycoproteins produced in insect cells constitute a barrier to their use as therapeutics. Attempts and strategies to "mammalianise" the N-glycosylation capacity of insect cells are discussed.
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Affiliation(s)
- F Altmann
- Institut für Chemie der Universität für Bodenkultur Wien.
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Abstract
Recently, several groups have published data on the shear sensitivity of suspended animal cells and the protective effect of certain polymers. These findings did not, at the time, seem to have great practical application because shear sensitivity did not cause great problems for large-scale applications in sparged and stirred-tank reactors using the then-current culture media and fermentation procedures. However, two recent developments might require renewed attention in sparged animal-cell cultures--protein-free media and new fermentation techniques.
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Affiliation(s)
- L van der Pol
- Gist-brocades/Bio-Intermediair, Groningen, The Netherlands
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