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1.
Mol Biotechnol ; 66(2): 354-364, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37162721

RESUMO

This work aimed to assess the Sf9 cell metabolism during growth, and infection steps with recombinant baculovirus bearing rabies virus proteins, to finally obtain rabies VLP in two culture systems: Schott flask (SF) and stirred tank reactor (STR). Eight assays were performed in SF and STR (four assays in each system) using serum-free SF900 III culture medium. Two non-infection growth kinetics assays and six recombinant baculovirus infection assays. The infection runs were carried out at 0.1 pfu/cell multiplicity of infection (MOI) for single baculovirus bearing rabies glycoprotein (BVG) and matrix protein (BVM) and a coinfection with both baculoviruses at MOI of 3 and 2 pfu/cell for BVG and BVM, respectively. The SF assays were done in triplicate. The glucose, glutamine, glutamate, lactate, and ammonium uptake or release specific rates were quantified over the exponential growth phase and infection stage. The highest uptake specific rate was observed for glucose (42.5 × 10-12 mmol cell/h) in SF and for glutamine (30.8 × 10-12 mmol/cell/h) in STR, in the exponential growth phases. A wave pattern was observed for assessed analytes throughout the infection phase and the glucose had the highest wave amplitude within the 10-10 mmol cell/h order. This alternative uptake and release behavior is in harmony with the lytic cycle of baculovirus in insect cells. The virus propagation and VLP generation were not limited by glucose, glutamine, and glutamate, neither by the toxicity of lactate nor ammonium under the conditions appraised in this work. The findings from this work can be useful to set baculovirus infection processes at high cell density to improve rabies VLP yield, purity, and productivity.


Assuntos
Compostos de Amônio , Vírus da Raiva , Raiva , Animais , Células Sf9 , Vírus da Raiva/genética , Glutamina , Baculoviridae/genética , Proteínas Recombinantes/genética , Meios de Cultura Livres de Soro , Ácido Glutâmico , Lactatos , Glucose , Spodoptera
2.
Pathogens ; 12(8)2023 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-37623961

RESUMO

Spodoptera frugiperda (fall armyworm) is one of the most important maize pests in the world and the baculovirus Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV), a natural pathogen of this pest, has been used as a biopesticide for its control. At present, in vivo strategies at the commercial scale are employed by multiplying the virus in the host insect in biofactory facilities; however, in vitro large-scale production is an interesting alternative to overcome the limitations of baculoviruses massal production. This study aimed to develop the process of the SfMNPV in vitro production by evaluating the effects of different multiplicities of infection (MOI) and nutritional supplements, morphological and molecular analysis of the infection on the growth of Sf9 cells and virus production. The Bioreactor Stirred Tank Reactor (STR) approach with glutamine-supplemented Sf-900 III serum free culture medium, combined with the MOI of 1.0, showed the best viral production performance, with a specific productivity above 300 occlusion bodies (OBs)/cell and volumetric productivity of 9.0 × 1011 OBs/L.

3.
Biotechnol Lett ; 45(7): 823-846, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37171697

RESUMO

Prior to clinical use, extensive in vitro proliferation of human adipose-derived stem cells (ASCs) is required. Among the current options, spinner-type stirred flasks, which use microcarriers to increase the yield of adherent cells, are recommended. Here, we propose a methodology for ASCs proliferation through cell suspension culture using Cultispher-S® microcarriers (MC) under agitation in a spinner flask, with the aim of establishing a system that reconciles the efficiency of cell yield with high viability of the culture during two distinct phases: seeding and proliferation. The results showed that cell adhesion was potentiated under intermittent stirring at 70 rpm in the presence of 10% FBS for an initial cell concentration of 2.4 × 104 cells/mL in the initial 24 h of cultivation. In the proliferation phase, kinetic analysis showed that cell growth was higher under continuous agitation at 50 rpm with a culture medium renewal regime of 50% every 72 h, which was sufficient to maintain the culture at optimal levels of nutrients and metabolites for up to nine days of cultivation, representing an 11.1-fold increase and a maximum cell productivity of 422 cells/mL/h (1.0 × 105 viable cells/mL). ASCs maintained the immunophenotypic characteristics and mesodermal differentiation potential of both cell lines from different donors. The established protocol represents a more efficient and cost-effective method to obtain a high proliferation rate of ASCs in a microcarrier-based system, which is necessary for large-scale use in cell therapy, highlighting that the manipulation of critical parameters optimizes the ASCs production process.


Assuntos
Células-Tronco Mesenquimais , Humanos , Cinética , Técnicas de Cultura de Células/métodos , Proliferação de Células , Meios de Cultura , Diferenciação Celular , Células Cultivadas
4.
J Biotechnol ; 363: 19-31, 2023 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-36587847

RESUMO

This work aimed to quantify growth and biochemical parameters (viable cell density, Xv; cell viability, CV; glucose, lactate, glutamine, glutamate, ammonium, and potassium concentrations) in upstream stages to obtain rabies virus-like particles (rabies VLP) from insect cell-baculovirus system using on-line and off-line Raman spectra to calibrate global models with minimal experimental data. Five cultivations in bioreactor were performed. The first one comprised the growth of uninfected Spodoptera frugiperda (Sf9) cells, the second and third runs to obtain recombinant baculovirus (rBV) bearing Rabies G glycoprotein and matrix protein, respectively. The fourth one involved the generation of rabies VLP from rBVs and the last one was a repetition of the third one with cell inoculum infected by rBV. The spectra were acquired through a Raman spectrometer with a 785-nm laser source. The fitted Partial Least Square models for nutrients and metabolites were comparable with those previously reported for mammalian cell lines (Relative error < 15 %). However, the use of this chemometrics approach for Xv and CV was not as accurate as it was for other parameters. The findings from this work established the basis for bioprocess Raman spectroscopical monitoring using insect cells for VLP manufacturing, which are gaining ground in the pharmaceutical industry.


Assuntos
Vírus da Raiva , Raiva , Animais , Vírus da Raiva/genética , Análise Espectral Raman , Linhagem Celular , Reatores Biológicos , Baculoviridae , Proteínas Recombinantes , Insetos , Spodoptera , Mamíferos
5.
Mol Biotechnol ; 65(6): 970-982, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36396754

RESUMO

This work aimed to describe the dynamics of the Sf9 insect cells death and primary metabolism when this host is infected simultaneously by two recombinant baculoviruses (BV) expressing rabies glycoprotein (BVG) and matrix protein (BVM) genes to produce rabies virus-like particles (VLP) at different multiplicities of infection (MOI). Schott flasks essays covering a wide range of MOI for both BV were performed. Viable cell density, cell viability, glucose, glutamine, glutamate, lactate, ammonium, and rabies proteins concentrations were monitored over the infection phase. The expression of both recombinant proteins was not limited by glucose, glutamine, and glutamate in a broad MOI (pfu/cell) range of BVG (0.15-12.5) and BVM (0.1-5.0) using SF900 III serum free culture medium. Death phase initiation and the specific death rate depend on BV MOI. The wave pattern of nutrient/metabolite profiles throughout the viral infection phase is related to the baculovirus lytic cycle. The optimal MOIs ratio between BVG (2.5-4.5) and BVM (1.0-3.0) for maximum protein expression was defined. The produced rabies VLP sizes are close to 78 nm. In general, these work outputs bring a better understanding of the metabolic performance of Sf9 cells when infected by BV for producing VLP, and specifically, for progressing in a rabies VLP vaccine development.


Assuntos
Vacina Antirrábica , Vírus da Raiva , Raiva , Animais , Humanos , Baculoviridae/genética , Baculoviridae/metabolismo , Células Sf9 , Linhagem Celular , Vírus da Raiva/genética , Glutamina/metabolismo , Glutamatos/metabolismo , Glucose/metabolismo
6.
J Chem Technol Biotechnol, in press, 2023
Artigo em Inglês | Sec. Est. Saúde SP, SESSP-IBPROD, Sec. Est. Saúde SP | ID: bud-5221

RESUMO

BACKGROUND This study aimed to establish chemometric models using Raman spectroscopy data for biochemical monitoring of rabies Virus-Like Particles (VLP) production based on baculovirus/insect cell system. The models were developed using fresh and stored samples from the initial development stages (Schott culture flasks). The following modeling techniques were assessed: partial least squares (PLS) and artificial neural networks (ANN). The effects of spectral filtering approaches, spectral ranges (400–1850 cm−1; 100–3425 cm−1), and sample cryopreservation were also considered. The applicability of the models was evaluated using experimental data from assays carried out in a benchtop bioreactor. RESULTS The results showed that the prediction capacity of the chemometric models was negatively impacted when samples from rabies VLP production were cryopreserved. Further studies are needed to confirm the maximum storage time for samples (< 4 months) without a significant difference in model predictions compared to those from an in line database. The dilution of the sample should be kept constant throughout the rabies VLP development stages. A nonlinear correlation was observed between dilution and the predicted values of biochemical parameters from Raman spectral data. The choice of spectral filtering has a major impact on the prediction accuracy of chemometric models. CONCLUSION The optimal filtering approach should be individually optimized for each biochemical parameter. The ANN models were significantly more suitable for biochemical monitoring than the PLS approach. The 400–1850 cm−1 Raman shift range is recommended for biochemical monitoring of rabies VLP using a baculovirus/insect cell platform when samples are cell-free.

7.
Mol Biotechnol, v. 66, p. 354-364, abr. 2023
Artigo em Inglês | Sec. Est. Saúde SP, SESSP-IBPROD, Sec. Est. Saúde SP | ID: bud-4915

RESUMO

This work aimed to assess the Sf9 cell metabolism during growth, and infection steps with recombinant baculovirus bearing rabies virus proteins, to fnally obtain rabies VLP in two culture systems: Schott fask (SF) and stirred tank reactor (STR). Eight assays were performed in SF and STR (four assays in each system) using serum-free SF900 III culture medium. Two non-infection growth kinetics assays and six recombinant baculovirus infection assays. The infection runs were carried out at 0.1 pfu/cell multiplicity of infection (MOI) for single baculovirus bearing rabies glycoprotein (BVG) and matrix protein (BVM) and a coinfection with both baculoviruses at MOI of 3 and 2 pfu/cell for BVG and BVM, respectively. The SF assays were done in triplicate. The glucose, glutamine, glutamate, lactate, and ammonium uptake or release specifc rates were quantifed over the exponential growth phase and infection stage. The highest uptake specifc rate was observed for glucose (42.5× 10–12 mmol cell/h) in SF and for glutamine (30.8× 10–12 mmol/cell/h) in STR, in the exponential growth phases. A wave pattern was observed for assessed analytes throughout the infection phase and the glucose had the highest wave amplitude within the 10–10 mmol cell/h order. This alternative uptake and release behavior is in harmony with the lytic cycle of baculovirus in insect cells. The virus propagation and VLP generation were not limited by glucose, glutamine, and glutamate, neither by the toxicity of lactate nor ammonium under the conditions appraised in this work. The fndings from this work can be useful to set baculovirus infection processes at high cell density to improve rabies VLP yield, purity, and productivity.

8.
Biotechnol Lett, v. 45, 823–846, mai. 2023
Artigo em Inglês | Sec. Est. Saúde SP, SESSP-IBPROD, Sec. Est. Saúde SP | ID: bud-4902

RESUMO

Prior to clinical use, extensive in vitro proliferation of human adipose-derived stem cells (ASCs) is required. Among the current options, spinner-type stirred flasks, which use microcarriers to increase the yield of adherent cells, are recommended. Here, we propose a methodology for ASCs proliferation through cell suspension culture using Cultispher-S® microcarriers (MC) under agitation in a spinner flask, with the aim of establishing a system that reconciles the efficiency of cell yield with high viability of the culture during two distinct phases: seeding and proliferation. The results showed that cell adhesion was potentiated under intermittent stirring at 70 rpm in the presence of 10% FBS for an initial cell concentration of 2.4 × 104 cells/mL in the initial 24 h of cultivation. In the proliferation phase, kinetic analysis showed that cell growth was higher under continuous agitation at 50 rpm with a culture medium renewal regime of 50% every 72 h, which was sufficient to maintain the culture at optimal levels of nutrients and metabolites for up to nine days of cultivation, representing an 11.1-fold increase and a maximum cell productivity of 422 cells/mL/h (1.0 × 105 viable cells/mL). ASCs maintained the immunophenotypic characteristics and mesodermal differentiation potential of both cell lines from different donors. The established protocol represents a more efficient and cost-effective method to obtain a high proliferation rate of ASCs in a microcarrier-based system, which is necessary for large-scale use in cell therapy, highlighting that the manipulation of critical parameters optimizes the ASCs production process.

9.
Proc Bioch, v. 124, p. 189-200, jan. 2023
Artigo em Inglês | Sec. Est. Saúde SP, SESSP-IBPROD, Sec. Est. Saúde SP | ID: bud-4718

RESUMO

The technologies used in rabies vaccines manufacturing for human use are based on the inactivated virus platform. An alternative to traditional vaccines is virus-like particles (VLPs). This work aimed to characterize the oxygen uptake and transfer rate parameters throughout recombinant baculovirus (rBV) and rabies VLPs production using Sf9 cells in stirred tank bioreactor (STB) for a better bioprocess understanding and scalability. Four runs in a bench STB were performed: cell culture without infection; cells infected singly with rBV bearing rabies virus glycoprotein (rBVG, multiplicity of infection, MOI=0.1 pfu/cell) and matrix protein (rBVM, MOI=0.1 pfu/cell), and coinfected with BVG and BVM at MOI of 3 and 2 pfu/cell, respectively. The specific oxygen uptake rate () and volumetric oxygen transfer coefficient () were monitored throughout the reactions, as well as viable cell concentration, viability, rBV titers, and protein concentration. According to the results herein, the aeration and agitation systems in a bioreactor at a higher scale could be designed using the criterium for scale-up of constant , without oxygen facilities. Besides, rabies VLPs volumetric yield of 2.8 mg/L with a typical size (55–68 nm) was obtained. These findings suggest a promising bioprocess for rabies VLPs at a commercial scale.

10.
Vaccines (Basel) ; 11(1)2022 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-36679884

RESUMO

This work aimed to assess, following upstream optimization in Schott flasks, the scalability from this culture platform to a stirred-tank bioreactor in order to yield rabies-recombinant baculovirus, bearing genes of G (BVG) and M (BVM) proteins, and to obtain rabies virus-like particles (VLP) from them, using Sf9 insect cells as a host. Equivalent assays in Schott flasks and a bioreactor were performed to compare both systems and a multivariate statistical approach was also carried out to maximize VLP production as a function of BVG and BVM's multiplicity of infection (MOI) and harvest time (HT). Viable cell density, cell viability, virus titer, BVG and BVM quantification by dot-blot, and BVG quantification by Enzyme-Linked Immunosorbent Assay (ELISA) were monitored throughout the assays. Furthermore, transmission electron microscopy was used to characterize rabies VLP. The optimal combination for maximum VLP expression was BVG and BVM MOI of 2.3 pfu/cell and 5.1 pfu/cell, respectively, and 108 h of harvest time. The current study confirmed that the utilization of Schott flasks and a benchtop bioreactor under the conditions applied herein are equivalent regarding the cell death kinetics corresponding to the recombinant baculovirus infection process in Sf9 cells. According to the results, the hydrodynamic and chemical differences in both systems seem to greatly affect the virus and VLP integrity after release.

11.
Mol Biotechnol, v. 65, 970–982, nov. 2022
Artigo em Inglês | Sec. Est. Saúde SP, SESSP-IBPROD, Sec. Est. Saúde SP | ID: bud-4717

RESUMO

This work aimed to describe the dynamics of the Sf9 insect cells death and primary metabolism when this host is infected simultaneously by two recombinant baculoviruses (BV) expressing rabies glycoprotein (BVG) and matrix protein (BVM) genes to produce rabies virus-like particles (VLP) at diferent multiplicities of infection (MOI). Schott fasks essays covering a wide range of MOI for both BV were performed. Viable cell density, cell viability, glucose, glutamine, glutamate, lactate, ammonium, and rabies proteins concentrations were monitored over the infection phase. The expression of both recombinant proteins was not limited by glucose, glutamine, and lutamate in a broad MOI (pfu/cell) range of BVG (0.15–12.5) and BVM (0.1–5.0) using SF900 III serum free culture medium. Death phase initiation and the specifc death rate depend on BV MOI. The wave pattern of nutrient/metabolite profles throughout the viral infection phase is related to the baculovirus lytic cycle. The optimal MOIs ratio between BVG (2.5–4.5) and BVM (1.0–3.0) for maximum protein expression was defned. The produced rabies VLP sizes are close to 78 nm. In general, these work outputs bring a better understanding of the metabolic performance of Sf9 cells when infected by BV for producing VLP, and specifcally, for progressing in a rabies VLP vaccine development.

12.
Prep Biochem Biotechnol ; 51(3): 277-288, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-32921254

RESUMO

L-asparaginase (ASNase) is an essential drug in the treatment of acute lymphoblastic leukemia (ALL). Commercial bacterial ASNases increase patient survival, but the consequent immunological reactions remain a challenge. Yeasts ASNase is closer to human congeners and could lead to lower side effects. Among 134 yeast strains isolated from marine-sediments in King George Island, Antarctica, nine were L-asparaginase producing yeasts and glutaminase-free. Leucosporidium muscorum CRM 1648 yielded the highest ASNase activity (490.41 U.L-1) and volumetric productivity (5.12 U.L-1 h-1). Sucrose, yeast extract and proline were the best carbon and nitrogen sources to support growth and ASNase production. A full factorial design analysis pointed the optimum media condition for yeast growth and ASNase yield: 20 g L-1 sucrose, 15 g L-1 yeast extract and 20 g L-1 proline, which resulted in 4582.5 U L-1 and 63.64 U L-1 h-1 of ASNase and volumetric productivity, respectively. Analysis of temperature, pH, inoculum and addition of seawater indicated the best condition for ASNase production by this yeast: 12-15 °C, pH 5.5-6.5 and seawater >25% (v/v). Inoculum concentration seems not to interfere. This work is pioneer on the production of ASNase by cold-adapted yeasts, highlighting the potential of these microbial resources as a source of glutaminase-free L-asparaginase for commercial purposes.


Assuntos
Asparaginase/química , Basidiomycota/metabolismo , Biotecnologia/métodos , Sedimentos Geológicos/química , Glutaminase/química , Regiões Antárticas , Antineoplásicos/farmacologia , Biomassa , Carbono/química , Geografia , Concentração de Íons de Hidrogênio , Prolina/química , Análise de Regressão , Água do Mar , Sacarose/química , Temperatura
13.
BMC Res Notes ; 13(1): 57, 2020 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-32019595

RESUMO

OBJECTIVE: Cell growth curves constitute one of the primary assays employed to analyze cell proliferation dynamics of in vitro cultured cells under specific culture conditions. From the cell growth curve, it is possible to assess the behavior of proliferating cells under different conditions, such as drug treatment and genomic editions. Traditionally, growth curves for adherent cells are obtained by seeding the cells in multiple-well plates and counting the total number of cells at different time points. Here, we compare this traditional method to the fluorescence-based method, which is based on the CFSE fluorescence decay over time. RESULTS: The fluorescence-based method is not dependent on the determination of the total number of cells, but rather is approached by assessing the fluorescence of a sample of single cells from a cell population at different time points after plating. Therefore, this method is not biased due to either cell loss during harvesting or to the presence of cellular debris and cell clumps. Moreover, the fluorescence-based method displays lower variation among different measurements of the same time point, which increases the reliability on the determination of lag, log and stationary phase transitions.


Assuntos
Contagem de Células/métodos , Células/citologia , Adesão Celular , Proliferação de Células , Fluoresceínas/metabolismo , Fluorescência , Células HEK293 , Humanos , Succinimidas/metabolismo
14.
BMC Res Notes, v. 13, 57, fev. 2020
Artigo em Inglês | Sec. Est. Saúde SP, SESSP-IBPROD, Sec. Est. Saúde SP | ID: bud-3152

RESUMO

Objective: Cell growth curves constitute one of the primary assays employed to analyze cell proliferation dynamics of in vitro cultured cells under specific culture conditions. From the cell growth curve, it is possible to assess the behavior of proliferating cells under different conditions, such as drug treatment and genomic editions. Traditionally, growth curves for adherent cells are obtained by seeding the cells in multiple-well plates and counting the total number of cells at different time points. Here, we compare this traditional method to the fluorescence-based method, which is based on the CFSE fluorescence decay over time. Results: The fluorescence-based method is not dependent on the determination of the total number of cells, but rather is approached by assessing the fluorescence of a sample of single cells from a cell population at different time points after plating. Therefore, this method is not biased due to either cell loss during harvesting or to the presence of cellular debris and cell clumps. Moreover, the fluorescence-based method displays lower variation among different measurements of the same time point, which increases the reliability on the determination of lag, log and stationary phase transitions.

15.
Biologicals ; 62: 93-101, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31495708

RESUMO

Adipose-derived mesenchymal stromal/stem cells (ASC) have acquired a prominent role in tissue engineering and regenerative medicine. However, the standardization of basic culture procedures in this cellular type is still not well established according to the main qualitative cellular attributes. We evaluate the cell growth profile of human ASC in a different culture medium volumes and their nutritional composition utilizing static cultivation. Culture medium volumes (5, 10 and 15 mL/25 cm2) in T-flasks were evaluated by kinetic parameters and the metabolic composition was determined by biochemical analysis and Fourier transform infrared (FT-IR) absorption spectroscopy. 50% renewal of culture medium volume every 48 h was adopted. Immunophenotypic characterization and cell differentiation were performed. There was no difference (p > 0.05) in the kinetic parameters of cell proliferation between the culture medium volumes or in FT-IR composition. However, the concentrations of glucose, glutamine, lactate, and glutamate varied significantly during the cultivation process as a function of the medium volume. ASC presented specific antigens and differentiation potential of mesenchymal stromal/stem cells. It was concluded that the minimal culture medium volume (5 mL/25 cm2 in static culture) was sufficient to maintain the stability, potency, and growth of ASC, representing an economic and safe standardization for this cell culture process.


Assuntos
Tecido Adiposo/metabolismo , Técnicas de Cultura de Células/normas , Proliferação de Células , Meios de Cultura/normas , Células-Tronco Mesenquimais/metabolismo , Tecido Adiposo/citologia , Antígenos de Diferenciação/metabolismo , Técnicas de Cultura de Células/métodos , Meios de Cultura/química , Humanos , Células-Tronco Mesenquimais/citologia
16.
Braz J Chem Eng, v. 35, n. 2, p. 441-458
Artigo em Inglês | Sec. Est. Saúde SP, SESSP-IBPROD, Sec. Est. Saúde SP | ID: bud-2580

RESUMO

Baby Hamster Kidney cells (BHK-21) are commonly used in research and the biopharmaceutical industry. This work aimed to model the kinetic performance in batch operation mode of BHK-21 cells cultured in two stirred tank configurations using different dissolved oxygen concentrations and pH control strategies. Viable and dead cell concentrations, as well as glucose, glutamine, lactate and ammonium concentrations, were monitored. Statistical multiple linear regression, logistic equation and multiplicative Monod kinetic models were fitted. Statistical models for viable cells concentration as a function of nutrient and metabolite concentrations were significant (R2 >0.91). Logistic model parameters: intrinsic growth rate, cell density level in the medium and time for reaching maximum cell concentrations were within 0.061-0.083 h-1, 1.85-5.39 x 109 cell L-1 and 52-90 h ranges, respectively. A Monod-type model was satisfactorily fitted to the experimental data. Relative errors were lower than 10% for six monitored state variables in most of the assessed experimental conditions. The three models developed in this work can be used in bioprocesses involving BHK-21 with good fitting.

17.
Braz. J. Chem. Eng. ; 35(2): p. 441-458, 2018.
Artigo em Inglês | Sec. Est. Saúde SP, SESSP-IBPROD, Sec. Est. Saúde SP | ID: but-ib15622

RESUMO

Baby Hamster Kidney cells (BHK-21) are commonly used in research and the biopharmaceutical industry. This work aimed to model the kinetic performance in batch operation mode of BHK-21 cells cultured in two stirred tank configurations using different dissolved oxygen concentrations and pH control strategies. Viable and dead cell concentrations, as well as glucose, glutamine, lactate and ammonium concentrations, were monitored. Statistical multiple linear regression, logistic equation and multiplicative Monod kinetic models were fitted. Statistical models for viable cells concentration as a function of nutrient and metabolite concentrations were significant (R2 >0.91). Logistic model parameters: intrinsic growth rate, cell density level in the medium and time for reaching maximum cell concentrations were within 0.061-0.083 h-1, 1.85-5.39 x 109 cell L-1 and 52-90 h ranges, respectively. A Monod-type model was satisfactorily fitted to the experimental data. Relative errors were lower than 10% for six monitored state variables in most of the assessed experimental conditions. The three models developed in this work can be used in bioprocesses involving BHK-21 with good fitting.

18.
Cytotechnology ; 68(1): 95-104, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24942228

RESUMO

Mammalian cells are the most frequently used hosts for biopharmaceutical proteins manufacturing. Inoculum quality is a key element for establishing an efficient bioconversion process. The main objective in inoculation expansion process is to generate large volume of viable cells in the shortest time. The aim of this paper was to optimize the inoculum preparation stage of baby hamster kidney (BHK)-21 cells for suspension cultures in benchtop bioreactors, by means of a combination of static and agitated culture systems. Critical parameters for static (liquid column height: 5, 10, 15 mm) and agitated (working volume: 35, 50, 65 mL, inoculum volume percentage: 10, 30 % and agitation speed: 25, 60 rpm) cultures were study in T-flask and spinner flask, respectively. The optimal liquid column height was 5 mm for static culture. The maximum viable cell concentration in spinner flask cultures was reached with 50 mL working volume and the inoculum volume percentage was not significant in the range under study (10-30 %) at 25 rpm agitation. Agitation speed at 60 rpm did not change the main kinetic parameters with respect to those observed for 25 rpm. These results allowed for a schedule to produce more than 4 × 10(9) BHK-21 cells from 4 × 10(6) cells in 13 day with 1,051 mL culture medium.

19.
Biotechnol Lett ; 37(6): 1153-63, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25700821

RESUMO

OBJECTIVE: To assess the expression of rabies virus G-glycoprotein (RVGP) expression using Semliki Forest virus as a vector in combination with BHK-21 cells cultured in suspension. RESULTS: A multilevel factorial design was used to quantify effects of temperature (33-37 °C), fresh medium addition after the viral adsorption step (100-200 % with respect to the initial cell suspension volume before infection) and harvest time (8-40 h) on RVGP production. Experimental runs were performed in 24-well cell culture plates at a multiplicity of infection (MOI) of 16. An additional experiment in spinner-flask was performed at MOI of 9, using the optimal conditions determined in cell culture plates. Values for temperature, fresh medium addition and harvest time of 33 °C, 100 % and 16 h, respectively, ensured the optimal RVGP production in culture plates. The volumetric yield (239 ng ml(-1)) in these conditions was higher than that reported previously for adherent cell culture. In spinner-flasks, the volumetric yield was improved (559 ng ml(-1)). CONCLUSION: These results establish the basis for designing bioprocess to produce RVGP.


Assuntos
Antígenos Virais/biossíntese , Reatores Biológicos , Células Epiteliais/metabolismo , Expressão Gênica , Glicoproteínas/biossíntese , Proteínas do Envelope Viral/biossíntese , Animais , Antígenos Virais/genética , Linhagem Celular , Cricetinae , Meios de Cultura/química , Vetores Genéticos , Glicoproteínas/genética , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/genética , Vírus da Floresta de Semliki/genética , Temperatura , Fatores de Tempo , Proteínas do Envelope Viral/genética
20.
Bioprocess Biosyst Eng ; 38(6): 1045-54, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25552348

RESUMO

Currently, mammalian cells are the most utilized hosts for biopharmaceutical production. The culture media for these cell lines include commonly in their composition a pH indicator. Spectroscopic techniques are used for biopharmaceutical process monitoring, among them, UV-Vis spectroscopy has found scarce applications. This work aimed to define artificial neural networks architecture and fit its parameters to predict some nutrients and metabolites, as well as viable cell concentration based on UV-Vis spectral data of mammalian cell bioprocess using phenol red in culture medium. The BHK-21 cell line was used as a mammalian cell model. Off-line spectra of supernatant samples taken from batches performed at different dissolved oxygen concentrations in two bioreactor configurations and with two pH control strategies were used to define two artificial neural networks. According to absolute errors, glutamine (0.13 ± 0.14 mM), glutamate (0.02 ± 0.02 mM), glucose (1.11 ± 1.70 mM), lactate (0.84 ± 0.68 mM) and viable cell concentrations (1.89 10(5) ± 1.90 10(5) cell/mL) were suitably predicted. The prediction error averages for monitored variables were lower than those previously reported using different spectroscopic techniques in combination with partial least squares or artificial neural network. The present work allows for UV-VIS sensor development, and decreases cost related to nutrients and metabolite quantifications.


Assuntos
Produtos Biológicos , Reatores Biológicos , Redes Neurais de Computação , Espectrofotometria Ultravioleta/métodos , Animais , Linhagem Celular , Cricetinae , Meios de Cultura , Concentração de Íons de Hidrogênio
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