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  1. Article ; Online: Increased recombinant adeno-associated virus production by HEK293 cells using small molecule chemical additives.

    Scarrott, Joseph M / Johari, Yusuf B / Pohle, Thilo H / Liu, Ping / Mayer, Ayda / James, David C

    Biotechnology journal

    2022  Volume 18, Issue 3, Page(s) e2200450

    Abstract: Recombinant adeno-associated virus (rAAV) has established itself as a highly efficacious gene delivery vector with a well characterised safety profile allowing broad clinical application. Recent successes in rAAV-mediated gene therapy clinical trials ... ...

    Abstract Recombinant adeno-associated virus (rAAV) has established itself as a highly efficacious gene delivery vector with a well characterised safety profile allowing broad clinical application. Recent successes in rAAV-mediated gene therapy clinical trials will continue to drive demand for improved rAAV production processes to reduce costs. Here, we demonstrate that small molecule bioactive chemical additives can significantly increase recombinant AAV vector production by human embryonic kidney (HEK) cells up to three-fold. Nocodazole (an anti-mitotic agent) and M344 (a selective histone deacetylase inhibitor) were identified as positive regulators of rAAV8 genome titre in a microplate screening assay. Addition of nocodazole to triple-transfected HEK293 suspension cells producing rAAV arrested cells in G2/M phase, increased average cell volume and reduced viable cell density relative to untreated rAAV producing cells at harvest. Final crude genome vector titre from nocodazole treated cultures was >2-fold higher compared to non-treated cultures. Further investigation showed nocodazole addition to cultures to be time critical. Genome titre improvement was found to be scalable and serotype independent across two distinct rAAV serotypes, rAAV8 and rAAV9. Furthermore, a combination of M344 and nocodazole produced a positive additive effect on rAAV8 genome titre, resulting in a three-fold increase in genome titre compared to untreated cells.
    MeSH term(s) Humans ; Genetic Vectors/genetics ; HEK293 Cells ; Dependovirus/genetics ; Nocodazole/pharmacology ; Vorinostat
    Chemical Substances Nocodazole (SH1WY3R615) ; Vorinostat (58IFB293JI)
    Language English
    Publishing date 2022-12-22
    Publishing country Germany
    Document type Journal Article
    ZDB-ID 2221885-3
    ISSN 1860-7314 ; 1860-6768
    ISSN (online) 1860-7314
    ISSN 1860-6768
    DOI 10.1002/biot.202200450
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Design of synthetic promoters for controlled expression of therapeutic genes in retinal pigment epithelial cells.

    Johari, Yusuf B / Mercer, Andrew C / Liu, Ye / Brown, Adam J / James, David C

    Biotechnology and bioengineering

    2021  Volume 118, Issue 5, Page(s) 2001–2015

    Abstract: Age-related macular degeneration (AMD) associated with dysfunction of retinal pigment epithelial (RPE) cells is the most common cause of untreatable blindness. To advance gene therapy as a viable treatment for AMD there is a need for technologies that ... ...

    Abstract Age-related macular degeneration (AMD) associated with dysfunction of retinal pigment epithelial (RPE) cells is the most common cause of untreatable blindness. To advance gene therapy as a viable treatment for AMD there is a need for technologies that enable controlled, RPE-specific expression of therapeutic genes. Here we describe design, construction and testing of compact synthetic promoters with a pre-defined transcriptional activity and RPE cell specificity. Initial comparative informatic analyses of RPE and photoreceptor (PR) cell transcriptomic data identified conserved and overrepresented transcription factor regulatory elements (TFREs, 8-19 bp) specifically associated with transcriptionally active RPE genes. Both RPE-specific TFREs and those derived from the generically active cytomegalovirus-immediate early (CMV-IE) promoter were then screened in vitro to identify sequence elements able to control recombinant gene transcription in model induced pluripotent stem (iPS)-derived and primary human RPE cells. Two libraries of heterotypic synthetic promoters varying in predicted RPE specificity and transcriptional activity were designed de novo using combinations of up to 20 discrete TFREs in series (323-602 bp) and their transcriptional activity in model RPE cells was compared to that of the endogenous BEST1 promoter (661 bp, plus an engineered derivative) and the highly active generic CMV-IE promoter (650 bp). Synthetic promoters with a highpredicted specificity, comprised predominantly of endogenous TFREs exhibited a range of activities up to 8-fold that of the RPE-specific BEST1 gene promoter. Moreover, albeit at a lower predicted specificity, synthetic promoter transcriptional activity in model RPE cells was enhanced beyond that of the CMV-IE promoter when viral elements were utilized in combination with endogenous RPE-specific TFREs, with a reduction in promoter size of 15%. Taken together, while our data reveal an inverse relationship between synthetic promoter activity and cell-type specificity, cell context-specific control of recombinant gene transcriptional activity may be achievable.
    MeSH term(s) Cells, Cultured ; Epithelial Cells/cytology ; Genes, Synthetic/genetics ; Genetic Therapy/methods ; Humans ; Organ Specificity/genetics ; Promoter Regions, Genetic/genetics ; Retinal Pigment Epithelium/cytology ; Synthetic Biology/methods ; Transcriptome/genetics
    Language English
    Publishing date 2021-03-03
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 280318-5
    ISSN 1097-0290 ; 0006-3592
    ISSN (online) 1097-0290
    ISSN 0006-3592
    DOI 10.1002/bit.27713
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Engineering of the CMV promoter for controlled expression of recombinant genes in HEK293 cells.

    Johari, Yusuf B / Scarrott, Joseph M / Pohle, Thilo H / Liu, Ping / Mayer, Ayda / Brown, Adam J / James, David C

    Biotechnology journal

    2022  Volume 17, Issue 8, Page(s) e2200062

    Abstract: Expression of recombinant genes in HEK293 cells is frequently utilized for production of recombinant proteins and viral vectors. These systems frequently employ the cytomegalovirus (CMV) promoter to drive recombinant gene transcription. However, the ... ...

    Abstract Expression of recombinant genes in HEK293 cells is frequently utilized for production of recombinant proteins and viral vectors. These systems frequently employ the cytomegalovirus (CMV) promoter to drive recombinant gene transcription. However, the mechanistic basis of CMV-mediated transcriptional activation in HEK293 cells is unknown and consequently there are no strategies to engineer CMV for controlled expression of recombinant genes. Extensive bioinformatic analyses of transcription factor regulatory elements (TFREs) within the human CMV sequence and transcription factor mRNAs within the HEK293 transcriptome revealed 80 possible regulatory interactions. Through in vitro functional testing using reporter constructs harboring discrete TFREs or CMV deletion variants we identified key TFRE components and clusters of TFREs (cis-regulatory modules) within the CMV sequence. Our data reveal that CMV activity in HEK293 cells is a function of the promoters various constituent TFREs including AhR:ARNT, CREB, E4F, Sp1, ZBED1, JunB, c-Rel, and NF-κB. We also identified critical Sp1-dependent upstream activator elements near the transcriptional start site that were required for efficient transcription and YY1 and RBP-Jκ binding sites that mediate transrepression. Our study shows for the first time that novel, compact CMV-derived promoters can be engineered that exhibit up to 50% higher transcriptional efficiency (activity per unit DNA sequence) or 14% increase in total activity compared to the wild-type counterpart.
    MeSH term(s) Cytomegalovirus/genetics ; Cytomegalovirus/metabolism ; Cytomegalovirus Infections/genetics ; HEK293 Cells ; Humans ; Promoter Regions, Genetic/genetics ; Transcription Factors/genetics
    Chemical Substances Transcription Factors ; ZBED1 protein, human
    Language English
    Publishing date 2022-05-06
    Publishing country Germany
    Document type Journal Article
    ZDB-ID 2221885-3
    ISSN 1860-7314 ; 1860-6768
    ISSN (online) 1860-7314
    ISSN 1860-6768
    DOI 10.1002/biot.202200062
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Metabolic phenotyping of CHO cells varying in cellular biomass accumulation and maintenance during fed-batch culture.

    Fernandez-Martell, Alejandro / Johari, Yusuf B / James, David C

    Biotechnology and bioengineering

    2017  Volume 115, Issue 3, Page(s) 645–660

    Abstract: CHO cell lines capable of high-level recombinant protein product biosynthesis during fed-batch culture are still generally obtained by intensive empirical screening of transfected cells rather than knowledge-guided cellular engineering. In this study, we ...

    Abstract CHO cell lines capable of high-level recombinant protein product biosynthesis during fed-batch culture are still generally obtained by intensive empirical screening of transfected cells rather than knowledge-guided cellular engineering. In this study, we investigate how CHO cell lines create and maintain cellular biosynthetic capacity during fed-batch culture to achieve the optimal combination of rapid exponential proliferation and extended maintenance of high cell biomass concentration. We perform a comparative meta-analysis of mitochondrial and glycolytic functions of 22 discrete parental CHO cell lineages varying in fed-batch culture performance to test the hypotheses that (i) "biomass-intensive" CHO cells exhibit conserved differences in metabolic programming and (ii) it is possible to isolate parental CHO cell lines with a biomass-intensive phenotype to support fed-batch bioproduction processes. We show that for most parental CHO cell lines, rapid proliferation and high late-stage culture performance are mutually exclusive objectives. However, quantitative dissection of mitochondrial and glycolytic functions revealed that a small proportion of clones utilize a conserved metabolic program that significantly enhances cellular glycolytic and mitochondrial oxidative capacity at the onset of late-stage culture. We reveal the central importance of dynamic metabolic re-programming to activate oxidative mitochondrial function as a necessary mechanism to support CHO cell biosynthetic performance during culture.
    MeSH term(s) Animals ; Biomass ; CHO Cells ; Cell Culture Techniques/methods ; Cricetulus ; Glycolysis ; Mitochondria/metabolism ; Oxidation-Reduction
    Language English
    Publishing date 2017-11-28
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 280318-5
    ISSN 1097-0290 ; 0006-3592
    ISSN (online) 1097-0290
    ISSN 0006-3592
    DOI 10.1002/bit.26485
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: CHO genome mining for synthetic promoter design.

    Johari, Yusuf B / Brown, Adam J / Alves, Christina S / Zhou, Yizhou / Wright, Chapman M / Estes, Scott D / Kshirsagar, Rashmi / James, David C

    Journal of biotechnology

    2019  Volume 294, Page(s) 1–13

    Abstract: Synthetic promoters are an attractive alternative for use in mammalian hosts such as CHO cells as they can be designed de novo with user-defined functionalities. In this study, we describe and validate a method for bioprocess-directed design of synthetic ...

    Abstract Synthetic promoters are an attractive alternative for use in mammalian hosts such as CHO cells as they can be designed de novo with user-defined functionalities. In this study, we describe and validate a method for bioprocess-directed design of synthetic promoters utilizing CHO genomic sequence information. We designed promoters with two objective features, (i) constitutive high-level recombinant gene transcription, and (ii) upregulated transcription under mild hypothermia or late-stage culture. CHO genes varying in transcriptional activity were selected based on a comparative analysis of RNA-Seq transcript levels in normal and biphasic cultures in combination with estimates of mRNA half-life from published genome scale datasets. Discrete transcription factor regulatory elements (TFREs) upstream of these genes were informatically identified and functionally screened in vitro to identify a subset of TFREs with the potential to support high activity recombinant gene transcription during biphasic cell culture processes. Two libraries of heterotypic synthetic promoters with varying TFRE combinations were then designed in silico that exhibited a maximal 2.5-fold increase in transcriptional strength over the CMV-IE promoter after transient transfection into host CHO-K1 cells. A subset of synthetic promoters was then used to create stable transfectant pools using CHO-K1 cells under glutamine synthetase selection. Whilst not achieving the maximal 2.5-fold increase in productivity over stable pools harboring the CMV promoter, all stably transfected cells utilizing synthetic promoters exhibited increased reporter production - up to 1.6-fold that of cells employing CMV, both in the presence or absence of intron A immediately downstream of the promoter. The increased productivity of stably transfected cells harboring synthetic promoters was maintained during fed-batch culture, with or without a transition to mild hypothermia at the onset of stationary phase. Our data exemplify that it is important to consider both host cell and intended bioprocess contexts as design criteria in the de novo construction of synthetic genetic parts for mammalian cell engineering.
    MeSH term(s) Animals ; CHO Cells ; Cricetulus ; Genome ; Promoter Regions, Genetic ; Regulatory Elements, Transcriptional
    Language English
    Publishing date 2019-01-28
    Publishing country Netherlands
    Document type Journal Article
    ZDB-ID 843647-2
    ISSN 1873-4863 ; 0168-1656 ; 1389-0352
    ISSN (online) 1873-4863
    ISSN 0168-1656 ; 1389-0352
    DOI 10.1016/j.jbiotec.2019.01.015
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article: CHO genome mining for synthetic promoter design

    Johari, Yusuf B / Adam J. Brown / Chapman M. Wright / Christina S. Alves / David C. James / Rashmi Kshirsagar / Scott D. Estes / Yizhou Zhou

    Journal of biotechnology. 2019 Mar. 20, v. 294

    2019  

    Abstract: Synthetic promoters are an attractive alternative for use in mammalian hosts such as CHO cells as they can be designed de novo with user-defined functionalities. In this study, we describe and validate a method for bioprocess-directed design of synthetic ...

    Abstract Synthetic promoters are an attractive alternative for use in mammalian hosts such as CHO cells as they can be designed de novo with user-defined functionalities. In this study, we describe and validate a method for bioprocess-directed design of synthetic promoters utilizing CHO genomic sequence information. We designed promoters with two objective features, (i) constitutive high-level recombinant gene transcription, and (ii) upregulated transcription under mild hypothermia or late-stage culture. CHO genes varying in transcriptional activity were selected based on a comparative analysis of RNA-Seq transcript levels in normal and biphasic cultures in combination with estimates of mRNA half-life from published genome scale datasets. Discrete transcription factor regulatory elements (TFREs) upstream of these genes were informatically identified and functionally screened in vitro to identify a subset of TFREs with the potential to support high activity recombinant gene transcription during biphasic cell culture processes. Two libraries of heterotypic synthetic promoters with varying TFRE combinations were then designed in silico that exhibited a maximal 2.5-fold increase in transcriptional strength over the CMV-IE promoter after transient transfection into host CHO-K1 cells. A subset of synthetic promoters was then used to create stable transfectant pools using CHO-K1 cells under glutamine synthetase selection. Whilst not achieving the maximal 2.5-fold increase in productivity over stable pools harboring the CMV promoter, all stably transfected cells utilizing synthetic promoters exhibited increased reporter production — up to 1.6-fold that of cells employing CMV, both in the presence or absence of intron A immediately downstream of the promoter. The increased productivity of stably transfected cells harboring synthetic promoters was maintained during fed-batch culture, with or without a transition to mild hypothermia at the onset of stationary phase. Our data exemplify that it is important to consider both host cell and intended bioprocess contexts as design criteria in the de novo construction of synthetic genetic parts for mammalian cell engineering.
    Keywords bioprocessing ; cell culture ; cell engineering ; data collection ; gene expression regulation ; genome mining ; glutamate-ammonia ligase ; half life ; hosts ; hypothermia ; introns ; mammals ; messenger RNA ; regulatory sequences ; sequence analysis ; transcription (genetics) ; transcription factors ; transfection
    Language English
    Dates of publication 2019-0320
    Size p. 1-13.
    Publishing place Elsevier B.V.
    Document type Article
    ZDB-ID 843647-2
    ISSN 1873-4863 ; 0168-1656 ; 1389-0352
    ISSN (online) 1873-4863
    ISSN 0168-1656 ; 1389-0352
    DOI 10.1016/j.jbiotec.2019.01.015
    Database NAL-Catalogue (AGRICOLA)

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  7. Article ; Online: Integrated cell and process engineering for improved transient production of a "difficult-to-express" fusion protein by CHO cells.

    Johari, Yusuf B / Estes, Scott D / Alves, Christina S / Sinacore, Marty S / James, David C

    Biotechnology and bioengineering

    2015  Volume 112, Issue 12, Page(s) 2527–2542

    Abstract: Based on an optimized electroporation protocol, we designed a rapid, milliliter-scale diagnostic transient production assay to identify limitations in the ability of Chinese hamster ovary (CHO) cells to produce a model "difficult-to-express" homodimeric ... ...

    Abstract Based on an optimized electroporation protocol, we designed a rapid, milliliter-scale diagnostic transient production assay to identify limitations in the ability of Chinese hamster ovary (CHO) cells to produce a model "difficult-to-express" homodimeric Fc-fusion protein, Sp35Fc, that exhibited very low volumetric titer and intracellular formation of disulfide-bonded oligomeric aggregates post-transfection. As expression of Sp35Fc induced an unfolded protein response in transfected host cells, we utilized the transient assay to compare, in parallel, multiple functionally diverse strategies to engineer intracellular processing of Sp35Fc in order to increase production and reduce aggregation as two discrete design objectives. Specifically, we compared the effect of (i) co-expression of ER-resident molecular chaperones (BiP, PDI, CypB) or active forms of UPR transactivators (ATF6c, XBP1s) at varying recombinant gene load, (ii) addition of small molecules known to act as chemical chaperones (PBA, DMSO, glycerol, betaine, TMAO) or modulate UPR signaling (PERK inhibitor GSK2606414) at varying concentration, (iii) a reduction in culture temperature to 32°C. Using this information, we designed a biphasic, Sp35Fc-specific transient manufacturing process mediated by lipofection that utilized CypB co-expression at an optimal Sp35Fc:CypB gene ratio of 5:1 to initially maximize transfected cell proliferation, followed by addition of a combination of PBA (0.5 mM) and glycerol (1% v/v) at the onset of stationary phase to maximize cell specific production and eliminate Sp35Fc aggregation. Using this optimal, engineered process transient Sp35Fc production was significantly increased sixfold over a 12 day production process with no evidence of disulfide-bonded aggregates. Finally, transient production in clonally derived sub-populations (derived from parental CHO host) screened for a heritably improved capability to produce Sp35Fc was also significantly improved by the optimized process, showing that protein-specific cell/process engineering can provide a solution that exceeds the limits of genetic/functional diversity within heterogeneous host cell populations. .
    MeSH term(s) Animals ; CHO Cells ; Cricetulus ; Gene Expression ; Immunoglobulin Fc Fragments/genetics ; Immunoglobulin Fc Fragments/metabolism ; Metabolic Engineering/methods ; Molecular Chaperones/metabolism ; Protein Aggregates ; Recombinant Fusion Proteins/genetics ; Recombinant Fusion Proteins/metabolism ; Temperature
    Chemical Substances Immunoglobulin Fc Fragments ; Molecular Chaperones ; Protein Aggregates ; Recombinant Fusion Proteins
    Language English
    Publishing date 2015-12
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 280318-5
    ISSN 1097-0290 ; 0006-3592
    ISSN (online) 1097-0290
    ISSN 0006-3592
    DOI 10.1002/bit.25687
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article ; Online: Production of trimeric SARS-CoV-2 spike protein by CHO cells for serological COVID-19 testing.

    Johari, Yusuf B / Jaffé, Stephen R P / Scarrott, Joseph M / Johnson, Abayomi O / Mozzanino, Théo / Pohle, Thilo H / Maisuria, Sheetal / Bhayat-Cammack, Amina / Lambiase, Giulia / Brown, Adam J / Tee, Kang Lan / Jackson, Philip J / Wong, Tuck Seng / Dickman, Mark J / Sargur, Ravishankar B / James, David C

    Biotechnology and bioengineering

    2020  Volume 118, Issue 2, Page(s) 1013–1021

    Abstract: We describe scalable and cost-efficient production of full length, His-tagged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike glycoprotein trimer by Chinese hamster ovary (CHO) cells that can be used to detect SARS-CoV-2 antibodies in ... ...

    Abstract We describe scalable and cost-efficient production of full length, His-tagged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike glycoprotein trimer by Chinese hamster ovary (CHO) cells that can be used to detect SARS-CoV-2 antibodies in patient sera at high specificity and sensitivity. Transient production of spike in both human embryonic kidney (HEK) and CHO cells mediated by polyethyleneimine was increased significantly (up to 10.9-fold) by a reduction in culture temperature to 32°C to permit extended duration cultures. Based on these data GS-CHO pools stably producing spike trimer under the control of a strong synthetic promoter were cultured in hypothermic conditions with combinations of bioactive small molecules to increase yield of purified spike product 4.9-fold to 53 mg/L. Purification of recombinant spike by Ni-chelate affinity chromatography initially yielded a variety of co-eluting protein impurities identified as host cell derived by mass spectrometry, which were separated from spike trimer using a modified imidazole gradient elution. Purified CHO spike trimer antigen was used in enzyme-linked immunosorbent assay format to detect immunoglobulin G antibodies against SARS-CoV-2 in sera from patient cohorts previously tested for viral infection by polymerase chain reaction, including those who had displayed coronavirus disease 2019 (COVID-19) symptoms. The antibody assay, validated to ISO 15189 Medical Laboratories standards, exhibited a specificity of 100% and sensitivity of 92.3%. Our data show that CHO cells are a suitable host for the production of larger quantities of recombinant SARS-CoV-2 trimer which can be used as antigen for mass serological testing.
    MeSH term(s) Animals ; CHO Cells ; COVID-19/diagnosis ; COVID-19/virology ; COVID-19 Testing/methods ; Cricetinae ; Cricetulus ; Humans ; Recombinant Proteins/biosynthesis ; SARS-CoV-2/metabolism ; Serologic Tests/methods ; Spike Glycoprotein, Coronavirus/biosynthesis
    Chemical Substances Recombinant Proteins ; Spike Glycoprotein, Coronavirus
    Keywords covid19
    Language English
    Publishing date 2020-11-11
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 280318-5
    ISSN 1097-0290 ; 0006-3592
    ISSN (online) 1097-0290
    ISSN 0006-3592
    DOI 10.1002/bit.27615
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article: Production of trimeric SARS-CoV-2 spike protein by CHO cells for serological COVID-19 testing

    Johari, Yusuf B / Jaffé, Stephen R P / Scarrott, Joseph M / Johnson, Abayomi O / Mozzanino, Théo / Pohle, Thilo H / Maisuria, Sheetal / Bhayat-Cammack, Amina / Lambiase, Giulia / Brown, Adam J / Tee, Kang Lan / Jackson, Philip J / Wong, Tuck Seng / Dickman, Mark J / Sargur, Ravishankar B / James, David C

    Biotechnol. bioeng

    Abstract: We describe scalable and cost-efficient production of full length, His-tagged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike glycoprotein trimer by Chinese hamster ovary (CHO) cells that can be used to detect SARS-CoV-2 antibodies in ... ...

    Abstract We describe scalable and cost-efficient production of full length, His-tagged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike glycoprotein trimer by Chinese hamster ovary (CHO) cells that can be used to detect SARS-CoV-2 antibodies in patient sera at high specificity and sensitivity. Transient production of spike in both human embryonic kidney (HEK) and CHO cells mediated by polyethyleneimine was increased significantly (up to 10.9-fold) by a reduction in culture temperature to 32°C to permit extended duration cultures. Based on these data GS-CHO pools stably producing spike trimer under the control of a strong synthetic promoter were cultured in hypothermic conditions with combinations of bioactive small molecules to increase yield of purified spike product 4.9-fold to 53 mg/L. Purification of recombinant spike by Ni-chelate affinity chromatography initially yielded a variety of co-eluting protein impurities identified as host cell derived by mass spectrometry, which were separated from spike trimer using a modified imidazole gradient elution. Purified CHO spike trimer antigen was used in enzyme-linked immunosorbent assay format to detect immunoglobulin G antibodies against SARS-CoV-2 in sera from patient cohorts previously tested for viral infection by polymerase chain reaction, including those who had displayed coronavirus disease 2019 (COVID-19) symptoms. The antibody assay, validated to ISO 15189 Medical Laboratories standards, exhibited a specificity of 100% and sensitivity of 92.3%. Our data show that CHO cells are a suitable host for the production of larger quantities of recombinant SARS-CoV-2 trimer which can be used as antigen for mass serological testing.
    Keywords covid19
    Publisher WHO
    Document type Article
    Note WHO #Covidence: #893204
    Database COVID19

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  10. Article ; Online: Production of Trimeric SARS-CoV-2 Spike Protein by CHO Cells for Serological COVID-19 Testing

    Johari, Yusuf B / Jaffé, Stephen R P / Scarrott, Joseph M / Johnson, Abayomi O / Mozzanino, Théo / Pohle, Thilo H / Maisuria, Sheetal / Bhayat-Cammack, Amina / Brown, Adam J / Lan Tee, Kang / Jackson, Philip J / Wong, Tuck Seng / Dickman, Mark J / Sargur, Ravishankar / James, David C

    medRxiv

    Abstract: We describe scalable and cost-efficient production of full length, His-tagged SARS-CoV-2 spike glycoprotein trimer by CHO cells that can be used to detect SARS-CoV-2 antibodies in patient sera at high specificity and sensitivity. Transient production of ... ...

    Abstract We describe scalable and cost-efficient production of full length, His-tagged SARS-CoV-2 spike glycoprotein trimer by CHO cells that can be used to detect SARS-CoV-2 antibodies in patient sera at high specificity and sensitivity. Transient production of spike in both HEK and CHO cells mediated by PEI was increased significantly (up to 10.9-fold) by a reduction in culture temperature to 32C to permit extended duration cultures. Based on these data GS-CHO pools stably producing spike trimer under the control of a strong synthetic promoter were cultured in hypothermic conditions with combinations of bioactive small molecules to increase yield of purified spike product 4.9-fold to 53 mg/L. Purification of recombinant spike by Ni-chelate affinity chromatography initially yielded a variety of co-eluting protein impurities identified as host cell-derived by mass spectrometry, which were separated from spike trimer using a modified imidazole gradient elution. Purified CHO spike trimer antigen was used in ELISA format to detect IgG antibodies against SARS-CoV-2 in sera from patient cohorts previously tested for viral infection by PCR, including those who had displayed COVID-19 symptoms. The antibody assay, validated to ISO 15189 Medical Laboratories standards, exhibited a specificity of 100% and sensitivity of 92.3%. Our data show that CHO cells are a suitable host for the production of larger quantities of recombinant SARS-CoV-2 trimer which can be used as antigen for mass serological testing.
    Keywords covid19
    Language English
    Publishing date 2020-08-13
    Publisher Cold Spring Harbor Laboratory Press
    Document type Article ; Online
    DOI 10.1101/2020.08.07.20169441
    Database COVID19

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