Publications by authors named "Akiko Ishii-Watabe"

81 Publications

Bioanalysis of therapeutic monoclonal antibody by peptide adsorption-controlled LC-MS.

Bioanalysis 2021 Feb 5;13(4):265-276. Epub 2021 Feb 5.

Division of Biological Chemistry & Biologicals, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-9501, Japan.

We aimed to develop an easy, low-cost and versatile mass spectrometric method for the bioanalysis of a therapeutic monoclonal antibody (mAb) in human serum that employs peptide adsorption-controlled (PAC)-LC/MS using selected reaction monitoring mode (LC-MS/MS-SRM). Rituximab was used as a model mAb. To apply the method to human serum samples, a peptide of the complementarity-determining region was selected as the surrogate peptide. The usefulness of PAC-LC-MS/MS-SRM was evaluated by a collaborative study. The calibration curve ranged from 0.5 (or 1.0) to 1000.0 μg/ml. The selectivity, linearity, accuracy and precision met the predefined acceptance criteria. Our method could be a useful bioanalytical method for the quantification of mAbs in clinical samples.
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http://dx.doi.org/10.4155/bio-2020-0262DOI Listing
February 2021

2020 White Paper on Recent Issues in Bioanalysis: Vaccine Assay Validation, qPCR Assay Validation, QC for CAR-T Flow Cytometry, NAb Assay Harmonization and ELISpot Validation ( - Recommendations on Immunogenicity Assay Strategies, NAb Assays, Biosimilars and FDA/EMA Immunogenicity Guidance/Guideline, Gene & Cell Therapy and Vaccine Assays).

Bioanalysis 2021 Mar 3;13(6):415-463. Epub 2021 Feb 3.

Intellia Therapeutics, Cambridge, MA, USA.

The 14 edition of the Workshop on Recent Issues in Bioanalysis (14 WRIB) was held virtually on June 15-29, 2020 with an attendance of over 1000 representatives from pharmaceutical/biopharmaceutical companies, biotechnology companies, contract research organizations, and regulatory agencies worldwide. The 14 WRIB included three Main Workshops, seven Specialized Workshops that together spanned 11 days in order to allow exhaustive and thorough coverage of all major issues in bioanalysis, biomarkers, immunogenicity, gene therapy and vaccine. Moreover, a comprehensive vaccine assays track; an enhanced cytometry track and updated Industry/Regulators consensus on BMV of biotherapeutics by LCMS were special features in 2020. As in previous years, this year's WRIB continued to gather a wide diversity of international industry opinion leaders and regulatory authority experts working on both small and large molecules to facilitate sharing and discussions focused on improving quality, increasing regulatory compliance and achieving scientific excellence on bioanalytical issues. This 2020 White Paper encompasses recommendations emerging from the extensive discussions held during the workshop and is aimed to provide the Global Bioanalytical Community with key information and practical solutions on topics and issues addressed, in an effort to enable advances in scientific excellence, improved quality and better regulatory compliance. Due to its length, the 2020 edition of this comprehensive White Paper has been divided into three parts for editorial reasons. This publication (Part 3) covers the recommendations on Vaccine, Gene/Cell Therapy, NAb Harmonization and Immunogenicity). Part 1 (Innovation in Small Molecules, Hybrid LBA/LCMS & Regulated Bioanalysis), Part 2A (BAV, PK LBA, Flow Cytometry Validation and Cytometry Innovation) and Part 2B (Regulatory Input) are published in volume 13 of Bioanalysis, issues 4 and 5 (2020), respectively.
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http://dx.doi.org/10.4155/bio-2021-0007DOI Listing
March 2021

2020 White Paper on Recent Issues in Bioanalysis: BAV Guidance, CLSI H62, Biotherapeutics Stability, Parallelism Testing, CyTOF and Regulatory Feedback ( - Recommendations on Biotherapeutics Stability, PK LBA Regulated Bioanalysis, Biomarkers Assays, Cytometry Validation & Innovation - Regulatory Agencies' Inputs on Bioanalysis, Biomarkers, Immunogenicity, Gene & Cell Therapy and Vaccine).

Bioanalysis 2021 Mar 29;13(5):295-361. Epub 2021 Jan 29.

Health Canada, Ottawa, ON, Canada.

The 14 edition of the Workshop on Recent Issues in Bioanalysis (14 WRIB) was held virtually on June 15-29, 2020 with an attendance of over 1000 representatives from pharmaceutical/biopharmaceutical companies, biotechnology companies, contract research organizations, and regulatory agencies worldwide. The 14 WRIB included three Main Workshops, seven Specialized Workshops that together spanned 11 days in order to allow exhaustive and thorough coverage of all major issues in bioanalysis, biomarkers, immunogenicity, gene therapy and vaccine. Moreover, a comprehensive vaccine assays track; an enhanced cytometry track and updated Industry/Regulators consensus on BMV of biotherapeutics by LCMS were special features in 2020. As in previous years, this year's WRIB continued to gather a wide diversity of international industry opinion leaders and regulatory authority experts working on both small and large molecules to facilitate sharing and discussions focused on improving quality, increasing regulatory compliance and achieving scientific excellence on bioanalytical issues. This 2020 White Paper encompasses recommendations emerging from the extensive discussions held during the workshop, and is aimed to provide the Global Bioanalytical Community with key information and practical solutions on topics and issues addressed, in an effort to enable advances in scientific excellence, improved quality and better regulatory compliance. Due to its length, the 2020 edition of this comprehensive White Paper has been divided into three parts for editorial reasons. This publication covers the recommendations on (Part 2A) BAV, PK LBA, Flow Cytometry Validation and Cytometry Innovation and (Part 2B) Regulatory Input. Part 1 (Innovation in Small Molecules, Hybrid LBA/LCMS & Regulated Bioanalysis), Part 3 (Vaccine, Gene/Cell Therapy, NAb Harmonization and Immunogenicity) are published in volume 13 of Bioanalysis, issues 4, and 6 (2021), respectively.
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http://dx.doi.org/10.4155/bio-2021-0005DOI Listing
March 2021

Characterization of Aggregated Antibody-Silicone Oil Complexes: From Perspectives of Morphology, 3D Image, and Fcγ Receptor Activation.

J Pharm Sci 2021 03 15;110(3):1189-1196. Epub 2020 Oct 15.

Division of Biological Chemistry and Biologicals, National Institute of Health Sciences, Kawasaki, Kanagawa 210-9501, Japan.

Pre-filled syringes (PFS) have been in widespread use as an administration device for therapeutic antibodies in recent decades. Generally, the inner barrel and syringe of PFS are coated with silicone oil (SO) for lubrication. Multiple studies have focused on the fact that the SO adsorbs denatured antibody molecules, and induces antibody aggregation. Aggregated antibodies are recognized as a potential risk for evoking immunogenic responses in patients. The characteristics of the aggregated antibody-SO complexes, including their concentration, population, shape, three-dimensional (3D) image, and Fcγ Receptors (FcγRs) activation have been obscurely acknowledged so far. In the present work, we prepared aggregated antibody-SO complexes by agitation and analyzed using multifaceted techniques such as flow imaging, confocal fluorescence microscopy, and cell-based assays for FcγRs activation. The results emphasized that the SO accelerates the increase in sub-visible particles and antibody aggregation. The confocal fluorescence microscopy analysis revealed the high-resolution 3D images of aggregated antibody-SO complexes. The FcγRs reporter cell assay clarified that the pre-mixed and agitated Ab + SO have higher FcγRs activation capability compared to the agitated Ab. Overall, this study advances the view that SO has an effect to increase the risk of agitation-induced aggregated antibody particles.
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http://dx.doi.org/10.1016/j.xphs.2020.10.022DOI Listing
March 2021

Establishment of a highly precise multi-attribute method for the characterization and quality control of therapeutic monoclonal antibodies.

Bioengineered 2020 12;11(1):984-1000

Division of Biological Chemistry and Biologicals, National Institute of Health Sciences , Kawasaki, Kanagawa, Japan.

The multi-attribute method (MAM) has garnered attention as a new quality control method of therapeutic monoclonal antibodies (mAbs). MAM analysis allows multiple relative quantifications of several structural attributes of therapeutic mAbs; however, some issues remain to be addressed in its procedures especially for sample preparation. The goal of this study was to optimize the sample preparation method for MAM analysis of mAbs. Using a model mAb, we compared five sample preparation methods based on sequence coverage, peptide redundancy, missed cleavage and chemical deamidation. It was found that low pH buffer and short digestion time reduced artificial deamidation. The desalting process after carboxymethylation was essential to obtaining high sequence coverage by a short digestion time. The generation of missed cleavage peptides was also improved by using a trypsin/lysyl endopeptidase (Lys-C) mixture. Next, we evaluated the usefulness of our method as a part of MAM analysis. Finally, 17 glycopeptides, 2 deamidated peptides and N- and C-terminal peptides of the heavy chain were successfully monitored with acceptable mass accuracy and coefficient of variation (CV, %) of the relative peak area. On the other hand, 4 oxidated peptides indicated the unavoidable slightly higher inter-assay CV (%) of the peak area ratio due to the instability in the MS sample solution. Collectively, we demonstrated that our method was applicable as an easy and reliable sample preparation method for MAM analysis, and the variation in the relative peak area could be influenced by the modification type rather than by the amount of each peptide.
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http://dx.doi.org/10.1080/21655979.2020.1814683DOI Listing
December 2020

Structural insight and stability of TNFR-Fc fusion protein (Etanercept) produced by using transgenic silkworms.

J Biochem 2021 Feb;169(1):25-33

Division of Biological Chemistry and Biologicals, National Institute of Health Sciences, 3-25-26, Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-9501, Japan.

Therapeutic proteins expressed using transgenic animals have been of great interest for several years. Especially, transgenic silkworm has been studied intensively because of its ease in handling, low-cost, high-yield and unique glycosylation patterns. However, the physicochemical property of the therapeutic protein expressed in transgenic silkworm remains elusive. Here, we constructed an expression system for the TNFR-Fc fusion protein (Etanercept) using transgenic silkworm. The TNFR-Fc fusion protein was employed to N-glycan analysis, which revealed an increased amount of afucosylated protein. Evidence from surface plasmon resonance analysis showed that the TNFR-Fc fusion protein exhibit increased binding affinity for Fcγ receptor IIIa and FcRn compared to the commercial Etanercept, emphasizing the profit of expression system using transgenic silkworm. We have further discussed the comparison of higher order structure, thermal stability and aggregation of the TNFR-Fc fusion protein.
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http://dx.doi.org/10.1093/jb/mvaa092DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7868081PMC
February 2021

[Role of the Japanese Pharmacopoeia in the Quality Assurance of Biologics].

Yakugaku Zasshi 2020 ;140(6):777-782

Division of Biological Chemistry and Biologicals, National Institute of Health Sciences.

Biologics listed in the Japanese Pharmacopoeia (JP) include drugs in which the active pharmaceutical ingredient is a peptide, protein, or polysaccharide. Biologics were previously manufactured by purification from biological sources, however, most recently developed products are manufactured using biotechnology such as genetic recombination and cell culture technologies. The JP provides useful information to ensure the quality of such products in the form of monographs, general test, and general information. A recent topic related to biologics is the adoption of general test 〈6.17〉 "Insoluble Particulate Matter Test for Protein Injections". Test 〈6.17〉 enables the determination of insoluble particulate matter using the light obscuration method with smaller sample volumes and indicates points to consider in handling protein samples. In addition, the draft general information "Basic Concept of Quality Assurance of Biotechnology Products (Biopharmaceuticals)" has been released for public consultation and will be listed in the 18th edition of the JP. In this review, the contents of JP monographs, general chapters, and general information on biologics are introduced, and future perspectives on the role of the JP for ensuring the quality of biologics are discussed.
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http://dx.doi.org/10.1248/yakushi.19-00253-5DOI Listing
September 2020

Highly sensitive HPLC analysis and biophysical characterization of N-glycans of IgG-Fc domain in comparison between CHO and 293 cells using FcγRIIIa ligand.

Biotechnol Prog 2020 11 6;36(6):e3016. Epub 2020 Jul 6.

School of Engineering, The University of Tokyo, Tokyo, Japan.

Quality control of monoclonal antibodies is challenging due in part to the diversity of post-translational modifications present. The regulation of the N-glycans of IgG-Fc domain is one of the key factors to maintain the safety and efficacy of antibody drugs. The FcγRIIIa affinity column is an attractive tool for the precise analysis of the N-glycans in IgG-Fc domain. We used the mutant FcγRIIIa, which is produced in Escherichia coli and is therefore not glycosylated, as an affinity reagent to analyze the N-glycans of monoclonal antibodies expressed in Expi293 and ExpiCHO cells. The monoclonal antibodies expressed in these cells showed very different chromatograms, because of differences in terminal galactose residues on the IgG-Fc domains. We also carried out kinetic and thermodynamic analyses to understand the interaction between monoclonal antibodies and the mutant FcγRIIIa. Expi293 cell-derived monoclonal antibodies had higher affinity for the mutant FcγRIIIa than those derived from ExpiCHO cells, due to slower off rates and lower binding entropy loss. Collectively, our results suggest that the FcγRIIIa column can be used to analyze the glycosylation of antibodies rapidly and specifically.
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http://dx.doi.org/10.1002/btpr.3016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7757244PMC
November 2020

Generic MS-based method for the bioanalysis of therapeutic monoclonal antibodies in nonclinical studies.

Bioanalysis 2020 Feb 24;12(4):231-243. Epub 2020 Feb 24.

Division of Biological Chemistry and Biologicals, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-9501, Japan.

A generic bioanalytical method was developed to quantify therapeutic IgG1 monoclonal antibodies (mAbs) in mouse sera by combining an easy sample preparation method with LC/MS using selected reaction monitoring. Rituximab and trastuzumab were used as model mAbs. A synthetic stable isotope-labeled peptide or a stable isotope-labeled mAb was used as an internal standard. The method feasibility was evaluated by a collaborative study involving six laboratories. The calibration curve ranged from 1.0 to 1000.0 μg/ml (correlation coefficient >0.99). The validation parameters including selectivity, linearity of calibration curve, accuracy and precision met the predefined acceptance criteria. Our method is a useful bioanalytical method for the quantification of therapeutic IgG mAbs in nonclinical animal studies.
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http://dx.doi.org/10.4155/bio-2019-0253DOI Listing
February 2020

Recent Achievements and Current Interests in Research on the Characterization and Quality Control of Biopharmaceuticals in Japan.

J Pharm Sci 2020 05 9;109(5):1652-1661. Epub 2020 Jan 9.

Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.

As reported in the previous commentary (Ishii-Watabe et al., J Pharm Sci 2017), the Japanese biopharmaceutical research group is promoting collaborative multilaboratory studies to evaluate and standardize new methodologies for biopharmaceutical characterization and quality control. We have conducted the studies and held 2 annual meetings in 2018 and 2019. At the 2018 meeting, Dr. Rukman DeSilva of the U.S. Food and Drug Administration and Dr. Srivalli Telikepalli of the National Institute of Standards and Technology participated as guest speakers. At the 2019 meeting, we invited Prof. John Carpenter of the University of Colorado, Prof. Gerhard Winter and Prof. Wolfgang Friess of Ludwig Maximilian University of Munich, and Dr. Tim Menzen of Coriolis Pharma Research, as guest commentators. In both meetings, the main research topic was strategies for the characterization and control of protein aggregates/subvisible particles in drug products. Specifically, the use of the light obscuration method for insoluble particulate matter testing with reduced injection volumes, and a comparison of analytical performance between flow imaging and light obscuration were discussed. Other topics addressed included host cell protein analysis, bioassay, and quality control strategies. In this commentary, the recent achievements of the research group, meeting discussions, and future perspectives are summarized.
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http://dx.doi.org/10.1016/j.xphs.2020.01.001DOI Listing
May 2020

Development of anti-drug monoclonal antibody panels against adalimumab and infliximab.

Biologicals 2020 Jan 27;63:39-47. Epub 2019 Dec 27.

Division of Biological Chemistry and Biologicals, National Institute of Health Sciences, Kanagawa, Japan.

The generation of anti-drug antibodies (ADAs) is one of the most serious problems in therapy using monoclonal antibodies (mAbs), because ADAs can impact the pharmacokinetics, efficacy, and safety of mAbs. It is therefore important to detect the generated ADAs in patients. For the appropriate detection of ADAs, methods that detect various types of ADAs (e.g., low- and high-affinity ADAs) are needed, but since there are no adequate reference preparations of ADAs relevant to human ADAs in most cases, it is difficult to determine whether or not the developed methods have enough analytical performance. Here, we developed human-rat chimeric ADA panels against the anti-TNF-α therapeutic antibodies infliximab and adalimumab. The developed ADA panels consist of 7 (for infliximab) and 11 (for adalimumab) ADAs with various binding characters, and most of the ADAs are neutralizing antibodies. Using these ADA panels, we compared the detectability of model methods, i.e., binding assays using SPR, BLI, and ECL, and a cell-based assay to detect neutralization activity. Since we obtained ADAs showing low and high responses with the various methods, the ADA panels we developed were shown to be useful for the development of ADA assays.
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http://dx.doi.org/10.1016/j.biologicals.2019.12.003DOI Listing
January 2020

2019 White Paper On Recent Issues in Bioanalysis: FDA BMV Guidance, ICH M10 BMV Guideline and Regulatory Inputs ( - Recommendations on 2018 FDA BMV Guidance, 2019 ICH M10 BMV Draft Guideline and Regulatory Agencies' Input on Bioanalysis, Biomarkers and Immunogenicity).

Bioanalysis 2019 Dec 9;11(23):2099-2132. Epub 2019 Dec 9.

US FDA, Silver Spring, MD, USA.

The 2019 13 Workshop on Recent Issues in Bioanalysis (WRIB) took place in New Orleans, LA on 1-5 April 2019 with an attendance of over 1000 representatives from pharmaceutical/biopharmaceutical companies, biotechnology companies, contract research organizations and regulatory agencies worldwide. WRIB was once again a 5-day, week-long event - a full immersion week of bioanalysis, biomarkers, immunogenicity and gene therapy. As usual, it was specifically designed to facilitate sharing, reviewing, discussing and agreeing on approaches to address the most current issues of interest including both small- and large-molecule bioanalysis involving LCMS, hybrid LBA/LCMS, LBA cell-based/flow cytometry assays and qPCR approaches. This 2019 White Paper encompasses recommendations emerging from the extensive discussions held during the workshop, and is aimed to provide the bioanalytical community with key information and practical solutions on topics and issues addressed, in an effort to enable advances in scientific excellence, improved quality and better regulatory compliance. Due to its length, the 2019 edition of this comprehensive White Paper has been divided into three parts for editorial reasons. This publication (Part 2) covers the recommendations on the 2018 FDA BMV guidance, 2019 ICH M10 BMV draft guideline and regulatory agencies' input on bioanalysis, biomarkers, immunogenicity and gene therapy. Part 1 (Innovation in small molecules and oligonucleotides and mass spectrometry method development strategies for large molecules bioanalysis) and Part 3 (New insights in biomarker assay validation, current and effective strategies for critical reagent management, flow cytometry validation in drug discovery and development and CLSI H62, interpretation of the 2019 FDA immunogenicity guidance and gene therapy bioanalytical challenges) are published in volume 10 of , issues 22 and 24 (2019), respectively.
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http://dx.doi.org/10.4155/bio-2019-0270DOI Listing
December 2019

Fcγ Receptor Activation by Human Monoclonal Antibody Aggregates.

J Pharm Sci 2020 01 30;109(1):576-583. Epub 2019 Oct 30.

Division of Biological Chemistry and Biologicals, National Institute of Health Sciences, Kawasaki, Kanagawa, Japan.

Protein aggregates are a potential risk factor for immunogenicity. The measurement, characterization, and control of protein aggregates in drug products are indispensable for the development of biopharmaceuticals, including therapeutic mAbs. In this study, Fcγ receptor (FcγR)-expressing reporter cell lines were used to analyze the FcγR-activation properties of mAb aggregates. Comparison of aggregates of mAbs harboring different IgG subclasses revealed that the FcγR-activation profiles of the mAb aggregates were dependent on IgG subclass. In addition, aggregates of Fc-engineered mAb with enhanced FcγR-activation properties exhibited stronger activation of FcγRs than was observed in the wild-type aggregates, whereas aggregates of Fc-engineered mAb with decreased FcγR-activation properties showed reduced activation. These results suggest that FcγR activation by mAb aggregates depends greatly on the Fc functions of the native (nonaggregated) mAbs. We also showed that aggregates of mAbs smaller than 1 μm in size have the potential to directly activate FcγRs. Unintended immune cell activation can be induced on account of FcγR activation by mAb aggregates and such FcγR activation may contribute to immunogenicity, and therefore, analysis of the FcγR-activation properties of mAb aggregates using FcγR-expressing reporter cell lines is a promising approach for the characterization of mAb aggregates.
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http://dx.doi.org/10.1016/j.xphs.2019.10.046DOI Listing
January 2020

Human-rat chimeric anti-occludin monoclonal antibodies inhibit hepatitis C virus infection.

Biochem Biophys Res Commun 2019 06 9;514(3):785-790. Epub 2019 May 9.

Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, Tokyo, 162-8640, Japan. Electronic address:

Occludin (OCLN), an integral tetra-spanning plasma membrane protein, is a host entry factor essential for hepatitis C virus (HCV) infection, making it a promising host-targeting molecule for HCV therapeutic intervention. We previously generated rat anti-OCLN monoclonal antibodies (mAbs) that strongly prevented HCV infection in vitro and in vivo. In the present study, we attempted to improve the druggability of the extracellular loop domain-recognizing anti-OCLN mAbs, namely clones 1-3 and 37-5, using genetic engineering. To avoid adverse reactions induced by antibody-dependent cellular cytotoxicity and enhance the antibody stability, we developed human-rat chimeric immunoglobulin G4 S228P mutant (IgG4m) forms of clones 1-3 and 37-5 (named Xi 1-3 and Xi 37-5, respectively) by grafting the variable regions of the light and heavy chains of each rat anti-OCLN mAb into those of human IgG4m. The constructed Xi 1-3 and Xi 37-5 chimeras demonstrated levels of affinity and specificity similar to each parental rat anti-OCLN mAb, and the Fcγ receptor Ⅲa was not activated by the antigen-bound chimeric mAbs, as expected. Both chimeric mAbs inhibited in vitro infection with various HCV genotypes. These results indicate that the IgG4m forms of human-rat chimeric anti-OCLN mAbs may be potential candidate molecules of host-targeting antivirals with pan-genotypic anti-HCV activity.
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http://dx.doi.org/10.1016/j.bbrc.2019.05.019DOI Listing
June 2019

Effects of terminal galactose residues in mannose α1-6 arm of Fc-glycan on the effector functions of therapeutic monoclonal antibodies.

MAbs 2019 07 8;11(5):826-836. Epub 2019 May 8.

a Division of Biological Chemistry and Biologicals , National Institute of Health Sciences , Kanagawa , Japan.

Typical crystallizable fragment (Fc) glycans attached to the CH2 domain in therapeutic monoclonal antibodies (mAbs) are core-fucosylated and asialo-biantennary complex-type glycans, e.g., G2F (full galactosylation), G1aF (terminal galactosylation on the Man α1-6 arm), G1bF (terminal galactosylation on the Man α1-3 arm), and G0F (non-galactosylation). Terminal galactose (Gal) residues of Fc-glycans are known to influence effector functions such as antibody-dependent cell-mediated cytotoxicity and complement-dependent cytotoxicity (CDC), but the impact of the G1F isomers (G1aF and G1bF) on the effector functions has not been reported. Here, we prepared four types of glycoengineered anti-CD20 mAbs bearing homogeneous G2F, G1aF, G1bF, or G0F (G2F mAb, G1aF mAb, G1bF mAb, or G0F mAb, respectively), and evaluated their biological activities. Interestingly, G1aF mAb showed higher C1q- and FcγR-binding activities, CDC activity, and FcγR-activation property than G1bF mAb. The activities of G1aF mAb and G1bF mAb were at the same level as G2F mAb and G0F mAb, respectively. Hydrogen-deuterium exchange/mass spectrometry analysis of dynamic structures of mAbs revealed the greater involvement of the terminal Gal residue on the Man α1-6 arm in the structural stability of the CH2 domain. Considering that mAbs interact with FcγR and C1q via their hinge proximal region in the CH2 domain, the structural stabilization of the CH2 domain by the terminal Gal residue on the Man α1-6 arm of Fc-glycans may be important for the effector functions of mAbs. To our knowledge, this is the first report showing the impact of G1F isomers on the effector functions and dynamic structure of mAbs. ABC, ammonium bicarbonate solution; ACN, acetonitrile; ADCC, antibody-dependent cell-mediated cytotoxicity; C1q, complement component 1q; CDC, complement-dependent cytotoxicity; CQA, critical quality attribute; Endo, endo-β--acetylglucosaminidase; FA, formic acid; Fc, crystallizable fragment; FcγR, Fcγ receptors; Fuc, fucose; Gal, galactose; GlcNAc, -acetylglucosamine; GST, glutathione S-transferase; HER2, human epidermal growth factor receptor 2; HDX, hydrogen-deuterium exchange; HILIC, hydrophilic interaction liquid chromatography; HLB-SPE, hydrophilic-lipophilic balance-solid-phase extraction; HPLC, high-performance liquid chromatography; mAb, monoclonal antibody; Man, mannose; MS, mass spectrometry; PBS, phosphate-buffered saline; SGP, hen egg yolk sialylglycopeptides.
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http://dx.doi.org/10.1080/19420862.2019.1608143DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6601563PMC
July 2019

Elucidation of the statistical factors that influence anti-drug antibody cut point setting through a multi-laboratory study.

Bioanalysis 2019 Mar 4;11(6):509-524. Epub 2019 Apr 4.

National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-9501, Japan.

Appropriateness of anti-drug antibody (ADA) assay is critical for immunogenicity assessment of biopharmaceuticals. Although cut point setting in ADA assay has a large impact on the results, a standard statistical approach for its setting has not been well established. In this multi-laboratory study, to elucidate factors influencing the cut point setting, we compared the statistical approaches and calculated cut points for multiple datasets of ADA assays using the individual procedure employed at each laboratory. We showed that outlier exclusion, false-positive rate and investigating data distribution have the greatest impact on both screening and confirmatory cut points. Our results would be useful for industry researchers and regulators engaged in immunogenicity assessment of biopharmaceuticals.
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http://dx.doi.org/10.4155/bio-2018-0178DOI Listing
March 2019

In-depth site-specific O-Glycosylation analysis of therapeutic Fc-fusion protein by electron-transfer/higher-energy collisional dissociation mass spectrometry.

Biologicals 2019 Mar 28;58:35-43. Epub 2019 Jan 28.

Division of Biological Chemistry and Biologicals, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa, 210-9501, Japan.

Unexpected O-glycosylations, including O-xylosylations and mucin-type O-glycosylations, have been reported in recent glycosylation analyses of Fc-fusion proteins produced in mammalian cell expression systems. This observation suggests that therapeutic proteins with novel structures can undergo unintended O-glycosylations, having implications regarding their efficacy and safety. Therefore, the implementation of O-glycosylation analysis during product developmental is essential. However, detail site-specific O-glycosylation analysis is difficult because no consensus sequence for mucin-type O-glycosylations is known, and O-glycopeptides often contain multiple or continuous glycosylation sites. Recently, a new mass spectrometric fragmentation method called electron-transfer/higher-energy collisional dissociation (EThcD) has been used for site-specific glycosylation analysis. In this study, we conducted site-specific O-glycosylation analysis of commercially available GLP1-Fc fusion protein with (G4S) linker peptide using liquid chromatography/mass spectrometry (LC/MS) with EThcD and a glycoproteomic database search. We successfully identified unexpected O-xylosylations at Ser residues in the (G4S) linker peptide, mucin-type O-glycosylations at Thr and Ser residues in the GLP-1 peptide, and Ser residues in the (G4S) linker peptide. This study is the first to report these unexpected O-xylosylations and mucin-type O-glycosylations in this therapeutic fusion protein. Mammalian-cell production of therapeutic fusion proteins that contain novel structures may require exhaustive O-glycosylation analysis to ensure their quality, efficacy, and safety.
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http://dx.doi.org/10.1016/j.biologicals.2019.01.005DOI Listing
March 2019

Biosimilarity assessment of biosimilar therapeutic monoclonal antibodies.

Drug Metab Pharmacokinet 2019 Feb 7;34(1):64-70. Epub 2018 Dec 7.

Yokohama University of Pharmacy, Japan.

The concept of biosimilar was established in the early 2000s in EU. Currently, the regulatory framework for biosimilar has also been established in the US, Japan, and other countries. As of 2018, biosimilars for infliximab, adalimumab, rituximab, trastuzumab, and bevacizumab have been approved. During the development of a biosimilar, product quality should be evaluated and compared with those of the reference product extensively. Among the quality attributes of therapeutic antibodies, FcRn binding and related structures are well known to affect the pharmacokinetic profile of the product. Other quality attributes such as antigen binding, glycan structure, and isoelectric point are considered to have a potential impact on the pharmacokinetic profile of the product. Based on the high similarity of the quality attributes of the biosimilar to those of its reference product, comparative non-clinical and clinical studies are conducted. Comparable pharmacokinetic profile of the biosimilar and the reference product is important for biosimilar evaluation. In this review, the basic concept of biosimilar development as well as pharmacokinetic data obtained via non-clinical and clinical studies of biosimilar therapeutic antibody is introduced, and future perspective is discussed.
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http://dx.doi.org/10.1016/j.dmpk.2018.11.004DOI Listing
February 2019

Interlaboratory comparison about feasibility of insoluble particulate matter test for injections with reduced test volume in light obscuration method.

Biologicals 2019 Jan 13;57:46-49. Epub 2018 Dec 13.

Division of Biological Chemistry and Biologicals, National Institute of Health Sciences, Tonomachi 3-25-26, Kawasaki-ku, Kanagawa, 210-9501, Japan.

Insoluble particulate matter test for injections in pharmacopoeia is mandatory for parenteral drug products. In this test using light obscuration, four measurements of at least 5-mL are required. Since therapeutic protein injections of low dosage volumes are getting more popular, reduction of test volumes is desired. In this collaborative study, the impact of lower measurement volume on the accuracy and precision of particle count was evaluated using 2, 5, 10, and 25-μm polystyrene count standards for the validity of test with reduced sample volumes. Good accuracy (3000 particles/mL ± 10%) was obtained at all measurement volumes, and the inter-run variability (RSD) was the same levels between 5 and 1 mL. Although the inter-run variability increased at 0.2 mL, it was below 5%. These results indicated that light obscuration method can be used with 5 mL-0.2 mL, and that it is feasible for monitoring particles ≥2 μm.
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http://dx.doi.org/10.1016/j.biologicals.2018.12.003DOI Listing
January 2019

A Cell-Based Reporter Assay Measuring the Activation of Fc Gamma Receptors Induced by Therapeutic Monoclonal Antibodies.

Methods Mol Biol 2019 ;1904:423-429

Division of Biological Chemistry and Biologicals, National Institute of Health Sciences, Kawasaki, Kanagawa, Japan.

Fc gamma receptors (FcγRs) are expressed on the surface of various immune cells, and the interactions between FcγRs and the Fc region of immunoglobulin G are involved in the activation of immune cells by antigen-bound antibodies. Fc-mediated immune-cell activations are related to both the efficacy and the safety of therapeutic monoclonal antibodies. It is indispensable to elucidate the Fc-mediated functions in the development of therapeutic monoclonal antibodies. Here, we describe a cell-based assay using FcγR-expressing reporter cell lines that can be used to evaluate the human FcγR-activation properties of therapeutic monoclonal antibodies by a rapid and simple procedure.
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http://dx.doi.org/10.1007/978-1-4939-8958-4_21DOI Listing
June 2019

[Site-specific O-Glycosylation Analysis of Therapeutic Fc-fusion Protein by Mass Spectrometry].

Yakugaku Zasshi 2018 ;138(12):1483-1494

Division of Biological Chemistry and Biologicals, National Institute of Health Sciences.

Therapeutic Fc-fusion proteins, created by linking bioactive peptides or receptor proteins to the Fc moiety of IgG, are currently being developed. In this development process, a Gly-Gly-Gly-Ser linker (G4S linker) is often used to link the peptide/protein and the Fc portion. O-xylose-type core glycans of glycosaminoglycan are known to attach to the Ser residue on the GSG motif in the G4S linker peptide repeats of the Fc fusion protein produced using the Chinese hamster ovary (CHO) cell expression system. In addition, a recent report demonstrated that unexpected mucin-type O-glycosylations occurred on a peptide in a bioactive peptide-Fc fusion protein; this glycosylation affected the bioactivity of the peptide. Therapeutic proteins with non-natural structures, such as Fc-fusion proteins, undergo unintended O-glycosylations; therefore, it is increasingly important to conduct detailed O-glycosylation analysis of fusion proteins during the developmental stages. In this paper, we have summarized recent reports on the unexpected O-glycosylation in fusion proteins, general O-glycosylation types and sequence motifs, and O-glycosylation analytical techniques involving O-linked oligosaccharide analysis and site-specific O-glycosylation analysis using LC/MS. In addition, we have introduced site-specific O-glycosylation analysis of Fc-fusion proteins with GS linker peptides by LC/MS using higher-energy collisional dissociation-tandem mass spectrometry (HCD-MS/MS) and electron-transfer dissociation (ETD)-MS/MS to obtain preferential dissociation of the peptide moiety in the glycopeptide.
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http://dx.doi.org/10.1248/yakushi.18-00020-2DOI Listing
February 2019

[Current Trends in Analytical Technologies Which Promote the Development of Biopharmaceuticals].

Yakugaku Zasshi 2018;138(12):1473-1474

Department of Biotechnology, Graduate School of Engineering, Osaka University.

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http://dx.doi.org/10.1248/yakushi.18-00020-FDOI Listing
April 2019

2018 White Paper on Recent Issues in Bioanalysis: focus on immunogenicity assays by hybrid LBA/LCMS and regulatory feedback (Part 2 - PK, PD & ADA assays by hybrid LBA/LCMS & regulatory agencies' inputs on bioanalysis, biomarkers and immunogenicity).

Bioanalysis 2018 Dec 29;10(23):1897-1917. Epub 2018 Nov 29.

F Hoffmann-La Roche, Basel, Switzerland.

The 2018 12 Workshop on Recent Issues in Bioanalysis took place in Philadelphia, PA, USA on April 9-13, 2018 with an attendance of over 900 representatives from pharmaceutical/biopharmaceutical companies, biotechnology companies, contract research organizations and regulatory agencies worldwide. WRIB was once again a 5-day, week-long event - a full immersion week of bioanalysis, biomarkers and immunogenicity. As usual, it was specifically designed to facilitate sharing, reviewing, discussing and agreeing on approaches to address the most current issues of interest including both small- and large-molecule bioanalysis involving LCMS, hybrid LBA/LCMS and LBA/cell-based assays approaches. This 2018 White Paper encompasses recommendations emerging from the extensive discussions held during the workshop and is aimed to provide the bioanalytical community with key information and practical solutions on topics and issues addressed, in an effort to enable advances in scientific excellence, improved quality and better regulatory compliance. Due to its length, the 2018 edition of this comprehensive White Paper has been divided into three parts for editorial reasons. This publication (Part 2) covers the recommendations for PK, PD and ADA assays by hybrid LBA/LCMS and regulatory agencies' input. Part 1 (LCMS for small molecules, peptides, oligonucleotides and small molecule biomarkers) and Part 3 (LBA/cell-based assays: immunogenicity, biomarkers and PK assays) are published in volume 10 of , issues 22 and 24 (2018), respectively.
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http://dx.doi.org/10.4155/bio-2018-0285DOI Listing
December 2018

2018 White Paper on Recent Issues in Bioanalysis: focus on flow cytometry, gene therapy, cut points and key clarifications on BAV (Part 3 - LBA/cell-based assays: immunogenicity, biomarkers and PK assays).

Bioanalysis 2018 Dec 29;10(24):1973-2001. Epub 2018 Nov 29.

Amador Bioscience, Pleasanton, CA, USA (formerly of OncoMed, Redwood City, CA, USA).

The 2018 12 Workshop on Recent Issues in Bioanalysis took place in Philadelphia, PA, USA on April 9-13, 2018 with an attendance of over 900 representatives from pharmaceutical/biopharmaceutical companies, biotechnology companies, contract research organizations and regulatory agencies worldwide. WRIB was once again a 5-day full immersion in bioanalysis, biomarkers and immunogenicity. As usual, it was specifically designed to facilitate sharing, reviewing, discussing and agreeing on approaches to address the most current issues of interest including both small- and large-molecule bioanalysis involving LCMS, hybrid LBA/LCMS and LBA/cell-based assays approaches. This 2018 White Paper encompasses recommendations emerging from the extensive discussions held during the workshop and is aimed to provide the bioanalytical community with key information and practical solutions on topics and issues addressed, in an effort to enable advances in scientific excellence, improved quality and better regulatory compliance. Due to its length, the 2018 edition of this comprehensive White Paper has been divided into three parts for editorial reasons. This publication (Part 3) covers the recommendations for large molecule bioanalysis, biomarkers and immunogenicity using LBA and cell-based assays. Part 1 (LCMS for small molecules, peptides, oligonucleotides and small molecule biomarkers) and Part 2 (hybrid LBA/LCMS for biotherapeutics and regulatory agencies' inputs) are published in volume 10 of , issues 22 and 23 (2018), respectively.
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http://dx.doi.org/10.4155/bio-2018-0287DOI Listing
December 2018

2018 White Paper on Recent Issues in Bioanalysis: 'A global bioanalytical community perspective on last decade of incurred samples reanalysis (ISR)' (Part 1 - small molecule regulated bioanalysis, small molecule biomarkers, peptides & oligonucleotide bioanalysis).

Bioanalysis 2018 Nov 29;10(22):1781-1801. Epub 2018 Nov 29.

UK MHRA, London, UK.

The 2018 12 Workshop on Recent Issues in Bioanalysis (12th WRIB) took place in Philadelphia, PA, USA on April 9-13, 2018 with an attendance of over 900 representatives from pharmaceutical/biopharmaceutical companies, biotechnology companies, contract research organizations and regulatory agencies worldwide. WRIB was once again a 5-day full immersion in bioanalysis, biomarkers and immunogenicity. As usual, it was specifically designed to facilitate sharing, reviewing, discussing and agreeing on approaches to address the most current issues of interest including both small- and large-molecule bioanalysis involving LC-MS, hybrid ligand binding assay (LBA)/LC-MS and LBA/cell-based assays approaches. This 2018 White Paper encompasses recommendations emerging from the extensive discussions held during the workshop, and is aimed to provide the bioanalytical community with key information and practical solutions on topics and issues addressed, in an effort to enable advances in scientific excellence, improved quality and better regulatory compliance. Due to its length, the 2018 edition of this comprehensive White Paper has been divided into three parts for editorial reasons. This publication (Part 1) covers the recommendations for LC-MS for small molecules, peptides, oligonucleotides and small molecule biomarkers. Part 2 (hybrid LBA/LC-MS for biotherapeutics and regulatory agencies' inputs) and Part 3 (large molecule bioanalysis, biomarkers and immunogenicity using LBA and cell-based assays) are published in volume 10 of Bioanalysis, issues 23 and 24 (2018), respectively.
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http://dx.doi.org/10.4155/bio-2018-0268DOI Listing
November 2018

Collaborative Study for Analysis of Subvisible Particles Using Flow Imaging and Light Obscuration: Experiences in Japanese Biopharmaceutical Consortium.

J Pharm Sci 2019 02 16;108(2):832-841. Epub 2018 Aug 16.

Division of Biological Chemistry and Biologicals, National Institute of Health Sciences, 3-25-26, Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-9501, Japan.

The evaluation of subvisible particles, including protein aggregates, in therapeutic protein products has been of great interest for both pharmaceutical manufacturers and regulatory agencies. To date, the flow imaging (FI) method has emerged as a powerful tool instead of light obscuration (LO) due to the fact that (1) protein aggregates contain highly transparent particles and thereby escape detection by LO and (2) FI provides detailed morphological characteristics of subvisible particles. However, the FI method has not yet been standardized nor listed in any compendium. In an attempt to assess the applicability of the standardization of the FI method, we conducted a collaborative study using FI and LO instruments in a Japanese biopharmaceutical consortium. Three types of subvisible particle preparations were shared across 12 laboratories and analyzed for their sizes and counts. The results were compared between the methods (FI and LO), inter-laboratories, and inter-instruments (Micro Flow Imaging and FlowCam). We clarified the marked difference between the detectability of FI and LO when counting highly transparent protein aggregates in the preparations. Although FlowCam provided a relatively higher number of particles compared with MFI, consistent results were obtained using the instrument from the same manufacturer in all 3 samples.
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http://dx.doi.org/10.1016/j.xphs.2018.08.006DOI Listing
February 2019

Effects of amino acid substitutions on the biological activity of anti-CD20 monoclonal antibody produced by transgenic silkworms (Bombyx mori).

Biochem Biophys Res Commun 2018 09 14;503(4):2633-2638. Epub 2018 Aug 14.

Division of Biological Chemistry and Biologicals, National Institute of Health Sciences, 3-25-26 Tonomachi Kawasaki-ku, Kawasaki, Kanagawa, 210-9501, Japan.

Recombinant monoclonal antibodies (mAbs) have been used in various therapeutic applications including cancer therapy. Fc-mediated effector functions play a pivotal role in the tumor-killing activities of some tumor-targeting mAbs, and Fc-engineering technologies with glyco-engineering or amino acid substitutions at the antibody Fc region have been used to enhance cytotoxic activities including antibody-dependent cellular cytotoxicity (ADCC). We previously reported that the mAbs produced using transgenic silkworms showed stronger ADCC activity and lower complement-dependent cytotoxicity (CDC) activity than mAbs derived from Chinese hamster ovary (CHO) cells due to their unique N-glycan structure (lack of core-fucose and non-reducing terminal galactose). In this study, we generated anti-CD20 mAbs with amino acid substitutions using transgenic silkworms and analyzed their biological activities to assess the effect of the combination of glyco-engineering and amino acid substitutions on the Fc-mediated function of mAbs. Three types of amino acid substitutions at the Fc region (G236A/S239D/I332E, L234A/L235A, and K326W/E333S) modified the Fc-mediated biological activities of silkworm-derived mAbs as in the case of CHO-derived mAbs, resulting in the generation of Fc-engineered mAbs with characteristic Fc-mediated functions. The combination of amino acid substitutions at the Fc region and glyco-engineering using transgenic silkworm made it possible to generate Fc-engineered mAbs with suitable Fc-mediated biological functions depending on the pharmacological mechanism of their actions. Transgenic silkworms were shown to be a promising system for the production of Fc-engineered mAbs.
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http://dx.doi.org/10.1016/j.bbrc.2018.08.015DOI Listing
September 2018

Collaborative study using common samples to evaluate the performance of anti-drug antibody assays constructed by different companies.

Drug Metab Pharmacokinet 2018 Apr 8;33(2):125-132. Epub 2018 Mar 8.

Division of Biological Chemistry and Biologicals, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku Kawasaki-shi, Kanagawa, 210-9501, Japan; Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan.

This study was undertaken to evaluate the performance of anti-drug antibody (ADA) assays constructed by each participating company using common samples including ADA, drug and human serum. The ADA assays constructed by each company showed good sensitivity and precision for evaluation of ADA. Cut points for screening and confirmatory assays and assay selectivity were determined by various calculation methods. In evaluations of blind ADA samples, nearly similar results were obtained by the study companies in determinations of whether samples were positive or negative except at the lowest sample concentration (5 ng/mL). In measurement of drug tolerance, for almost samples containing ADA and drugs, more positive results were obtained in assays using acid dissociation compared to those without acid dissociation. Overall, the performance of ADA assays constructed by the 10 companies participating in this study was acceptable in terms of sensitivity and reproducibility for detection and evaluation of immunogenicity in both patients and healthy subjects. On the other hand, based on results for samples containing ADA and drugs, validity of results for ADA assays conducted without acid dissociation was less meaningful and more difficult to evaluate. Thus, acid dissociation was confirmed to be useful for improving drug tolerance.
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http://dx.doi.org/10.1016/j.dmpk.2018.03.002DOI Listing
April 2018

Assessing the Heterogeneity of the Fc-Glycan of a Therapeutic Antibody Using an engineered FcγReceptor IIIa-Immobilized Column.

Sci Rep 2018 03 2;8(1):3955. Epub 2018 Mar 2.

Division of Biological Chemistry and Biologicals, National Institute of Health Sciences, Tokyo, 158-8501, Japan.

The N-glycan moiety of IgG-Fc has a significant impact on multifaceted properties of antibodies such as in their effector function, structure, and stability. Numerous studies have been devoted to understanding its biological effect since the exact composition of the Fc N-glycan modulates the magnitude of effector functions such as the antibody-dependent cell mediated cytotoxicity (ADCC), and the complement-dependent cytotoxicity (CDC). To date, systematic analyses of the properties and influence of glycan variants have been of great interest. Understanding the principles on how N-glycosylation modulates those properties is important for the molecular design, manufacturing, process optimization, and quality control of therapeutic antibodies. In this study, we have separated a model therapeutic antibody into three fractions according to the composition of the N-glycan by using a novel FcγRIIIa chromatography column. Notably, Fc galactosylation was a major factor influencing the affinity of IgG-Fc to the FcγRIIIa immobilized on the column. Each antibody fraction was employed for structural, biological, and physicochemical analysis, illustrating the mechanism by which galactose modulates the affinity to FcγRIIIa. In addition, we discuss the benefits of the FcγRIIIa chromatography column to assess the heterogeneity of the N-glycan.
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http://dx.doi.org/10.1038/s41598-018-22199-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5834517PMC
March 2018

Characterization of glycoengineered anti-HER2 monoclonal antibodies produced by using a silkworm-baculovirus expression system.

J Biochem 2018 Jun;163(6):481-488

Department of Bioengineering, School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan.

Silkworm-baculovirus expression systems are efficient means for the production of recombinant proteins that provide high expression levels and post-translational modifications. Here, we characterized the stability, glycosylation pattern and antibody-dependent cell-mediated cytotoxicity activity of anti-HER2 monoclonal antibodies containing native or glycoengineered mammalian-like N-glycans that were produced by using a silkworm-baculovirus expression system. Compared with a monoclonal antibody produced by using a Chinese hamster ovary cell expression system, the glycoengineered monoclonal antibody had comparable thermal stability and a higher antibody-dependent cell-mediated cytotoxicity activity. These results suggest that silkworm-baculovirus expression systems are next-generation expression systems potentially useful for the cost-effective production of therapeutic antibodies.
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http://dx.doi.org/10.1093/jb/mvy021DOI Listing
June 2018