Tokushima University / Educator and Researcher Directory --- Onitsuka, Masayoshi

Personal Web Page

https://researchmap.jp/biologics_onitsuka (researchmap)

Field of Study

○	Biochemical Engineering

Subject of Study

○	Production of biologics, Recombinant protein production, Protein Science (Bioprocess engineering, Cell engineering and design, protein engineering, Mammalian cells, Therapeutic antibody)

Book / Paper

Book:

1.	Masayoshi Onitsuka : アップストリームプロセスにおける抗体医薬品の凝集メカニズム∼宿主細胞や培養液では何が起こっているのか?∼, シーエムシーリサーチ, Nov. 2022.
2.	緒方法親, 松田朋子 and Masayoshi Onitsuka : CHO細胞と組換え抗体の不均一性∼細胞開発と培養プロセスについて∼, サイエンス&テクノロジー, Oct. 2022.
3.	Masayoshi Onitsuka : 抗体生産CHO細胞の培養プロセスにおける凝集化抗体の発生化機構と抑制への考察, Technical Information Institute Co., Ltd., Apr. 2021.
4.	Masayoshi Onitsuka : 培養プロセスにおける凝集形成と制御について ∼抗体生産CHO細胞を中心に∼, サイエンス&テクノロジー, Aug. 2019.
5.	Masayoshi Onitsuka and Takeshi Omasa : 第3編細胞構築・培地設計第4章ケミカルシャペロンを用いた蛋白質凝集防止培地の開発, 株式会社シーエムシー出版, Mar. 2015.
6.	Masayoshi Onitsuka and Takeshi Omasa : 第2節[7]細胞培養過程における抗体凝集抑制―ケミカルシャペロン:トレハロースの影響―, 情報技術協会, Apr. 2014.
7.	Masayoshi Onitsuka and Takeshi Omasa : 第3章動物細胞を用いた糖タンパク質医薬品生産―CHO細胞を中心にした糖鎖修飾制御, CMC Publishing Co.,Ltd., Nov. 2011.
8.	金昱東, Masayoshi Onitsuka and Takeshi Omasa : バイオシミラー生産における課題および今後の展開―主として細胞株構築，培養プロセス構築の観点から―, 情報機構, Jan. 2010.

Academic Paper (Judged Full Paper):

1.	Saeko Yanaka, Rina Yogo, Hirokazu Yagi, Masayoshi Onitsuka, Natsumi Wakaizumi, Yuki Yamaguchi, Susumu Uchiyama and Koichi Kato : Negative interference with antibody-dependent cellular cytotoxicity mediated by rituximab from its interactions with human serum proteins, Frontiers in Immunology, Vol.14, 2023. (Summary) Although interactions of small molecular drugs with serum proteins have been widely studied from pharmacokinetic and pharmacodynamic perspectives, there have been few reports on the effects of serum components on therapeutic antibody functions. This study reports the effect of abundant serum proteins on antibody-dependent cellular cytotoxicity (ADCC) mediated by rituximab and Fcγ receptor III (FcγRIII). Human serum albumin (HSA) and the Fab fragment from the pooled serum polyclonal IgG were found to compromise ADCC as non-competitive inhibitors. Our nuclear magnetic resonance data provided direct evidence for the interactions of HSA with both the Fab and Fc regions of rituximab and also with the extracellular region of FcγRIII (sFcγRIII). The degree of involvement in the interaction decreased in the order of rituximab-Fab > rituximab-Fc > sFcγRIII, suggesting preferential binding of HSA to net positively charged proteins. Although much less pronounced than the effect of HSA, polyclonal IgG-Fab specifically interacted with rituximab-Fc. The NMR data also showed that the serum protein interactions cover the Fc surface extensively, suggesting that they can act as pan-inhibitors against various Fc receptor-mediated functions and pharmacokinetics. Our findings highlight the importance of considering serum-protein interactions in the design and application of antibody-based drugs with increased efficacy and safety. (Keyword) Humans / Rituximab / Immunoglobulin G / Antibody-Dependent Cell Cytotoxicity / Receptors, Fc / Phagocytosis (Link to Publication Site) ● Publication site (DOI): 10.3389/fimmu.2023.1090898 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 36761774 ● Search Scopus @ Elsevier (PMID): 36761774 ● Search Scopus @ Elsevier (DOI): 10.3389/fimmu.2023.1090898 (DOI: 10.3389/fimmu.2023.1090898, PubMed: 36761774)
2.	Yuto Horii, Toshiki Iniwa, Masayoshi Onitsuka, Jun Tsukimoto, Yuki Tanaka, Hironobu Ike, Yuri Fukushi, Haruna Andoh, Yoshie Takeuchi, So-ichiro Nishioka, Daisuke Tsuji, Mariko Ikuo, Naoshi Yamazaki, Yoshiharu Takiguchi, Naozumi Ishimaru and Kouji Itou : Reversal of neuroinflammation in novel galactosialidosis model mice by single intracerebroventricular administration of CHO-derived human recombinant cathepsin A precursor protein., Molecular Therapy. Methods & Clinical Development, Vol.25, No.June, 297-310, 2022. (Tokushima University Institutional Repository) ● Metadata: 117739 (Link to Publication Site) ● Publication site (DOI): 10.1016/j.omtm.2022.04.001 (Link to Search Site for Scientific Articles) ● Search Scopus @ Elsevier (DOI): 10.1016/j.omtm.2022.04.001 (Tokushima University Institutional Repository: 117739, DOI: 10.1016/j.omtm.2022.04.001)
3.	Yukako Senga, Motomichi Doi, Masayoshi Onitsuka and Shinya Honda : Live-cell imaging to analyze intracellular aggregation of recombinant IgG in CHO cells., Cell Chemical Biology, Vol.29, No.1, 120-132, 2022. (Summary) Recombinant immunoglobulin G (IgG) aggregates are formed during their production. However, the process underlying intracellular/extracellular aggregation in cell culture conditions is not well understood, and no effective method exists to assess IgG aggregates. Here, we establish an approach to detect intracellular aggregates using AF.2A1, a small artificial protein that binds to non-native IgG conformers and aggregates. Fluorescent-labeled AF.2A1 is prepared via conjugation and transfected into antibody-producing Chinese hamster ovary (CHO) cells. Micrographic images show intracellular IgG aggregates in CHO cells. The relative amount of intracellular aggregates (versus total intracellular IgG) differed depending on the type of additives used during cell culture. Interestingly, the relative amount of intracellular aggregates moderately correlates with that of in vitro extracellular IgG aggregates, suggesting they are secreted. This method will allow the investigation of antibody aggregation in cells, and may guide the production of therapeutic antibodies with high yield/quality. (Keyword) Animals / CHO Cells / Cricetulus / Immunoglobulin G / Protein Aggregates / Protein Binding / Recombinant Proteins (Tokushima University Institutional Repository) ● Metadata: 117434 (Link to Publication Site) ● Publication site (DOI): 10.1016/j.chembiol.2021.08.010 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 34739851 ● Search Scopus @ Elsevier (PMID): 34739851 ● Search Scopus @ Elsevier (DOI): 10.1016/j.chembiol.2021.08.010 (Tokushima University Institutional Repository: 117434, DOI: 10.1016/j.chembiol.2021.08.010, PubMed: 34739851)
4.	Saeko Yanaka, Hirokazu Yagi, Rina Yogo, Masayoshi Onitsuka and Koichi Kato : Glutamine-free mammalian expression of recombinant glycoproteins with uniform isotope labeling: an application for NMR analysis of pharmaceutically relevant Fc glycoforms of human immunoglobulin G1, Journal of Biomolecular NMR, Vol.76, No.1-2, 17-22, 2022. (Summary) Mammalian cells are widely used for producing recombinant glycoproteins of pharmaceutical interest. However, a major drawback of using mammalian cells is the high production costs associated with uniformly isotope-labeled glycoproteins due to the large quantity of labeled L-glutamine required for their growth. To address this problem, we developed a cost-saving method for uniform isotope labeling by cultivating the mammalian cells under glutamine-free conditions, which was achieved by co-expression of glutamine synthase. We demonstrate the utility of this approach using fucosylated and non-fucosylated Fc glycoforms of human immunoglobulin G1. (Keyword) Animals / Glutamine / Glycoproteins / Humans / Immunoglobulins / Isotope Labeling / Mammals / Nuclear Magnetic Resonance, Biomolecular / Recombinant Proteins (Link to Publication Site) ● Publication site (DOI): 10.1007/s10858-021-00387-5 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 34978013 ● Search Scopus @ Elsevier (PMID): 34978013 ● Search Scopus @ Elsevier (DOI): 10.1007/s10858-021-00387-5 (DOI: 10.1007/s10858-021-00387-5, PubMed: 34978013)
5.	Hajime Enatsu, Nako Okamoto, Yoshiki Nomura, Masayoshi Onitsuka, Noriko Yamano-Adachi, Yuichi Koga and Takeshi Omasa : Production of monoclonal shark-derived immunoglobulin new antigen receptor antibodies using Chinese hamster ovary cell expression system, Journal of Bioscience and Bioengineering, Vol.132, No.3, 302-309, 2021. (Summary) Cartilaginous fishes such as sharks have adaptive immune systems based on immunoglobulins similar to those in mammals. During their evolution, cartilaginous fishes individually have acquired their adaptive immune system called immunoglobulin new antigen receptor (IgNARs). IgNARs maintain their functions in the harsh environment of shark serum, which contains a high concentration of urea to prevent water loss in seawater. Therefore, IgNARs have high structural stability, and are expected to be used as next-generation antibodies in applications different from those of conventional IgG antibodies. However, no recombinant expression system for IgNAR, which has a molecular weight of approximately 147 kDa as a dimer and multiple N-glycosylation sites, has yet been constructed. This has stalled research into IgNAR development. Here, we constructed a recombinant expression system for IgNAR using Chinese hamster ovary (CHO) cells, widely used as hosts for IgG antibody production. Using this system, IgNAR was successfully expressed and purified as a human IgG Fc fusion protein and showed antigen-binding ability. After Protein A affinity purification, followed by specific cleavage and removal of the human Fc-region, the final yield of IgNAR was 1.07 mg/L-medium. Moreover, this CHO cell expression system modified IgNAR with various N-glycans, including high-mannose and complex types. This expression system will allow us to analyze the structure, physicochemical properties, and biological functions of IgNAR. This fundamental information will advance the development of IgNARs for industrial and biotechnological applications. (Link to Publication Site) ● Publication site (DOI): 10.1016/j.jbiosc.2021.04.015 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 34119424 ● Search Scopus @ Elsevier (PMID): 34119424 ● Search Scopus @ Elsevier (DOI): 10.1016/j.jbiosc.2021.04.015 (DOI: 10.1016/j.jbiosc.2021.04.015, PubMed: 34119424)
6.	Kei Komatsu, Kento Kumon, Mayuno Arita, Masayoshi Onitsuka, Takeshi Omasa and Masafumi Yohda : Effect of the disulfide isomerase PDIa4 on the antibody production of Chinese hamster ovary cells., Journal of Bioscience and Bioengineering, Vol.130, No.6, 637-643, 2020. (Summary) Therapeutic monoclonal antibodies recognize and bind specific molecules on the surface of target cells, stimulating the immune system, which can attack these targeted cells. These antibodies are produced by mammalian cells, including Chinese hamster ovary (CHO) cells, because the formation of antibodies requires complicated posttranslational modifications, including peptidyl-prolyl cis/trans isomerization, disulfide bond formation, and glycosylation. Currently, it is thought that the efficient production of secretory proteins is limited by posttranslational processes. The ER is the biosynthesis site of all secreted and membrane proteins. The accumulation of unfolded proteins in the ER causes the ER stress response. During the ER stress state, various molecular chaperones are expressed to prevent proteins from the aggregate formation. The molecular chaperone involved in ER stress likely plays an essential role in the production of secretory proteins. The purpose of this study was to improve the production of monoclonal antibodies by cells. We elucidated the function of ER chaperones in the production of a monoclonal antibody. First, we quantitatively measured the mRNA expression levels of protein disulfide-isomerase family members. In CHO HcD6 cells treated with tunicamycin, the expression level of pdia4 was significantly increased. Second, we investigated the relationship between PDIa4 and antibody productivity in pdia4-knockdown cells. Both a decrease in the amount of secreted antibody and the accumulation of immature antibodies inside the cells were observed. Recombinant PDIa4 was able to refold the antibodies and Fabs. These results indicate that PDIa4 affects the production of monoclonal antibodies by catalyzing disulfide bond formation in these antibodies in CHO cells. (Keyword) Animals / Antibodies, Monoclonal / CHO Cells / Cricetinae / Cricetulus / Gene Expression Regulation, Enzymologic / Protein Disulfide-Isomerases / RNA, Messenger (Link to Publication Site) ● Publication site (DOI): 10.1016/j.jbiosc.2020.08.001 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 32878739 ● Summary page in Scopus @ Elsevier: 2-s2.0-85090018528 (DOI: 10.1016/j.jbiosc.2020.08.001, PubMed: 32878739, Elsevier: Scopus)
7.	Hirokazu Yagi, Saeko Yanaka, Rina Yogo, Akari Ikeda, Masayoshi Onitsuka, Toshio Yamazaki, Ttsuya Kato, Enoch Y. Park, Jun Yokoyama and Koichi Kato : Silkworm pupae function as efficient producers of recombinant glycoproteins with stable-isotope labeling., Biomolecules, Vol.10, No.11, 1482, 2020. (Summary) Baculovirus-infected silkworms are promising bioreactors for producing recombinant glycoproteins, including antibodies. Previously, we developed a method for isotope labeling of glycoproteins for nuclear magnetic resonance (NMR) studies using silkworm larvae reared on an artificial diet containing N-labeled yeast crude protein extract. Here, we further develop this method by introducing a technique for the expression of isotope-labeled glycoproteins by silkworm pupae, which has several potential advantages relative to larvae-based techniques in terms of production yield, ease of handling, and storage. Here, we fed fifth instar larvae an artificial diet with an optimized composition containing [methyl-C]methionine, leading to pupation. Nine-day-old pupae were then injected with recombinant nucleopolyhedrovirus (BmNPV) bacmid for expression of recombinant human immunoglobulin G (IgG). From the whole-body homogenates of pupae, 0.35 mg/pupa of IgG was harvested, which is a yield that is five times higher than can be obtained from larvae. Recombinant IgG, thus prepared, exhibited mainly three kinds of pauci-mannose-type oligosaccharides and had a C-enrichment ratio of approximately 80%. This enabled selective observation of NMR signals originating from the methionyl methyl group of IgG, confirming its conformational integrity. These data demonstrate the utility of silkworm pupae as factories for producing recombinant glycoproteins with amino-acid-selective isotope labeling. (Tokushima University Institutional Repository) ● Metadata: 115880 (Link to Publication Site) ● Publication site (DOI): 10.3390/biom10111482 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 33114581 ● Summary page in Scopus @ Elsevier: 2-s2.0-85094185161 (Tokushima University Institutional Repository: 115880, DOI: 10.3390/biom10111482, PubMed: 33114581, Elsevier: Scopus)
8.	Ryutaro Asano, Katsuhiro Hosokawa, Shintaro Taki, Shota Konno, Ippei Shimomura, Hiromi Ogata, Mai Okada, Kyoko Arai, Masayoshi Onitsuka, Takeshi Omasa, Takeshi Nakanishi, Mitsuo Umetsu and Izumi Kumagai : Build-up functionalization of anti-EGFR × anti-CD3 bispecific diabodies by integrating high-affinity mutants and functional molecular formats., Scientific Reports, Vol.10, 4913, 2020. (Summary) Designing non-natural antibody formats is a practical method for developing highly functional next-generation antibody drugs, particularly for improving the therapeutic efficacy of cancer treatments. One approach is constructing bispecific antibodies (bsAbs). We previously reported a functional humanized bispecific diabody (bsDb) that targeted epidermal growth factor receptor and CD3 (hEx3-Db). We enhanced its cytotoxicity by constructing an Fc fusion protein and rearranging order of the V domain. In this study, we created an additional functional bsAb, by integrating the molecular formats of bsAb and high-affinity mutants previously isolated by phage display in the form of Fv. Introducing the high-affinity mutations into bsDbs successfully increased their affinities and enhanced their cytotoxicity in vitro and in vivo. However, there were some limitations to affinity maturation of bsDb by integrating high-affinity Fv mutants, particularly in Fc-fused bsDb with intrinsic high affinity, because of their bivalency. The tetramers fractionated from the bsDb mutant exhibited the highest in vitro growth inhibition among the small bsAbs and was comparable to the in vivo anti-tumor effects of Fc-fused bsDbs. This molecule shows cost-efficient bacterial production and high therapeutic potential. (Keyword) Antibodies, Bispecific / Antineoplastic Agents, Immunological / CD3 Complex / Drug Design / ErbB Receptors / Mutation / Protein Binding / Protein Engineering / Recombinant Fusion Proteins / Structure-Activity Relationship (Tokushima University Institutional Repository) ● Metadata: 115833 (Link to Publication Site) ● Publication site (DOI): 10.1038/s41598-020-61840-3 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 32188928 ● Summary page in Scopus @ Elsevier: 2-s2.0-85082085940 (Tokushima University Institutional Repository: 115833, DOI: 10.1038/s41598-020-61840-3, PubMed: 32188928, Elsevier: Scopus)
9.	Rina Yogo, Yuki Yamaguchi, Hiroki Watanabe, Hirokazu Yagi, Tadashi Satoh, Mahito Nakanishi, Masayoshi Onitsuka, Takeshi Omasa, Mari Shimada, Takahiro Maruno, Tetsuo Torisu, Shio Watanabe, Daisuke Higo, Takayuki Uchihashi, Saeko Yanaka, Susumu Uchiyama and Koichi Kato : The Fab portion of immunoglobulin G contributes to its binding to Fcγ receptor III, Scientific Reports, Vol.9, No.1, 11957, 2019. (Summary) Most cells active in the immune system express receptors for antibodies which mediate a variety of defensive mechanisms. These receptors interact with the Fc portion of the antibody and are therefore collectively called Fc receptors. Here, using high-speed atomic force microscopy, we observe interactions of human, humanized, and mouse/human-chimeric immunoglobulin G1 (IgG1) antibodies and their cognate Fc receptor, FcγRIIIa. Our results demonstrate that not only Fc but also Fab positively contributes to the interaction with the receptor. Furthermore, hydrogen/deuterium exchange mass spectrometric analysis reveals that the Fab portion of IgG1 is directly involved in its interaction with FcγRIIIa, in addition to the canonical Fc-mediated interaction. By targeting the previously unidentified receptor-interaction sites in IgG-Fab, our findings could inspire therapeutic antibody engineering. (Tokushima University Institutional Repository) ● Metadata: 114953 (Link to Publication Site) ● Publication site (DOI): 10.1038/s41598-019-48323-w (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 31420591 ● Search Scopus @ Elsevier (PMID): 31420591 ● Search Scopus @ Elsevier (DOI): 10.1038/s41598-019-48323-w (Tokushima University Institutional Repository: 114953, DOI: 10.1038/s41598-019-48323-w, PubMed: 31420591)
10.	Noriko Yamano-Adachi, Norichika Ogata, Sho Tanaka, Masayoshi Onitsuka and Takeshi Omasa : Characterization of Chinese hamster ovary cells with disparate chromosome numbers: Reduction of the amount of mRNA relative to total protein, Journal of Bioscience and Bioengineering, Vol.129, No.1, 121-128, 2019. (Keyword) Aneuploidy / antibody / Chinese hamster ovary cell / Chromosomal aberration / Omics (Link to Publication Site) ● Publication site (DOI): 10.1016/j.jbiosc.2019.06.012 (Link to Search Site for Scientific Articles) ● Search Scopus @ Elsevier (DOI): 10.1016/j.jbiosc.2019.06.012 (DOI: 10.1016/j.jbiosc.2019.06.012)
11.	Masayoshi Onitsuka, Yukinori Kadoya and Takeshi Omasa : Secretory leakage of IgG1 aggregates from recombinant Chinese hamster ovary cells, Journal of Bioscience and Bioengineering, Vol.127, No.6, 752-757, 2019. (Summary) Aggregation of therapeutic antibodies is one of the most important issues to be resolved in manufacturing processes because of reduced efficacy and immunogenicity. Despite aggregation studies in vitro, little is known about the aggregation mechanism in cell culture processes. In this study, we investigated the process of aggregate formation of IgG1 antibodies during the culture of Chinese hamster ovary (CHO) cells to determine how aggregation occurs. A recombinant CHO cell line was cultivated in a bioreactor, and purified IgG1 from daily culture supernatants was analyzed by size exclusion chromatography. We found a linear correlation between the peak plots of IgG1 by-products, dimeric and aggregated IgG1, and integrated viable cell density, indicating that these by-products were secreted from CHO cells at a constant secretion rate. In addition, aggregate formation was not reproduced in pseudo-culture experiments, and the solution structures of intracellular and extracellular IgG1 aggregates were similar. These results support the concept of secretory leakage of IgG1 by-products. Secreted aggregates appeared to be in an alternatively folded state, which can pass through the protein quality control system in mammalian cells. (Link to Publication Site) ● Publication site (DOI): 10.1016/j.jbiosc.2018.11.015 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 30580968 ● Summary page in Scopus @ Elsevier: 2-s2.0-85058714330 (DOI: 10.1016/j.jbiosc.2018.11.015, PubMed: 30580968, Elsevier: Scopus)
12.	Kohei Kaneyoshi, Kouki Kuroda, Keiji Uchiyama, Masayoshi Onitsuka, Noriko Yamano-Adachi, Yuichi Koga and Takeshi Omasa : Secretion analysis of intracellular difficult-to-express immunoglobulin G (IgG) in Chinese hamster ovary (CHO) cells, Cytotechnology, Vol.71, No.1, 305-316, 2019. (Summary) The Chinese hamster ovary (CHO) cell line is the most widely used host cell for therapeutic antibody production. Although its productivity has been improved by various strategies to satisfy the growing global demand, some difficult-to-express (DTE) antibodies remain at low secretion levels. To improve the production of various therapeutic antibodies, it is necessary to determine possible rate-limiting steps in DTE antibody secretion in comparison with other high IgG producers. Here, we analyzed the protein secretion process in CHO cells producing the DTE immunoglobulin G (IgG) infliximab. The results from chase assays using a translation inhibitor revealed that infliximab secretion could be nearly completed within 2 h, at which time the cells still retained about 40% of heavy chains and 65% of light chains. Using fluorescent microscopy, we observed that these IgG chains remained in the endoplasmic reticulum and Golgi apparatus. The cells inefficiently form fully assembled heterodimer IgG by making LC aggregates, which may be the most serious bottleneck in the production of DTE infliximab compared with other IgG high producers. Our study could contribute to establish the common strategy for constructing DTE high-producer cells on the basis of rate-limiting step analysis. (Link to Publication Site) ● Publication site (DOI): 10.1007/s10616-018-0286-5 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 30637508 ● Summary page in Scopus @ Elsevier: 2-s2.0-85060048909 (DOI: 10.1007/s10616-018-0286-5, PubMed: 30637508, Elsevier: Scopus)
13.	Kohei Kaneyoshi, Keiji Uchiyama, Masayoshi Onitsuka, Noriko Yamano, Yuichi Koga and Takeshi Omasa : Analysis of intracellular IgG secretion in Chinese hamster ovary cells to improve IgG production., Journal of Bioscience and Bioengineering, Vol.127, No.1, 107-113, 2019. (Summary) The production of biopharmaceutical immunoglobulin G (IgG) using cultured mammalian cells, especially Chinese hamster ovary (CHO) cells is well established and has been markedly improved through the modification of cells and cell culture engineering technologies. The establishment of high-production cell lines remains a challenge. The intracellular secretion of IgG has been investigated to identify and solve the rate-limiting steps in antibody production. However, strategies that regulate the expression of proteins that are related to antibody secretory pathway have not consistently improved their production. In this study, key features and limitations of the antibody secretion process in recombinant CHO cells were analyzed to develop more efficient approaches for establishing high-production cells. By chase assay with protein translation inhibitors, IgG secretion reached a plateau when at least 20% of IgG remained in the cells. The secretion kinetics and retention ratio of IgG varied between IgG subclasses (two types of IgG1 and an IgG3 subclass). Immunofluorescent microscopy and size exclusion chromatography showed that the remaining intracellular IgG localized mainly within the endoplasmic reticulum (ER) and less with the cis-Golgi network, despite the formation of fully assembled IgG. These results show that remaining intracellular IgG is a target for enhancing antibody secretion, even in high-production CHO cells. (Link to Publication Site) ● Publication site (DOI): 10.1016/j.jbiosc.2018.06.018 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 30017708 ● Search Scopus @ Elsevier (PMID): 30017708 ● Search Scopus @ Elsevier (DOI): 10.1016/j.jbiosc.2018.06.018 (DOI: 10.1016/j.jbiosc.2018.06.018, PubMed: 30017708)
14.	Qing Tang, Masayoshi Onitsuka, Atsushi Tabata, Toshifumi Tomoyasu and Hideaki Nagamune : Construction of Anti-HER2 Recombinants as Targeting Modules for a Drug-delivery System Against HER2-positive Cells, Anticancer Research, Vol.38, No.7, 4319-4325, 2018. (Summary) Recombinant antibodies have been investigated and used in applications such as targeting modules of drug-delivery systems (DDS) against cancers. This study aimed to prepare recombinant antibodies against HER2, containing sortase A (SrtA) recognition sequence, that are applicable as targeting modules in DDS after linkage with the drug-carrier containing oligoglycine-acceptor peptide by SrtA transpeptidation. The recombinant trastuzumab fragment antibodies (scFvs and Fab) with the SrtA-recognition motif (LPXTG) at their C-terminal were constructed and expressed in Escherichia coli and Chinese hamster ovary (CHO) cells, respectively. The reactivity of the purified recombinant antibodies towards HER2-expressing cells was also evaluated via immunofluorescent staining. Fab demonstrated higher yield and purity and better reactivity towards HER2-expressing cells (HCT-15 and HeLa) when compared to scFvs. The CHO expression system possesses superior yield and purity when compared to the E. coli expression system with respect to the preparation of recombinant antibodies applicable in targeting modules for DDS (DDS-TM). Moreover, a Fab variant prepared in this study demonstrated the potential to be a DDS-TM against HER2-expressing cancer cells. (Keyword) drug delivery system / cancer therapy (Link to Publication Site) ● Publication site (DOI): 10.21873/anticanres.12731 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 29970568 ● Summary page in Scopus @ Elsevier: 2-s2.0-85049804969 (DOI: 10.21873/anticanres.12731, PubMed: 29970568, Elsevier: Scopus)
15.	Masayoshi Onitsuka, Yukie Kinoshita, Akitoshi Nishizawa, Tomomi Tsutsui and Takeshi Omasa : Enhanced IgG1 production by overexpression of nuclear factor kappa B inhibitor zeta (NFKBIZ) in Chinese hamster ovary cells, Cytotechnology, Vol.70, No.2, 675-685, 2018. (Summary) Several engineering strategies have been employed to improve the production of therapeutic recombinant proteins in Chinese hamster ovary (CHO) cell lines. We have focused on unfolded protein response-based engineering and reported that ATF4 overexpression increases protein production. In this study, transcriptome analysis of ATF4-overexpressed CHO cells was performed using high-coverage expression profiling, to search for another key factor contributing to recombinant protein production. We observed the upregulated expression of transcription factor, nuclear factor (NF)-kappa-B inhibitor zeta (NFKBIZ or Iκbζ), in ATF4-overexpressed cells. A total of 1917 bp of CHO NFKBIZ cDNA was cloned, and two stable cell lines overexpressing NFKBIZ were constructed. We investigated the effects of NFKBIZ on IgG1 production in CHO cells. Although the two stable cell lines, NFKBIZ-A and -B, had the opposite phenotypes in cell growth, the specific IgG1 production rate of both cell lines was enhanced by 1.2-1.4-fold. In the NFKBIZ-A cell line, the synergistic effect between enhanced viable cell density and improved specific IgG1 production rate brought about a large increase in the final IgG1 titer. Luciferase-based NF-κB signaling assay results suggest that altered p50/p50 signaling seems to be due to the opposite phenotypes in cell growth. No difference was observed in the translational levels and intracellular assembly states of IgG1 between mock and two NFKBIZ cell lines, indicating that the secretion machinery of correctly folded IgG1 was enhanced in NFKBIZ-overexpressing cell lines. (Keyword) High-coverage expression profiling (HiCEP) / NF-kappa B inhibitor zeta (NFKBIZ) / Antibody production / Chinese hamster ovary (CHO) cells (Link to Publication Site) ● Publication site (DOI): 10.1007/s10616-017-0170-8 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 29188404 ● Summary page in Scopus @ Elsevier: 2-s2.0-85035361000 (DOI: 10.1007/s10616-017-0170-8, PubMed: 29188404, Elsevier: Scopus)
16.	Noriko Yamano, Mai Takahashi, Haghparast Mohammad Ali Seyed, Masayoshi Onitsuka, Toshitaka Kumamoto, Jana Frank and Takeshi Omasa : Increased recombinant protein production owing to expanded opportunities for vector integration in high chromosome number Chinese hamster ovary cells, Journal of Bioscience and Bioengineering, Vol.122, No.2, 226-231, 2016. (Summary) Chromosomal instability is a characteristic of Chinese hamster ovary (CHO) cells. Cultures of these cells gradually develop heterogeneity even if established from a single cell clone. We isolated cells containing different numbers of chromosomes from a CHO-DG44-based human granulocyte-macrophage colony stimulating factor (hGM-CSF)-producing cell line and found that high chromosome number cells showed higher hGM-CSF productivity. Therefore, we focused on the relationship between chromosome aneuploidy of CHO cells and high recombinant protein-producing cell lines. Distribution and stability of chromosomes were examined in CHO-DG44 cells, and two cell lines expressing different numbers of chromosomes were isolated from the original CHO-DG44 cell line to investigate the effect of aneuploid cells on recombinant protein production. Both cell lines were stably transfected with a vector that expresses immunoglobulin G3 (IgG3), and specific antibody production rates were compared. Cells containing more than 30 chromosomes had higher specific antibody production rates than those with normal chromosome number. Single cell analysis of enhanced green fluorescent protein (Egfp)-gene transfected cells revealed that increased GFP expression was relative to the number of gene integration sites rather than the difference in chromosome numbers or vector locations. Our results suggest that CHO cells with high numbers of chromosomes contain more sites for vector integration, a characteristic that could be advantageous in biopharmaceutical production. (Link to Publication Site) ● Publication site (DOI): 10.1016/j.jbiosc.2016.01.002 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 26850366 ● Summary page in Scopus @ Elsevier: 2-s2.0-84956706908 (DOI: 10.1016/j.jbiosc.2016.01.002, PubMed: 26850366, Elsevier: Scopus)
17.	Bahadur Md Badsha, Hiroyuki Kurata, Masayoshi Onitsuka, Takushi Oga and Takeshi Omasa : Metabolic analysis of antibody producing Chinese hamster ovary cell culture under different stresses conditions., Journal of Bioscience and Bioengineering, 2016. (Summary) Chinese hamster ovary (CHO) cells are commonly used as the host cell lines concerning their ability to produce therapeutic proteins with complex post-translational modifications. In this study, we have investigated the time course extra- and intracellular metabolome data of the CHO-K1 cell line, under a control and stress conditions. The addition of NaCl and trehalose greatly suppressed cell growth, where the maximum viable cell density of NaCl and trehalose cultures were 2.2-fold and 2.8-fold less than that of a control culture. Contrariwise, the antibody production of both the NaCl and trehalose cultures was sustained for a longer time to surpass that of the control culture. The NaCl and trehalose cultures showed relatively similar dynamics of cell growth, antibody production, and substrate/product concentrations, while they indicated different dynamics from the control culture. The principal component analysis of extra- and intracellular metabolome dynamics indicated that their dynamic behaviors were consistent with biological functions. The qualitative pattern matching classification and hierarchical clustering analyses for the intracellular metabolome identified the metabolite clusters whose dynamic behaviors depend on NaCl and trehalose. The volcano plot revealed several reporter metabolites whose dynamics greatly change between in the NaCl and trehalose cultures. The elastic net identified some critical, intracellular metabolites that are distinct between the NaCl and trehalose. While a relatively small number of intracellular metabolites related to the cell growth, glucose, glutamine, lactate and ammonium ion concentrations, the mechanism of antibody production was suggested to be very complicated or not to be explained by elastic net regression analysis. (Link to Publication Site) ● Publication site (DOI): 10.1016/j.jbiosc.2015.12.013 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 26803706 ● Summary page in Scopus @ Elsevier: 2-s2.0-85027930962 (DOI: 10.1016/j.jbiosc.2015.12.013, PubMed: 26803706, Elsevier: Scopus)
18.	Rima Matsuyama, Tomomi Tsutsui, Ho Kyoung Lee, Masayoshi Onitsuka and Takeshi Omasa : Improved gene amplification by cell-cycle engineering combined with the Cre-loxP system in Chinese hamster ovary cells., Journal of Bioscience and Bioengineering, Vol.120, No.6, 701-708, 2015. (Summary) The dihydrofolate reductase gene amplification system is widely used in Chinese hamster ovary (CHO) cells for the industrial production of therapeutic proteins. To enhance the efficiency of conventional gene amplification systems, we previously presented a novel method using cell-cycle checkpoint engineering. Here, we constructed high-producing and stable cells by the conditional expression of mutant cell division cycle 25 homolog B (CDC25B) using the Cre-loxP system. A bispecific antibody-producing CHO DG44-derived cell line was transfected with floxed mutant CDC25B. After inducing gene amplification in the presence of 250 nM methotrexate, mutant CDC25B sequence was removed by Cre recombinase protein expression. Overexpression of the floxed mutant CDC25B significantly enhanced the efficiency of transgene amplification and productivity. Moreover, the specific production rate of the isolated clone CHO Cre-1 and Cre-2 were approximately 11-fold and 15-fold higher than that of mock-transfected clone CHO Mock-S. Chromosomal aneuploidy was increased by mutant CDC25B overexpression, but Cre-1 and Cre-2 did not show any changes in chromosome number during long-term cultivation, as is the case with CHO Mock-S. Our results suggest that high-producing and stable cells can be constructed by conditionally controlling a cell-cycle checkpoint integrated in conventional gene amplification systems. (Link to Publication Site) ● Publication site (DOI): 10.1016/j.jbiosc.2015.04.009 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 26108159 ● Search Scopus @ Elsevier (PMID): 26108159 ● Search Scopus @ Elsevier (DOI): 10.1016/j.jbiosc.2015.04.009 (DOI: 10.1016/j.jbiosc.2015.04.009, PubMed: 26108159)
19.	Akihiro Shirai, Masayoshi Onitsuka, Hideaki Maseda and Takeshi Omasa : Effect of polyphenols on reactive oxygen species production and cell growth of human dermal fibroblasts after irradiation with ultraviolet-A light, Biocontrol Science, Vol.20, No.1, 27-33, 2015. (Summary) Ultraviolet-A (UV-A) can damage microbes by generating reactive oxygen species (ROS), singlet oxygen, superoxides, hydrogen peroxide and hydroxyl radicals. These species readily react with lipids, proteins, DNA and other constituents of cells, leading to oxidative deterioration and the eventual death of the microbe. However, the oxidative ability of these reactive species also harms the viability of mammalian cells such as fibroblasts and keratinocytes, as they cause both acute and chronic damage, photo-aging, and photo-carcinogenesis. This study describes a UV-A treatment that does not affect the viability or growth of human neonate dermal fibroblasts, as determined by examining the post-irradiation cell density after the addition of polyphenols as antioxidants. The results demonstrate the possible wide applicability of UV-A sterilization. The potency of polyphenols for attenuating UV-A-induced ROS generation in cells was tested using (+)-catechin hydrate, (-)- epigallocatechin gallate hydrate, morin hydrate, quercetin hydrate and resveratrol. The lowest concentration of polyphenols required to reduce ROS by 50% in cells upon exposure to a dose of 15 J cm-2 was determined and defined as its IC50. Pre-treatment with morin hydrate at its IC50 allowed cells irradiated with 5.0 J cm-2 UV-A to recover to the level of the specific growth rate of cells incubated without UV-A irradiation. However, the growth rate of cells exposed to 15 J cm-2 UV-A irradiation was scarcely influenced by co-incubation with morin hydrate; this dose of UV-A also suppressed cell growthcompletely in the absence of morin hydrate, although co-incubation resulted in no decrease in cell viability. This study demonstrates the potential of polyphenols for protecting both the viability of cells and their ability to proliferate from damage caused by UV-A-irradiation. (Keyword) Polyphenol / Ultraviolet-A / Reactive oxygen species / Cell proliferation (Link to Publication Site) ● Publication site (DOI): 10.4265/bio.20.27 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 25817810 ● CiNii @ National Institute of Informatics (CRID): 1390282679440670976 ● Summary page in Scopus @ Elsevier: 2-s2.0-84926366827 (DOI: 10.4265/bio.20.27, PubMed: 25817810, CiNii: 1390282679440670976, Elsevier: Scopus)
20.	Masayoshi Onitsuka and Takeshi Omasa : Rapid evaluation of N-glycosylation status of antibodies with chemiluminescent lectin-binding assay., Journal of Bioscience and Bioengineering, Vol.120, No.1, 107-110, 2014. (Summary) We constructed an assay system for the rapid detection of the glycosylation status of antibodies with a chemiluminescence-based lectin-binding assay, and investigated the glycosylation dynamics during the culture of recombinant Chinese hamster ovary cells. This rapid detection system is applicable to the high-throughput evaluation of therapeutic glycoproteins. (Keyword) Animals / Antibodies / CHO Cells / Cricetulus / Glycoproteins / Glycosylation / Humans / Lectins / Luminescence / Luminescent Measurements / Protein Binding / Time Factors (Link to Publication Site) ● Publication site (DOI): 10.1016/j.jbiosc.2014.11.015 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 25548123 ● Search Scopus @ Elsevier (PMID): 25548123 ● Search Scopus @ Elsevier (DOI): 10.1016/j.jbiosc.2014.11.015 (DOI: 10.1016/j.jbiosc.2014.11.015, PubMed: 25548123)
21.	Ryutaro Asano, Ippei Shimomura, Shota Konno, Akiko Ito, Yosuke Masakari, Ryota Orimo, Shintaro Taki, Kyoko Arai, Hiromi Ogata, Mai Okada, Shozo Furumoto, Masayoshi Onitsuka, Takeshi Omasa, Hiroki Hayashi, Yu Katayose, Michiaki Unno, Toshio Kudo, Mitsuo Umetsu and Izumi Kumagai : Rearranging the domain order of a diabody-based IgG-like bispecific antibody enhances its antitumor activity and improves its degradation resistance and pharmacokinetics., mAbs, Vol.6, No.5, 1243-1254, 2014. (Summary) One approach to creating more beneficial therapeutic antibodies is to develop bispecific antibodies (bsAbs), particularly IgG-like formats with tetravalency, which may provide several advantages such as multivalent binding to each target antigen. Although the effects of configuration and antibody-fragment type on the function of IgG-like bsAbs have been studied, there have been only a few detailed studies of the influence of the variable fragment domain order. Here, we prepared four types of hEx3-scDb-Fc, IgG-like bsAbs, built from a single-chain hEx3-Db (humanized bispecific diabody [bsDb] that targets epidermal growth factor receptor and CD3), to investigate the influence of domain order and fusion manner on the function of a bsDb with an Fc fusion format. Higher cytotoxicities were observed with hEx3-scDb-Fcs with a variable light domain (VL)-variable heavy domain (VH) order (hEx3-scDb-Fc-LHs) compared with a VH-VL order, indicating that differences in the Fc fusion manner do not affect bsDb activity. In addition, flow cytometry suggested that the higher cytotoxicities of hEx3-scDb-Fc-LH may be attributable to structural superiority in cross-linking. Interestingly, enhanced degradation resistance and prolonged in vivo half-life were also observed with hEx3-scDb-Fc-LH. hEx3-scDb-Fc-LH and its IgG2 variant exhibited intense in vivo antitumor effects, suggesting that Fc-mediated effector functions are dispensable for effective anti-tumor activities, which may cause fewer side effects. Our results show that merely rearranging the domain order of IgG-like bsAbs can enhance not only their antitumor activity, but also their degradation resistance and in vivo half-life, and that hEx3-scDb-Fc-LHs are potent candidates for next-generation therapeutic antibodies. (Keyword) Animals / Antibodies, Bispecific / Antigens, CD3 / Antineoplastic Agents / Area Under Curve / Binding Sites / Cell Line, Tumor / Cell Proliferation / Cell Survival / Dose-Response Relationship, Drug / Female / Humans / Immunoglobulin G / Interferon-gamma / MCF-7 Cells / Mice, SCID / Neoplasms / Protein Binding / Receptor, Epidermal Growth Factor / Tumor Burden / Xenograft Model Antitumor Assays (Link to Publication Site) ● Publication site (DOI): 10.4161/mabs.29445 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 25517309 ● Search Scopus @ Elsevier (PMID): 25517309 ● Search Scopus @ Elsevier (DOI): 10.4161/mabs.29445 (DOI: 10.4161/mabs.29445, PubMed: 25517309)
22.	Masayoshi Onitsuka, Miki Tatsuzawa, Ryutaro Asano, Izumi Kumagai, Akihiro Shirai, Hideaki Maseda and Takeshi Omasa : Trehalose suppresses antibody aggregation during the culture of Chinese hamster ovary cells, Journal of Bioscience and Bioengineering, Vol.117, No.5, 632-638, 2014. (Summary) The aggregation of therapeutic antibodies during the manufacturing process is problematic because of the potential risks posed by the aggregates, such as an unexpected immune response. One of the hallmark effects of trehalose, a disaccharide consisting of two alpha-glucose units, is as a chemical chaperone with anti-aggregation activity. In this study, Chinese hamster ovary (CHO) cell line producing a diabody-type bispecific antibody were cultured in medium containing trehalose and the aggregation of the secreted proteins during the culture process was analyzed. An analysis of the various forms of the antibody (monomeric, dimeric, and large aggregates) showed that trehalose decreased the relative content of large aggregates by two thirds. The aggregation kinetics indicated that trehalose directly inhibited the polymerization and aggregation steps in a nucleation-dependent aggregation mechanism. Moreover, both specific and volumetric antibody production were increased in CHO cells cultured in trehalose-containing medium. Thus, the addition of trehalose to recombinant CHO cell cultures would offer a practical strategy for quality improvement in the production of therapeutic antibodies. (Keyword) Animals / Antibodies, Bispecific / Bioreactors / CHO Cells / Cricetinae / Cricetulus / Culture Media / Kinetics / Protein Binding / Trehalose (Link to Publication Site) ● Publication site (DOI): 10.1016/j.jbiosc.2013.10.022 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 24315529 ● CiNii @ National Institute of Informatics (CRID): 1522262180374430720 ● Summary page in Scopus @ Elsevier: 2-s2.0-84897055074 (DOI: 10.1016/j.jbiosc.2013.10.022, PubMed: 24315529, CiNii: 1522262180374430720, Elsevier: Scopus)
23.	Masayoshi Onitsuka, Akira Kawaguchi, Ryutaro Asano, Izumi Kumagai, Kohsuke Honda, Hisao Ohtake and Takeshi Omasa : Glycosylation analysis of an aggregated antibody produced by Chinese hamster ovary cells in bioreactor culture, Journal of Bioscience and Bioengineering, Vol.117, No.5, 639-644, 2014. (Summary) N-Glycosylation of therapeutic antibodies contributes not only to their biological function, but also to their stability and tendency to aggregate. Here, we investigated the impact of the glycosylation status of an aggregated antibody that accumulated during the bioreactor culture of Chinese hamster ovary cells. High-performance liquid chromatography analysis showed that there was no apparent difference in the glycosylation patterns of monomeric, dimeric, and large aggregated forms of the antibody. In contrast, lectin binding assays, which enable the total amounts of specific sugar residues to be detected, showed that both galactose and fucose residues in dimers and large aggregates were reduced to 70-80% of the amount in monomers. These results strongly suggest that the lack of N-linked oligosaccharides, a result of deglycosylation or aglycosylation, occurred in a proportion of the dimeric and large aggregated components. The present study demonstrates that glycosylation heterogeneities are a potential cause of antibody aggregation in cell culture of Chinese hamster ovary cells, and that the lack of N-glycosylation promotes the formation of dimers and finally results in large aggregates. (Keyword) Chinese hamster ovary cell / Cell culture / Antibody production / Antibody aggregation / Glycosylation heterogeneity / Bispecific diabody (Link to Publication Site) ● Publication site (DOI): 10.1016/j.jbiosc.2013.11.001 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 24326352 ● CiNii @ National Institute of Informatics (CRID): 1521980705029265664 ● Summary page in Scopus @ Elsevier: 2-s2.0-84897065464 (DOI: 10.1016/j.jbiosc.2013.11.001, PubMed: 24326352, CiNii: 1521980705029265664, Elsevier: Scopus)
24.	Lee Ho Kyoung, Masayoshi Onitsuka, Kohsuke Honda, Hisao Ohtake and Takeshi Omasa : Rapid construction of transgene-amplified CHO cell lines by cell cycle checkpoint engineering, Applied Microbiology and Biotechnology, Vol.97, No.13, 5731-5741, 2013. (Summary) The process of establishing high-producing cell lines for the manufacture of therapeutic proteins is usually both time-consuming and laborious due to the low probability of obtaining high-producing clones from a pool of transfected cells and slow cell growth under the strong selective pressure of screening to identify high-producing clones. We present a novel method to rapidly generate more high-producing cells by accelerating transgene amplification. A small interfering RNA (siRNA) expression vector against ataxia telangiectasia and Rad3 related (ATR), a cell cycle checkpoint kinase, was transfected into Chinese hamster ovary (CHO) cells. The influences of ATR downregulation on gene amplification and the productivity were investigated in CHO cells producing green fluorescent protein (GFP) and secreting monoclonal antibody (mAb). The ATR-downregulated cells showed up to a 6-fold higher ratio of GFP-positive cells than that of the control cell pool. Moreover, the downregulated mAb-producing cells had about a 4-fold higher specific production rate and a 3-fold higher volumetric productivity as compared with the mock cells. ATR-downregulated cells showed a much faster increase in transgene copy numbers during the gene amplification process via methotrexate (MTX) treatment in both GFP- and mAb-producing cells. Our results suggest that a pool of high-producing cells can be more rapidly generated by ATR downregulation as compared with conventional gene amplification by MTX treatment. This novel method may be a promising approach to reduce time and labor in the process of cell line development. (Keyword) Animals / biotechnology / CHO Cells / Cell Cycle Checkpoints / Cell Cycle Proteins / Cricetulus / gene expression / Gene Silencing / Genes, Reporter / genetic engineering / Green Fluorescent Proteins / Molecular Sequence Data / Recombinant Proteins / Sequence Analysis, DNA / Transgenes (Link to Publication Site) ● Publication site (DOI): 10.1007/s00253-013-4923-9 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 23615744 ● Summary page in Scopus @ Elsevier: 2-s2.0-84879418366 (DOI: 10.1007/s00253-013-4923-9, PubMed: 23615744, Elsevier: Scopus)
25.	Masayoshi Onitsuka, Wook-Dong Kim, H. Ozaki, Akira Kawaguchi, Kohsuke Honda, H. Kajiura, K. Fujiyama, Ryutaro Asano, Izumi Kumagai, Hisao Ohtake and Takeshi Omasa : Enhancement of sialylation on humanized lgG-like bispecific antibody by overexpression of 2,6-sialyltransferase derived from Chainese hamster ovary cells, Applied Microbiology and Biotechnology, Vol.94, No.1, 69-80, 2012. (Summary) Improvement of glycosylation is one of the most important topics in the industrial production of therapeutic antibodies. We have focused on terminal sialylation with alpha-2,6 linkage, which is crucial for anti-inflammatory activity. In the present study, we have successfully cloned cDNA of beta-galactosyl alpha-2,6 sialyltransferase (ST6Gal I) derived from Chinese hamster ovary (CHO) cells regardless of reports that stated this was not endogenously expressed in CHO cells. After expressing cloned ST6Gal I in Escherichia coli, the transferase activity was confirmed by HPLC and lectin binding assay. Then, we applied ST6Gal I to alpha-2,6 sialylation of the recombinant antibody; the ST6Gal I expression vector was transfected into the CHO cell line producing a bispecific antibody. The N-glycosylation pattern of the antibody was estimated by HPLC and sialidase digestion. About 70% of the total N-linked oligosaccharide was alpha-2,6 sialylated in the transfected cell line whereas no sialylation was observed in the non-transfected cell line. The improvement of sialylation would be of practical importance for the industrial production of therapeutic antibodies. (Keyword) Animals / Antibodies, Bispecific / Antibodies, Monoclonal, Humanized / CHO Cells / Cricetinae / Escherichia coli / Female / Gene Expression / Humans / Immunoglobulin G / Ovary / Recombinant Proteins / Sialyltransferases / Up-Regulation (Link to Publication Site) ● Publication site (DOI): 10.1007/s00253-011-3814-1 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 22205442 ● Search Scopus @ Elsevier (PMID): 22205442 ● Search Scopus @ Elsevier (DOI): 10.1007/s00253-011-3814-1 (DOI: 10.1007/s00253-011-3814-1, PubMed: 22205442)

Academic Paper (Unrefereed Paper):

1.	YuanShan Lai, Noriko Yamano, Masayoshi Onitsuka and Takeshi Omasa : Increased antibody productivity in Chinese Hamster Ovary cells through induction of chromosomal instability by cell fusion, BMC Proceedings, Vol.9, No.Supplement 9, P11, 2015. (Link to Publication Site) ● Publication site (DOI): 10.1186/1753-6561-9-S9-P11 (Link to Search Site for Scientific Articles) ● Search Scopus @ Elsevier (DOI): 10.1186/1753-6561-9-S9-P11 (DOI: 10.1186/1753-6561-9-S9-P11)
2.	Marina Aga, Noriko Yamano, Toshitaka Kumamoto, Jana Frank, Masayoshi Onitsuka and Takeshi Omasa : Construction of a gene knockout CHO cell line using a simple gene targeting method, BMC Proceedings, Vol.9, No.Supplement 9, P2, 2015. (Link to Publication Site) ● Publication site (DOI): 10.1186/1753-6561-9-S9-P2 (Link to Search Site for Scientific Articles) ● Search Scopus @ Elsevier (DOI): 10.1186/1753-6561-9-S9-P2 (DOI: 10.1186/1753-6561-9-S9-P2)
3.	Noriko Yamano, Toshitaka Kumamoto, Mai Takahashi, Jana Frank, Masayoshi Onitsuka and Takeshi Omasa : Stability difference of each chromosome in Chinese Hamster Ovary cell line, BMC Proceedings, Vol.9, No.Supplement 9, P1, 2015. (Link to Publication Site) ● Publication site (DOI): 10.1186/1753-6561-9-S9-P1 (Link to Search Site for Scientific Articles) ● Search Scopus @ Elsevier (DOI): 10.1186/1753-6561-9-S9-P1 (DOI: 10.1186/1753-6561-9-S9-P1)

Review, Commentary:

1.	Masayoshi Onitsuka, 緒方法親 and 田地野浩司 : 「合理的」な抗体生産CHO細胞構築への挑戦, Seibutsu-kogaku Kaishi, Vol.97, No.6, 331-334, Jun. 2019. (Link to Search Site for Scientific Articles) ● CiNii @ National Institute of Informatics (CRID): 1520009409542319488 (CiNii: 1520009409542319488)
2.	Masayoshi Onitsuka, Akihiro Shirai and Takeshi Omasa : 糖タンパク質生産における翻訳後プロセスの解明と制御(バイオ医薬製造技術シリーズ), PHARM TECH JAPAN, Vol.28, No.5, 73-78, Apr. 2012.
3.	曹溢華, 木村修一, Masayoshi Onitsuka and Takeshi Omasa : 生産細胞の品質保証について考える-はたしてゲノム解析はパンドラの匣か-, PHARM TECH JAPAN, Vol.26, No.13, 95-102, Dec. 2010. (Keyword) バイオ医薬製造技術シリーズ
4.	Takeshi Omasa, Masayoshi Onitsuka and Wook-Dong Kim : Cell engineering and cultivation of Chinese hamster ovary (CHO) cells, Current Pharmaceutical Biotechnology, Vol.11, No.3, 232-240, Apr. 2010. (Summary) Mammalian cell lines are important host cells for the industrial production of pharmaceutical proteins owing to their capacity for correct folding, assembly and post-translational modification. In particular, Chinese hamster ovary (CHO) cells are the most dependable host cells for the industrial production of therapeutic proteins. Growing demand for therapeutic proteins promotes the development of technologies for high quality and productivity in CHO expression systems. The following are fundamentally important for effective production. 1) Construction of cultivation process. The CHO-based cultivation process is well established and is a general platform of therapeutic antibody production. The cost of therapeutic protein production using CHO cells is equivalent to that using microbial culture. 2) Cell line development. Recent developments in omics technologies have been essential for the development of rational methods of constructing a cell line. 3) Cell engineering for post-translational steps. Improvement of secretion, folding and glycosylaiton is an important key issue for mammalian cell production systems. This review provides an overview of the industrial production of therapeutic proteins using a CHO cell expression system. (Keyword) Animals / CHO Cells / Cell Culture Techniques / Cricetinae / Cricetulus / Protein Engineering / Protein Folding / Recombinant Proteins (Link to Publication Site) ● Publication site (DOI): 10.2174/138920110791111960 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 20210750 ● Search Scopus @ Elsevier (PMID): 20210750 ● Search Scopus @ Elsevier (DOI): 10.2174/138920110791111960 (DOI: 10.2174/138920110791111960, PubMed: 20210750)

Proceeding of International Conference:

1.	Masayoshi Onitsuka : Non-Natively Structured Antibodies in CHO bioprocessing, The 36th Annual and International Meeting of Japanese Association for Animal Cell Technology (JAACT), Nagoya, Japan, Nov. 2023.
2.	Fukuma Nanako, Yamauchi Seiji, Tajino Koji and Masayoshi Onitsuka : Development of CHO cells Haboring Production Enhancer Genes (PEGs), The 36th Annual and International Meeting of Japanese Association for Animal Cell Technology (JAACT), Nagoya, Japan, Nov. 2023.
3.	Okamoto Muneyoshi, Kato Hiroaki, Shibuya Keisuke, Amo Hiroe and Masayoshi Onitsuka : Assessing the Impact of Cell Culture Condition on Recombinant Antibody Production in CHO Perfusion Culture, The 36th Annual and International Meeting of Japanese Association for Animal Cell Technology (JAACT), Nagoya, Japan, Nov. 2023.
4.	Kohta Satoh, Hiroe Amou, Atsuko Shimazu and Masayoshi Onitsuka : Improved Terminal Galactosylation of Recombinant Antibody by Extracellular Glycosylation Reaction, The 33rd Annual and International Meeting of Japanese Association for Animal Cell Technology (JAACT), Fuchu, Japan, Nov. 2020.
5.	Yuika Hirata, Hiroe Amou, Atsuko Shimazu and Masayoshi Onitsuka : Rapid Identification of Production Enhancer Gene (PEG) for Recombinant Antibody Production in CHO cells, The 33rd Annual and International Meeting of Japanese Association for Animal Cell Technology (JAACT), Fuchu, Japan, Nov. 2020.
6.	Masayoshi Onitsuka and Atsuko Shimazu : Benchmark Study of Commercially Available Serum-free Media for CHO Cell Culture, The 33rd Annual and International Meeting of Japanese Association for Animal Cell Technology (JAACT), Fuchu, Japan, Nov. 2020.
7.	Masayoshi Onitsuka, Atsuko Shimazu and Hiroe Amou : Extracellular glycosylation for therapeutic antibody production with improved glycoforms, The 31st Annual and International Meeting of the Japanese Association for Animal Cell Technology, Nov. 2018.
8.	Tang Qing, Masayoshi Onitsuka, Atsushi Tabata, Toshifumi Tomoyasu and Hideaki Nagamune : Characterizatio of anti-HER2 scFv and Fab as a targeting module for novel drug-delivery system against HER2-positive cancer, 24th IUBMB congress & 15th FAOBMB congress, Seoul, Korea, Jun. 2018.
9.	K Kaneyoshi, Keiji Uchiyama, Masayoshi Onitsuka, Noriko Yamano, Y Koga and Takeshi Omasa : Intracellular secretion analysis of recombinant therapeutic antibodies in engineered CHO cells aiming to establish high produce., The 25th Meeting of the European Society for Animal Cell Technology (ESACT2017), May 2017.
10.	W. Tanaka, K. Yoshitomi, Noriko Yamano, Masayoshi Onitsuka, Y. Koga and Takeshi Omasa : ENHANCEMENT OF ANTIBODY PRODUCTIVITY IN RECOMBINANT CHO CELLS CONSTRUCTED BY TARGETING THE IGG1 GENE TO THE STABLE CHROMOSOME, The 25th Meeting of the European Society for Animal Cell Technology (ESACT) 2017, Lausanne, Switzerland, May 2017.
11.	Noriko Yamano, S. Tanaka, N. Ogata, Masayoshi Onitsuka, Y. Koga and Takeshi Omasa : CHARACTERIZATION OF ANTIBODY-PRODUCING CHO CELLS WITH CHROMOSOME ANEUPLOIDY, The 25th Meeting of the European Society for Animal Cell Technology (ESACT) 2017, Lausanne, Switzerland, May 2017.
12.	Masayoshi Onitsuka, Y. Fujino, N. Kawamura and Takeshi Omasa : CONSTRUCTION OF A SYSTEM FOR RAPID EVALUATION OF PRODUCTION ENHANCER GENE IN CHO ANTIBODY PRODUCTION, The 25th Meeting of the European Society for Animal Cell Technology (ESACT) 2017, Lausanne, Switzerland, May 2017.
13.	K. Kaneyoshi, K. Uchiyama, Masayoshi Onitsuka, Noriko Yamano, Y. Koga and Takeshi Omasa : INTRACELLULAR SECRETION ANALYSIS OF RECOMBINANT THERAPEUTIC ANTIBODIES IN ENGINEERED CHO CELLS AIMING TO ESTABLISH HIGH PRODUCER, The 25th Meeting of the European Society for Animal Cell Technology (ESACT) 2017, Lausanne, Switzerland, May 2017.
14.	Masayoshi Onitsuka and Takeshi Omasa : Dynamical Analysis of Aggregate Accumulation of IgG1 in recombinant CHO cell Culture, The 29th Annual and International Meeting of the Japanese Association for Animal Cell Technology (JAACT2016 Kobe), Nov. 2016.
15.	Jana Frank, Masayoshi Onitsuka, Noriko Yamano and Takeshi Omasa : Improved protein production of Chinese hamster ovary DG44 cells treated with aphidicolin, The 29th Annual and International Meeting of the Japanese Association for Animal Cell Technology (JAACT2016 Kobe), Nov. 2016.
16.	Yoshiki Nomura, Masayoshi Onitsuka, Noriko Yamano, Yuichi Koga and Takeshi Omasa : Secretory expression of Immunoglobulin New Antigen Receptor in Chinese Hamster Ovary cells, The 29th Annual and International Meeting of the Japanese Association for Animal Cell Technology (JAACT2016 Kobe), Kobe, Nov. 2016.
17.	Ryonosuke Harata, Masayoshi Onitsuka, Takahiro Kikawada, Shizuyo Koide, Noriko Yamano, Yuichi Koga and Takeshi Omasa : Suppressed antibody aggregation and improved cell growth by exogenous expression of Tret1 in recombinant CHO cells, The 29th Annual and International Meeting of the Japanese Association for Animal Cell Technology (JAACT2016 Kobe), Kobe, Nov. 2016.
18.	Kota Yoshitomi, Noriko Yamano, Wataru Tanaka, Masayoshi Onitsuka, Yuichi Koga and Takeshi Omasa : Improved antibody productivities of CHO cells constructed by targeting gene-rich chromosomal regions on the stable chromosome, The 29th Annual and International Meeting of the Japanese Association for Animal Cell Technology (JAACT2016 Kobe), Kobe, Nov. 2016.
19.	Sho Tanaka, Noriko Yamano, Norichika Ogata, Masayoshi Onitsuka, Yuichi Koga and Takeshi Omasa : Genome-wide analysis of gene expression in antibody-producing CHO cells with chromosome aneuploidy, The 29th Annual and International Meeting of the Japanese Association for Animal Cell Technology (JAACT2016 Kobe), Kobe, Nov. 2016.
20.	Kohei Kaneyoshi, Keiji Uchiyama, Masayoshi Onitsuka, Noriko Yamano, Yuichi Koga and Takeshi Omasa : Analysis of intracellular recombinant IgG secretion in engineered CHO cells, The 29th Annual and International Meeting of the Japanese Association for Animal Cell Technology (JAACT2016 Kobe), Nov. 2016.
21.	Takeshi Omasa and Masayoshi Onitsuka : Metabolic analysis of antibody-producing Chinese hamster ovary cell culture suppressing antibody aggregation, Metabolic Engineering 11, Jun. 2016.
22.	Takeshi Omasa, Noriko Yamano and Masayoshi Onitsuka : Mammalian cell factory- CHO cell and its application for biopharmaceutical production, World Congress on In Vitro Biology, Jun. 2016.
23.	Takeshi Omasa, Rima Matsuyama, Tomomi Tsutsui, Kyoungho Lee, Noriko Yamano and Masayoshi Onitsuka : Cre-loxP-controlled cell-cycle checkpoint engineering in Chinese Hamster ovary cells, Cell Culture Engineering XV, May 2016.
24.	Noriko Yamano, Toshitaka Kumamoto, Kota Yoshitomi, Jana Frank, Masayoshi Onitsuka and Takeshi Omasa : Varied productivity according to the differences between targeted locations of antibody expression vectors in Chinese Hamster ovary cells, Cell Culture Engineering XV, May 2016.
25.	Marina Aga, Noriko Yamano, Toshitaka Kumamoto, Jana Frank, Masayoshi Onitsuka and Takeshi Omasa : Construction of a gene knockout CHO cell line using a simple gene targeting method, The 24th Meeting of the European Society for Animal Cell Technology (ESACT) 2015, May 2015.
26.	YuanShan Lai, Noriko Yamano, Masayoshi Onitsuka and Takeshi Omasa : Increased antibody productivity in Chinese Hamster Ovary cells through induction of chromosomal instability by cell fusion, The 24th Meeting of the European Society for Animal Cell Technology (ESACT) 2015, May 2015.
27.	Noriko Yamano, Toshitaka Kumamoto, Mai Takahashi, Jana Frank, Masayoshi Onitsuka and Takeshi Omasa : Stability difference of each chromosome in Chinese Hamster Ovary cell line, The 24th Meeting of the European Society for Animal Cell Technology (ESACT) 2015, May 2015.
28.	Takeshi Omasa, Masayoshi Onitsuka, Tatsuzawa Miki and Noda Masahiro : Analysis of anti-aggregation effect in trehalose-supplemented CHO cell culture., Cell Culture Engineering XIV, Quebec City, Canada, P-142, May 2015.
29.	Matsuyama Rima, Tsutsui Tomomi, Lee Ho Kyoung, Masayoshi Onitsuka and Takeshi Omasa : Generation of high-producing cell lines by cell cycle checkpoint engineering in CHO cells., Cell Culture Engineering XIV, Quebec City, Canada, P-44, May 2015.
30.	Toshitaka Kumamoto, Mai Takahashi, Masayoshi Onitsuka and Takeshi Omasa : Analysis of chromosome number and its application to antibody production in Chinese hamster ovary cells., Culture Engineering XIV, Quebec City, Canada, P-18, May 2015.
31.	Masayoshi Onitsuka and Takeshi Omasa : Antibody Aggregation in CHO Cell Culture: Mechanism and Suppression, Symposium 3 "Advanced Technologies for Next Generation Cell and Cell Culture Engineering'' in 27th Annual and international meeting of Japanese Association for Animal Cell Technology (JAACT 2014), Nov. 2014.
32.	Masayoshi Onitsuka, Ide Teruhiko and Takeshi Omasa : Separation of antibody aggregation with FcRI column, 27th Annual and international meeting of Japanese Association for Animal Cell Technology (JAACT '14), P.89, Kitakyushu, Japan, Nov. 2014.
33.	Jana Frank, Kumamoto Toshitaka, Noriko Yamano, Masayoshi Onitsuka and Takeshi Omasa : Function of chromosome fragile sites in engineeiring of Chinese hamster ovary DG44-based cell line, 27th Annual and international meeting of Japanese Association for Animal Cell Technology (JAACT '14), P.88, Kitakyushu, Japan, Nov. 2014.
34.	Kinoshita Yukie, Masayoshi Onitsuka and Takeshi Omasa : Enhanced antibody production by transcription factor NFKBIZ in CHO cells, 27th Annual and international meeting of Japanese Association for Animal Cell Technology (JAACT '14), P.75, Kitakyushu, Japan, Nov. 2014.
35.	Matsuyama Rima, Tsutsui Tomomi, Lee Ho Kyoung, Masayoshi Onitsuka and Takeshi Omasa : Accelerated gene amplification by checkpoint bypass with cell division cycle 25 homolog B (CBC25B), 7th Annual and international meeting of Japanese Association for Animal Cell Technology (JAACT 2014), P.74, Nov. 2014.
36.	Jana Frank, Toshitaka Kumamoto, Masayoshi Onitsuka, Noriko Yamano and Takeshi Omasa : Chromosome rearrangements and instability in Chinese hamster ovary cell line, The 20th Symposium of Young Asian Biochemical Engineers' Community (YABEC) 2014, Nov. 2014.
37.	Noriko Yamano, Mai Takahashi, Toshitaka Kumamoto, Tomoharu Murakami, Jana Frank, Masayoshi Onitsuka and Takeshi Omasa : The effect of chromosome number to antibody production in Chinese Hamster Ovary Cells, The 20th Symposium of Young Asian Biochemical Engineers' Community (YABEC) 2014, Nov. 2014.
38.	Akihiro Shirai, Matsumura Kyohei, Masayoshi Onitsuka, Hideaki Maseda and Takeshi Omasa : Application of photochromism to the molecular design of antimicrobial agents: synthesis of phenolic derivatives and their bactericidal activity based on a photo-reaction with ultraviolet-A light, III International Conference on Antimicrobial Research, No.T64, 289, Madrid, Oct. 2014.
39.	Tomomi Tsutsui, Ho Kyong Lee, Rina Matsuyama, Masayoshi Onitsuka and Takeshi Omasa : Cell cycle checkpoint engineering: novel construction method of gene-amplified CHO cell line for therapeutic antibody production, The 12th Tunisian-Japanese Symposium on Society, Science and Technology (TJASSST2013), 14, Tsunisia, Nov. 2013.
40.	Noda Masahiro, Tatsuzawa Miki, Masayoshi Onitsuka, Akihiro Shirai and Takeshi Omasa : Chemical shaperon suppresses the antibody aggregation in CHO cell culture, ESACT Meeting 2013 in Lille, No.A121, 97, Lille,France, Jun. 2013.
41.	Masayoshi Onitsuka, Tatsuzawa Miki, Noda Masahiro, Koguma Ichiro, Akihiro Shirai and Takeshi Omasa : Dynamical analysis of antibody aggregation in the CHO cell culture with thermo responsive protein A (TRPA) column, ESACT Meeting 2013 in Lille, No.A122, 97, Jun. 2013.
42.	Kyongho Lee, Masayoshi Onitsuka, Kohsuke Honda, Hisao Ohtake and Takeshi Omasa : Accelerated gene amplification by cell cycle checkpoint engineering and its industrial applications, 25th Annual and international meeting of Japanese Association for Animal Cell Technology (JAACT 2012), 116, Nagoya, Nov. 2012.
43.	Mai Takahashi, Syuichi Kimura, Haghparast Mohammad Ali Seyed, Yihua Cao, Takayuki Itoi, Akihiro Shirai, Masayoshi Onitsuka and Takeshi Omasa : Relationship between chromosomal instability an cell characterization in Chinese hamster ovary cell line, 25th Annual and international meeting of Japanese Association for Animal Cell Technology (JAACT 2012), 108, Nagoya, Nov. 2012.
44.	Tomomi Tsutsui, Akitoshi Nishizawa, Akihiro Shirai, Masayoshi Onitsuka, Hideaki Maseda and Takeshi Omasa : Expression profiling in UPR-regulated Chinese hamster ovary cell line, 25th Annual and international meeting of Japanese Association for Animal Cell Technology (JAACT 2012), 107, Nagoya, Nov. 2012.
45.	Miki Tatsuzawa, Masayoshi Onitsuka, Akihiro Shirai, Hideaki Maseda and Takeshi Omasa : Trehalose suppress the antibody aggregation in CHO cell culture, 25th Annual and international meeting of Japanese Association for Animal Cell Technology (JAACT 2012), 106, Nagoya, Nov. 2012.
46.	Masayoshi Onitsuka, Akihiro Shirai and Takeshi Omasa : Rapid evalution of glycosylation CHO antibody production, 25th Annual and international meeting of Japanese Association for Animal Cell Technology (JAACT 2012), 110, Nagoya, Nov. 2012.
47.	Masayoshi Onitsuka, Miki Tatsuzawa, Kazuo Okuyama, Ichiro Koguma, Akihiro Shirai and Takeshi Omasa : Purification and aggregation analysis of humanized IgG-like bispecific diabody-Fc with thermo responsive Protein A (TRPA) column, 25th Annual and international meeting of Japanese Association for Animal Cell Technology (JAACT 2012), 111, Nagoya, Nov. 2012.
48.	Kyongho Lee, Masayoshi Onitsuka, Kohsuke Honda, Hisao Ohtake and Takeshi Omasa : Construction of High-Producing CHO Cell Lines by Controlling Cell Cycle Checkpoint, The 18th Young Asian Biochemical Engineers' Community (YABEC), 119, Tokushima, Oct. 2012.
49.	Michiko Hoashi, Mai Takahashi, Masayoshi Onitsuka, Akihiro Shirai, Hideaki Maseda and Takeshi Omasa : Construction of new mammalian expression vector on the basis of gene-amplified structure in CHO genome, The 18th Young Asian Biochemical Engineers' Community (YABEC), 118, Tokushima, Oct. 2012.
50.	Mai Takahashi, Syuichi Kimura, Haphparast Mohammad Ali Seyed, Yihua Cao, Takayuki Itoi, Akihiro Shirai, Masayoshi Onitsuka and Takeshi Omasa : Clonal variability and chromosomal heterogeneity in Chinese hamster ovary cell lines during long-term cultivation, The 18th Young Asian Biochemical Engineers' Community (YABEC), 117, Tokushima, Oct. 2012.
51.	Tomomi Tsutsui, Akitoshi Nishizawa, Akihiro Shirai, Masayoshi Onitsuka, Hideaki Maseda and Takeshi Omasa : Expression profiling in UPR-engineered Chinese hamster ovary cell line, The 18th Young Asian Biochemical Engineers' Community (YABEC), 116, Tokushima, Oct. 2012.
52.	Miki Tatsuzawa, Masayoshi Onitsuka, Akihiro Shirai, Hideaki Maseda and Takeshi Omasa : Aggregation-controlled Chinese hamster ovary cell cultivation in antibody production, The 18th Young Asian Biochemical Engineers' Community (YABEC), 115, Tokushima, Oct. 2012.
53.	Masayoshi Onitsuka, Akira Kawaguchi, Miki Tatsuzawa, Kohsuke Honda, Hisao Ohtake and Takeshi Omasa : Deglycosylation induces antibody aggregation in culture process of Chinese hamster ovary cell, The 18th Young Asian Biochemical Engineers' Community (YABEC), 114, Tokushima, Oct. 2012.
54.	Akihiro Shirai, Koichiro Sato, Masayoshi Onitsuka, Hideaki Maseda and Takeshi Omasa : The effect of WFS1 over-expression on recombinant protein production in Chinese Hamster Ovary Cells, The 18th Young Asian Biochemical Engineers' Community (YABEC), 113, Tokushima, Oct. 2012.
55.	Masayoshi Onitsuka, Miki Tatsuzawa, Akihiro Shirai, Hideaki Maseda and Takeshi Omasa : Suppression of antibody aggregation in CHO cell culture by trehalose addition, Cell Culture Engineering XIII, 210, Scottsdale, Arizona, USA, Apr. 2012.
56.	Tomomi Tsutsui, Akitoshi Nishizawa, Akihiro Shirai, Masayoshi Onitsuka, Hideaki Maseda and Takeshi Omasa : Gene expression profiles in ATF4-overexpressing CHO cell line, Cell Culture Engineering XIII, 275, Scottsdale, Arizona, USA, Apr. 2012.
57.	Masayoshi Onitsuka, Tatsuzawa Miki, Akihiro Shirai, Hideaki Maseda and Takeshi Omasa : Effects of trehalose on antibody production: Supression of protein aggregation and enhancement of productivity, The 17th Young Asian Biochemical Engineers' Community (YABEC), No.F-9, 121, Incheon, Oct. 2011.
58.	Akihiro Shirai, kuboyama Yasunori, Masayoshi Onitsuka, Katsu Satoshi, Takami Takayuki, Hideaki Maseda and Takeshi Omasa : The effects of CHOP over-expression/down-regulation on recombinant Antithrombin III production in Chinese Hamster Ovary Cells, The 17th Young Asian Biochemical Engineers' Community (YABEC), No.F-8, 120, Incheon, Oct. 2011.
59.	Takeshi Omasa, Masayoshi Onitsuka and Yihua Cao : Next Generation Mammalian Host Cell for Biopharmaceutical Production, Asian Congress on Biotechnology, 97, Shanghai, May 2011.
60.	Masayoshi Onitsuka, Wook-Dong Kim, Hiroyuki Ozaki, Akira Kawaguchi, Kohsuke Honda, Hisao Ohtake and Takeshi Omasa : Improvement of glycosylation pattern of humanized IgG-like bispecificantibody produced by recombinant CHO cells, 23th Annual and international meeting of Japanese Association for Animal Cell Technology (JAACT '10), 170, Sappporo, Sep. 2010.
61.	Masayoshi Onitsuka, Wook-Dong Kim, Hiroyuki Ozaki, Akira Kawaguchi, Kohsuke Honda, Hisao Ohtake and Takeshi Omasa : Improvement of glycosylation pattern of humanized IgG-like bispecificantibody produced by recombinant CHO cells, 23th Annual and international meeting of Japanese Association for Animal Cell Technology (JAACT '10), 97, Sappporo, Sep. 2010.

Proceeding of Domestic Conference:

1.	Masayoshi Onitsuka : Challenges and Future in the upstream process of recombinant antibody production, 第75回日本生物工学会大会, Sep. 2023.
2.	Nanako Fukuma, 天羽宏枝, 伊藤洋一郎, 石井純, 近藤昭彦, 梅津光央 and Masayoshi Onitsuka : Expression and molecular characterization of bispecific scFv antibodies in CHO cells, 第75回日本生物工学会大会, Sep. 2023.
3.	Muneyoshi Okamoto, 加藤宏明, 渋谷啓介 and Masayoshi Onitsuka : Enhancing bioprocess for recombinant antibody production using perfusion culture, 第75回日本生物工学会大会, Sep. 2023.
4.	伊藤優花, Masayoshi Onitsuka and 本田真也 : CHO細胞培養時に発生するヘリックス構造を持つ非天然構造抗体, 第23回日本蛋白質科学会年, Jul. 2023.
5.	Kaito Kawai, Kei Kiriyama, YOSHIOKA Yuma, Masayoshi Onitsuka, TERU Mizuno, Keisuke Fujioka, 広川貴次, 佐藤あやの and Kouji Itou : N型糖鎖改変に基づく昆⾍由来リソソーム酵素の細胞内取り込み制御機構の解析, 第45回日本分子生物学会年会, Dec. 2022.
6.	伊藤優花, Muneyoshi Okamoto, 本田真也 and Masayoshi Onitsuka : CHO細胞培養における非天然構造抗体の分泌現象の解析, 日本生物工学会大会西日本支部大会第6回講演会, Nov. 2022.
7.	Nanako Fukuma, 天羽宏枝, 伊藤洋一郎, 石井純, 近藤昭彦, 梅津光央 and Masayoshi Onitsuka : 動物細胞を利用したタンデム型二重特異性 scFv 抗体の製造適合性評価, 第1回日本抗体学会設立記念学術大会, Nov. 2022.
8.	Muneyoshi Okamoto, 加藤宏明, 天羽宏枝 and Masayoshi Onitsuka : 細胞培養プロセスにおける抗体品質制御への灌流培養の応用, 第1回日本抗体学会設立記念, Nov. 2022.
9.	Kaito Kawai, Kei Kiriyama, YOSHIOKA Yuma, Masayoshi Onitsuka, TERU Mizuno, Keisuke Fujioka, 広川貴次, 佐藤あやの and Kouji Itou : 哺乳類細胞を用いた昆虫細胞由来リソソーム酵素β-ヘキソサミニダーゼの発現と糖鎖改変による影響, 第95回日本生化学会大会, Nov. 2022.
10.	Masayoshi Onitsuka, 平田結風 and 天羽宏枝 : CHO細胞を用いた組換え抗体生産に有効な高機能化因子の探索, 第74回日本生物工学会大会, Oct. 2022.
11.	Nanako Fukuma, 山内清司, 田地野浩司 and Masayoshi Onitsuka : 高機能化因子を利用した組換えCHO細胞の高度化, 第74回日本生物工学会大会, Oct. 2022.
12.	Muneyoshi Okamoto, 樋口拓哉, 鈴木真史, 奥谷聡志 and Masayoshi Onitsuka : CHO細胞灌流培養における組換えIgG1抗体特性の動的変化解析, 第74回日本生物工学会大会, Oct. 2022.
13.	Kaito Kawai, Kei Kiriyama, YOSHIOKA Yuma, Masayoshi Onitsuka, TERU Mizuno, Keisuke Fujioka, 広川貴次, 佐藤あやの and Kouji Itou : 昆虫由来リソソーム酵素の N 型糖鎖改変と細胞内取り込みへの影響, 第41回日本糖質学会年会, Sep. 2022.
14.	Kaito Kawai, Kei Kiriyama, YOSHIOKA Yuma, Masayoshi Onitsuka, Keisuke Fujioka, TERU Mizuno, 広川貴次 and Kouji Itou : 昆虫細胞由来リソソーム酵素β-ヘキソサミニダーゼの立体構造予測と糖鎖改変, 第63回日本生化学会中国・四国支部例会, May 2022.
15.	Kaito Kawai, Kei Kiriyama, YOSHIOKA Yuma, Masayoshi Onitsuka, Keisuke Fujioka, Teru Mizuno and Kouji Itou : 昆虫由来リソソーム性β-ヘキソサミダーゼの糖鎖改変と発現解析, 日本薬学会第142年会(名古屋), Mar. 2022.
16.	Masayoshi Onitsuka and Hiroe Amou : Structural properties of aggregated antibody produced in recombinant CHO cell culture process, 第73回日本生物工学会大会, Oct. 2021.
17.	Yuma Yoshioka, Hiroe Amou and Masayoshi Onitsuka : Attempt to create a new constant region of antibody by fusing shark-derived IgNAR, 第73回日本生物工学会大会, Oct. 2021.
18.	Yuka Itoh, Masayoshi Onitsuka, 天羽宏枝 and 本田真也 : Separation and characterization of non-native antibody in CHO cell culture, 第73回日本生物工学会大会, Oct. 2021.
19.	ITOH Yuka, 嶋津敦子, 石川周太郎 and Masayoshi Onitsuka : CHO細胞灌流培養における抗体特性の動的変化の解析, 第34回日本動物細胞工学会2021年度大会 (JAACT2021), Jul. 2021.
20.	Yuma Yoshioka, 嶋津敦子, 天羽宏枝 and Masayoshi Onitsuka : CHO細胞を利用した新規抗体創製の試み ~IgNAR抗体とIgG1抗体の配列融合~, 第34回日本動物細胞工学会2021年度大会 (JAACT2021), Jul. 2021.
21.	Yuri Fukushi, Yuto Horii, NAKAMURA Nodoka, 広川貴次, Masayoshi Onitsuka and Kouji Itou : ガラクトシアリドーシスの治療を目指したN型糖鎖追加型カテプシンAの分子機能解析, 日本薬学会第141年会, Mar. 2021.
22.	Masayoshi Onitsuka, Atsuko Shimadu and Shutaro Ishikawa : Reduced aggregation and altered N-glycosylation status of recombinant IgG1 in perfusion mammalian cell culture, 第20回日本蛋白質科学会年会, Jul. 2020.
23.	Masayoshi Onitsuka : Aggregation and misfolding of therapeutic antibodies in bioprocessing, The 57th Annual Meeting of the Biophysical Society of Japan, Symposium: The Quality of Proteins Multiple Approaches for Protein Evaluation, Sep. 2019.
24.	Masayoshi Onitsuka, 嶋津敦子 and 天羽宏枝 : 抗体医薬品生産の高度化を目指した高機能化因子迅速評価システムの開発, 日本生物工学会第71回大会, Sep. 2019.
25.	Masayoshi Onitsuka and 本田真也 : Secretion of an aggregated antibody from recombinant CHO cells revealed by artificial protein sensor AF.2A1, 第19回日本蛋白質科学会年会, Jun. 2019.
26.	Masayoshi Onitsuka : 動物細胞培養から考える抗体医薬品の分子不均一性, 日本生物工学会第70回大会ランチョンセミナー, Sep. 2018.
27.	Masayoshi Onitsuka, 嶋津敦子 and 天羽宏枝 : 改変型糖鎖をもつ抗体医薬品生産を目指した細胞外糖鎖修飾反応の開発, 日本生物工学会第70回大会, Sep. 2018.
28.	Masayoshi Onitsuka and Takeshi Omasa : Characterizing the aggregation of therapeutic antibodies in bioprocessing, 第18回日本蛋白質科学会年会, Jun. 2018.
29.	Masayoshi Onitsuka : 抗体品質制御のための凝集抗体解析と動物細胞培養法の開発, 第38回動物細胞工学シンポジウム, Mar. 2018.
30.	Qing Tang, Masayoshi Onitsuka, Atsushi Tabata, Toshifumi Tomoyasu and Hideaki Nagamune : 癌治療用新規DDSツール作製に用いるリガンド分子の調製とその機能評価, 第21回バイオ治療法研究会, Dec. 2017. (Keyword) cancer therapy
31.	Masayoshi Onitsuka and Takeshi Omasa : Rapid evaluation of production enhancer genes in CHO cells, 化学工学会第49回秋季大会, Sep. 2017.
32.	兼吉航平, Keiji Uchiyama, Masayoshi Onitsuka, Noriko Yamano, 古賀雄一 and Takeshi Omasa : 高生産株の構築を目指した抗体生産CHO細胞内の分泌過程解, 第69回日本生物工学会大会, Sep. 2017.
33.	Masayoshi Onitsuka and Takeshi Omasa : Secretory leakage of an aggregated antibody from CHO cells and its structural characterization, 第17回日本蛋白質科学会年会ワークショップ抗体医薬の構造・物性・機能1-高機能化に向けた構造物性解析の高度化-, Jun. 2017.
34.	Yuki Fujino, Masayoshi Onitsuka, Noriko Yamano and Takeshi Omasa : ATP供給強化を指向した抗体産生CHO細胞の構築と解析, 第3回日本生物工学会西日本支部講演会, Dec. 2016.
35.	Yuma Kagawa, Masayoshi Onitsuka, 野村嘉紀, Noriko Yamano and Takeshi Omasa : ヒト及びサメ由来抗体配列の融合による新規抗体創製の試み, 第3回日本生物工学会西日本支部講演会, Dec. 2016.
36.	Marina Aga, Masayoshi Onitsuka, Noriko Yamano and Takeshi Omasa : 抗体高生産株選抜を目的としたメチル化DNA測定法構築の試み, 第3回日本生物工学会西日本支部講演会, Dec. 2016.
37.	Namiko Kawamura, Masayoshi Onitsuka, 小出静代, Noriko Yamano and Takeshi Omasa : 難発現性抗体生産プロセス構築を指向した抗体凝集性の解析と抑制の試み, 第3回日本生物工学会西日本支部講演会, Dec. 2016.
38.	小松圭, 公文健人, 福谷洋介, Masayoshi Onitsuka, Takeshi Omasa and 養王田正文 : CHO 細胞におけるPDIa4 の抗体産生に及ぼす影響, 第68回日本生物工学会大会, Sep. 2016.
39.	森下明彦, Masayoshi Onitsuka, Takeshi Omasa and 秦信子 : CHO 細胞を用いた抗体生産プロセスにおける糖鎖構造解析, 第68回日本生物工学会大会, Sep. 2016.
40.	野村嘉紀, Masayoshi Onitsuka, 香川悠馬, Noriko Yamano, 古賀雄一 and Takeshi Omasa : CHO細胞を用いたサメ由来重鎖抗体の分泌発現コンストラクトの検討, 第68回日本生物工学会大会, Sep. 2016.
41.	原田涼之介, Masayoshi Onitsuka, 黄川田隆洋, 小出静代, 古賀雄一, Noriko Yamano and Takeshi Omasa : Tret1遺伝子導入によるCHO細胞の抗体凝集抑制と細胞増殖能の改善, 第68回日本生物工学会大会, Sep. 2016.
42.	田中翔, Noriko Yamano, 緒方法親, Masayoshi Onitsuka, 古賀雄一 and Takeshi Omasa : 染色体異数性を持つ抗体生産CHO細胞の網羅的遺伝子発現解析, 第68回日本生物工学会大会, Sep. 2016.
43.	吉冨耕太, Noriko Yamano, Masayoshi Onitsuka, 古賀雄一 and Takeshi Omasa : CHO細胞における安定染色体の遺伝子地図作成とCRISPR/Cas9システムを用いた遺伝子ターゲッティングによる抗体生産株の構築, 第68回日本生物工学会大会, Sep. 2016.
44.	香川悠馬, 野村嘉紀, Masayoshi Onitsuka, Noriko Yamano, Akihiro Shirai and Takeshi Omasa : ヒト及びサメ由来抗体配列の融合による新規定常領域創製の試み, 化学工学会第81年会, Mar. 2016.
45.	阿賀万里菜, Noriko Yamano, 隈元信貴, Jana Frank, Masayoshi Onitsuka, Akihiro Shirai and Takeshi Omasa : de novo型DNAメチル化酵素欠損CHO細胞株の構築とその応用, 化学工学会第81年会, Mar. 2016.
46.	Takeshi Omasa, Noriko Yamano and Masayoshi Onitsuka : Characteristics of Bio-based Production for Biologics Therapeutic Antibodies-, プロセス化学会2015ウィンターシンポジウム, Nov. 2015.
47.	Yuanshan Lai, Noriko Yamano, Masayoshi Onitsuka, Jana Frank, Akihiro Shirai and Takeshi Omasa : Artificially induced chromosomal instability leads to increased antibody productivity in Chinese hamster ovary cells, 第67回日本生物工学会大会, Oct. 2015.
48.	隈元信貴, Noriko Yamano, Masayoshi Onitsuka and Takeshi Omasa : Cell line construction by gene targeting using CRISPR/Cas9 system in CHO cells, 第67回日本生物工学会大会, Oct. 2015.
49.	阿賀万里菜, Noriko Yamano, 隈元信貴, Jana Frank, Masayoshi Onitsuka, Akihiro Shirai and Takeshi Omasa : Construction of Dnmt3 knock out CHO cell lines by CRISPR/Cas9 system, 第67回日本生物工学会大会, Oct. 2015.
50.	川村菜美子, 松山莉麻, 筒井智美, Kyoungho Lee, Noriko Yamano, Masayoshi Onitsuka, Akihiro Shirai and Takeshi Omasa : Establishment of efficient gene amplification system by the cell cycle checkpoint regulation, and its application to recombinant protein production, 第67回日本生物工学会大会, Oct. 2015.
51.	Noriko Yamano, 高橋舞, Jana Frank, Masayoshi Onitsuka, Akihiro Shirai and Takeshi Omasa : Stability difference and sequence analysis of each chromosome in CHO cells by using the genomic library, 第67回日本生物工学会大会, Oct. 2015.
52.	Yuma Kagawa, Masayoshi Onitsuka, Noriko Yamano, Akihiro Shirai and Takeshi Omasa : 2P-266 Expression and purification of IgNAR heavy chain antibody in CHO cells, 日本生物工学会大会講演要旨集, Vol.67, 241, Oct. 2015. (Link to Search Site for Scientific Articles) ● CiNii @ National Institute of Informatics (CRID): 1541135670268993920 (CiNii: 1541135670268993920)
53.	Yuki Fujino, Toshitaka Kumamoto, Masayoshi Onitsuka, Noriko Yamano, Akihiro Shirai and Takeshi Omasa : 2P-261 Construction of IgG1-producing CHO cells by a combination of transcriptional and post-translational technology, 日本生物工学会大会講演要旨集, Vol.67, 240, Oct. 2015. (Link to Search Site for Scientific Articles) ● CiNii @ National Institute of Informatics (CRID): 1541980095199124992 (CiNii: 1541980095199124992)
54.	Masayoshi Onitsuka, Takushi Ouga, Shigeo Tojo and Takeshi Omasa : 2P-267 Cell culture of IgG1-producing CHO cells in the presence of antiaggregation additive and its metabolome analysis, 日本生物工学会大会講演要旨集, Vol.67, 241, Sep. 2015. (Link to Search Site for Scientific Articles) ● CiNii @ National Institute of Informatics (CRID): 1543387470082679424 (CiNii: 1543387470082679424)
55.	Koji Tajino, Kana Ueda, Natsuko Tada, Mayumi Nishimura, Shuichi Kuno, Aya Torisawa, Takahisa Genji, Masayoshi Onitsuka, Takeshi Omasa and Seiji Yamauchi : 2P-256 Improved antibody production in CHO cells by ATF4 expression control with MAC vector., 日本生物工学会大会講演要旨集, Vol.67, 238, Sep. 2015. (Link to Search Site for Scientific Articles) ● CiNii @ National Institute of Informatics (CRID): 1540854195292281472 (CiNii: 1540854195292281472)
56.	Akihiko Morishita, Masayoshi Onitsuka, Takeshi Omasa and Shinko Hata : 2P-227 Leading to antibody-dependent cellular cytotoxicity (ADCC) activity of the antibody drugs, study of CHO cell culture environment factors, 日本生物工学会大会講演要旨集, Vol.67, 231, Sep. 2015. (Link to Search Site for Scientific Articles) ● CiNii @ National Institute of Informatics (CRID): 1541980095199117952 (CiNii: 1541980095199117952)
57.	Kei Komatsu, Mayuno Arita, Masayoshi Onitsuka, Takeshi Omasa and Masafumi Yohda : 1P-083 Effect of Protein disulfide isomerase PDIa4 on antibody production of CHO cells, 日本生物工学会大会講演要旨集, Vol.67, 109, Sep. 2015. (Link to Search Site for Scientific Articles) ● CiNii @ National Institute of Informatics (CRID): 1542261570175728512 (CiNii: 1542261570175728512)
58.	浜垣秀平, Masayoshi Onitsuka, 角屋行紀, Noriko Yamano, Akihiro Shirai and Takeshi Omasa : 抗体医薬品の凝集抑制を目指したケミカルシャペロン添加培養法の開発, 第15回日本蛋白質科学会年会, Jun. 2015.
59.	Masayoshi Onitsuka, 野田真広, 浅野竜太郎, 熊谷泉, Noriko Yamano, Akihiro Shirai and Takeshi Omasa : CHO細胞培養における非天然型抗体の凝集性解析, 第15回日本蛋白質科学会年会, Jun. 2015.
60.	Masayoshi Onitsuka and Takeshi Omasa : 動物細胞培養から考えるバイオ医薬品の蛋白質科学, 第15回蛋白質科学会年会ワークショップ「バイオ医薬品の品質管理技術と蛋白質科学」, Jun. 2015.
61.	Akihiro Shirai, Kyohei Matsumura, Masayoshi Onitsuka, Hideaki Maseda and Takeshi Omasa : 新規抗菌剤の分子設計におけるフォトクロミック特性の応用, 日本防菌防黴学会第41回年次大会要旨集, No.24Ap-12, 55, Sep. 2014.
62.	Daiki Oka, Masayoshi Onitsuka and Takeshi Omasa : 2P-203 Effects of chaperone co-expression on full-length IgG1 expression in Escherichia coli, 日本生物工学会大会講演要旨集, Vol.66, 157, Aug. 2014. (Link to Search Site for Scientific Articles) ● CiNii @ National Institute of Informatics (CRID): 1543387470082467328 (CiNii: 1543387470082467328)
63.	Yukinori Kadoya, Masayoshi Onitsuka and Takeshi Omasa : 2P-197 Dynamical analysis of antibody aggregation in CHO cell culture., 日本生物工学会大会講演要旨集, Vol.66, 156, Aug. 2014. (Link to Search Site for Scientific Articles) ● CiNii @ National Institute of Informatics (CRID): 1543105995105755904 (CiNii: 1543105995105755904)
64.	野田真広, Masayoshi Onitsuka, Akihiro Shirai, Hideaki Maseda and Takeshi Omasa : 二重特異性抗体のドメイン配置が凝集性に及ぼす影響, 第65回日本生物工学会大会, 245, Sep. 2013.
65.	森下明彦, 高橋舞, Masayoshi Onitsuka, Akihiro Shirai, Hideaki Maseda and Takeshi Omasa : 異数性を有するChinese hamster ovary細胞における染色体不安定性解析, 第65回日本生物工学大会, 245, Sep. 2013.
66.	高橋舞, 森下明彦, Masayoshi Onitsuka, Akihiro Shirai, Hideaki Maseda and Takeshi Omasa : Chinese hamster ovary 細胞株における染色体不安定性解析と抗体生産への応用, 第65回日本生物工学大会, 73, Sep. 2013.
67.	筒井智美, Kyoung Ho Lee, Masayoshi Onitsuka, Akihiro Shirai, Hideaki Maseda and Takeshi Omasa : 細胞周期制御による抗体医薬品高生産CHO細胞株構築系の確立, 第65回日本生物工学大会, 73, Sep. 2013.
68.	Masayoshi Onitsuka and Takeshi Omasa : レクチンを用いた抗体糖鎖の迅速検出とその可能性, 化学工学会第45回秋季大会, Sep. 2013.
69.	Yukie Kinoshita, Tomomi Tsutsui, Masayoshi Onitsuka, Akihiro Shirai, Hideaki Maseda and Takeshi Omasa : 抗体生産CHO細胞株におけるNFKBIZ発現の影響, 日本動物細胞工学会2013年度大会(JAACT2013), 68, Jul. 2013.
70.	Tomomi Tsutsui, KyoungHo Lee, Masayoshi Onitsuka, Akihiro Shirai, Hideaki Maseda and Takeshi Omasa : 細胞周期エンジニアリングによるChinese hamster ovary (CHO) 細胞における効率的な遺伝子増幅システムの構築, 日本動物細胞工学会2013年度大会(JAACT2013), 50, Jul. 2013.
71.	Shizuka Matsumura, Shota Ikawa, Masayoshi Onitsuka, Akihiro Shirai, Hideaki Maseda, Keiji Uchiyama and Takeshi Omasa : CHO細胞における小胞出芽関連因子Arfのクローニングと発現抑制によるタンパク質生産への影響, 日本動物細胞工学会2013年度大会(JAACT2013), 69, Jul. 2013.
72.	Akihiko Morishita, Mai Takahashi, Masayoshi Onitsuka, Akihiro Shirai, Hideaki Maseda and Takeshi Omasa : 組換えバイオ医薬品生産CHO細胞株構築過程における染色体不安定性解析, 化学工学会第77年会, Mar. 2013.
73.	Masahiro Noda, Miki Tatsuzawa, Masayoshi Onitsuka, Akihiro Shirai, Hideaki Maseda and Takeshi Omasa : トレハロース添加によるCHO細胞培養過程の抗体凝集抑制, 化学工学会第77年会, Mar. 2013.
74.	Yukie Kinoshita, Tomomi Tsutsui, Masayoshi Onitsuka, Akihiro Shirai, Hideaki Maseda and Takeshi Omasa : NFKBIZ発現による高生産CHO細胞株の構築と解析, 化学工学会第77年会, Mar. 2013.
75.	Kyongho Lee, Masayoshi Onitsuka, Kohsuke Honda, Hisao Ohtake and Takeshi Omasa : Rapid Construction of Transgene-amplified CHO Cell Lines by Cell Cycle Regulator Engneering, 第64回日本生物工学会大会, 189, Oct. 2012.
76.	Masayoshi Onitsuka, 川口央, 龍澤実季, 本田孝祐, 大竹久夫 and Takeshi Omasa : 糖鎖構造が細胞培養過程の抗体凝集形成に与える影響, 第64回日本生物工学会大会, 34, Oct. 2012.
77.	Akihiro Shirai, 佐藤浩一郎, Masayoshi Onitsuka, Hideaki Maseda and Takeshi Omasa : 組換えタンパク質高生産CHO細胞株におけるWFS1発現の影響, 第64回日本生物工学会大会, 33, Oct. 2012.
78.	龍澤実季, Masayoshi Onitsuka, Akihiro Shirai, Hideaki Maseda and Takeshi Omasa : トレハロースを用いたCHO細胞培養における抗体の凝集抑制, 第64回日本生物工学会大会, 33, Oct. 2012.
79.	筒井智美, Akihiro Shirai, Masayoshi Onitsuka, 西沢明敏, Hideaki Maseda, 本田孝祐, 大竹久夫 and Takeshi Omasa : ATF-4高発現CHO細胞における遺伝子発現解析, 第64回日本生物工学会大会, 33, Oct. 2012.
80.	Miki Tatsuzawa, Masayoshi Onitsuka, Akihiro Shirai, Hideaki Maseda and Takeshi Omasa : CHO細胞培養における凝集体抑制培養:トレハロース添加の影響, 日本生物工学会西日本支部第2回講演会, 33, Jul. 2012.
81.	松本知浩, Masayoshi Onitsuka, Akihiro Shirai, Hideaki Maseda and Takeshi Omasa : The effect of medium additive on glycosylation of antibody produced by CHO cell, 第63回日本生物工学会大会講演要旨集, No.1Gp14, 51, Sep. 2011.
82.	帆足理子, Masayoshi Onitsuka, 木村修一, Akihiro Shirai, Hideaki Maseda and Takeshi Omasa : Construction of mammalian expression vector using gene-amplified structure, 第63回日本生物工学会大会講演要旨集, No.1Gp13, 51, Sep. 2011.
83.	Yasunori Kuboyama, Akihiro Shirai, Masayoshi Onitsuka, Satoshi Katsu, 高見貴之, Hideaki Maseda and Takeshi Omasa : The effects of CHOP over/down-regulation on recombinant AT-III production, 第63回日本生物工学会大会講演要旨集, No.1Gp12, 51, Sep. 2011.
84.	龍澤実季, Masayoshi Onitsuka, Akihiro Shirai, Hideaki Maseda and Takeshi Omasa : トレハロースを用いた細胞培養過程における抗体凝集抑制の検討, 化学工学会第43回秋季大会, 628, Sep. 2011.
85.	龍澤実季, Masayoshi Onitsuka, Akihiro Shirai, Hideaki Maseda and Takeshi Omasa : トレハロース添加による一本鎖二重特異性抗体の凝集抑制効果の検討, 日本農芸化学会中四国支部第30回講演会, 30, May 2011.

Et cetera, Workshop:

1.	Masayoshi Onitsuka : 動物細胞培養プロセスにおけるタンパク質・抗体医薬品の凝集形成と制御, サイエンス&テクノロジー社セミナー「バイオ医薬品で起こる蛋白質凝集メカニズム,凝集体形成防止・製剤安定化と培養プロセスでの凝集抑制・凝集体除去/高品質化の細胞構築」, Jan. 2023.
2.	Masayoshi Onitsuka : 蛋白質生産細胞の培養プロセスでの凝集抑制・凝集体除去と抗体医薬品高品質化の細胞構築/培養, サイエンス&テクノロジー社セミナー「バイオ医薬品で起こる蛋白質凝集メカニズム,凝集体形成防止・製剤安定化と培養プロセスでの凝集抑制・凝集体除去/高品質化の細胞構築」, Aug. 2021.
3.	Masayoshi Onitsuka : Fcレセプター固定化カラムが切り開く，抗体医薬品製造プロセス開発, 第2回東ソーバイオセミナー(オンライン), Mar. 2021.
4.	Masayoshi Onitsuka : タンパク質医薬品生産における高品質化の細胞構築/培養と生産性向上への考察, サイエンス&テクノロジー社セミナー「タンパク質薬品生産における高品質化の細胞構築・生産性向上とCHO細胞の高機能化/工業化」, Jan. 2020.
5.	Masayoshi Onitsuka : 培養プロセスにおける凝集形成と制御について ∼抗体生産CHO細胞を中心に∼, サイエンス&テクノロジー社セミナー発刊記念講演会「凝集体の抑制と材質設計を意識したバイオ医薬品に適したプレフィルドシリンジ開発」, Dec. 2019.
6.	Masayoshi Onitsuka : 細胞培養プロセスにおける抗体分子の不均一性: 凝集化機構の解明と糖鎖制御法開発の挑戦, 東ソーセミナー2019 「産学における抗体生産，精製，解析の最新技術」, Oct. 2019.
7.	Masayoshi Onitsuka : 蛋白質生産細胞の培養プロセスでの凝集抑制・凝集体除去と抗体医薬品高品質化の細胞構築/培養, サイエンス&テクノロジー社セミナー「バイオ医薬品で起こる蛋白質凝集メカニズム,凝集体形成防止・製剤安定化と培養プロセスでの凝集抑制・凝集体除去/高品質化の細胞構築」, Aug. 2019.
8.	Masayoshi Onitsuka : アカデミアにおける製造技術研究, 日本動物細胞工学会若手活動委員会主催バイオ医薬品製造プロセス研究会, Apr. 2019.
9.	Masayoshi Onitsuka : 蛋白質生産細胞の培養プロセスでの凝集抑制・凝集体除去, サイエンス&テクノロジー社セミナー「バイオ医薬品で起こる蛋白質凝集メカニズム,凝集体形成防止・製剤安定化と培養プロセスでの凝集抑制・凝集体除去」, Nov. 2018.
10.	Masayoshi Onitsuka : 抗体凝集メカニズムから考える抗体医薬品高品質化の細胞構築と培養, バイオ医薬品で起こる蛋白質凝集メカニズム,凝集体形成防止,製剤安定化と培養プロセスでの凝集抑制・凝集体除去(Science & Technology社セミナー), Dec. 2017.
11.	Masayoshi Onitsuka : 蛋白質生産細胞の培養プロセスでの凝集抑制・凝集体除去, バイオ医薬品で起こる蛋白質凝集メカニズム,凝集体形成防止,製剤安定化と培養プロセスでの凝集抑制・凝集体除去(Science & Technology社セミナー), Apr. 2017.
12.	Masayoshi Onitsuka and Takeshi Omasa : CHO細胞の抗体生産を代謝解析から考える, 第67回日本生物工学会年会ランチョンセミナー, Oct. 2015.
13.	Masayoshi Onitsuka and Takeshi Omasa : 細胞構築から始まるバイオ医薬品生産におけるプロセスの重要性-AlphaScreenの応用-, PerkinElmer Japan35周年記念イベント RGHS Biotherapeutics 抗体医薬研究の未来を拓くテクノロジー, Nov. 2013.
14.	Masayoshi Onitsuka : 次世代型抗体医薬品生産のためのバイオプロセス構築, NAIST 未来開拓コロキウム明日をつくる分子・人材ネットワーク, Aug. 2013.
15.	Masayoshi Onitsuka and Takeshi Omasa : トレハロースを用いた細胞培養過程における抗体凝集抑制作用, 第16回トレハロースシンポジウム, 24-27, Oct. 2012.

Grants-in-Aid for Scientific Research (KAKEN Grants Database @ NII.ac.jp)

Construction of mammalian cell-based cell and bioprocess engineering (Project/Area Number: 22H00276 )
バイオ医薬品生産細胞における老化現象の解明と制御 (Project/Area Number: 21K04794 )
Integrated platform for mammalian cell-based cell and bioprocess engineering (Project/Area Number: 17H06157 )
The effect of expression of Yamanaka factors on CHO cells (Project/Area Number: 23656530 )
Next generation protein production on cellular quality-control process (Project/Area Number: 23360371 )
Search by Researcher Number (80571174)

Associate Professor : Onitsuka, Masayoshi

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Grants-in-Aid for Scientific Research (KAKEN Grants Database @ NII.ac.jp)