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Mieczkowski C, Bahmanjah S, Yu Y, Baker J, Raghunathan G, Tomazela D, Hsieh M, McCoy M, Strickland C, Fayadat-Dilman L. Crystal Structure and Characterization of Human Heavy-Chain Only Antibodies Reveals a Novel, Stable Dimeric Structure Similar to Monoclonal Antibodies. Antibodies (Basel) 2020; 9:antib9040066. [PMID: 33266498 PMCID: PMC7709113 DOI: 10.3390/antib9040066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 10/20/2020] [Accepted: 11/09/2020] [Indexed: 11/23/2022] Open
Abstract
We report the novel crystal structure and characterization of symmetrical, homodimeric humanized heavy-chain-only antibodies or dimers (HC2s). HC2s were found to be significantly coexpressed and secreted along with mAbs from transient CHO HC/LC cotransfection, resulting in an unacceptable mAb developability attribute. Expression of full-length HC2s in the absence of LC followed by purification resulted in HC2s with high purity and thermal stability similar to conventional mAbs. The VH and CH1 portion of the heavy chain (or Fd) was also efficiently expressed and yielded a stable, covalent, and reducible dimer (Fd2). Mutagenesis of all heavy chain cysteines involved in disulfide bond formation revealed that Fd2 intermolecular disulfide formation was similar to Fabs and elucidated requirements for Fd2 folding and expression. For one HC2, we solved the crystal structure of the Fd2 domain to 2.9 Å, revealing a highly symmetrical homodimer that is structurally similar to Fabs and is mediated by conserved (CH1) and variable (VH) contacts with all CDRs positioned outward for target binding. Interfacial dimer contacts revealed by the crystal structure were mutated for two HC2s and were found to dramatically affect HC2 formation while maintaining mAb bioactivity, offering a potential means to modulate novel HC2 formation through engineering. These findings indicate that human heavy-chain dimers can be secreted efficiently in the absence of light chains, may show good physicochemical properties and stability, are structurally similar to Fabs, offer insights into their mechanism of formation, and may be amenable as a novel therapeutic modality.
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Affiliation(s)
- Carl Mieczkowski
- Discovery Biologics, Protein Sciences, Merck & Co., Inc., South San Francisco, CA 94080, USA; (Y.Y.); (J.B.); (G.R.); (D.T.); (M.H.); (L.F.-D.)
- Correspondence: ; Tel.: +1-650-496-6501
| | - Soheila Bahmanjah
- Department of Chemistry, Modeling and Informatics, Merck & Co., Inc., Kenilworth, NJ 07033, USA; (S.B.); (C.S.)
| | - Yao Yu
- Discovery Biologics, Protein Sciences, Merck & Co., Inc., South San Francisco, CA 94080, USA; (Y.Y.); (J.B.); (G.R.); (D.T.); (M.H.); (L.F.-D.)
| | - Jeanne Baker
- Discovery Biologics, Protein Sciences, Merck & Co., Inc., South San Francisco, CA 94080, USA; (Y.Y.); (J.B.); (G.R.); (D.T.); (M.H.); (L.F.-D.)
| | - Gopalan Raghunathan
- Discovery Biologics, Protein Sciences, Merck & Co., Inc., South San Francisco, CA 94080, USA; (Y.Y.); (J.B.); (G.R.); (D.T.); (M.H.); (L.F.-D.)
| | - Daniela Tomazela
- Discovery Biologics, Protein Sciences, Merck & Co., Inc., South San Francisco, CA 94080, USA; (Y.Y.); (J.B.); (G.R.); (D.T.); (M.H.); (L.F.-D.)
| | - Mark Hsieh
- Discovery Biologics, Protein Sciences, Merck & Co., Inc., South San Francisco, CA 94080, USA; (Y.Y.); (J.B.); (G.R.); (D.T.); (M.H.); (L.F.-D.)
| | - Mark McCoy
- Department of Pharmacology, Mass Spectrometry & Biophysics, Merck & Co., Inc., Kenilworth, NJ 07033, USA;
| | - Corey Strickland
- Department of Chemistry, Modeling and Informatics, Merck & Co., Inc., Kenilworth, NJ 07033, USA; (S.B.); (C.S.)
| | - Laurence Fayadat-Dilman
- Discovery Biologics, Protein Sciences, Merck & Co., Inc., South San Francisco, CA 94080, USA; (Y.Y.); (J.B.); (G.R.); (D.T.); (M.H.); (L.F.-D.)
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2
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Tang D, Sandoval W, Lam C, Haley B, Liu P, Xue D, Roy D, Patapoff T, Louie S, Snedecor B, Misaghi S. UBR E3 ligases and the PDIA3 protease control degradation of unfolded antibody heavy chain by ERAD. J Cell Biol 2020; 219:151862. [PMID: 32558906 PMCID: PMC7337499 DOI: 10.1083/jcb.201908087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 02/03/2020] [Accepted: 04/06/2020] [Indexed: 12/01/2022] Open
Abstract
Accumulation of unfolded antibody chains in the ER triggers ER stress that may lead to reduced productivity in therapeutic antibody manufacturing processes. We identified UBR4 and UBR5 as ubiquitin E3 ligases involved in HC ER-associated degradation. Knockdown of UBR4 and UBR5 resulted in intracellular accumulation, enhanced secretion, and reduced ubiquitination of HC. In concert with these E3 ligases, PDIA3 was shown to cleave ubiquitinated HC molecules to accelerate HC dislocation. Interestingly, UBR5, and to a lesser degree UBR4, were down-regulated as cellular demand for antibody expression increased in CHO cells during the production phase, or in plasma B cells. Reducing UBR4/UBR5 expression before the production phase increased antibody productivity in CHO cells, possibly by redirecting antibody molecules from degradation to secretion. Altogether we have characterized a novel proteolysis/proteasome-dependent pathway involved in degradation of unfolded antibody HC. Proteins characterized in this pathway may be novel targets for CHO cell engineering.
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Affiliation(s)
- Danming Tang
- Cell Culture and Bioprocess Operations Department, Genentech Inc., South San Francisco, CA
| | - Wendy Sandoval
- Department of Microchemistry, Proteomics and Lipidomics, Genentech Inc., South San Francisco, CA
| | - Cynthia Lam
- Cell Culture and Bioprocess Operations Department, Genentech Inc., South San Francisco, CA
| | - Benjamin Haley
- Department of Molecular Biology, Genentech Inc., South San Francisco, CA
| | - Peter Liu
- Department of Microchemistry, Proteomics and Lipidomics, Genentech Inc., South San Francisco, CA
| | - Di Xue
- Department of Research Biology, Genentech Inc., South San Francisco, CA
| | - Deepankar Roy
- Cell Culture and Bioprocess Operations Department, Genentech Inc., South San Francisco, CA
| | - Tom Patapoff
- Department of Early Stage Pharmaceutical Development, Genentech Inc., South San Francisco, CA
| | - Salina Louie
- Cell Culture and Bioprocess Operations Department, Genentech Inc., South San Francisco, CA
| | - Brad Snedecor
- Cell Culture and Bioprocess Operations Department, Genentech Inc., South San Francisco, CA
| | - Shahram Misaghi
- Cell Culture and Bioprocess Operations Department, Genentech Inc., South San Francisco, CA
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3
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Adams BM, Ke H, Gierasch LM, Gershenson A, Hebert DN. Proper secretion of the serpin antithrombin relies strictly on thiol-dependent quality control. J Biol Chem 2019; 294:18992-19011. [PMID: 31662433 DOI: 10.1074/jbc.ra119.010450] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 10/24/2019] [Indexed: 01/04/2023] Open
Abstract
The protein quality control machinery of the endoplasmic reticulum (ERQC) ensures that client proteins are properly folded. ERQC substrates may be recognized as nonnative by the presence of exposed hydrophobic surfaces, free thiols, or processed N-glycans. How these features dictate which ERQC pathways engage a given substrate is poorly understood. Here, using metabolic labeling, immunoprecipitations, various biochemical assays, and the human serpin antithrombin III (ATIII) as a model, we explored the role of ERQC systems in mammalian cells. Although ATIII has N-glycans and a hydrophobic core, we found that its quality control depended solely on free thiol content. Mutagenesis of all six Cys residues in ATIII to Ala resulted in its efficient secretion even though the product was not natively folded. ATIII variants with free thiols were retained in the endoplasmic reticulum but not degraded. These results provide insight into the hierarchy of ERQC systems and reveal a fundamental vulnerability of ERQC in a case of reliance on the thiol-dependent quality control pathway.
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Affiliation(s)
- Benjamin M Adams
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003.,Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, Massachusetts 01003
| | - Haiping Ke
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003
| | - Lila M Gierasch
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003.,Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, Massachusetts 01003.,Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003
| | - Anne Gershenson
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003.,Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, Massachusetts 01003
| | - Daniel N Hebert
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003 .,Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, Massachusetts 01003
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4
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Richter F, Seifert O, Herrmann A, Pfizenmaier K, Kontermann RE. Improved monovalent TNF receptor 1-selective inhibitor with novel heterodimerizing Fc. MAbs 2019; 11:653-665. [PMID: 30929560 DOI: 10.1080/19420862.2019.1596512] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The development of alternative therapeutic strategies to tumor necrosis factor (TNF)-blocking antibodies for the treatment of inflammatory diseases has generated increasing interest. In particular, selective inhibition of TNF receptor 1 (TNFR1) promises a more precise intervention, tackling only the pro-inflammatory responses mediated by TNF while leaving regenerative and pro-survival signals transduced by TNFR2 untouched. We recently generated a monovalent anti-TNFR1 antibody fragment (Fab 13.7) as an efficient inhibitor of TNFR1. To improve the pharmacokinetic properties of Fab 13.7, the variable domains of the heavy and light chains were fused to the N-termini of newly generated heterodimerizing Fc chains. This novel Fc heterodimerization technology, designated "Fc-one/kappa" (Fc1κ) is based on interspersed constant Ig domains substituting the CH3 domains of a γ1 Fc. The interspersed immunoglobulin (Ig) domains originate from the per se heterodimerizing constant CH1 and CLκ domains and contain sequence stretches of an IgG1 CH3 domain, destined to enable interaction with the neonatal Fc receptor, and thus promote extended serum half-life. The resulting monovalent Fv-Fc1κ fusion protein (Atrosimab) retained strong binding to TNFR1 as determined by enzyme-linked immunosorbent assay and quartz crystal microbalance, and potently inhibited TNF-induced activation of TNFR1. Atrosimab lacks agonistic activity for TNFR1 on its own and in the presence of anti-human IgG antibodies and displays clearly improved pharmacokinetic properties.
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Affiliation(s)
- Fabian Richter
- a Institute of Cell Biology and Immunology , University of Stuttgart , Stuttgart , Germany.,b Stuttgart Research Center Systems Biology , University of Stuttgart , Stuttgart , Germany
| | - Oliver Seifert
- a Institute of Cell Biology and Immunology , University of Stuttgart , Stuttgart , Germany.,b Stuttgart Research Center Systems Biology , University of Stuttgart , Stuttgart , Germany
| | | | - Klaus Pfizenmaier
- a Institute of Cell Biology and Immunology , University of Stuttgart , Stuttgart , Germany.,b Stuttgart Research Center Systems Biology , University of Stuttgart , Stuttgart , Germany
| | - Roland E Kontermann
- a Institute of Cell Biology and Immunology , University of Stuttgart , Stuttgart , Germany.,b Stuttgart Research Center Systems Biology , University of Stuttgart , Stuttgart , Germany
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5
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Ho SCL, Wang T, Song Z, Yang Y. IgG Aggregation Mechanism for CHO Cell Lines Expressing Excess Heavy Chains. Mol Biotechnol 2015; 57:625-34. [DOI: 10.1007/s12033-015-9852-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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6
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Nishimiya D. Proteins improving recombinant antibody production in mammalian cells. Appl Microbiol Biotechnol 2013; 98:1031-42. [PMID: 24327213 DOI: 10.1007/s00253-013-5427-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 11/20/2013] [Accepted: 11/21/2013] [Indexed: 12/13/2022]
Abstract
Mammalian cells have been successfully used for the industrial manufacture of antibodies due to their ability to synthesize antibodies correctly. Nascent polypeptides must be subjected to protein folding and assembly in the ER and the Golgi to be secreted as mature proteins. If these reactions do not proceed appropriately, unfolded or misfolded proteins are degraded by the ER-associated degradation (ERAD) pathway. The accumulation of unfolded proteins or intracellular antibody crystals accompanied by this failure triggers the unfolded protein response (UPR), which can considerably attenuate the levels of translation, folding, assembly, and secretion, resulting in reduction of antibody productivity. Accumulating studies by omics-based analysis of recombinant mammalian cells suggest that not only protein secretion processes including protein folding and assembly but also translation are likely to be the rate-limiting factors for increasing antibody production. Here, this review describes the mechanism of antibody folding and assembly and recent advantages which could improve recombinant antibody production in mammalian cells by utilizing proteins such as ER chaperones or UPR-related proteins.
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Affiliation(s)
- Daisuke Nishimiya
- New Modality Research Laboratories, R&D Division, Daiichi Sankyo Co., Ltd., 1-2-58 Hiromachi, Shinagawa-ku, Tokyo, 140-8710, Japan,
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7
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Gidalevitz T, Stevens F, Argon Y. Orchestration of secretory protein folding by ER chaperones. BIOCHIMICA ET BIOPHYSICA ACTA 2013; 1833:2410-24. [PMID: 23507200 PMCID: PMC3729627 DOI: 10.1016/j.bbamcr.2013.03.007] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 02/27/2013] [Accepted: 03/01/2013] [Indexed: 02/06/2023]
Abstract
The endoplasmic reticulum is a major compartment of protein biogenesis in the cell, dedicated to production of secretory, membrane and organelle proteins. The secretome has distinct structural and post-translational characteristics, since folding in the ER occurs in an environment that is distinct in terms of its ionic composition, dynamics and requirements for quality control. The folding machinery in the ER therefore includes chaperones and folding enzymes that introduce, monitor and react to disulfide bonds, glycans, and fluctuations of luminal calcium. We describe the major chaperone networks in the lumen and discuss how they have distinct modes of operation that enable cells to accomplish highly efficient production of the secretome. This article is part of a Special Issue entitled: Functional and structural diversity of endoplasmic reticulum.
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Affiliation(s)
- Tali Gidalevitz
- Department of Biology, Drexel University, Drexel University, 418 Papadakis Integrated Science Bldg, 3245 Chestnut Street, Philadelphia, PA 19104
| | | | - Yair Argon
- Division of Cell Pathology, Department of Pathology and Lab Medicine, The Children's Hospital of Philadelphia and the University of Pennsylvania, 3615 Civic Center Blvd., Philadelphia, PA 19104, USA, , Phone: 267-426-5131, Fax: 267-426-5165)
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8
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Huh JH, White AJ, Brych SR, Franey H, Matsumura M. The identification of free cysteine residues within antibodies and a potential role for free cysteine residues in covalent aggregation because of agitation stress. J Pharm Sci 2013; 102:1701-1711. [PMID: 23559428 DOI: 10.1002/jps.23505] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 02/10/2013] [Accepted: 02/18/2013] [Indexed: 11/09/2022]
Abstract
Human immunoglobulin G1 (IgG1) and immunoglobulin G2 (IgG2) antibodies contain multiple disulfide bonds, which are an integral part of the structure and stability of the protein. Open disulfide bonds have been detected in a number of therapeutic and serum derived antibodies. This report details a method that fluorescently labels free cysteine residues, quantifies, and identifies the proteolytic fragments by liquid chromatography coupled to online mass spectrometry. The majority of the open disulfide bonds in recombinant and serum derived IgG1 and IgG2 antibodies were in the constant domains. This method was applied to the identification of cysteines in an IgG2 antibody that are involved in the formation of covalent intermolecular bonds because of the application of a severe agitation stress. The free cysteine in the CH 1 domain of the IgG2 decreased upon application of the stress and implicates open disulfide bonds in this domain as the likely source of free cysteines involved in the formation of intermolecular disulfide bonds. The presence of comparable levels of open disulfide bonds in recombinant and endogenous antibodies suggests that open disulfide bonds are an inherent feature of antibodies and that the susceptibility of intermolecular disulfide bond formation is similar for recombinant and serum-derived IgG antibodies.
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Affiliation(s)
- Joon H Huh
- Process and Product Development Department, Amgen Inc., Thousand Oaks California 91320-1799.
| | - April J White
- Process and Product Development Department, Amgen Inc., Thousand Oaks California 91320-1799
| | - Stephen R Brych
- Process and Product Development Department, Amgen Inc., Thousand Oaks California 91320-1799
| | - Heather Franey
- Process and Product Development Department, Amgen Inc., Thousand Oaks California 91320-1799
| | - Masazumi Matsumura
- Process and Product Development Department, Amgen Inc., Thousand Oaks California 91320-1799
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9
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Han C, Ihara M, Ueda H. Expression of an antibody-enzyme complex by the L-chain fusion method. J Biosci Bioeng 2013; 116:17-21. [PMID: 23415663 DOI: 10.1016/j.jbiosc.2013.01.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Revised: 12/26/2012] [Accepted: 01/16/2013] [Indexed: 11/16/2022]
Abstract
In this report, we describe a novel method for directly preparing enzyme-labeled antibodies harvested from IgM-producing hybridoma cells. We constructed expression vectors for antibody light (L) chain-enzyme fusion proteins by linking either the genes for the murine lambda L chain or its constant region (C(L)) with one of two proteins, either the secreted placental alkaline phosphatase or Gaussia luciferase (Gluc). When the vectors were transfected into anti-NP (4-hydroxy-3-nitrophacetyl) IgM-producing myeloma cells, secretion of the IgM-enzyme complex from the gene-transfected cells was confirmed by a direct enzyme-linked immunosorbent assay with an immobilized antigen. Furthermore, when human hybridoma HF10B4, a cell line that produces anti-human lung cancer IgM, was transfected with the vector containing L-Gluc, a significantly stronger signal was obtained for the human lung carcinoma SBC-1 cells than for cervical HeLa cells. Because successful production of an active IgM-enzyme complex containing a heterologous L chain-enzyme fusion was observed, the L-chain fusion method will be a generally applicable method for preparing various IgM-enzyme complexes.
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Affiliation(s)
- Chungyong Han
- Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
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10
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Protein Quality Control, Retention, and Degradation at the Endoplasmic Reticulum. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2011; 292:197-280. [DOI: 10.1016/b978-0-12-386033-0.00005-0] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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11
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Makino T, Skretas G, Kang TH, Georgiou G. Comprehensive engineering of Escherichia coli for enhanced expression of IgG antibodies. Metab Eng 2010; 13:241-51. [PMID: 21130896 DOI: 10.1016/j.ymben.2010.11.002] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Revised: 09/29/2010] [Accepted: 11/15/2010] [Indexed: 01/30/2023]
Abstract
The expression of IgG antibodies in Escherichia coli is of increasing interest for analytical and therapeutic applications. In this work, we describe a comprehensive and systematic approach to the development of a dicistronic expression system for enhanced IgG expression in E. coli encompassing: (i) random mutagenesis and high-throughput screening for the isolation of over-expressing strains using flow cytometry and (ii) optimization of translation initiation via the screening of libraries of synonymous codons in the 5' region of the second cistron (heavy chain). The effects of different promoters and co-expression of molecular chaperones on full-length IgG production were also investigated. The optimized system resulted in reliable expression of fully assembled IgG at yields between 1 and 4 mg/L of shake flask culture for different antibodies.
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Affiliation(s)
- Tomohiro Makino
- Department of Chemical Engineering, The University of Texas at Austin, Austin, TX 78712-0231, USA
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12
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Acosta J, Carpio Y, Morales R, Águila JC, Acanda Y, Herrera F, Estrada MP. New insights into the biological activity and secretion properties of a polypeptide derived from tilapia somatotropin. Comp Biochem Physiol B Biochem Mol Biol 2010; 156:264-72. [DOI: 10.1016/j.cbpb.2010.04.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2010] [Revised: 04/05/2010] [Accepted: 04/06/2010] [Indexed: 11/30/2022]
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13
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Feige MJ, Groscurth S, Marcinowski M, Shimizu Y, Kessler H, Hendershot LM, Buchner J. An unfolded CH1 domain controls the assembly and secretion of IgG antibodies. Mol Cell 2009; 34:569-79. [PMID: 19524537 DOI: 10.1016/j.molcel.2009.04.028] [Citation(s) in RCA: 188] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2008] [Revised: 03/05/2009] [Accepted: 04/28/2009] [Indexed: 01/24/2023]
Abstract
A prerequisite for antibody secretion and function is their assembly into a defined quaternary structure, composed of two heavy and two light chains for IgG. Unassembled heavy chains are actively retained in the endoplasmic reticulum (ER). Here, we show that the C(H)1 domain of the heavy chain is intrinsically disordered in vitro, which sets it apart from other antibody domains. It folds only upon interaction with the light-chain C(L) domain. Structure formation proceeds via a trapped intermediate and can be accelerated by the ER-specific peptidyl-prolyl isomerase cyclophilin B. The molecular chaperone BiP recognizes incompletely folded states of the C(H)1 domain and competes for binding to the C(L) domain. In vivo experiments demonstrate that requirements identified for folding the C(H)1 domain in vitro, including association with a folded C(L) domain and isomerization of a conserved proline residue, are essential for antibody assembly and secretion in the cell.
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Affiliation(s)
- Matthias J Feige
- Center for Integrated Protein Science Munich and Department Chemie, Technische Universität München, Lichtenbergstrasse 4, 85747 Garching, Germany
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14
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Muyldermans S, Baral TN, Retamozzo VC, De Baetselier P, De Genst E, Kinne J, Leonhardt H, Magez S, Nguyen VK, Revets H, Rothbauer U, Stijlemans B, Tillib S, Wernery U, Wyns L, Hassanzadeh-Ghassabeh G, Saerens D. Camelid immunoglobulins and nanobody technology. Vet Immunol Immunopathol 2008; 128:178-83. [PMID: 19026455 DOI: 10.1016/j.vetimm.2008.10.299] [Citation(s) in RCA: 362] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
It is well established that all camelids have unique antibodies circulating in their blood. Unlike antibodies from other species, these special antibodies are devoid of light chains and are composed of a heavy-chain homodimer. These so-called heavy-chain antibodies (HCAbs) are expressed after a V-D-J rearrangement and require dedicated constant gamma-genes. An immune response is raised in these so-called heavy-chain antibodies following classical immunization protocols. These HCAbs are easily purified from serum, and the antigen-binding fragment interacts with parts of the target that are less antigenic to conventional antibodies. Since the antigen-binding site of the dromedary HCAb is comprised in one single domain, referred to as variable domain of heavy chain of HCAb (VHH) or nanobody (Nb), we designed a strategy to clone the Nb repertoire of an immunized dromedary and to select the Nbs with specificity for our target antigens. The monoclonal Nbs are well produced in bacteria, are very stable and highly soluble, and bind their cognate antigen with high affinity and specificity. We have successfully developed recombinant Nbs for research purposes, as probe in biosensors, to diagnose infections, and to treat diseases like cancer or trypanosomosis.
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Affiliation(s)
- S Muyldermans
- Laboratory of Cellular and Molecular Immunology, Department of Molecular and Cellular Interactions, VIB, Vrije Universiteit Brussel, Brussels, Belgium.
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15
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Alternative pathways of disulfide bond formation yield secretion-competent, stable and functional immunoglobulins. Mol Immunol 2008; 46:97-105. [PMID: 18692901 DOI: 10.1016/j.molimm.2008.07.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2008] [Revised: 07/06/2008] [Accepted: 07/08/2008] [Indexed: 11/23/2022]
Abstract
Disulfide bonds within and between proteins are responsible for stabilizing folding and covalent assembly. They are thought to form by an obligatory pathway that leads to a single native structure compatible with secretion. We have previously demonstrated that the intradomain disulfide in the C(H)1 domain of the Ig gamma2b heavy chains was dispensable for secretion [Elkabetz, Y., Argon, Y., Bar-Nun, S., 2005. Cysteines in C(H)1 underlie retention of unassembled Ig heavy chains. J. Biol. Chem. 280, 14402-14412]. Here we show that the heavy chain-light chain interchain disulfide is also dispensable. gamma2b with mutated Cys128, which normally disulfide bonds with the light chain, still assembled with lambdaI light chain into a secretion-competent, tetrameric IgG2b. This assembly comprised of a covalent homo-dimer of mutant heavy chains (C128S(2)) accompanied non-covalently by a covalent homo-dimer of light chains (lambda(2)). The lambda(2) homo-dimer formed only upon association with C128S(2), through disulfide bonding of the two "orphan" heavy chain-interacting Cys214 in lambdaI. The unique Ig tetramer was secreted efficiently as a functional antibody whose antigen-binding capacity resembled that of normal IgG2b. Therefore, disulfide bonding of Ig manifests considerable plasticity and can generate more than one functional structure that is considered native by the cellular quality control system.
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16
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Christis C, Lubsen NH, Braakman I. Protein folding includes oligomerization - examples from the endoplasmic reticulum and cytosol. FEBS J 2008; 275:4700-27. [DOI: 10.1111/j.1742-4658.2008.06590.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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17
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Efficient antibody production upon suppression of O mannosylation in the yeast Ogataea minuta. Appl Environ Microbiol 2007; 74:446-53. [PMID: 18039826 DOI: 10.1128/aem.02106-07] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
When antibodies were expressed in the methylotrophic yeast Ogataea minuta, we found that abnormal O mannosylation occurred in the secreted antibody. Yeast-specific O mannosylation is initiated by the addition of mannose at serine (Ser) or threonine (Thr) residues in the endoplasmic reticulum via protein O mannosyltransferase (Pmt) activity. To suppress the addition of O-linked sugar chains on antibodies, we examined the possibility of inhibiting Pmt activity by the addition of a Pmt inhibitor during cultivation. The Pmt inhibitor was found to partially suppress the O mannosylation on the antibodies. Surprisingly, the suppression of O mannosylation was associated with an increased amount of assembled antibody (H2L2) and enhanced the antigen-binding activity of the secreted antibody. In this study, we demonstrated the expression of human antibody in O. minuta and elucidated the relationship between O mannosylation and antibody production in yeast.
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