1
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Yamamoto M, Funada R, Taki R, Shiroishi M. Production and characterization of an Fv-clasp of rheumatoid factor, a low-affinity human autoantibody. J Biochem 2024; 175:387-394. [PMID: 38102734 DOI: 10.1093/jb/mvad112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 11/23/2023] [Indexed: 12/17/2023] Open
Abstract
Rheumatoid factor (RF) is an autoantibody against IgG that affects autoimmune diseases and inhibits the effectiveness of pharmaceuticals and diagnostic agents. Although RFs derived from various germline genes have been identified, little is known about their molecular recognition mechanisms. In this study, the Fv-clasp format was used to prepare YES8c, an RF. We developed an Escherichia coli secretion expression system capable of producing milligram-scale of YES8c Fv-clasp per 1 L of culture. Although YES8c is an autoantibody with very low affinity, the produced Fv-clasp maintained specific binding to IgG. Interestingly, the molecules prepared by E. coli secretion had a higher affinity than those prepared by refolding. In the structure of the YES8c-Fc complex, the N-terminus of the light chain is close to Fc; therefore, it is suggested that the addition of the N-terminal methionine may cause collisions with Fc, resulting in reduced affinity. Our findings suggest that the Fv-clasp, which provides sufficient stability and a high bacterial yield, is a useful format for studying RFs with very low affinity. Furthermore, the Fv-clasp produced from a secretion expression system, which can properly process the N-terminus, would be suitable for analysis of RFs in which the N-terminus may be involved in interactions.
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Affiliation(s)
- Maruto Yamamoto
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo, 125-8585, Japan
| | - Ryoma Funada
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo, 125-8585, Japan
| | - Ryota Taki
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo, 125-8585, Japan
| | - Mitsunori Shiroishi
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo, 125-8585, Japan
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2
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Romei MG, Leonard B, Katz ZB, Le D, Yang Y, Day ES, Koo CW, Sharma P, Bevers Iii J, Kim I, Dai H, Farahi F, Lin M, Shaw AS, Nakamura G, Sockolosky JT, Lazar GA. i-shaped antibody engineering enables conformational tuning of biotherapeutic receptor agonists. Nat Commun 2024; 15:642. [PMID: 38245524 PMCID: PMC10799922 DOI: 10.1038/s41467-024-44985-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 01/11/2024] [Indexed: 01/22/2024] Open
Abstract
The ability to leverage antibodies to agonize disease relevant biological pathways has tremendous potential for clinical investigation. Yet while antibodies have been successful as antagonists, immune mediators, and targeting agents, they are not readily effective at recapitulating the biology of natural ligands. Among the important determinants of antibody agonist activity is the geometry of target receptor engagement. Here, we describe an engineering approach inspired by a naturally occurring Fab-Fab homotypic interaction that constrains IgG in a unique i-shaped conformation. i-shaped antibody (iAb) engineering enables potent intrinsic agonism of five tumor necrosis factor receptor superfamily (TNFRSF) targets. When applied to bispecific antibodies against the heterodimeric IL-2 receptor pair, constrained bispecific IgG formats recapitulate IL-2 agonist activity. iAb engineering provides a tool to tune agonist antibody function and this work provides a framework for the development of intrinsic antibody agonists with the potential for generalization across broad receptor classes.
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Affiliation(s)
- Matthew G Romei
- Department of Antibody Engineering, Genentech Inc., South San Francisco, CA, USA
| | - Brandon Leonard
- Department of Antibody Engineering, Genentech Inc., South San Francisco, CA, USA
| | - Zachary B Katz
- Department of Research Biology, Genentech Inc., South San Francisco, CA, USA
| | - Daniel Le
- Department of Microchemistry, Proteomic, Lipidomics, and Next Generation Sequencing, Genentech Inc., South San Francisco, CA, USA
| | - Yanli Yang
- Department of Antibody Engineering, Genentech Inc., South San Francisco, CA, USA
| | - Eric S Day
- Department of Pharma Technical Development, Genentech Inc., South San Francisco, CA, USA
| | - Christopher W Koo
- Department of Structural Biology, Genentech Inc., South San Francisco, CA, USA
| | - Preeti Sharma
- Department of Antibody Engineering, Genentech Inc., South San Francisco, CA, USA
| | - Jack Bevers Iii
- Department of Antibody Engineering, Genentech Inc., South San Francisco, CA, USA
| | - Ingrid Kim
- Department of Antibody Engineering, Genentech Inc., South San Francisco, CA, USA
| | - Huiguang Dai
- Department of Antibody Engineering, Genentech Inc., South San Francisco, CA, USA
| | - Farzam Farahi
- Department of Antibody Engineering, Genentech Inc., South San Francisco, CA, USA
| | - May Lin
- Department of Protein Chemistry, Genentech Inc., South San Francisco, CA, USA
| | - Andrey S Shaw
- Department of Research Biology, Genentech Inc., South San Francisco, CA, USA
| | - Gerald Nakamura
- Department of Antibody Engineering, Genentech Inc., South San Francisco, CA, USA
| | | | - Greg A Lazar
- Department of Antibody Engineering, Genentech Inc., South San Francisco, CA, USA.
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3
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Trier NH. Characterization of Peptide Antibodies by Epitope Mapping Using Resin-Bound and Soluble Peptides. Methods Mol Biol 2024; 2821:179-193. [PMID: 38997489 DOI: 10.1007/978-1-0716-3914-6_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/14/2024]
Abstract
Characterization of peptide antibodies through identification of their target epitopes is of utmost importance, as information about epitopes provide important knowledge, among others, for discovery and development of new therapeutics, vaccines, and diagnostics.This chapter describes a strategy for mapping of continuous peptide antibody epitopes using resin-bound and soluble peptides. The approach combines three different types of peptide sets for full characterization of peptide antibodies; (i) overlapping peptides, used to locate antigenic regions; (ii) truncated peptides, used to identify the minimal peptide length required for antibody binding; and (iii) substituted peptides, used to identify the key residues important for antibody binding and to determine the specific contribution of key residues. For initial screening, resin-bound peptides are used for epitope estimation, while soluble peptides subsequently are used for final epitope characterization and identification of critical hot spot residues. The combination of resin-bound peptides and soluble peptides for epitope mapping provides a time-saving and straightforward approach for characterization of antibodies recognizing continuous epitopes, which applies to peptide antibodies and occasionally antibodies directed to larger proteins as well.
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4
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Trier NH, Friis T. Production of Antibodies to Peptide Targets Using Hybridoma Technology. Methods Mol Biol 2024; 2821:135-156. [PMID: 38997486 DOI: 10.1007/978-1-0716-3914-6_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/14/2024]
Abstract
Hybridoma technology is a well-established and indispensable tool for generating high-quality monoclonal antibodies and has become one of the most common methods for monoclonal antibody production. In this process, antibody-producing B cells are isolated from mice following immunization of mice with a specific immunogen and fused with an immortal myeloma cell line to form antibody-producing hybridoma cell lines. Hybridoma-derived monoclonal antibodies not only serve as powerful research and diagnostic reagents but have also emerged as the most rapidly expanding class of therapeutic biologicals. In spite of the development of new high-throughput monoclonal antibody generation technologies, hybridoma technology still is applied for antibody production due to its ability to preserve innate functions of immune cells and to preserve natural cognate antibody paring information. In this chapter, an overview of hybridoma technology and the laboratory procedures used for hybridoma production and antibody screening of peptide-specific antibodies are presented.
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Affiliation(s)
| | - Tina Friis
- Department of Congenital Disorders, Statens Serum Institut, Copenhagen S, Denmark
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5
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Oskam N, Ooijevaar-De Heer P, Kos D, Jeremiasse J, van Boheemen L, Verstappen GM, Kroese FGM, van Schaardenburg D, Wolbink G, Rispens T. Rheumatoid factor autoantibody repertoire profiling reveals distinct binding epitopes in health and autoimmunity. Ann Rheum Dis 2023:ard-2023-223901. [PMID: 37055152 DOI: 10.1136/ard-2023-223901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 04/02/2023] [Indexed: 04/15/2023]
Abstract
BACKGROUND Rheumatoid factors (RF) are one of the hallmark autoantibodies characteristic of rheumatoid arthritis (RA), and are frequently observed in other diseases and in healthy individuals. RFs comprise multiple subtypes with different specificities towards the constant region of human IgG. Studies indicate that these patterns differ between naturally occurring RFs and RFs associated with disease. However, individual specificities characteristic of either have not been clearly defined. METHODS In this study, we developed an extended set of engineered IgG-fragment crystallisable (Fc) targets with preferential RF binding to specific (conformational) epitopes, which was subsequently used for profiling of RF binding patterns in a compiled exploration cohort, consisting of sera from healthy donors with measurable RF and patients with RA, primary Sjögren's syndrome (pSS) and seropositive arthralgia. RESULTS We identified an epitope that is strongly associated with RA, which was targeted by both IgM-RF and IgA-RF. We also identified an epitope that is preferentially targeted by healthy donor (IgM) RFs. IgM-RFs derived from healthy donors and patients with RA and pSS all target distinct regions on the IgG-Fc, whereas overall, the IgA-RF repertoire is largely restricted to pathology-associated specificities. Using monoclonal RFs with different specificities, we furthermore demonstrate that the capacity to activate complement or even inhibit IgG-mediated complement activation varies according to the epitopes to which RFs bind. CONCLUSIONS Our results demonstrate both the need and feasibility to redefine 'RF' into pathological and physiological autoantibody subtypes.
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Affiliation(s)
- Nienke Oskam
- Immunopathology, Sanquin Research, Amsterdam, The Netherlands
| | | | - Dorien Kos
- Sanquin Reagents, Amsterdam, The Netherlands
| | - Jorn Jeremiasse
- Immunopathology, Sanquin Research, Amsterdam, The Netherlands
| | | | - Gwenny M Verstappen
- Rheumatology & Clinical Immunology, University of Groningen, Groningen, The Netherlands
| | - Frans G M Kroese
- Rheumatology & Clinical Immunology, University of Groningen, Groningen, The Netherlands
| | | | - Gertjan Wolbink
- Amsterdam Rheumatology and Immunology Center, Amsterdam, The Netherlands
| | - Theo Rispens
- Immunopathology, Sanquin Research, Amsterdam, The Netherlands
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6
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Romei MG, Leonard B, Kim I, Kim HS, Lazar GA. Antibody-guided proteases enable selective and catalytic degradation of challenging therapeutic targets. J Biol Chem 2023; 299:104685. [PMID: 37031819 DOI: 10.1016/j.jbc.2023.104685] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 03/08/2023] [Accepted: 03/23/2023] [Indexed: 04/11/2023] Open
Abstract
The exquisite specificity, natural biological functions, and favorable development properties of antibodies make them highly effective agents as drugs. Monoclonal antibodies are particularly strong as inhibitors of systemically accessible targets where trough-level concentrations can sustain full target occupancy. Yet beyond this pharmacologic wheelhouse, antibodies perform suboptimally for targets of high abundance and those not easily accessible from circulation. Fundamentally, this restraint on broader application is due largely to the stoichiometric nature of their activity - one drug molecule is generally able to inhibit a maximum of two target molecules at a time. Enzymes in contrast are able to catalytically turnover multiple substrates, making them a natural sub-stoichiometric solution for targets of high abundance or in poorly accessible sites of action. However, enzymes have their own limitations as drugs, including, in particular the polypharmacology and broad specificity often seen with native enzymes. In this study, we introduce antibody-guided proteolytic enzymes to enable selective sub-stoichiometric turnover of therapeutic targets. We demonstrate that antibody-mediated substrate targeting can enhance enzyme activity and specificity, with proof of concept for two challenging target proteins, amyloid-β (Aβ) and immunoglobulin G (IgG). This work advances a new biotherapeutic platform that combines the favorable properties of antibodies and proteolytic enzymes to more effectively suppress high-bar therapeutic targets.
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Affiliation(s)
- Matthew G Romei
- Department of Antibody Engineering, Genentech Inc., South San Francisco, CA, USA.
| | - Brandon Leonard
- Department of Antibody Engineering, Genentech Inc., South San Francisco, CA, USA
| | - Ingrid Kim
- Department of Antibody Engineering, Genentech Inc., South San Francisco, CA, USA
| | - Hok Seon Kim
- Department of Antibody Engineering, Genentech Inc., South San Francisco, CA, USA
| | - Greg A Lazar
- Department of Antibody Engineering, Genentech Inc., South San Francisco, CA, USA
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7
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Oskam N, Ooijevaar-de Heer P, Derksen NIL, Kruithof S, de Taeye SW, Vidarsson G, Reijm S, Kissel T, Toes REM, Rispens T. At Critically Low Antigen Densities, IgM Hexamers Outcompete Both IgM Pentamers and IgG1 for Human Complement Deposition and Complement-Dependent Cytotoxicity. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2022; 209:16-25. [PMID: 35705253 DOI: 10.4049/jimmunol.2101196] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 04/21/2022] [Indexed: 06/15/2023]
Abstract
IgM is secreted as a pentameric polymer containing a peptide called the joining chain (J chain). However, integration of the J chain is not required for IgM assembly and in its absence IgM predominantly forms hexamers. The conformations of pentameric and hexameric IgM are remarkably similar with a hexagonal arrangement in solution. Despite these similarities, hexameric IgM has been reported to be a more potent complement activator than pentameric IgM, but reported relative potencies vary across different studies. Because of these discrepancies, we systematically investigated human IgM-mediated complement activation. We recombinantly generated pentameric and hexameric human IgM (IgM+J and IgM-J, respectively) mAbs and measured their ability to induce complement deposition and complement-dependent cytotoxicity when bound to several Ags at varying densities. At high Ag densities, hexameric and pentameric IgM activate complement to a similar extent as IgG1. However, at low densities, hexameric IgM outcompeted pentameric IgM and even more so IgG1. These differences became progressively more pronounced as antigenic density became critically low. Our findings highlight that the differential potency of hexameric and pentameric IgM for complement activation is profoundly dependent on the nature of its interactions with Ag. Furthermore, it underscores the importance of IgM in immunity because it is a more potent complement activator than IgG1 at low Ag densities.
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Affiliation(s)
- Nienke Oskam
- Department of Immunopathology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, Amsterdam, the Netherlands;
| | - Pleuni Ooijevaar-de Heer
- Department of Immunopathology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, Amsterdam, the Netherlands
| | - Ninotska I L Derksen
- Department of Immunopathology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, Amsterdam, the Netherlands
| | - Simone Kruithof
- Department of Immunopathology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, Amsterdam, the Netherlands
| | - Steven W de Taeye
- Department of Experimental Immunohematology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, Amsterdam, the Netherlands; and
| | - Gestur Vidarsson
- Department of Experimental Immunohematology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, Amsterdam, the Netherlands; and
| | - Sanne Reijm
- Department of Rheumatology, Leiden University Medical Center, Leiden, the Netherlands
| | - Theresa Kissel
- Department of Rheumatology, Leiden University Medical Center, Leiden, the Netherlands
| | - René E M Toes
- Department of Rheumatology, Leiden University Medical Center, Leiden, the Netherlands
| | - Theo Rispens
- Department of Immunopathology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, Amsterdam, the Netherlands
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8
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Reed JH. Transforming mutations in the development of pathogenic B cell clones and autoantibodies. Immunol Rev 2022; 307:101-115. [PMID: 35001403 DOI: 10.1111/imr.13064] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 12/31/2021] [Accepted: 01/01/2022] [Indexed: 12/16/2022]
Abstract
Autoimmune diseases are characterized by serum autoantibodies, some of which are pathogenic, causing severe manifestations and organ injury. However, autoantibodies of the same antigenic reactivity are also present in the serum of asymptomatic people years before they develop any clinical signs of autoimmunity. Autoantibodies can arise during multiple stages of B cell development, and various genetic and environmental factors drive their production. However, what drives the development of pathogenic autoantibodies is poorly understood. Advances in single-cell technology have enabled the deep analysis of rare B cell clones producing pathogenic autoantibodies responsible for vasculitis in patients with primary Sjögren's syndrome complicated by mixed cryoglobulinaemia. These findings demonstrated a cascade of genetic events involving stereotypic immunoglobulin V(D)J recombination and transforming somatic mutations in lymphoma genes and V(D)J regions that disrupted antibody quality control mechanisms and decreased autoantibody solubility. Most studies consider V(D)J mutations that enhance autoantibody affinity to drive pathology; however, V(D)J mutations that increase autoantibody propensity to form insoluble complexes could be a major contributor to autoantibody pathogenicity. Defining the molecular characteristics of pathogenic autoantibodies and failed tolerance checkpoints driving their formation will improve prognostication, enabling early treatment to prevent escalating organ damage and B cell malignancy.
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Affiliation(s)
- Joanne H Reed
- Westmead Institute for Medical Research, Centre for Immunology and Allergy Research, Westmead, NSW, Australia.,Faculty of Medicine and Health, School of Medical Sciences, The University of Sydney, Sydney, NSW, Australia
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9
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Li Z, Zhang Y, Han M, Deng H, Wu F, Liu G, Chen GQ. Lysine β-Hydroxybutyrylation Improves Stability of COVID-19 Antibody. Biomacromolecules 2021; 23:454-463. [PMID: 34879647 DOI: 10.1021/acs.biomac.1c01435] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
β-Hydroxybutyrate (3HB) is a small molecule produced as a ketone body in mammalian animals. It has been found that 3HB provides not only energy for a body, it also participates in cell signal transduction events as a signal molecule. This study focuses on investigation of 3HB immunomodulatory mechanisms. Proteomic analysis indicates a new post-translational modification of β-hydroxybutyrylation (Kbhb) on antibodies. Because of the low level of Kbhb antibodies and the associated difficulty in purifying them, simulated Kbhb antibody was produced using chemical modification in vitro. The chemically modified Kbhb antibody was shown to improve the stability of antibodies to protease and heat treatments. Furthermore, Kbhb of antibodies stabilizes the antibodies in plasma. As a remarkable example, COVID-19 neutralizing antibody B38 produced by 293T cells was Kbhb modified and stabilized in vivo, providing a strategy for the possibility of extending the protection effects of COVID-19 antibodies.
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Affiliation(s)
- Zihua Li
- School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China
| | - Yudian Zhang
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Meng Han
- Protein and Chemistry Platform, Tsinghua University, Beijing 100084, China
| | - Haiteng Deng
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Fuqing Wu
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Gang Liu
- School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China
| | - Guo-Qiang Chen
- School of Life Sciences, Tsinghua University, Beijing 100084, China.,Center for Synthetic and Systems Biology, Tsinghua University, Beijing 100084, China.,MOE Key Lab of Industrial Biocatalysis, Dept of Chemical Engineering, Tsinghua University, Beijing 100084, China
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10
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Xiao X, Zhou Q, Zhu J, Sun L, Zhang H, Sun Y, Zhao J, Cui L. False-positive colloidal gold-based immunochromatographic strip assay reactions for antibodies to SARS-CoV-2 in patients with autoimmune diseases. ANNALS OF TRANSLATIONAL MEDICINE 2021; 9:534. [PMID: 33987232 DOI: 10.21037/atm-20-6509] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Background The outbreak of the novel 2019 coronavirus disease (COVID-19) was declared a global pandemic by the World Health Organization (WHO) on March 11, 2020. The diagnosis of COVID-19 is frequently based on a positive serological test. We noted the occurrence of false-positive results for COVID-19 in the colloidal gold-based immunochromatographic strip (ICS) assay in sera from patients with autoimmune diseases (ADs). This study aimed to evaluate the possible reasons for the false-positive results in two ICS assays (Wondfo ICS and Innovita ICS) and to investigate the effect of urea dissociation in reducing false-positive results. Methods The sera of 135 patients with ADs, 13 confirmed COVID-19 patients, 95 disease controls, and 120 healthy controls were tested for immunoglobin M (IgM) and IgG against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) using Wondfo and Innovita ICS kits. The distributions of auto-antibodies in antibody-positive and antibody-negative groups were also compared, and bivariable logistic regression was used to assess auto-antibodies associated with false-positive results. A urea dissociation test of ICS was performed for the SARS-CoV-2 antibody-positive samples. Results Specificity of Wondfo ICS for the 95 disease controls was 94.74% compared to 98.95% and 96.84% for Innovita SARS-CoV-2 IgM and IgG, respectively. Specificity of Wondfo ICS for the 120 healthy controls was 97.5% compared to 100% and 99.17% for Innovita SARS-CoV-2 IgM and IgG, respectively. Specificity of Wondfo ICS for AD patients was 73.33% compared to 97.78% and 96.30% for Innovita SARS-CoV-2 IgM and IgG, respectively. Sensitivity was 74.07% for Wondfo compared to 70.37% for Innovita IgM and 66.67% for Innovita IgG. Using the Wondfo ICS, the percentage of elevated rheumatoid factor (RF) level (>20 IU/mL) was higher in the SARS-CoV-2 antibody-positive group compared with the antibody-negative group [27/36 (75.0%) vs. 34/99 (34.34%), P=0.001]. The elevated RF was associated with antibody positivity, with an odds ratio of 4.671 [95% confidence interval (CI), 1.88-11.69]. The specificity of the Wondfo ICS assay for the AD patients was increased from 73.33% to 94.07% after the urea dissociation assay. Conclusions An elevated serum RF level could lead to false-positive results when detecting SARS-CoV-2 antibodies using the Wondfo ICS kit, and the urea dissociation assay would be helpful in reducing the incidence of false-positive results.
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Affiliation(s)
- Xiumei Xiao
- The Department of Laboratory Medicine, Peking University Third Hospital, Beijing, China
| | - Qingtao Zhou
- The Department of Respiratory and Critical Care Medicine, Peking University Third Hospital, Beijing, China
| | - Jinghao Zhu
- The Department of Laboratory Medicine, Peking University Third Hospital, Beijing, China
| | - Lin Sun
- The Department of Rheumatology and Immunology, Peking University Third Hospital, Beijing, China
| | - Hua Zhang
- Research Center of Clinical Epidemiology, Peking University Third Hospital, Beijing, China
| | - Yongchang Sun
- The Department of Respiratory and Critical Care Medicine, Peking University Third Hospital, Beijing, China
| | - Jinxia Zhao
- The Department of Rheumatology and Immunology, Peking University Third Hospital, Beijing, China
| | - Liyan Cui
- The Department of Laboratory Medicine, Peking University Third Hospital, Beijing, China
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11
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Arvey A, Rowe M, Legutki JB, An G, Gollapudi A, Lei A, Colston B, Putterman C, Smith D, Stiles J, Tarasow T, Ramamoorthy P. Age-associated changes in the circulating human antibody repertoire are upregulated in autoimmunity. IMMUNITY & AGEING 2020; 17:28. [PMID: 33042204 PMCID: PMC7539520 DOI: 10.1186/s12979-020-00193-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 07/24/2020] [Indexed: 12/26/2022]
Abstract
Background The immune system undergoes a myriad of changes with age. While it is known that antibody-secreting plasma and long-lived memory B cells change with age, it remains unclear how the binding profile of the circulating antibody repertoire is impacted. Results To understand humoral immunity changes with respect to age, we characterized serum antibody binding to high density peptide microarrays in a diverse cohort of 1675 donors. We discovered thousands of peptides that bind antibodies in age-dependent fashion, many of which contain di-serine motifs. Peptide binding profiles were aggregated into an “immune age” by a machine learning regression model that was highly correlated with chronological age. Applying this regression model to previously-unobserved donors, we found that a donor’s predicted immune age is longitudinally consistent over years, suggesting it could be a robust long-term biomarker of humoral immune ageing. Finally, we assayed serum from donors with autoimmune disease and found a significant association between “accelerated immune ageing” and autoimmune disease activity. Conclusions The circulating antibody repertoire has increased binding to thousands of di-serine peptide containing peptides in older donors, which can be represented as an immune age. Increased immune age is associated with autoimmune disease, acute inflammatory disease severity, and may be a broadly relevant biomarker of immune function in health, disease, and therapeutic intervention.
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Affiliation(s)
- Aaron Arvey
- iCarbonX 2424 Camino Ramon, Suite 125, San Ramon, CA 94583 USA
| | - Michael Rowe
- iCarbonX 2424 Camino Ramon, Suite 125, San Ramon, CA 94583 USA
| | | | - Gang An
- iCarbonX 2424 Camino Ramon, Suite 125, San Ramon, CA 94583 USA
| | | | - Anna Lei
- HealthTell, 145 S. 79th St., Chandler, AZ 85226 USA
| | - Bill Colston
- iCarbonX 2424 Camino Ramon, Suite 125, San Ramon, CA 94583 USA
| | - Chaim Putterman
- Albert Einstein College of Medicine, Division of Rheumatology, Forchheimer 701N, 1300 Morris Park Ave, Bronx, NY 10461 USA.,Azrieli Faculty of Medicine, Bar-Ilan University, Zefat, Israel.,Research Institute, Galilee Medical Center, Nahariya, Israel
| | - David Smith
- HealthTell, 145 S. 79th St., Chandler, AZ 85226 USA
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12
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Falkenburg WJJ, Oskam N, Koers J, van Boheemen L, Ooijevaar-de Heer P, Verstappen GM, Bootsma H, Kroese FGM, van Schaardenburg D, Wolbink G, Rispens T. Identification of Clinically and Pathophysiologically Relevant Rheumatoid Factor Epitopes by Engineered IgG Targets. Arthritis Rheumatol 2020; 72:2005-2016. [PMID: 32648642 DOI: 10.1002/art.41430] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 06/16/2020] [Indexed: 12/24/2022]
Abstract
OBJECTIVE Rheumatoid factors (RFs), which are anti-IgG autoantibodies strongly associated with rheumatoid arthritis (RA), are also found in other diseases and in healthy individuals. RFs bind to various epitopes in the constant (Fc-) domain of IgG. Therefore, disease-specific reactivity patterns may exist. This study was undertaken in order to develop a new approach to dissecting RF epitope binding patterns across different diseases. METHODS We analyzed RF reactivity patterns in serum from patients with seropositive arthralgia, patients with RA, and patients with primary Sjögren's syndrome (SS) using bioengineered, natively folded IgG-Fc targets that demonstrated selective RF binding toward several distinct regions of the IgG-Fc domain. RESULTS Rheumatoid factor responses primarily bound the Fc Elbow region, with a smaller number of RFs binding the Fc Tail region, while the Fc receptor binding region was hardly targeted. A restricted reactivity against the IgG-Fc Tail region was associated with less positivity for anti-citrullinated protein antibodies (ACPAs) and less arthritis development in arthralgia, whereas combined reactivity toward IgG-Fc Tail and Elbow regions was associated with more arthritis development. Reactivity toward the IgG-Fc Tail region was observed far more frequently in RA than in primary SS. CONCLUSION Bioengineered IgG targets enable serologic characterization of RF reactivity patterns, and use of this approach appears to reveal patterns associated with ACPA detection and arthritis development in patients with arthralgia. These patterns are able to distinguish RA patients from primary SS patients. This new methodology improves the clinical value of RFs and our understanding of their pathophysiologic processes.
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Affiliation(s)
- Willem J J Falkenburg
- Amsterdam Rheumatology and Immunology Center, Reade, Sanquin Research, and Academic Medical Center, Amsterdam, The Netherlands
| | - Nienke Oskam
- Sanquin Research and Academic Medical Center, Amsterdam, The Netherlands
| | - Jana Koers
- Sanquin Research and Academic Medical Center, Amsterdam, The Netherlands
| | | | | | - Gwenny M Verstappen
- University of Groningen and University Medical Center Groningen, Groningen, The Netherlands
| | - Hendrika Bootsma
- University of Groningen and University Medical Center Groningen, Groningen, The Netherlands
| | - Frans G M Kroese
- University of Groningen and University Medical Center Groningen, Groningen, The Netherlands
| | - Dirkjan van Schaardenburg
- Amsterdam Rheumatology and Immunology Center, Reade, and, Academic Medical Center, Amsterdam, The Netherlands
| | - Gertjan Wolbink
- Amsterdam Rheumatology and Immunology Center and Reade, Amsterdam, The Netherlands
| | - Theo Rispens
- Sanquin Research and Academic Medical Center, Amsterdam, The Netherlands
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13
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Lešnik S, Hodošček M, Podobnik B, Konc J. Loop Grafting between Similar Local Environments for Fc-Silent Antibodies. J Chem Inf Model 2020; 60:5475-5486. [PMID: 32379970 PMCID: PMC7686954 DOI: 10.1021/acs.jcim.9b01198] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
![]()
Reduction
of the affinity of the fragment crystallizable (Fc) region with immune
receptors by substitution of one or a few amino acids, known as Fc-silencing,
is an established approach to reduce the immune effector functions
of monoclonal antibody therapeutics. This approach to Fc-silencing,
however, is problematic as it can lead to instability and immunogenicity
of the developed antibodies. We evaluated loop grafting as a novel
approach to Fc-silencing in which the Fc loops responsible for immune
receptor binding were replaced by loops of up to 20 amino acids from
similar local environments in other human and mouse antibodies. Molecular
dynamics simulations of the designed variants of an Fc region in a
complex with the immune receptor FcγIIIa confirmed that loop
grafting potentially leads to a significant reduction in the binding
of the antibody variants to the receptor, while retaining their stability.
In comparison, standard variants with less than eight substituted
amino acids showed possible instability and a lower degree of Fc-silencing
due to the occurrence of compensatory interactions. The presented
approach to Fc-silencing is general and could be used to modulate
undesirable side effects of other antibody therapeutics without affecting
their stability or increasing their immunogenicity.
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Affiliation(s)
- Samo Lešnik
- National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia
| | - Milan Hodošček
- National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia
| | - Barbara Podobnik
- Biologics Technical Development Mengeš, Technical Research & Development Novartis, Lek Pharmaceuticals d.d., Kolodvorska 27, SI-1234 Mengeš, Slovenia
| | - Janez Konc
- National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia
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14
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Shimizu Y, Kohyama M, Yorifuji H, Jin H, Arase N, Suenaga T, Arase H. FcγRIIIA-mediated activation of NK cells by IgG heavy chain complexed with MHC class II molecules. Int Immunol 2020; 31:303-314. [PMID: 30721990 DOI: 10.1093/intimm/dxz010] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2018] [Accepted: 01/31/2019] [Indexed: 01/09/2023] Open
Abstract
Natural killer (NK) cells are a major FcγRIIIA-expressing lymphocyte population that mediate antibody-dependent cellular cytotoxicity. Although NK cells are critical for immunity against viruses and tumors, they are also activated in the joints of patients with rheumatoid arthritis (RA) and may be involved in disease progression. We previously found that human leukocyte antigen (HLA) class II molecules transport misfolded cellular proteins, such as IgG heavy chain (IgGH), to the cell surface via association with their peptide-binding grooves. Furthermore, we found that IgGHs bound to HLA class II molecules encoded by RA susceptibility alleles are specific targets for rheumatoid factor, an auto-antibody involved in RA. Here, we report that IgGHs bound to HLA class II molecules preferentially stimulate FcγRIIIA-expressing but not FcγRI-expressing cells. A significant correlation was observed between the reactivity of FcγRIIIA-expressing cells to IgGH complexed with a specific HLA-DR allele and the odds ratio for HLA-DR allele's association with RA. Moreover, primary human NK cells expressing FcγRIIIA demonstrated IFN-γ production and cytotoxicity against cells expressing IgGH complexed with HLA class II molecules. Our findings suggest that IgGH complexed with HLA class II molecules are involved in the activation of FcγRIIIA-expressing NK cells observed within arthritic joints.
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Affiliation(s)
- Yuta Shimizu
- Department of Immunochemistry, Research Institute for Microbial Diseases.,Laboratory of Immunochemistry, WPI Immunology Frontier Research Center
| | - Masako Kohyama
- Department of Immunochemistry, Research Institute for Microbial Diseases.,Laboratory of Immunochemistry, WPI Immunology Frontier Research Center
| | - Hideki Yorifuji
- Department of Immunochemistry, Research Institute for Microbial Diseases.,Laboratory of Immunochemistry, WPI Immunology Frontier Research Center.,Department of Respiratory Medicine and Clinical Immunology, Graduate School of Medicine
| | - Hui Jin
- Laboratory of Immunochemistry, WPI Immunology Frontier Research Center
| | - Noriko Arase
- Department of Immunochemistry, Research Institute for Microbial Diseases.,Department of Dermatology, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan
| | - Tadahiro Suenaga
- Department of Immunochemistry, Research Institute for Microbial Diseases.,Laboratory of Immunochemistry, WPI Immunology Frontier Research Center
| | - Hisashi Arase
- Department of Immunochemistry, Research Institute for Microbial Diseases.,Laboratory of Immunochemistry, WPI Immunology Frontier Research Center
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15
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Comarmond C, Lorin V, Marques C, Maciejewski-Duval A, Joher N, Planchais C, Touzot M, Biard L, Hieu T, Quiniou V, Desbois AC, Rosenzwajg M, Klatzmann D, Cacoub P, Mouquet H, Saadoun D. TLR9 signalling in HCV-associated atypical memory B cells triggers Th1 and rheumatoid factor autoantibody responses. J Hepatol 2019; 71:908-919. [PMID: 31279905 DOI: 10.1016/j.jhep.2019.06.029] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 06/24/2019] [Accepted: 06/27/2019] [Indexed: 01/22/2023]
Abstract
BACKGROUND & AIMS Hepatitis C virus (HCV) infection contributes to the development of autoimmune disorders such as cryoglobulinaemia vasculitis (CV). However, it remains unclear why only some individuals with HCV develop HCV-associated CV (HCV-CV). HCV-CV is characterized by the expansion of anergic CD19+CD27+CD21low/- atypical memory B cells (AtMs). Herein, we report the mechanisms by which AtMs participate in HCV-associated autoimmunity. METHODS The phenotype and function of peripheral AtMs were studied by multicolour flow cytometry and co-culture assays with effector T cells and regulatory T cells in 20 patients with HCV-CV, 10 chronicallyHCV-infected patients without CV and 8 healthy donors. We performed gene expression profile analysis of AtMs stimulated or not by TLR9. Immunoglobulin gene repertoire and antibody reactivity profiles of AtM-expressing IgM antibodies were analysed following single B cell FACS sorting and expression-cloning of monoclonal antibodies. RESULTS The Tbet+CD11c+CD27+CD21- AtM population is expanded in patients with HCV-CV compared to HCV controls without CV. TLR9 activation of AtMs induces a specific transcriptional signature centred on TNFα overexpression, and an enhanced secretion of TNFα and rheumatoid factor-type IgMs in patients with HCV-CV. AtMs stimulated through TLR9 promote type 1 effector T cell activation and reduce the proliferation of CD4+CD25hiCD127-/lowFoxP3+ regulatory T cells. AtM expansions display intraclonal diversity with immunoglobulin features of antigen-driven maturation. AtM-derived IgM monoclonal antibodies do not react against ubiquitous autoantigens or HCV antigens including NS3 and E2 proteins. Rather, AtM-derived antibodies possess rheumatoid factor activity and target unique epitopes on the human IgG-Fc region. CONCLUSION Our data strongly suggest a central role for TLR9 activation of AtMs in driving HCV-CV autoimmunity through rheumatoid factor production and type 1 T cell responses. LAY SUMMARY B cells are best known for their capacity to produce antibodies, which often play a deleterious role in the development of autoimmune diseases. During chronic hepatitis C, self-reactive B cells proliferate and can be responsible for autoimmune symptoms (arthritis, purpura, neuropathy, renal disease) and/or lymphoma. Direct-acting antiviral therapy clears the hepatitis C virus and eliminates deleterious B cells.
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Affiliation(s)
- Cloé Comarmond
- Sorbonne Université, INSERM UMR_S 959, Immunologie-Immunopathologie-Immunotherapie, i3 and Département Hospitalo-Universitaire Inflammation-Immunopathologie-Biotherapie, i2B, F-75651 Paris, France; AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Service de Biothérapie, F-75013 Paris, France; AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Département de Médecine Interne et Immunologie Clinique, F-75013 Paris, France; Laboratory of Humoral Immunology, Department of Immunology, Institut Pasteur, Paris, France; INSERM U1222, Paris, France
| | - Valérie Lorin
- Laboratory of Humoral Immunology, Department of Immunology, Institut Pasteur, Paris, France; INSERM U1222, Paris, France
| | - Cindy Marques
- AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Département de Médecine Interne et Immunologie Clinique, F-75013 Paris, France; Laboratory of Humoral Immunology, Department of Immunology, Institut Pasteur, Paris, France; INSERM U1222, Paris, France
| | - Anna Maciejewski-Duval
- Sorbonne Université, INSERM UMR_S 959, Immunologie-Immunopathologie-Immunotherapie, i3 and Département Hospitalo-Universitaire Inflammation-Immunopathologie-Biotherapie, i2B, F-75651 Paris, France; AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Service de Biothérapie, F-75013 Paris, France; AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Département de Médecine Interne et Immunologie Clinique, F-75013 Paris, France
| | - Nizar Joher
- Laboratory of Humoral Immunology, Department of Immunology, Institut Pasteur, Paris, France; INSERM U1222, Paris, France
| | - Cyril Planchais
- Laboratory of Humoral Immunology, Department of Immunology, Institut Pasteur, Paris, France; INSERM U1222, Paris, France
| | - Maxime Touzot
- INSERM U932, 26 rue d'Ulm, 75005 Paris, France; Institut Curie, Section Recherche, 26 rue d'Ulm, 75005 Paris, France; Laboratoire d'Immunologie Clinique, Institut Curie, 26 rue d'Ulm, 75005 Paris, France
| | - Lucie Biard
- AP-HP, SBIM, Hôpital Saint-Louis, Université Paris Diderot, Paris 7, Paris, France; INSERM, ECSTRA Team, CRESS UMR-S 1153, 75010 Paris, France
| | - Thierry Hieu
- Laboratory of Humoral Immunology, Department of Immunology, Institut Pasteur, Paris, France; INSERM U1222, Paris, France
| | - Valentin Quiniou
- Sorbonne Université, INSERM UMR_S 959, Immunologie-Immunopathologie-Immunotherapie, i3 and Département Hospitalo-Universitaire Inflammation-Immunopathologie-Biotherapie, i2B, F-75651 Paris, France; AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Service de Biothérapie, F-75013 Paris, France
| | - Anne-Claire Desbois
- Sorbonne Université, INSERM UMR_S 959, Immunologie-Immunopathologie-Immunotherapie, i3 and Département Hospitalo-Universitaire Inflammation-Immunopathologie-Biotherapie, i2B, F-75651 Paris, France; AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Service de Biothérapie, F-75013 Paris, France; AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Département de Médecine Interne et Immunologie Clinique, F-75013 Paris, France
| | - Michelle Rosenzwajg
- Sorbonne Université, INSERM UMR_S 959, Immunologie-Immunopathologie-Immunotherapie, i3 and Département Hospitalo-Universitaire Inflammation-Immunopathologie-Biotherapie, i2B, F-75651 Paris, France; AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Service de Biothérapie, F-75013 Paris, France
| | - David Klatzmann
- Sorbonne Université, INSERM UMR_S 959, Immunologie-Immunopathologie-Immunotherapie, i3 and Département Hospitalo-Universitaire Inflammation-Immunopathologie-Biotherapie, i2B, F-75651 Paris, France; AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Service de Biothérapie, F-75013 Paris, France; AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Département de Médecine Interne et Immunologie Clinique, F-75013 Paris, France
| | - Patrice Cacoub
- Sorbonne Université, INSERM UMR_S 959, Immunologie-Immunopathologie-Immunotherapie, i3 and Département Hospitalo-Universitaire Inflammation-Immunopathologie-Biotherapie, i2B, F-75651 Paris, France; AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Service de Biothérapie, F-75013 Paris, France; AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Département de Médecine Interne et Immunologie Clinique, F-75013 Paris, France
| | - Hugo Mouquet
- Laboratory of Humoral Immunology, Department of Immunology, Institut Pasteur, Paris, France; INSERM U1222, Paris, France.
| | - David Saadoun
- Sorbonne Université, INSERM UMR_S 959, Immunologie-Immunopathologie-Immunotherapie, i3 and Département Hospitalo-Universitaire Inflammation-Immunopathologie-Biotherapie, i2B, F-75651 Paris, France; AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Service de Biothérapie, F-75013 Paris, France; AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Département de Médecine Interne et Immunologie Clinique, F-75013 Paris, France.
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16
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Vivoli Vega M, Cascella R, Chen SW, Fusco G, De Simone A, Dobson CM, Cecchi C, Chiti F. The Toxicity of Misfolded Protein Oligomers Is Independent of Their Secondary Structure. ACS Chem Biol 2019; 14:1593-1600. [PMID: 31074957 DOI: 10.1021/acschembio.9b00324] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The self-assembly of proteins into structured fibrillar aggregates is associated with a range of neurodegenerative diseases, including Alzheimer's and Parkinson's diseases, in which an important cytotoxic role is thought to be played by small soluble oligomers accumulating during the aggregation process or released by mature fibrils. As the structural characteristics of such species and their links with toxicity are still not fully defined, we have compared six examples of preformed misfolded protein oligomers with different β-sheet content, as determined using Fourier transform infrared spectroscopy, and with different toxicity, as determined by three cellular readouts of cell viability. The results show the absence of any measurable correlation between the nature of their secondary structure and their cellular toxicity, both when comparing the six types of oligomers as a group and when comparing species in subgroups characterized by either the same size or the same exposure of hydrophobic moieties.
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Affiliation(s)
- Mirella Vivoli Vega
- Department of Experimental and Clinical Biomedical Sciences, Section of Biochemistry, University of Florence, 50134 Florence, Italy
| | - Roberta Cascella
- Department of Experimental and Clinical Biomedical Sciences, Section of Biochemistry, University of Florence, 50134 Florence, Italy
| | - Serene W Chen
- Department of Life Sciences, Imperial College London, London SW7 2AZ, U.K
| | - Giuliana Fusco
- Centre for Misfolding disease, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K
| | - Alfonso De Simone
- Department of Life Sciences, Imperial College London, London SW7 2AZ, U.K
| | - Christopher M. Dobson
- Centre for Misfolding disease, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K
| | - Cristina Cecchi
- Department of Experimental and Clinical Biomedical Sciences, Section of Biochemistry, University of Florence, 50134 Florence, Italy
| | - Fabrizio Chiti
- Department of Experimental and Clinical Biomedical Sciences, Section of Biochemistry, University of Florence, 50134 Florence, Italy
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17
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Valdarnini N, Holm B, Hansen P, Rovero P, Houen G, Trier N. Fine Mapping of Glutamate Decarboxylase 65 Epitopes Reveals Dependency on Hydrophobic Amino Acids for Specific Interactions. Int J Mol Sci 2019; 20:ijms20122909. [PMID: 31207885 PMCID: PMC6627456 DOI: 10.3390/ijms20122909] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 06/06/2019] [Accepted: 06/11/2019] [Indexed: 01/10/2023] Open
Abstract
Characterization of multiple antibody epitopes has revealed the necessity of specific groups of amino acid residues for reactivity. This applies to the majority of antibody-antigen interactions, where especially charged and hydrophilic amino acids have been reported to be essential for antibody reactivity. This study describes thorough characterization of glutamic acid decarboxylase (GAD) 65 antigenic epitopes, an immunodominant autoantigen in type 1 diabetes (T1D). As linear epitopes are sparsely described for GAD65 in T1D, we aimed to identify and thoroughly characterize two GAD65 antibodies using immunoassays. A monoclonal antibody recognized an epitope in the N-terminal domain of GAD65, 8FWSFGSE14, whereas a polyclonal antibody recognized two continuous epitopes in the C-terminal domain, corresponding to amino acids 514RTLED518 and 549PLGDKVNF556. Hydrophobic amino acids were essential for antibody reactivity, which was verified by competitive inhibition assays. Moreover, the epitopes were located in flexible linker regions and turn structures. These findings confirm the versatile nature of antibody-antigen interactions and describe potential continuous epitopes related to T1D, which predominantly have been proposed to be of discontinuous nature.
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Affiliation(s)
- Niccolò Valdarnini
- Interdepartmental Laboratory of Peptide and Protein Chemistry and Biology, Department of NeuroFarBa, University of Florence, Via Ugo Schiff, 6, 50019 Sesto Fiorentino, Italy.
| | - Bettina Holm
- Department of Clinical Immunology, Rigshospitalet, Ole Maaløes vej 26, 2200 Copenhagen N, Denmark.
| | - Paul Hansen
- Department of Drug Design and Pharmacology, Universitetsparken 2, 2100 Copenhagen Ø, Denmark.
| | - Paolo Rovero
- Interdepartmental Laboratory of Peptide and Protein Chemistry and Biology, Department of NeuroFarBa, University of Florence, Via Ugo Schiff, 6, 50019 Sesto Fiorentino, Italy.
| | - Gunnar Houen
- Department of Neurology, Rigshospitalet Glostrup, Nordre Ringvej 57, 2600 Glostrup, Denmark.
| | - Nicole Trier
- Department of Neurology, Rigshospitalet Glostrup, Nordre Ringvej 57, 2600 Glostrup, Denmark.
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18
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Maibom-Thomsen SL, Trier NH, Holm BE, Hansen KB, Rasmussen MI, Chailyan A, Marcatili P, Højrup P, Houen G. Immunoglobulin G structure and rheumatoid factor epitopes. PLoS One 2019; 14:e0217624. [PMID: 31199818 PMCID: PMC6568389 DOI: 10.1371/journal.pone.0217624] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 05/15/2019] [Indexed: 12/14/2022] Open
Abstract
Antibodies are important for immunity and exist in several classes (IgM, IgD, IgA, IgG, IgE). They are composed of symmetric dimeric molecules with two antigen binding regions (Fab) and a constant part (Fc), usually depicted as Y-shaped molecules. Rheumatoid factors found in patients with rheumatoid arthritis are autoantibodies binding to IgG and paradoxically appear to circulate in blood alongside with their antigen (IgG) without reacting with it. Here, it is shown that rheumatoid factors do not react with native IgG in solution, and that their epitopes only become accessible upon certain physico-chemical treatments (e.g. heat treatment at 57 °C), by physical adsorption on a hydrophobic surface or by antigen binding. Moreover, chemical cross-linking in combination with mass spectrometry showed that the native state of IgG is a compact (closed) form and that the Fab parts of IgG shield the Fc region and thereby control access of rheumatoid factors and presumably also some effector functions. It can be inferred that antibody binding to pathogen surfaces induces a conformational change, which exposes the Fc part with its effector sites and rheumatoid factor epitopes. This has strong implications for understanding antibody structure and physiology and necessitates a conceptual reformulation of IgG models.
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Affiliation(s)
| | - Nicole Hartwig Trier
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
- Department of Autoimmunology, Statens Serum Institut, Copenhagen, Denmark
| | - Bettina Eide Holm
- Department of Autoimmunology, Statens Serum Institut, Copenhagen, Denmark
| | - Kirsten Beth Hansen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
- Department of Autoimmunology, Statens Serum Institut, Copenhagen, Denmark
| | - Morten Ib Rasmussen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Anna Chailyan
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Paolo Marcatili
- Department of Bioinformatics, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Peter Højrup
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Gunnar Houen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
- Department of Autoimmunology, Statens Serum Institut, Copenhagen, Denmark
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19
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Yageta S, Imamura H, Shibuya R, Honda S. C H2 domain orientation of human immunoglobulin G in solution: Structural comparison of glycosylated and aglycosylated Fc regions using small-angle X-ray scattering. MAbs 2019; 11:453-462. [PMID: 30513259 PMCID: PMC6512918 DOI: 10.1080/19420862.2018.1546086] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 10/24/2018] [Accepted: 10/31/2018] [Indexed: 01/27/2023] Open
Abstract
The N-linked glycan in immunoglobulin G is critical for the stability and function of the crystallizable fragment (Fc) region. Alteration of these protein properties upon the removal of the N-linked glycan has often been explained by the alteration of the CH2 domain orientation in the Fc region. To confirm this hypothesis, we examined the small-angle X-ray scattering (SAXS) profile of the glycosylated Fc region (gFc) and aglycosylated Fc region (aFc) in solution. Conformational characteristics of the CH2 domain orientation were validated by comparison with SAXS profiles theoretically calculated from multiple crystal structures of the Fc region with different CH2 domain orientations. The reduced chi-square values from the fitting analyses of gFc and aFc associated with the degree of openness or closure of each crystal structure, as determined from the first principal component that partially governed the variation of the CH2 domain orientation extracted by a singular value decomposition analysis. For both gFc and aFc, the best-fitted SAXS profiles corresponded to ones calculated based on the crystal structure of gFc that formed a "semi-closed" CH2 domain orientation. Collectively, the data indicated that the removal of the N-linked glycan only negligibly affected the CH2 domain orientation in solution. These findings will guide the development of methodology for the production of highly refined functional Fc variants.
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Affiliation(s)
- Seiki Yageta
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, Japan
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, the University of Tokyo, Kashiwa, Chiba, Japan
- Manufacturing Technology Association of Biologics, Tsukuba, Ibaraki, Japan
| | - Hiroshi Imamura
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, Japan
- Department of Applied Chemistry, College of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Risa Shibuya
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, the University of Tokyo, Kashiwa, Chiba, Japan
| | - Shinya Honda
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, Japan
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, the University of Tokyo, Kashiwa, Chiba, Japan
- Manufacturing Technology Association of Biologics, Tsukuba, Ibaraki, Japan
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20
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Idborg H, Zandian A, Sandberg AS, Nilsson B, Elvin K, Truedsson L, Sohrabian A, Rönnelid J, Mo J, Grosso G, Kvarnström M, Gunnarsson I, Lehtiö J, Nilsson P, Svenungsson E, Jakobsson PJ. Two subgroups in systemic lupus erythematosus with features of antiphospholipid or Sjögren's syndrome differ in molecular signatures and treatment perspectives. Arthritis Res Ther 2019; 21:62. [PMID: 30777133 PMCID: PMC6378708 DOI: 10.1186/s13075-019-1836-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 01/24/2019] [Indexed: 01/31/2023] Open
Abstract
Background Previous studies and own clinical observations of patients with systemic lupus erythematosus (SLE) suggest that SLE harbors distinct immunophenotypes. This heterogeneity might result in differences in response to treatment in different subgroups and obstruct clinical trials. Our aim was to understand how SLE subgroups may differ regarding underlying pathophysiology and characteristic biomarkers. Methods In a cross-sectional study, including 378 well-characterized SLE patients and 316 individually matched population controls, we defined subgroups based on the patients’ autoantibody profile at inclusion. We selected a core of an antiphospholipid syndrome-like SLE (aPL+ group; positive in the lupus anticoagulant (LA) test and negative for all three of SSA (Ro52 and Ro60) and SSB antibodies) and a Sjögren’s syndrome-like SLE (SSA/SSB+ group; positive for all three of SSA (Ro52 and Ro60) and SSB antibodies but negative in the LA test). We applied affinity-based proteomics, targeting 281 proteins, together with well-established clinical biomarkers and complementary immunoassays to explore the difference between the two predefined SLE subgroups. Results The aPL+ group comprised 66 and the SSA/SSB+ group 63 patients. The protein with the highest prediction power (receiver operating characteristic (ROC) area under the curve = 0.89) for separating the aPL+ and SSA/SSB+ SLE subgroups was integrin beta-1 (ITGB1), with higher levels present in the SSA/SSB+ subgroup. Proteins with the lowest p values comparing the two SLE subgroups were ITGB1, SLC13A3, and CERS5. These three proteins, rheumatoid factor, and immunoglobulin G (IgG) were all increased in the SSA/SSB+ subgroup. This subgroup was also characterized by a possible activation of the interferon system as measured by high KRT7, TYK2, and ETV7 in plasma. In the aPL+ subgroup, complement activation was more pronounced together with several biomarkers associated with systemic inflammation (fibrinogen, α-1 antitrypsin, neutrophils, and triglycerides). Conclusions Our observations indicate underlying pathogenic differences between the SSA/SSB+ and the aPL+ SLE subgroups, suggesting that the SSA/SSB+ subgroup may benefit from IFN-blocking therapies while the aPL+ subgroup is more likely to have an effect from drugs targeting the complement system. Stratifying SLE patients based on an autoantibody profile could be a way forward to understand underlying pathophysiology and to improve selection of patients for clinical trials of targeted treatments. Electronic supplementary material The online version of this article (10.1186/s13075-019-1836-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Helena Idborg
- Division of Rheumatology, Department of Medicine Solna, Karolinska Institutet, Karolinska University Hospital, 171 76, Stockholm, Sweden
| | - Arash Zandian
- Division of Affinity Proteomics, SciLifeLab, Department of Protein Science, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Ann-Sofi Sandberg
- Clinical Proteomics Mass Spectrometry, Department of Oncology-Pathology, Science for Life Laboratory and Karolinska Institutet, Stockholm, Sweden
| | - Bo Nilsson
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Kerstin Elvin
- Unit of Clinical Immunology, Department of Clinical Immunology and Transfusion Medicine, Karolinska University Hospital, Karolinska Institutet, Solna, Stockholm, Sweden
| | - Lennart Truedsson
- Section of Microbiology, Immunology and Glycobiology, Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Azita Sohrabian
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Johan Rönnelid
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - John Mo
- Patient Safety Respiratory, Inflammation, Autoimmunity, Infection and Vaccines, AstraZeneca R&D, Gothenburg, Sweden
| | - Giorgia Grosso
- Division of Rheumatology, Department of Medicine Solna, Karolinska Institutet, Karolinska University Hospital, 171 76, Stockholm, Sweden
| | - Marika Kvarnström
- Division of Rheumatology, Department of Medicine Solna, Karolinska Institutet, Karolinska University Hospital, 171 76, Stockholm, Sweden
| | - Iva Gunnarsson
- Division of Rheumatology, Department of Medicine Solna, Karolinska Institutet, Karolinska University Hospital, 171 76, Stockholm, Sweden
| | - Janne Lehtiö
- Clinical Proteomics Mass Spectrometry, Department of Oncology-Pathology, Science for Life Laboratory and Karolinska Institutet, Stockholm, Sweden
| | - Peter Nilsson
- Division of Affinity Proteomics, SciLifeLab, Department of Protein Science, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Elisabet Svenungsson
- Division of Rheumatology, Department of Medicine Solna, Karolinska Institutet, Karolinska University Hospital, 171 76, Stockholm, Sweden.
| | - Per-Johan Jakobsson
- Division of Rheumatology, Department of Medicine Solna, Karolinska Institutet, Karolinska University Hospital, 171 76, Stockholm, Sweden.
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Shiroishi M, Ito Y, Shimokawa K, Lee JM, Kusakabe T, Ueda T. Structure-function analyses of a stereotypic rheumatoid factor unravel the structural basis for germline-encoded antibody autoreactivity. J Biol Chem 2018. [PMID: 29523691 DOI: 10.1074/jbc.m117.814475] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Rheumatoid factors (RFs) are autoantibodies against the fragment-crystallizable (Fc) region of IgG. In individuals with hematological diseases such as cryoglobulinemia and certain B cell lymphoma forms, the RFs derived from specific heavy- and light-chain germline pairs, so-called "stereotypic RFs," are frequently produced in copious amounts and form immune complexes with IgG in serum. Of note, many structural details of the antigen recognition mechanisms in RFs are unclear. Here we report the crystal structure of the RF YES8c derived from the IGHV1-69/IGKV3-20 germline pair, the most common of the stereotypic RFs, in complex with human IgG1-Fc at 2.8 Å resolution. We observed that YES8c binds to the CH2-CH3 elbow in the canonical antigen-binding manner involving a large antigen-antibody interface. On the basis of this observation, combined with mutational analyses, we propose a recognition mechanism common to IGHV1-69/IGKV3-20 RFs: (1) the interaction of the Leu432-His435 region of Fc enables the highly variable complementarity-determining region (CDR)-H3 to participate in the binding, (2) the hydrophobic tip in the CDR-H2 typical of IGHV1-69 antibodies recognizes the hydrophobic patch on Fc, and (3) the interaction of the highly conserved RF light chain with Fc is important for RF activity. These features may determine the putative epitope common to the IGHV1-69/IGKV3-20 RFs. We also showed that some mutations in the binding site of RF increase the affinity to Fc, which may aggravate hematological diseases. Our findings unravel the structural basis for germline-encoded antibody autoreactivity.
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Affiliation(s)
- Mitsunori Shiroishi
- From the Laboratory of Protein Structure, Function, and Design, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan and
| | - Yuji Ito
- From the Laboratory of Protein Structure, Function, and Design, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan and
| | - Kenta Shimokawa
- From the Laboratory of Protein Structure, Function, and Design, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan and
| | - Jae Man Lee
- the Laboratory of Insect Genome Science, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka 812-8581, Japan
| | - Takahiro Kusakabe
- the Laboratory of Insect Genome Science, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka 812-8581, Japan
| | - Tadashi Ueda
- From the Laboratory of Protein Structure, Function, and Design, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan and
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22
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Falkenburg WJ, von Richthofen HJ, Koers J, Weykamp C, Schreurs MW, Bakker-Jonges LE, Haagen IA, Lems WF, Hamann D, van Schaardenburg D, Rispens T. Clinically relevant discrepancies between different rheumatoid factor assays. ACTA ACUST UNITED AC 2018; 56:1749-1758. [DOI: 10.1515/cclm-2017-0988] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 12/14/2017] [Indexed: 01/12/2023]
Abstract
Abstract
Background:
Accurate measurements of rheumatoid factors (RFs), autoantibodies binding IgG, are important for diagnosing rheumatoid arthritis (RA) and for predicting disease course. Worldwide, various RF assays are being used that differ in technique and target antigens. We studied whether assay choice leads to clinically important discrepancies in RF status and level.
Methods:
RF measurements using four commercial RF assays were compared in 32 RF+ samples. Using enzyme-linked immunosorbent assays (ELISAs), the influence of the target antigen source – human IgG (hIgG) versus rabbit IgG (rIgG) – on measured RF levels was investigated in arthralgia patients and RA patients.
Results:
Substantial discrepancies were found between RF levels measured in the four commercial assays. Six samples (19%) with RF levels below or slightly above the cutoff in the rIgG-based Phadia assay were RF+ in three assays using hIgG as the target antigen, some with very high levels. Direct ELISA comparisons of RF reactivity against hIgG and rIgG estimated that among 173 ACPA+ arthralgia patients, originally RF negative in rIgG-based assays, up to 10% were single positive against hIgG. Monoclonal RFs binding to hIgG and rIgG or hIgG only supported these findings. In a cohort of 69 early RA patients, virtually all RF responses reacted with both targets, although levels were still variable.
Conclusions:
The use of RF assays that differ in technique and target antigen, together with the different specificities of RF responses, leads to discrepancies in RF status and levels. This has important consequences for patient care if RA diagnosis and disease progression assessments are based on RF test results.
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Affiliation(s)
- Willem J.J. Falkenburg
- Amsterdam Rheumatology and Immunology Center , Reade, Amsterdam , The Netherlands
- Department of Immunopathology, Sanquin Research , Amsterdam , The Netherlands
| | | | - Jana Koers
- Department of Immunopathology, Sanquin Research , Amsterdam , The Netherlands
| | - Cas Weykamp
- Queen Beatrix Hospital , Winterswijk , The Netherlands
| | - Marco W.J. Schreurs
- Department of Immunology, Laboratory Medical Immunology , Erasmus MC University Medical Center Rotterdam , Rotterdam , The Netherlands
| | | | - Inez-Anne Haagen
- Department of Hematology and Clinical Chemistry Laboratories, Onze Lieve Vrouwe Gasthuis , Amsterdam , The Netherlands
| | - Willem F. Lems
- Amsterdam Rheumatology and Immunology Center , Reade, Amsterdam , The Netherlands
- Amsterdam Rheumatology and Immunology Center , VU University Medical Center , Amsterdam , The Netherlands
| | - Dörte Hamann
- Department of Immunopathology and Blood Coagulation, Sanquin Diagnostic Services , Amsterdam , The Netherlands
| | - Dirkjan van Schaardenburg
- Amsterdam Rheumatology and Immunology Center , Reade, Amsterdam , The Netherlands
- Amsterdam Rheumatology and Immunology Center, Academic Medical Center , Amsterdam , The Netherlands
| | - Theo Rispens
- Department of Immunopathology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center , University of Amsterdam , Amsterdam , The Netherlands
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23
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Lee JM, Kim JY, Bok J, Kim KS, Choi JY, Kim SH. Identification of evidence for autoimmune pathology of bilateral sudden sensorineural hearing loss using proteomic analysis. Clin Immunol 2017. [DOI: 10.1016/j.clim.2017.06.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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24
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Rheumatoid factors do not preferentially bind to ACPA-IgG or IgG with altered galactosylation. Rheumatology (Oxford) 2017; 56:2025-2030. [DOI: 10.1093/rheumatology/kex284] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Indexed: 11/14/2022] Open
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25
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Maeda A, Iwayanagi Y, Haraya K, Tachibana T, Nakamura G, Nambu T, Esaki K, Hattori K, Igawa T. Identification of human IgG1 variant with enhanced FcRn binding and without increased binding to rheumatoid factor autoantibody. MAbs 2017; 9:844-853. [PMID: 28387635 PMCID: PMC5524163 DOI: 10.1080/19420862.2017.1314873] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Various studies have demonstrated that Fc engineering to enhance neonatal Fc receptor (FcRn) binding is effective for elongating half-life or increasing cellular uptake of IgG. A previous study has shown that a N434H mutation to enhance FcRn binding resulted in increased binding to rheumatoid factor (RF) autoantibody, which is not desirable for therapeutic use in autoimmune disease. In this study, we first showed that all the existing Fc variants with enhanced FcRn binding also show increased RF binding, and then identified specific mutations that could be introduced to those Fc variants to reduce the RF binding. Furthermore, we generated novel Fc variants that do not increase RF binding and show half-lives of 45 d in cynomolgus monkey, which is longer than those of previously reported Fc variants. In addition, we generated novel Fc variants with antigen sweeping activity that do not increase RF binding. We expect that these novel Fc variants will be useful as antibody therapeutics against autoimmune diseases.
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Affiliation(s)
- Atsuhiko Maeda
- a Chugai Pharmaceutical Co. Ltd., Pharmaceutical Technology Division, Ukima Research Labs. , Ukima, Kita-ku , Tokyo , Japan
| | - Yuki Iwayanagi
- b Chugai Pharmaceutical Co. Ltd., Research Division, Kamakura Research Labs , Kajiwara, Kamakura , Kanagawa , Japan
| | - Kenta Haraya
- c Chugai Pharmabody Research Pte. Ltd. , Synapse , Singapore
| | - Tatsuhiko Tachibana
- b Chugai Pharmaceutical Co. Ltd., Research Division, Kamakura Research Labs , Kajiwara, Kamakura , Kanagawa , Japan
| | - Genki Nakamura
- d Chugai Pharmaceutical Co. Ltd., Research Division, Fuji Gotemba Research Labs , Komakado, Gotemba , Shizuoka , Japan
| | - Takeru Nambu
- d Chugai Pharmaceutical Co. Ltd., Research Division, Fuji Gotemba Research Labs , Komakado, Gotemba , Shizuoka , Japan
| | - Keiko Esaki
- d Chugai Pharmaceutical Co. Ltd., Research Division, Fuji Gotemba Research Labs , Komakado, Gotemba , Shizuoka , Japan
| | - Kunihiro Hattori
- b Chugai Pharmaceutical Co. Ltd., Research Division, Kamakura Research Labs , Kajiwara, Kamakura , Kanagawa , Japan
| | - Tomoyuki Igawa
- d Chugai Pharmaceutical Co. Ltd., Research Division, Fuji Gotemba Research Labs , Komakado, Gotemba , Shizuoka , Japan
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26
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Abstract
IgG4, the least represented human IgG subclass in serum, is an intriguing antibody with unique biological properties, such as the ability to undergo Fab-arm exchange and limit immune complex formation. The lack of effector functions, such as antibody-dependent cell-mediated cytotoxicity and complement-dependent cytotoxicity, is desirable for therapeutic purposes. IgG4 plays a protective role in allergy by acting as a blocking antibody, and inhibiting mast cell degranulation, but a deleterious role in malignant melanoma, by impeding IgG1-mediated anti-tumor immunity. These findings highlight the importance of understanding the interaction between IgG4 and Fcγ receptors. Despite a wealth of structural information for the IgG1 subclass, including complexes with Fcγ receptors, and structures for intact antibodies, high-resolution crystal structures were not reported for IgG4-Fc until recently. Here, we highlight some of the biological properties of human IgG4, and review the recent crystal structures of IgG4-Fc. We discuss the unexpected conformations adopted by functionally important Cγ2 domain loops, and speculate about potential implications for the interaction between IgG4 and FcγRs.
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Affiliation(s)
- Anna M Davies
- Randall Division of Cell and Molecular Biophysics, King's College London, London, UK.,Medical Research Council & Asthma UK Centre in Allergic Mechanisms of Asthma, London, UK
| | - Brian J Sutton
- Randall Division of Cell and Molecular Biophysics, King's College London, London, UK.,Medical Research Council & Asthma UK Centre in Allergic Mechanisms of Asthma, London, UK
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27
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Association between IgG4 Autoantibody and Complement Abnormalities in Systemic Lupus Erythematosus. Mediators Inflamm 2016; 2016:2196986. [PMID: 27597802 PMCID: PMC4997081 DOI: 10.1155/2016/2196986] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 07/13/2016] [Indexed: 12/24/2022] Open
Abstract
In order to investigate the association between IgG4 autoantibody and complement abnormalities in systemic lupus erythematosus (SLE), 72 newly diagnosed SLE patients, 67 rheumatoid arthritis (RA) patients, and 41 healthy normals were employed. Serum levels of antinuclear IgG4 and IgG4-specific IgM-rheumatoid factor (RF) were measured, and the correlations between serum levels of antinuclear IgG4 and several clinical parameters were analyzed. Also, the levels of IgG subclasses, C1q, and C3 deposition in lupus nephritis (LN) were detected. The results showed that serum levels of antinuclear IgG4 were higher in SLE patients relative to healthy normals (P < 0.01). Serum levels of antinuclear IgG4 in SLE patients were positively correlated with serum levels of total IgG4, albumin, and C3 (r = 0.61, P < 0.05; r = 0.40, P < 0.05; and r = 0.54, P < 0.05, resp.) and negatively correlated with 24-hour urinary protein (r = 0.49, P < 0.05). Serum levels of IgG4-specific IgM-RF were higher in RA patients than in SLE patients (P < 0.001). Also, the ratio of the deposition score for IgG4/(IgG1 + IgG2 + IgG3 + IgG4) was negatively correlated with the score for C1q and C3 deposition in LN (r = 0.34, P < 0.05; r = 0.51, P < 0.01, resp.). In summary, the IgG4 autoantibody may dampen the inflammatory response in SLE, thus maybe providing a novel therapeutic target for SLE.
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28
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Agostino M, Mancera RL, Ramsland PA, Fernández-Recio J. Optimization of protein-protein docking for predicting Fc-protein interactions. J Mol Recognit 2016; 29:555-568. [PMID: 27445195 DOI: 10.1002/jmr.2555] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 06/12/2016] [Accepted: 06/14/2016] [Indexed: 01/08/2023]
Abstract
The antibody crystallizable fragment (Fc) is recognized by effector proteins as part of the immune system. Pathogens produce proteins that bind Fc in order to subvert or evade the immune response. The structural characterization of the determinants of Fc-protein association is essential to improve our understanding of the immune system at the molecular level and to develop new therapeutic agents. Furthermore, Fc-binding peptides and proteins are frequently used to purify therapeutic antibodies. Although several structures of Fc-protein complexes are available, numerous others have not yet been determined. Protein-protein docking could be used to investigate Fc-protein complexes; however, improved approaches are necessary to efficiently model such cases. In this study, a docking-based structural bioinformatics approach is developed for predicting the structures of Fc-protein complexes. Based on the available set of X-ray structures of Fc-protein complexes, three regions of the Fc, loosely corresponding to three turns within the structure, were defined as containing the essential features for protein recognition and used as restraints to filter the initial docking search. Rescoring the filtered poses with an optimal scoring strategy provided a success rate of approximately 80% of the test cases examined within the top ranked 20 poses, compared to approximately 20% by the initial unrestrained docking. The developed docking protocol provides a significant improvement over the initial unrestrained docking and will be valuable for predicting the structures of currently undetermined Fc-protein complexes, as well as in the design of peptides and proteins that target Fc.
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Affiliation(s)
- Mark Agostino
- School of Biomedical Sciences, Curtin Health Innovation Research Institute and Curtin Institute for Computation, Curtin University, Perth, Australia.,Joint BSC-CRG-IRB Research Program in Computational Biology, Life Sciences Department, Barcelona Supercomputing Center, Barcelona, Spain.,Centre for Biomedical Research, Burnet Institute, Melbourne, Australia
| | - Ricardo L Mancera
- School of Biomedical Sciences, Curtin Health Innovation Research Institute and Curtin Institute for Computation, Curtin University, Perth, Australia
| | - Paul A Ramsland
- Centre for Biomedical Research, Burnet Institute, Melbourne, Australia. .,School of Science, RMIT University, Bundoora, Australia. .,Department of Surgery Austin Health, University of Melbourne, Heidelberg, Australia. .,Department of Immunology, Monash University, Alfred Medical Research and Education Precinct, Melbourne, Australia.
| | - Juan Fernández-Recio
- Joint BSC-CRG-IRB Research Program in Computational Biology, Life Sciences Department, Barcelona Supercomputing Center, Barcelona, Spain.
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29
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IgG Subclass Specificity Discriminates Restricted IgM Rheumatoid Factor Responses From More Mature Anti-Citrullinated Protein Antibody-Associated or Isotype-Switched IgA Responses. Arthritis Rheumatol 2015; 67:3124-34. [DOI: 10.1002/art.39299] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 07/21/2015] [Indexed: 02/03/2023]
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30
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Anquetil F, Clavel C, Offer G, Serre G, Sebbag M. IgM and IgA rheumatoid factors purified from rheumatoid arthritis sera boost the Fc receptor- and complement-dependent effector functions of the disease-specific anti-citrullinated protein autoantibodies. THE JOURNAL OF IMMUNOLOGY 2015; 194:3664-74. [PMID: 25769920 DOI: 10.4049/jimmunol.1402334] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 02/06/2015] [Indexed: 11/19/2022]
Abstract
Rheumatoid factors (RF) and the disease-specific anti-citrullinated protein autoantibodies (ACPA) coexist in the joints of rheumatoid arthritis (RA) patients where they probably contribute to synovitis. We investigated the influence of IgM and IgA RF on the FcR- and complement-dependent effects of ACPA immune complexes (ACPA-IC). When stimulated by ACPA-IC formed in the presence of IgM RF or IgA RF fractions purified from RA serum pools, M-CSF-generated macrophages skewed their cytokine response toward inflammation, with increases in the TNF-α/IL-10 ratio and in IL-6 and IL-8 secretion, and decreases in the IL-1Ra/IL-1β ratio. In the IgM RF-mediated amplification of the inflammatory response of macrophages, the participation of an IgM receptor was excluded, notably by showing that they did not express any established receptor for IgM. Rather, this amplification depended on the IgM RF-mediated recruitment of more IgG into the ACPA-IC. However, the macrophages expressed FcαRI and blocking its interaction with IgA inhibited the IgA RF-mediated amplification of TNF-α secretion induced by ACPA-IC, showing its major implication in the effects of RF of the IgA class. LPS further amplified the TNF-α response of macrophages to RF-containing ACPA-IC. Lastly, the presence of IgM or IgA RF increased the capacity of ACPA-IC to activate the complement cascade. Therefore, specifically using autoantibodies from RA patients, the strong FcR-mediated or complement-dependent pathogenic potential of IC including both ACPA and IgM or IgA RF was established. Simultaneous FcR triggering by these RF-containing ACPA-IC and TLR4 ligation possibly makes a major contribution to RA synovitis.
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Affiliation(s)
- Florence Anquetil
- Unité Différenciation Épidermique et Autoimmunité Rhumatoïde, Unité Mixte de Recherche 1056, INSERM, 31059 Toulouse Cedex 9, France; Unité Mixte de Recherche 5165, Centre National de la Recherche Scientifique, 31059 Toulouse Cedex 9, France; Université de Toulouse, 31059 Toulouse Cedex 9, France; and Laboratoire de Biologie Cellulaire et Cytologie, Centre Hospitalier Universitaire de Toulouse, 31059 Toulouse Cedex 9, France
| | - Cyril Clavel
- Unité Différenciation Épidermique et Autoimmunité Rhumatoïde, Unité Mixte de Recherche 1056, INSERM, 31059 Toulouse Cedex 9, France; Unité Mixte de Recherche 5165, Centre National de la Recherche Scientifique, 31059 Toulouse Cedex 9, France; Université de Toulouse, 31059 Toulouse Cedex 9, France; and Laboratoire de Biologie Cellulaire et Cytologie, Centre Hospitalier Universitaire de Toulouse, 31059 Toulouse Cedex 9, France
| | - Géraldine Offer
- Unité Différenciation Épidermique et Autoimmunité Rhumatoïde, Unité Mixte de Recherche 1056, INSERM, 31059 Toulouse Cedex 9, France; Unité Mixte de Recherche 5165, Centre National de la Recherche Scientifique, 31059 Toulouse Cedex 9, France; Université de Toulouse, 31059 Toulouse Cedex 9, France; and
| | - Guy Serre
- Unité Différenciation Épidermique et Autoimmunité Rhumatoïde, Unité Mixte de Recherche 1056, INSERM, 31059 Toulouse Cedex 9, France; Unité Mixte de Recherche 5165, Centre National de la Recherche Scientifique, 31059 Toulouse Cedex 9, France; Université de Toulouse, 31059 Toulouse Cedex 9, France; and Laboratoire de Biologie Cellulaire et Cytologie, Centre Hospitalier Universitaire de Toulouse, 31059 Toulouse Cedex 9, France
| | - Mireille Sebbag
- Unité Différenciation Épidermique et Autoimmunité Rhumatoïde, Unité Mixte de Recherche 1056, INSERM, 31059 Toulouse Cedex 9, France; Unité Mixte de Recherche 5165, Centre National de la Recherche Scientifique, 31059 Toulouse Cedex 9, France; Université de Toulouse, 31059 Toulouse Cedex 9, France; and
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31
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Holm BE, Sandhu N, Tronstrøm J, Lydolph M, Trier NH, Houen G. Species cross-reactivity of rheumatoid factors and implications for immunoassays. Scandinavian Journal of Clinical and Laboratory Investigation 2014; 75:51-63. [DOI: 10.3109/00365513.2014.965738] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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32
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Holmdahl R, Malmström V, Burkhardt H. Autoimmune priming, tissue attack and chronic inflammation - the three stages of rheumatoid arthritis. Eur J Immunol 2014; 44:1593-9. [PMID: 24737176 DOI: 10.1002/eji.201444486] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2014] [Revised: 02/27/2014] [Accepted: 04/10/2014] [Indexed: 12/28/2022]
Abstract
Extensive genome-wide association studies have recently shed some light on the causes of chronic autoimmune diseases and have confirmed a central role of the adaptive immune system. Moreover, better diagnostics using disease-associated autoantibodies have been developed, and treatment has improved through the development of biologicals with precise molecular targets. Here, we use rheumatoid arthritis (RA) as a prototype for chronic autoimmune disease to propose that the pathogenesis of autoimmune diseases could be divided into three discrete stages. First, yet unknown environmental challenges seem to activate innate immunity thereby providing an adjuvant signal for the induction of adaptive immune responses that lead to the production of autoantibodies and determine the subsequent disease development. Second, a joint-specific inflammatory reaction occurs. This inflammatory reaction might be clinically diagnosed as the earliest signs of the disease. Third, inflammation is converted to a chronic process leading to tissue destruction and remodeling. In this review, we discuss the stages involved in RA pathogenesis and the experimental approaches, mainly involving animal models that can be used to investigate each disease stage. Although we focus on RA, it is possible that a similar stepwise development of disease also occurs in other chronic autoimmune settings such as multiple sclerosis (MS), type 1 diabetes, and systemic lupus erythematosus.
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Affiliation(s)
- Rikard Holmdahl
- Department of Medical Biochemistry and Biophysics, Medical Inflammation Research, Karolinska Institutet, Stockholm, Sweden
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33
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Laurent L, Anquetil F, Clavel C, Ndongo-Thiam N, Offer G, Miossec P, Pasquali JL, Sebbag M, Serre G. IgM rheumatoid factor amplifies the inflammatory response of macrophages induced by the rheumatoid arthritis-specific immune complexes containing anticitrullinated protein antibodies. Ann Rheum Dis 2014; 74:1425-31. [PMID: 24618262 DOI: 10.1136/annrheumdis-2013-204543] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 02/16/2014] [Indexed: 12/31/2022]
Abstract
OBJECTIVES Anticitrullinated protein antibodies (ACPA) are specifically associated with rheumatoid arthritis (RA) and produced in inflamed synovial membranes where citrullinated fibrin, their antigenic target, is abundant. We showed that immune complexes containing IgG ACPA (ACPA-IC) induce FcγR-mediated tumour necrosis factor (TNF)-α secretion in macrophages. Since IgM rheumatoid factor (RF), an autoantibody directed to the Fc fragment of IgG, is also produced and concentrated in the rheumatoid synovial tissue, we evaluated its influence on macrophage stimulation by ACPA-IC. METHODS With monocyte-derived macrophages from more than 40 healthy individuals and different human IgM cryoglobulins with RF activity, using a previously developed human in vitro model, we evaluated the effect of the incorporation of IgM RF into ACPA-IC. RESULTS IgM RF induced an important amplification of the TNF-α secretion. This effect was not observed in monocytes and depended on an increase in the number of IgG-engaged FcγR. It extended to the secretion of interleukin (IL)-1β and IL-6, was paralleled by IL-8 secretion and was not associated with overwhelming secretion of IL-10 or IL-1Ra. Moreover, the RF-induced increased proinflammatory bioactivity of the cytokine response to ACPA-IC was confirmed by an enhanced, not entirely TNF-dependent, capacity of the secreted cytokine cocktail to prompt IL-6 secretion by RA synoviocytes. CONCLUSIONS By showing that it can greatly enhance the proinflammatory cytokine response induced in macrophages by the RA-specific ACPA-IC, these results highlight a previously undescribed, FcγR-dependent strong proinflammatory potential of IgM RF. They clarify the pathophysiological link between the presence of ACPA and IgM RF, and RA severity.
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Affiliation(s)
- Lætitia Laurent
- Unité Différenciation Épidermique et Auto-Immunité Rhumatoïde, INSERM Unité Mixte de Recherche 1056, Toulouse, France Unité Différenciation Épidermique et Auto-Immunité Rhumatoïde, CNRS UMR 5165, Toulouse, France Laboratory of Epidermis Differentiation and Rheumatoid Autoimmunity, Université de Toulouse, Université Paul Sabatier, Toulouse, France
| | - Florence Anquetil
- Unité Différenciation Épidermique et Auto-Immunité Rhumatoïde, INSERM Unité Mixte de Recherche 1056, Toulouse, France Unité Différenciation Épidermique et Auto-Immunité Rhumatoïde, CNRS UMR 5165, Toulouse, France Laboratory of Epidermis Differentiation and Rheumatoid Autoimmunity, Université de Toulouse, Université Paul Sabatier, Toulouse, France Laboratory of Cell Biology and Cytology, Centre Hospitalier Universitaire (CHU) de Toulouse, Institut Fédératif de Biologie, Toulouse, France
| | - Cyril Clavel
- Unité Différenciation Épidermique et Auto-Immunité Rhumatoïde, INSERM Unité Mixte de Recherche 1056, Toulouse, France Unité Différenciation Épidermique et Auto-Immunité Rhumatoïde, CNRS UMR 5165, Toulouse, France Laboratory of Epidermis Differentiation and Rheumatoid Autoimmunity, Université de Toulouse, Université Paul Sabatier, Toulouse, France Laboratory of Cell Biology and Cytology, Centre Hospitalier Universitaire (CHU) de Toulouse, Institut Fédératif de Biologie, Toulouse, France
| | - Ndiémé Ndongo-Thiam
- Immunogenomics and inflammation research unit EA 4130, University of Lyon 1, Hôpital Edouard Herriot, Lyon, France
| | - Géraldine Offer
- Unité Différenciation Épidermique et Auto-Immunité Rhumatoïde, INSERM Unité Mixte de Recherche 1056, Toulouse, France Unité Différenciation Épidermique et Auto-Immunité Rhumatoïde, CNRS UMR 5165, Toulouse, France Laboratory of Epidermis Differentiation and Rheumatoid Autoimmunity, Université de Toulouse, Université Paul Sabatier, Toulouse, France
| | - Pierre Miossec
- Immunogenomics and inflammation research unit EA 4130, University of Lyon 1, Hôpital Edouard Herriot, Lyon, France
| | - Jean-Louis Pasquali
- CNRS Unité 9021, Laboratory of Immunology and Therapeutical chemistry, Institut de Biologie Moléculaire et Cellulaire, Federative Research Center 1589, Strasbourg, France
| | - Mireille Sebbag
- Unité Différenciation Épidermique et Auto-Immunité Rhumatoïde, INSERM Unité Mixte de Recherche 1056, Toulouse, France Unité Différenciation Épidermique et Auto-Immunité Rhumatoïde, CNRS UMR 5165, Toulouse, France Laboratory of Epidermis Differentiation and Rheumatoid Autoimmunity, Université de Toulouse, Université Paul Sabatier, Toulouse, France
| | - Guy Serre
- Unité Différenciation Épidermique et Auto-Immunité Rhumatoïde, INSERM Unité Mixte de Recherche 1056, Toulouse, France Unité Différenciation Épidermique et Auto-Immunité Rhumatoïde, CNRS UMR 5165, Toulouse, France Laboratory of Epidermis Differentiation and Rheumatoid Autoimmunity, Université de Toulouse, Université Paul Sabatier, Toulouse, France Laboratory of Cell Biology and Cytology, Centre Hospitalier Universitaire (CHU) de Toulouse, Institut Fédératif de Biologie, Toulouse, France
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Isolation, characterization, and molecular modeling of a rheumatoid factor from a Hepatitis C virus infected patient with Sjögren's syndrome. ScientificWorldJournal 2013; 2013:516516. [PMID: 24489505 PMCID: PMC3892945 DOI: 10.1155/2013/516516] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 10/16/2013] [Indexed: 11/18/2022] Open
Abstract
We have previously isolated several IgG rheumatoid factors (RFs) from patients with both rheumatoid arthritis and idiopathic thrombocytopenia purpura using phage display system. To study IgG RFs in patients with other autoimmune diseases, phage display antibody libraries from a hepatitis C virus infected patient with Sjögren's syndrome were constructed. After panning, a specific clone RFL11 was isolated for characterization in advance. The binding activity and specificity of RFL11 to IgG Fc fragment were comparable to those of RFs previously isolated. The analysis with existed RF-Fc complex structures indicated the homology model of RFL11 is similar to IgM RF61 complex with high binding affinity of about 6 × 10⁻⁸ M. This effect resulted from longer complementarity-determining region (CDR) combining key somatic mutations. In the RFL11-Fc interfaces, the CDR-H3 loop forms a finger-like structure extending into the bottom of Fc pocket and resulting in strong ion and cation-pi interactions. Moreover, a process of antigen-driven maturation was proven by somatically mutated VH residues on H2 and H3 CDR loops in the interfaces. Taken together, these results suggested that high affinity IgG RFs can be generated in patients with Sjögren's syndrome and may play an important role in the pathogenesis of this autoimmune disease.
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Davies AM, Rispens T, Ooijevaar-de Heer P, Gould HJ, Jefferis R, Aalberse RC, Sutton BJ. Structural determinants of unique properties of human IgG4-Fc. J Mol Biol 2013; 426:630-44. [PMID: 24211234 PMCID: PMC3905167 DOI: 10.1016/j.jmb.2013.10.039] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 10/19/2013] [Accepted: 10/29/2013] [Indexed: 12/24/2022]
Abstract
Human IgG4, normally the least abundant of the four subclasses of IgG in serum, displays a number of unique biological properties. It can undergo heavy-chain exchange, also known as Fab-arm exchange, leading to the formation of monovalent but bispecific antibodies, and it interacts poorly with FcγRII and FcγRIII, and complement. These properties render IgG4 relatively “non-inflammatory” and have made it a suitable format for therapeutic monoclonal antibody production. However, IgG4 is also known to undergo Fc-mediated aggregation and has been implicated in auto-immune disease pathology. We report here the high-resolution crystal structures, at 1.9 and 2.35 Å, respectively, of human recombinant and serum-derived IgG4-Fc. These structures reveal conformational variability at the CH3–CH3 interface that may promote Fab-arm exchange, and a unique conformation for the FG loop in the CH2 domain that would explain the poor FcγRII, FcγRIII and C1q binding properties of IgG4 compared with IgG1 and -3. In contrast to other IgG subclasses, this unique conformation folds the FG loop away from the CH2 domain, precluding any interaction with the lower hinge region, which may further facilitate Fab-arm exchange by destabilisation of the hinge. The crystals of IgG4-Fc also display Fc–Fc packing contacts with very extensive interaction surfaces, involving both a consensus binding site in IgG-Fc at the CH2–CH3 interface and known hydrophobic aggregation motifs. These Fc–Fc interactions are compatible with intact IgG4 molecules and may provide a model for the formation of aggregates of IgG4 that can cause disease pathology in the absence of antigen. The first high-resolution crystal structures of IgG4-Fc have been solved. Arg409 adopts two conformations, each with a different effect on the CH3–CH3 interface. Crystal packing analysis reveals a novel Fc–Fc interface. The CH2 domain FG loop adopts a unique conformation, affecting FcγR and C1q binding. The IgG4-Fc crystal structures explain unique biological properties of IgG4.
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Affiliation(s)
- Anna M Davies
- Randall Division of Cell and Molecular Biophysics, King's College London, London SE1 1UL, United Kingdom; Medical Research Council and Asthma UK Centre in Allergic Mechanisms of Asthma, London SE1 9RT, United Kingdom.
| | - Theo Rispens
- Sanquin Research, Amsterdam 1066 CX, The Netherlands; Academic Medical Centre Landsteiner Laboratory, University of Amsterdam, Amsterdam 1066 CX, The Netherlands
| | - Pleuni Ooijevaar-de Heer
- Sanquin Research, Amsterdam 1066 CX, The Netherlands; Academic Medical Centre Landsteiner Laboratory, University of Amsterdam, Amsterdam 1066 CX, The Netherlands
| | - Hannah J Gould
- Randall Division of Cell and Molecular Biophysics, King's College London, London SE1 1UL, United Kingdom; Medical Research Council and Asthma UK Centre in Allergic Mechanisms of Asthma, London SE1 9RT, United Kingdom
| | - Roy Jefferis
- College of Medical and Dental Sciences, School of Immunity and Infection, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Rob C Aalberse
- Sanquin Research, Amsterdam 1066 CX, The Netherlands; Academic Medical Centre Landsteiner Laboratory, University of Amsterdam, Amsterdam 1066 CX, The Netherlands
| | - Brian J Sutton
- Randall Division of Cell and Molecular Biophysics, King's College London, London SE1 1UL, United Kingdom; Medical Research Council and Asthma UK Centre in Allergic Mechanisms of Asthma, London SE1 9RT, United Kingdom.
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Amrutkar SD, Trier NH, Hansen PR, Houen G. Fine mapping of a monoclonal antibody to the N-Methyl D-aspartate receptor reveals a short linear epitope. Biopolymers 2013. [PMID: 23203762 DOI: 10.1002/bip.22165] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Anti-N-Methyl D-aspartate receptor encephalitis is an autoimmune disease in which autoantibodies are produced against extracellular regions of the N-Methyl D-aspartate receptor (NMDAR). In this study, we used resin-bound peptides equipped with a base labile linker to map the epitope of a monoclonal NMDAR antibody against the NMDAR NR1 subunit. The antigenicity of the synthesized resin-bound peptides was determined by enzyme-linked immunosorbent assay. Distinct reactivity was found to two extracellular overlapping peptides (amino acids, 658-687). Using N- and C-terminally truncated resin-bound peptides, the minimum functional epitope was identified as the NPSDK sequence. The peptide sequence RNPSDK (amino acids, 673-678) was identified as the complete epitope, which was found to be located in the extracellular S2 domain of the NR1 subunit. Especially, the N-terminal arginine residue was found to be essential for reactivity, whereas the remaining amino acids could be replaced with amino acids of similar side-chain functionality, indicating the importance of backbone interaction in antibody reactivity.
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Affiliation(s)
- Surekha Dipak Amrutkar
- Department of Clinical Biochemistry, Immunology and Genetics, Statens Serum Institut, Copenhagen S 2300, Denmark
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Jones JD, Shyu I, Newkirk MM, Rigby WFC. A rheumatoid factor paradox: inhibition of rituximab effector function. Arthritis Res Ther 2013; 15:R20. [PMID: 23351360 PMCID: PMC3672827 DOI: 10.1186/ar4152] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 01/25/2013] [Indexed: 01/20/2023] Open
Abstract
Introduction Rituximab (RTX) therapy of rheumatoid arthritis (RA) exhibits enhanced effectiveness in seropositive patients. Using patient sera, we tested if this improved efficacy was associated with enhanced RTX mediated complement-dependent cytotoxicity (RTX-CDC). Methods We developed an in vitro assay for RTX-CDC using patient sera and the Daudi human B cell line. Using propidium iodide uptake and flow cytometry, we compared RTX-CDC with rheumatoid factor (RF)+ sera relative to normal volunteer, non-RA and RF- sera. Additional studies examined mixing studies of RF+ and RF- sera, as well as the effect of monoclonal IgA or IgM RF. Finally, the effect of RF on RTX mediated trogocytosis of normal B cells was evaluated. Results Using human sera, addition of RTX resulted in rapid and profound (> 50%) Daudi cell death that was complement dependent. Surprisingly, RF+ patient sera exhibited reduced RTX-CDC relative to RF- sera, with an inverse relationship of RTX-CDC and RF titer. Mixing studies indicated the presence of an inhibitor of RTX-CDC in RF+ sera. The addition of monoclonal IgM or IgA RF to RF- sera markedly inhibited RTX-CDC. This effect was specific for RF binding to the Fc portion of RTX as it was not apparent with the F(ab)' domains of RTX engineered onto IgG3 heavy chain. RF also modestly inhibited RTX mediated trogocytosis. Conclusions Contrary to expectations, RF+ sera exhibits reduced RTX-CDC due to the presence of RF. The enhanced efficacy of RTX in seropositive RA patients cannot be attributed to improved B cell depletion through CDC. This result indicates that high RF levels may potentially modulate the efficacy of any therapeutic monoclonal antibody dependent on Fc effector function.
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Welner S, Trier NH, Houen G, Hansen PR. Identification and mapping of a linear epitope of centromere protein F using monoclonal antibodies. J Pept Sci 2013; 19:95-101. [DOI: 10.1002/psc.2478] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Revised: 10/31/2012] [Accepted: 11/18/2012] [Indexed: 11/09/2022]
Affiliation(s)
- Simon Welner
- Department of Clinical Biochemistry, Immunology and Genetics; Statens Serum Institut; Artillerivej 5 2300 Copenhagen S Denmark
- IGM - Bioorganic Chemistry, Faculty of Life Sciences; University of Copenhagen; Thorvaldsensvej 40 1871 Frederiksberg C Denmark
- Present address: LEO Pharma A/S; Industriparken 55 2750 Ballerup Denmark
| | - Nicole H. Trier
- Department of Clinical Biochemistry, Immunology and Genetics; Statens Serum Institut; Artillerivej 5 2300 Copenhagen S Denmark
- IGM - Bioorganic Chemistry, Faculty of Life Sciences; University of Copenhagen; Thorvaldsensvej 40 1871 Frederiksberg C Denmark
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences; University of Copenhagen; Universitetsparken 2 2100 Copenhagen Ø Denmark
| | - Gunnar Houen
- Department of Clinical Biochemistry, Immunology and Genetics; Statens Serum Institut; Artillerivej 5 2300 Copenhagen S Denmark
| | - Paul R. Hansen
- IGM - Bioorganic Chemistry, Faculty of Life Sciences; University of Copenhagen; Thorvaldsensvej 40 1871 Frederiksberg C Denmark
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences; University of Copenhagen; Universitetsparken 2 2100 Copenhagen Ø Denmark
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Davies AM, Rispens T, den Bleker TH, McDonnell JM, Gould HJ, Aalberse RC, Sutton BJ. Crystal structure of the human IgG4 C(H)3 dimer reveals the role of Arg409 in the mechanism of Fab-arm exchange. Mol Immunol 2012; 54:1-7. [PMID: 23164605 DOI: 10.1016/j.molimm.2012.10.029] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 10/16/2012] [Accepted: 10/18/2012] [Indexed: 12/20/2022]
Abstract
Antibodies of the human IgG4 subclass uniquely undergo a process of Fab-arm exchange in which the heavy-chains of antibodies of different specificities can dissociate and then recombine. The mechanism by which the resulting functionally monovalent but bi-specific antibodies are formed is not only key to understanding their biological role, but is also important for the design of therapeutic monoclonal antibodies. Both the hinge region and the C(H)3 domain interface are known to be involved, and of the residues that differ between human IgG1 and IgG4 in C(H)3, residue 409, the only difference at the interface itself, has been implicated. We report the high resolution (1.8Å) structure of the C(H)3 domain dimer of IgG4, and find that Arg409 in IgG4, when compared with Lys409 observed in high resolution IgG1 structures, disrupts a network of water-mediated hydrogen bonding that is conserved in IgG1. Other conformational differences were detected that are a consequence of the presence of Arg409, such as a widening of the separation between residues Asn390 in one domain and Ser 400 in the other, which opens up a groove at the edge of the interface in IgG4 compared with IgG1. The effect of all these differences on the C(H)3 interface, doubled as a result of the interface's two-fold symmetry, is weakening of the inter-domain interaction in IgG4 compared with IgG1. This suggests a mechanism by which Arg409 weakens the C(H)3 interface in IgG4, predisposing this human antibody subclass to Fab-arm exchange.
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Affiliation(s)
- Anna M Davies
- King's College London, Randall Division of Cell and Molecular Biophysics, London, SE1 1UL, United Kingdom
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Cha SS, An YJ, Jeong CS, Kim MK, Lee SG, Lee KH, Oh BH. Experimental phasing using zinc anomalous scattering. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2012; 68:1253-8. [PMID: 22948927 PMCID: PMC3489106 DOI: 10.1107/s0907444912024420] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 05/29/2012] [Indexed: 02/06/2023]
Abstract
Zinc is a suitable metal for anomalous dispersion phasing methods in protein crystallography. Structure determination using zinc anomalous scattering has been almost exclusively limited to proteins with intrinsically bound zinc(s). Here, it is reported that multiple zinc ions can easily be charged onto the surface of proteins with no intrinsic zinc-binding site by using zinc-containing solutions. Zn derivatization of protein surfaces appears to be a largely unnoticed but promising method of protein structure determination.
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Affiliation(s)
- Sun-Shin Cha
- Marine Biotechnology Research Center, Korea Institute of Ocean Science and Technology, Ansan 426-744, Republic of Korea.
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Pone EJ, Xu Z, White CA, Zan H, Casali P. B cell TLRs and induction of immunoglobulin class-switch DNA recombination. Front Biosci (Landmark Ed) 2012; 17:2594-615. [PMID: 22652800 DOI: 10.2741/4073] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Toll-like receptors (TLRs) are a family of conserved pattern recognition receptors (PRRs). Engagement of B cell TLRs by microbe-associated molecular patterns (MAMPs) induces T-independent (TI) antibody responses and plays an important role in the early stages of T-dependent (TD) antibody responses before specific T cell help becomes available. The role of B cell TLRs in the antibody response is magnified by the synergy of B cell receptor (BCR) crosslinking and TLR engagement in inducing immunoglobulin (Ig) class switch DNA recombination (CSR), which crucially diversifies the antibody biological effector functions. Dual BCR/TLR engagement induces CSR to all Ig isotypes, as directed by cytokines, while TLR engagement alone induces marginal CSR. Integration of BCR and TLR signaling results in activation of the canonical and non-canonical NF-κB pathways, induction of activation-induced cytidine deaminase (AID) and germline transcription of IgH switch (S) regions. A critical role of B cell TLRs in CSR and the antibody response is emphasized by the emergence of several TLR ligands as integral components of vaccines that greatly boost humoral immunity in a B cell-intrinsic fashion.
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Affiliation(s)
- Egest J Pone
- Institute for Immunology, School of Medicine, University of California, Irvine, CA 92697-4120, USA
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42
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Jefferis R. Isotype and glycoform selection for antibody therapeutics. Arch Biochem Biophys 2012; 526:159-66. [PMID: 22465822 DOI: 10.1016/j.abb.2012.03.021] [Citation(s) in RCA: 183] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 03/12/2012] [Accepted: 03/17/2012] [Indexed: 12/15/2022]
Abstract
We live in a hostile environment but are protected by the innate and adaptive immune system. A major component of the latter is mediated by antibody molecules that bind to pathogens, with exquisite specificity, and the immune complex formed activates cellular mechanisms leading to the removal and destruction of the complex. Five classes of antibody are identified; however, the IgG class predominates in serum and a majority of monoclonal antibody (mAb) therapeutics are based on the IgG format. Selection within the antibody repertoire allows the generation of (mAb) having specificity for any selected target, including human antigens. This review focuses on the structure and function of the Fc region of IgG molecules that mediates biologic functions, within immune complexes, by interactions with cellular Fc receptors (FcγR) and/or the C1q component of complement. A property of IgG that is suited to its use as a therapeutic is the long catabolic half life of ~21 days, mediated through the structurally distinct neonatal Fc receptor (FcRn). Our understanding of structure/function relationships is such that we can contemplate engineering the IgG-Fc to enhance or eliminate biologic activities to generate therapeutics considered optimal for a given disease indication. There are four subclasses of human IgG that exhibit high sequence homology but a unique profile of biologic activities. The FcγR and the C1q binding functions are dependent on glycosylation of the IgG-Fc. Normal human serum IgG is comprised of multiple glycoforms and biologic activities, other than catabolism, varies between glycoforms.
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Wines BD, Trist HM, Farrugia W, Ngo C, Trowsdale J, Areschoug T, Lindahl G, Fraser JD, Ramsland PA. A conserved host and pathogen recognition site on immunoglobulins: structural and functional aspects. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 946:87-112. [PMID: 21948364 DOI: 10.1007/978-1-4614-0106-3_6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A common site in the constant region (Fc) of immunoglobulins is recognized by host receptors and is a frequent target of proteins expressed by pathogens. This site is located at the junction of two constant domains in the antibody heavy chains and produces a large shallow cavity formed by loops of the CH2 and CH3 domains in IgG and IgA (CH3 and CH4 domains in IgM). Crystal structures have been determined for complexes of IgG-Fc and IgA-Fc with a structurally diverse set of host, pathogen and in vitro selected ligands. While pathogen proteins may directly block interactions with the immunoglobulins thereby evading host immunity, it is likely that the same pathogen molecules also interact with other host factors to carry out their primary biological function. Herein we review the structural and functional aspects of host and pathogen molecular recognition of the common site on the Fc of immunoglobulins. We also propose that some pathogen proteins may promote virulence by affecting the bridging between innate and adaptive immunity.
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Affiliation(s)
- Bruce D Wines
- Centre for Immunology, Burnet Institute, Melbourne, VIC 3004, Australia.
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Pejchal R, Doores KJ, Walker LM, Khayat R, Huang PS, Wang SK, Stanfield RL, Julien JP, Ramos A, Crispin M, Depetris R, Katpally U, Marozsan A, Cupo A, Maloveste S, Liu Y, McBride R, Ito Y, Sanders RW, Ogohara C, Paulson JC, Feizi T, Scanlan CN, Wong CH, Moore JP, Olson WC, Ward AB, Poignard P, Schief WR, Burton DR, Wilson IA. A potent and broad neutralizing antibody recognizes and penetrates the HIV glycan shield. Science 2011; 334:1097-103. [PMID: 21998254 DOI: 10.1126/science.1213256] [Citation(s) in RCA: 579] [Impact Index Per Article: 44.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The HIV envelope (Env) protein gp120 is protected from antibody recognition by a dense glycan shield. However, several of the recently identified PGT broadly neutralizing antibodies appear to interact directly with the HIV glycan coat. Crystal structures of antigen-binding fragments (Fabs) PGT 127 and 128 with Man(9) at 1.65 and 1.29 angstrom resolution, respectively, and glycan binding data delineate a specific high mannose-binding site. Fab PGT 128 complexed with a fully glycosylated gp120 outer domain at 3.25 angstroms reveals that the antibody penetrates the glycan shield and recognizes two conserved glycans as well as a short β-strand segment of the gp120 V3 loop, accounting for its high binding affinity and broad specificity. Furthermore, our data suggest that the high neutralization potency of PGT 127 and 128 immunoglobulin Gs may be mediated by cross-linking Env trimers on the viral surface.
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Affiliation(s)
- Robert Pejchal
- Department of Molecular Biology, Skaggs Institute for Chemical Biology and International AIDS Vaccine Initiative (IAVI) Neutralizing Antibody Center, nhe Scripps Research Institute, La Jolla, CA 92037, USA
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Schmitz H, Gabriel M, Emmerich P. Specific detection of antibodies to different flaviviruses using a new immune complex ELISA. Med Microbiol Immunol 2011; 200:233-9. [PMID: 21533786 DOI: 10.1007/s00430-011-0195-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Indexed: 10/18/2022]
Abstract
Immune complex (IC) ELISAs for IgG antibodies to various virus antigens have turned out to be both highly specific and sensitive. During incubation of a labelled antigen with the serum samples, ICs are formed, which bind to microtiter plates coated with rheumatoid factor (RF) IgM. Here, we describe an improved coating of the solid-phase support comparing various Fc-receptor molecules. IC ELISAs were applied to detect human IgG antibodies to the highly virus-specific ED3 domain of West Nile- and tick-borne encephalitis virus envelopes. Compared with other Fc-receptor molecules like RF or C1q, FcγRIIA (CD32) turned out to bind the ICs composed of IgG antibodies and peroxidase-labelled ED3 antigens more efficiently. Due to low background reactions, sera could be tested at a dilution of 1:10. Moreover, using CD32 instead of RF coating, anti-flavivirus antibodies could be detected in various animal species.
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Affiliation(s)
- Herbert Schmitz
- Department of Virology, Bernhard-Nocht-Institute for Tropical Medicine, Bernhard-Nocht-Str.74, 20359 Hamburg, Germany.
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Jefferis R. The antibody paradigm: present and future development as a scaffold for biopharmaceutical drugs. Biotechnol Genet Eng Rev 2011; 26:1-42. [PMID: 21415874 DOI: 10.5661/bger-26-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Early studies of the humoral immune response revealed an apparent paradox: an infinite diversity of antibody specificities encoded within a finite genome. In consequence antibodies became a focus of interest for biochemists and geneticists. It resulted in the elucidation of the basic structural unit, the immunoglobulin (Ig) domain, comprised of ~ 100 amino acid residues that generate the characteristic "immunoglobulin (Ig) fold". The Ig fold has an anti-parallel ß-pleated sheet (barrel) structure that affords structural stability whilst the ß-bends allow for essentially infinite structural variation and functional diversity. This versatility is reflected in the Ig domain being the most widely utilised structural unit within the proteome. Human antibodies are comprised of multiple Ig domains and their structural diversity may be enhanced through the attachment of oligosaccharides. This review summarizes our current understanding of the immunoglobulin structure/function relationships and the application of protein and oligosaccharide engineering to further develop the Ig domain as a scaffold for the generation of new and novel antibody based therapeutics.
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Affiliation(s)
- Roy Jefferis
- School of Immunity and Infection, The College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK.
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47
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Fast and efficient characterization of an anti-gliadin monoclonal antibody epitope related to celiac disease using resin-bound peptides. J Immunol Methods 2011; 365:174-82. [DOI: 10.1016/j.jim.2010.12.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Revised: 12/08/2010] [Accepted: 12/21/2010] [Indexed: 11/20/2022]
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Yang H, Gurgel PV, Williams DK, Bobay BG, Cavanagh J, Muddiman DC, Carbonell RG. Binding site on human immunoglobulin G for the affinity ligand HWRGWV. J Mol Recognit 2010; 23:271-82. [PMID: 20049844 PMCID: PMC3906645 DOI: 10.1002/jmr.967] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Affinity ligand HWRGWV has demonstrated the ability to isolate human immunoglobulin G (hIgG) from mammalian cell culture media. The ligand specifically binds hIgG through its Fc portion. This work shows that deglycosylation of hIgG has no influence on its binding to the HWRGWV ligand and the ligand does not compete with Protein A or Protein G in binding hIgG. It is suggested by the mass spectrometry (MS) data and docking simulation that HWRGWV binds to the pFc portion of hIgG and interacts with the amino acids in the loop Ser383-Asn389 (SNGQPEN) located in the C(H)3 domain. Subsequent modeling has suggested a possible three-dimensional minimized solution structure for the interaction of hIgG and the HWRGWV ligand. The results support the fact that a peptide as small as a hexamer can have specific interactions with large proteins such as hIgG.
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Affiliation(s)
- Haiou Yang
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA
| | - Patrick V. Gurgel
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA
| | - D. Keith Williams
- W.M. Keck FT-ICR Mass Spectrometry Laboratory, Department of Chemistry, North Carolina State University, Raleigh, NC 27695, USA
| | - Benjamin G. Bobay
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC 27695, USA
- North Carolina Research Campus, Kannapolis, Kannapolis, NC 28081, USA
| | - John Cavanagh
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC 27695, USA
| | - David C. Muddiman
- W.M. Keck FT-ICR Mass Spectrometry Laboratory, Department of Chemistry, North Carolina State University, Raleigh, NC 27695, USA
| | - Ruben G. Carbonell
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA
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Mahler M, Fritzler MJ. Epitope specificity and significance in systemic autoimmune diseases. Ann N Y Acad Sci 2010; 1183:267-87. [DOI: 10.1111/j.1749-6632.2009.05127.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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50
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