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Götz MP, Duque Villegas MA, Fageräng B, Kerfin A, Skjoedt MO, Garred P, Rosbjerg A. Transient Binding Dynamics of Complement System Pattern Recognition Molecules on Pathogens. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2024; 212:1493-1503. [PMID: 38488502 DOI: 10.4049/jimmunol.2300768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 02/26/2024] [Indexed: 04/17/2024]
Abstract
Previous studies of pattern recognition molecules (PRMs) of the complement system have revealed difficulties in observing binding on pathogens such as Aspergillus fumigatus and Escherichia coli, despite complement deposition indicative of classical and lectin pathway activation. Thus, we investigated the binding dynamics of PRMs of the complement system, specifically C1q of the classical pathway and mannose-binding lectin (MBL) of the lectin pathway. We observed consistently increasing deposition of essential complement components such as C4b, C3b, and the terminal complement complex on A. fumigatus and E. coli. However, C1q and MBL binding to the surface rapidly declined during incubation after just 2-4 min in 10% plasma. The detachment of C1q and MBL can be linked to complement cascade activation, as the PRMs remain bound in the absence of plasma. The dissociation and the fate of C1q and MBL seem to have different mechanistic functions. Notably, C1q dynamics were associated with local C1 complex activation. When C1s was inhibited in plasma, C1q binding not only remained high but further increased over time. In contrast, MBL binding was inversely correlated with total and early complement activation due to MBL binding being partially retained by complement inhibition. Results indicate that detached MBL might be able to functionally rebind to A. fumigatus. In conclusion, these results reveal a (to our knowledge) novel "hit-and-run" complement-dependent PRM dynamic mechanism on pathogens. These dynamics may have profound implications for host defense and may help increase the functionality and longevity of complement-dependent PRMs in circulation.
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Affiliation(s)
- Maximilian Peter Götz
- Laboratory of Molecular Medicine, Department of Clinical Immunology, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark
- Department of Immunology and Infectious Diseases, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Institute for Systemic Inflammation Research, Medicine Section, University of Lübeck, Lübeck, Germany
| | - Mario Alejandro Duque Villegas
- Laboratory of Molecular Medicine, Department of Clinical Immunology, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark
- Infection Immunology, Research Center Borstel, Borstel, Germany
- Molecular and Experimental Mycobacteriology, Research Center Borstel, Borstel, Germany
| | - Beatrice Fageräng
- Laboratory of Molecular Medicine, Department of Clinical Immunology, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark
- Department of Immunology, University of Oslo, Oslo University Hospital, Oslo, Norway
| | - Aileen Kerfin
- Laboratory of Molecular Medicine, Department of Clinical Immunology, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark
- Institute for Systemic Inflammation Research, Medicine Section, University of Lübeck, Lübeck, Germany
| | - Mikkel-Ole Skjoedt
- Laboratory of Molecular Medicine, Department of Clinical Immunology, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Peter Garred
- Laboratory of Molecular Medicine, Department of Clinical Immunology, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Anne Rosbjerg
- Laboratory of Molecular Medicine, Department of Clinical Immunology, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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2
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Mellors J, Carroll M. Direct enhancement of viral neutralising antibody potency by the complement system: a largely forgotten phenomenon. Cell Mol Life Sci 2024; 81:22. [PMID: 38200235 PMCID: PMC10781860 DOI: 10.1007/s00018-023-05074-2] [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] [Revised: 11/24/2023] [Accepted: 11/29/2023] [Indexed: 01/12/2024]
Abstract
Neutralisation assays are commonly used to assess vaccine-induced and naturally acquired immune responses; identify correlates of protection; and inform important decisions on the screening, development, and use of therapeutic antibodies. Neutralisation assays are useful tools that provide the gold standard for measuring the potency of neutralising antibodies, but they are not without limitations. Common methods such as the heat-inactivation of plasma samples prior to neutralisation assays, or the use of anticoagulants such as EDTA for blood collection, can inactivate the complement system. Even in non-heat-inactivated samples, the levels of complement activity can vary between samples. This can significantly impact the conclusions regarding neutralising antibody potency. Restoration of the complement system in these samples can be achieved using an exogenous source of plasma with preserved complement activity or with purified complement proteins. This can significantly enhance the neutralisation titres for some antibodies depending on characteristics such as antibody isotype and the epitope they bind, enable neutralisation with otherwise non-neutralising antibodies, and demonstrate a better relationship between in vitro and in vivo findings. In this review, we discuss the evidence for complement-mediated enhancement of antibody neutralisation against a range of viruses, explore the potential mechanisms which underpin this enhancement, highlight current gaps in the literature, and provide a brief summary of considerations for adopting this approach in future research applications.
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Affiliation(s)
- Jack Mellors
- Centre for Human Genetics and the Pandemic Sciences Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
| | - Miles Carroll
- Centre for Human Genetics and the Pandemic Sciences Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
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3
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Dijkstra DJ, van de Bovenkamp FS, Abendstein L, Zuijderduijn R, Pool J, Kramer CSM, Slot LM, Drijfhout JW, de Vor L, Gelderman KA, Rooijakkers SHM, Zaldumbide A, Vidarsson G, Sharp TH, Parren PWHI, Trouw LA. Human anti-C1q autoantibodies bind specifically to solid-phase C1q and enhance phagocytosis but not complement activation. Proc Natl Acad Sci U S A 2023; 120:e2310666120. [PMID: 38048459 PMCID: PMC10723154 DOI: 10.1073/pnas.2310666120] [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: 06/26/2023] [Accepted: 10/27/2023] [Indexed: 12/06/2023] Open
Abstract
Autoantibodies directed against complement component C1q are commonly associated with autoimmune diseases, especially systemic lupus erythematosus. Importantly, these anti-C1q autoantibodies are specific for ligand-bound, solid-phase C1q and do not bind to fluid-phase C1q. In patients with anti-C1q, C1q levels are in the normal range, and the autoantibodies are thus not depleting. To study these human anti-C1q autoantibodies at the molecular level, we isolated C1q-reactive B cells and recombinantly produced nine monoclonal antibodies (mAbs) from four different healthy individuals. The isolated mAbs were of the IgG isotype, contained extensively mutated variable domains, and showed high affinity to the collagen-like region of C1q. The anti-C1q mAbs exclusively bound solid-phase C1q in complex with its natural ligands, including immobilized or antigen-bound IgG, IgM or CRP, and necrotic cells. Competition experiments reveal that at least 2 epitopes, also targeted by anti-C1q antibodies in sera from SLE patients, are recognized. Electron microscopy with hexameric IgG-C1q immune complexes demonstrated that multiple mAbs can interact with a single C1q molecule and identified the region of C1q targeted by these mAbs. The opsonization of immune complexes with anti-C1q greatly enhanced Fc-receptor-mediated phagocytosis but did not increase complement activation. We conclude that human anti-C1q autoantibodies specifically bind neo-epitopes on solid-phase C1q, which results in an increase in Fc-receptor-mediated effector functions that may potentially contribute to autoimmune disease immunopathology.
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Affiliation(s)
- Douwe J. Dijkstra
- Department of Immunology, Leiden University Medical Center, Leiden2300 RC, The Netherlands
| | - Fleur S. van de Bovenkamp
- Department of Immunology, Leiden University Medical Center, Leiden2300 RC, The Netherlands
- Lava Therapeutics, Utrecht3584 CM, The Netherlands
| | - Leoni Abendstein
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden2300 RC, The Netherlands
| | - Rob Zuijderduijn
- Department of Immunology, Leiden University Medical Center, Leiden2300 RC, The Netherlands
| | - Jos Pool
- Department of Immunology, Leiden University Medical Center, Leiden2300 RC, The Netherlands
| | - Cynthia S. M. Kramer
- Department of Immunology, Leiden University Medical Center, Leiden2300 RC, The Netherlands
| | - Linda M. Slot
- Department of Rheumatology, Leiden University Medical Center, Leiden2300 RC, The Netherlands
| | - Jan W. Drijfhout
- Department of Immunology, Leiden University Medical Center, Leiden2300 RC, The Netherlands
| | - Lisanne de Vor
- Department of Medical Microbiology, University Medical Center, Utrecht3584 CX, The Netherlands
| | | | - Suzan H. M. Rooijakkers
- Department of Medical Microbiology, University Medical Center, Utrecht3584 CX, The Netherlands
| | - Arnaud Zaldumbide
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden2300 RC, The Netherlands
| | - Gestur Vidarsson
- Department of Experimental Immunohematology, Sanquin Research, Amsterdam1066 CX, The Netherlands
| | - Thomas H. Sharp
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden2300 RC, The Netherlands
| | - Paul W. H. I. Parren
- Department of Immunology, Leiden University Medical Center, Leiden2300 RC, The Netherlands
- Gyes BV, Naarden1411 DC, The Netherlands
| | - Leendert A. Trouw
- Department of Immunology, Leiden University Medical Center, Leiden2300 RC, The Netherlands
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4
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Damelang T, de Taeye SW, Rentenaar R, Roya-Kouchaki K, de Boer E, Derksen NIL, van Kessel K, Lissenberg-Thunnissen S, Rooijakkers SHM, Jongerius I, Mebius MM, Schuurman J, Labrijn AF, Vidarsson G, Rispens T. The Influence of Human IgG Subclass and Allotype on Complement Activation. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2023; 211:1725-1735. [PMID: 37843500 PMCID: PMC10656437 DOI: 10.4049/jimmunol.2300307] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 09/20/2023] [Indexed: 10/17/2023]
Abstract
Complement activation via the classical pathway is initiated when oligomeric Igs on target surfaces are recognized by C1 of the complement cascade. The strength of this interaction and activation of the complement system are influenced by structural variation of the Ab, including Ab isotype, subclass, and glycosylation profile. Polymorphic variants of IgG have also been described to influence Fc-dependent effector functions. Therefore, we assessed complement binding, deposition, and complement-dependent cytotoxicity (CDC) of 27 known IgG allotypes with anti-trinitrophenyl specificity. Differences between allotypes within subclasses were minor for IgG1, IgG3, and IgG4 allotypes, and more substantial for IgG2. Allelic variant IGHG2*06, containing a unique serine at position 378 in the CH3 domain, showed less efficient complement activation and CDC compared with other IgG2 polymorphisms. We also observed variable cell lysis between IgG1 and IgG3, with IgG3 being superior in lysis of human RBCs and Ramos cells, and IgG1 being superior in lysis of Raji and Wien133 cells, demonstrating that a long-standing conundrum in the literature depends on cellular context. Furthermore, we compared IgG1 and IgG3 under different circumstances, showing that Ag density and Ab hinge length, but not complement regulators, define the context dependency of Ab-mediated CDC activity. Our results point toward a variation in the capacity of IgG subclasses to activate complement due to single amino acid changes and hinge length differences of allotypes to activate complement, which might give new insights on susceptibility to infectious, alloimmune, or autoimmune diseases and aid the design of Ab-based therapeutics.
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Affiliation(s)
- Timon Damelang
- Department of Immunopathology, Sanquin Research and Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
- Department of Experimental Immunohematology, Sanquin Research, Amsterdam, the Netherlands
- Department of Biomolecular Mass Spectrometry and Proteomics, Utrecht Institute for Pharmaceutical Sciences and Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, the Netherlands
| | - Steven W. de Taeye
- Department of Immunopathology, Sanquin Research and Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
- Department of Experimental Immunohematology, Sanquin Research, Amsterdam, the Netherlands
| | - Rosa Rentenaar
- Department of Immunopathology, Sanquin Research and Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - Kasra Roya-Kouchaki
- Department of Experimental Immunohematology, Sanquin Research, Amsterdam, the Netherlands
| | - Esther de Boer
- Department of Immunopathology, Sanquin Research and Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
- Department of Pediatric Immunology, Rheumatology and Infectious Diseases, Emma Children’s Hospital, Amsterdam UMC, Amsterdam, the Netherlands
| | - Ninotska I. L. Derksen
- Department of Immunopathology, Sanquin Research and Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - Kok van Kessel
- Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | | | - Suzan H. M. Rooijakkers
- Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Ilse Jongerius
- Department of Immunopathology, Sanquin Research and Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
- Department of Pediatric Immunology, Rheumatology and Infectious Diseases, Emma Children’s Hospital, Amsterdam UMC, Amsterdam, the Netherlands
| | | | | | | | - Gestur Vidarsson
- Department of Experimental Immunohematology, Sanquin Research, Amsterdam, the Netherlands
- Department of Biomolecular Mass Spectrometry and Proteomics, Utrecht Institute for Pharmaceutical Sciences and Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, the Netherlands
| | - Theo Rispens
- Department of Immunopathology, Sanquin Research and Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
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5
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Muts RM, den Boer MA, Bardoel BW, Aerts PC, de Haas CJC, Heck AJR, Rooijakkers SHM, Heesterbeek DAC. Artificial surface labelling of Escherichia coli with StrepTagII antigen to study how monoclonal antibodies drive complement-mediated killing. Sci Rep 2023; 13:18836. [PMID: 37914798 PMCID: PMC10620216 DOI: 10.1038/s41598-023-46026-x] [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: 06/21/2023] [Accepted: 10/26/2023] [Indexed: 11/03/2023] Open
Abstract
Antibodies play a key role in the immune defence against Gram-negative bacteria. After binding to bacterial surface antigens, IgG and IgM can activate the complement system and trigger formation of lytic membrane attack complex (MAC) pores. Molecular studies to compare functional activity of antibodies on bacteria are hampered by the limited availability of well-defined antibodies against bacterial surface antigens. Therefore, we genetically engineered E. coli by expressing the StrepTagII antigen into outer membrane protein X (OmpX) and validated that these engineered bacteria were recognised by anti-StrepTagII antibodies. We then combined this antigen-antibody system with a purified complement assay to avoid interference of serum components and directly compare MAC-mediated bacterial killing via IgG1 and pentameric IgM. While both IgG1 and IgM could induce MAC-mediated killing, we show that IgM has an increased capacity to induce complement-mediated killing of E. coli compared to IgG1. While Fc mutations that enhance IgG clustering after target binding could not improve MAC formation, mutations that cause formation of pre-assembled IgG hexamers enhanced the complement activating capacity of IgG1. Altogether, we here present a system to study antibody-dependent complement activation on E. coli and show IgM's enhanced capacity over IgG to induce complement-mediated lysis of E. coli.
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Affiliation(s)
- Remy M Muts
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX, Utrecht, The Netherlands
| | - Maurits A den Boer
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute of Pharmaceutical Sciences, Utrecht University, 3584 CH, Utrecht, The Netherlands
- Netherlands Proteomic Center, 3584 CH, Utrecht, The Netherlands
| | - Bart W Bardoel
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX, Utrecht, The Netherlands
| | - Piet C Aerts
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX, Utrecht, The Netherlands
| | - Carla J C de Haas
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX, Utrecht, The Netherlands
| | - Albert J R Heck
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute of Pharmaceutical Sciences, Utrecht University, 3584 CH, Utrecht, The Netherlands
- Netherlands Proteomic Center, 3584 CH, Utrecht, The Netherlands
| | - Suzan H M Rooijakkers
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX, Utrecht, The Netherlands
| | - Dani A C Heesterbeek
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX, Utrecht, The Netherlands.
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6
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Chornenkyy Y, Yamamoto T, Hara H, Stowell SR, Ghiran I, Robson SC, Cooper DKC. Future prospects for the clinical transfusion of pig red blood cells. Blood Rev 2023; 61:101113. [PMID: 37474379 PMCID: PMC10968389 DOI: 10.1016/j.blre.2023.101113] [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: 04/24/2023] [Revised: 06/23/2023] [Accepted: 07/09/2023] [Indexed: 07/22/2023]
Abstract
Transfusion of allogeneic human red blood cell (hRBCs) is limited by supply and compatibility between individual donors and recipients. In situations where the blood supply is constrained or when no compatible RBCs are available, patients suffer. As a result, alternatives to hRBCs that complement existing RBC transfusion strategies are needed. Pig RBCs (pRBCs) could provide an alternative because of their abundant supply, and functional similarities to hRBCs. The ability to genetically modify pigs to limit pRBC immunogenicity and augment expression of human 'protective' proteins has provided major boosts to this research and opens up new therapeutic avenues. Although deletion of expression of xenoantigens has been achieved in genetically-engineered pigs, novel genetic methods are needed to introduce human 'protective' transgenes into pRBCs at the high levels required to prevent hemolysis and extend RBC survival in vivo. This review addresses recent progress and examines future prospects for clinical xenogeneic pRBC transfusion.
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Affiliation(s)
- Yevgen Chornenkyy
- Department of Pathology, McGaw Medical Center of Northwestern University, Feinberg School of Medicine, Chicago, IL, USA
| | - Takayuki Yamamoto
- Center for Transplantation Science, Massachusetts General Hospital/Harvard Medical School, Boston, MA, USA; Division of Transplantation, Department of Surgery, Massachusetts General Hospital/Harvard Medical School, Boston, MA, USA.
| | - Hidetaka Hara
- College of Veterinary Medicine, Yunnan Agricultural University, Kunming, Yunnan, China
| | - Sean R Stowell
- Joint Program in Transfusion Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Ionita Ghiran
- Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, MA, USA
| | - Simon C Robson
- Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, MA, USA
| | - David K C Cooper
- Center for Transplantation Science, Massachusetts General Hospital/Harvard Medical School, Boston, MA, USA
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7
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van der Lans SPA, Janet-Maitre M, Masson FM, Walker KA, Doorduijn DJ, Janssen AB, van Schaik W, Attrée I, Rooijakkers SHM, Bardoel BW. Colistin resistance mutations in phoQ can sensitize Klebsiella pneumoniae to IgM-mediated complement killing. Sci Rep 2023; 13:12618. [PMID: 37537263 PMCID: PMC10400624 DOI: 10.1038/s41598-023-39613-5] [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: 02/07/2023] [Accepted: 07/27/2023] [Indexed: 08/05/2023] Open
Abstract
Due to multi-drug resistance, physicians increasingly use the last-resort antibiotic colistin to treat infections with the Gram-negative bacterium Klebsiella pneumoniae. Unfortunately, K. pneumoniae can also develop colistin resistance. Interestingly, colistin resistance has dual effects on bacterial clearance by the immune system. While it increases resistance to antimicrobial peptides, colistin resistance has been reported to sensitize certain bacteria for killing by human serum. Here we investigate the mechanisms underlying this increased serum sensitivity, focusing on human complement which kills Gram-negatives via membrane attack complex (MAC) pores. Using in vitro evolved colistin resistant strains and a fluorescent MAC-mediated permeabilization assay, we showed that two of the three tested colistin resistant strains, Kp209_CSTR and Kp257_CSTR, were sensitized to MAC. Transcriptomic and mechanistic analyses focusing on Kp209_CSTR revealed that a mutation in the phoQ gene locked PhoQ in an active state, making Kp209_CSTR colistin resistant and MAC sensitive. Detailed immunological assays showed that complement activation on Kp209_CSTR in human serum required specific IgM antibodies that bound Kp209_CSTR but did not recognize the wild-type strain. Together, our results show that developing colistin resistance affected recognition of Kp209_CSTR and its killing by the immune system.
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Affiliation(s)
- Sjors P A van der Lans
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Manon Janet-Maitre
- Bacterial Pathogenesis and Cellular Responses Group, UMR5075, Institute of Structural Biology, University Grenoble Alpes, Grenoble, France
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Frerich M Masson
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Kimberly A Walker
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Dennis J Doorduijn
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Axel B Janssen
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Willem van Schaik
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Ina Attrée
- Bacterial Pathogenesis and Cellular Responses Group, UMR5075, Institute of Structural Biology, University Grenoble Alpes, Grenoble, France
| | - Suzan H M Rooijakkers
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Bart W Bardoel
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands.
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8
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MatRahim NA, Jones KM, Keegan BP, Strych U, Zhan B, Lee HY, AbuBakar S. TonB-Dependent Receptor Protein Displayed on Spores of Bacillus subtilis Stimulates Protective Immune Responses against Acinetobacter baumannii. Vaccines (Basel) 2023; 11:1106. [PMID: 37376495 DOI: 10.3390/vaccines11061106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 06/06/2023] [Accepted: 06/13/2023] [Indexed: 06/29/2023] Open
Abstract
The emergence of antibiotic-resistant Acinetobacter baumannii strains with limited treatment options has become a significant global health concern. Efforts to develop vaccines against the bacteria have centred on several potential protein targets, including the TonB-dependent receptors (TBDRs). In the present study, TBDRs from A. baumannii were displayed on the surface of Bacillus subtilis spores. The immunogenicity of the recombinant spores was evaluated in orally vaccinated mice. None of the immunized mice demonstrated signs of illness and were observed to be healthy throughout the study. Sera and the intestinal secretions from the recombinant spores-treated mice demonstrated mucosal and humoral antibody responses to the vaccine antigen. In addition, bactericidal activities of the sera against A. baumannii clinical isolates were demonstrated. These observations suggest that the B. subtilis spore-displayed TBDRs should be further explored as much-needed potential oral vaccine candidates against A. baumannii.
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Affiliation(s)
- Nor-Aziyah MatRahim
- Tropical Infectious Diseases Research and Education Center (TIDREC), Universiti Malaya, Kuala Lumpur 50603, Malaysia
- Texas Children's Hospital Center for Vaccine Development, Baylor College of Medicine, Houston, TX 77030, USA
- Virology Unit, Infectious Diseases Research Centre, Institute for Medical Research, National Institutes of Health, Shah Alam 40170, Malaysia
| | - Kathryn Marie Jones
- Texas Children's Hospital Center for Vaccine Development, Baylor College of Medicine, Houston, TX 77030, USA
| | - Brian P Keegan
- Texas Children's Hospital Center for Vaccine Development, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ulrich Strych
- Texas Children's Hospital Center for Vaccine Development, Baylor College of Medicine, Houston, TX 77030, USA
| | - Bin Zhan
- Texas Children's Hospital Center for Vaccine Development, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hai-Yen Lee
- Tropical Infectious Diseases Research and Education Center (TIDREC), Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Sazaly AbuBakar
- Tropical Infectious Diseases Research and Education Center (TIDREC), Universiti Malaya, Kuala Lumpur 50603, Malaysia
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9
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Aguinagalde Salazar L, den Boer MA, Castenmiller SM, Zwarthoff SA, de Haas C, Aerts PC, Beurskens FJ, Schuurman J, Heck AJR, van Kessel K, Rooijakkers SHM. Promoting Fc-Fc interactions between anti-capsular antibodies provides strong immune protection against Streptococcus pneumoniae. eLife 2023; 12:80669. [PMID: 36947116 PMCID: PMC10032657 DOI: 10.7554/elife.80669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 03/09/2023] [Indexed: 03/23/2023] Open
Abstract
Streptococcus pneumoniae is the leading cause of community-acquired pneumonia and an important cause of childhood mortality. Despite the introduction of successful vaccines, the global spread of both non-vaccine serotypes and antibiotic-resistant strains reinforces the development of alternative therapies against this pathogen. One possible route is the development of monoclonal antibodies (mAbs) that induce killing of bacteria via the immune system. Here, we investigate whether mAbs can be used to induce killing of pneumococcal serotypes for which the current vaccines show unsuccessful protection. Our study demonstrates that when human mAbs against pneumococcal capsule polysaccharides (CPS) have a poor capacity to induce complement activation, a critical process for immune protection against pneumococci, their activity can be strongly improved by hexamerization-enhancing mutations. Our data indicate that anti-capsular antibodies may have a low capacity to form higher-order oligomers (IgG hexamers) that are needed to recruit complement component C1. Indeed, specific point mutations in the IgG-Fc domain that strengthen hexamerization strongly enhance C1 recruitment and downstream complement activation on encapsulated pneumococci. Specifically, hexamerization-enhancing mutations E430G or E345K in CPS6-IgG strongly potentiate complement activation on S. pneumoniae strains that express capsular serotype 6 (CPS6), and the highly invasive serotype 19A strain. Furthermore, these mutations improve complement activation via mAbs recognizing CPS3 and CPS8 strains. Importantly, hexamer-enhancing mutations enable mAbs to induce strong opsonophagocytic killing by human neutrophils. Finally, passive immunization with CPS6-IgG1-E345K protected mice from developing severe pneumonia. Altogether, this work provides an important proof of concept for future optimization of antibody therapies against encapsulated bacteria.
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Affiliation(s)
| | - Maurits A den Boer
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, Netherlands
- Netherlands Proteomics Center, Utrecht, Netherlands
| | - Suzanne M Castenmiller
- Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Seline A Zwarthoff
- Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Carla de Haas
- Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Piet C Aerts
- Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | | | | | - Albert J R Heck
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, Netherlands
- Netherlands Proteomics Center, Utrecht, Netherlands
| | - Kok van Kessel
- Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Suzan H M Rooijakkers
- Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
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10
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Boero E, Gorham RD, Francis EA, Brand J, Teng LH, Doorduijn DJ, Ruyken M, Muts RM, Lehmann C, Verschoor A, van Kessel KPM, Heinrich V, Rooijakkers SHM. Purified complement C3b triggers phagocytosis and activation of human neutrophils via complement receptor 1. Sci Rep 2023; 13:274. [PMID: 36609665 PMCID: PMC9822988 DOI: 10.1038/s41598-022-27279-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 12/29/2022] [Indexed: 01/07/2023] Open
Abstract
The complement system provides vital immune protection against infectious agents by labeling them with complement fragments that enhance phagocytosis by immune cells. Many details of complement-mediated phagocytosis remain elusive, partly because it is difficult to study the role of individual complement proteins on target surfaces. Here, we employ serum-free methods to couple purified complement C3b onto E. coli bacteria and beads and then expose human neutrophils to these C3b-coated targets. We examine the neutrophil response using a combination of flow cytometry, confocal microscopy, luminometry, single-live-cell/single-target manipulation, and dynamic analysis of neutrophil spreading on opsonin-coated surfaces. We show that purified C3b can potently trigger phagocytosis and killing of bacterial cells via Complement receptor 1. Comparison of neutrophil phagocytosis of C3b- versus antibody-coated beads with single-bead/single-target analysis exposes a similar cell morphology during engulfment. However, bulk phagocytosis assays of C3b-beads combined with DNA-based quenching reveal that these are poorly internalized compared to their IgG1 counterparts. Similarly, neutrophils spread slower on C3b-coated compared to IgG-coated surfaces. These observations support the requirement of multiple stimulations for efficient C3b-mediated uptake. Together, our results establish the existence of a direct pathway of phagocytic uptake of C3b-coated targets and present methodologies to study this process.
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Affiliation(s)
- Elena Boero
- grid.5477.10000000120346234Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands ,grid.425088.3GSK, 53100 Siena, Italy
| | - Ronald D. Gorham
- grid.5477.10000000120346234Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands ,grid.417555.70000 0000 8814 392XSanofi, Waltham, MA 02451 USA
| | - Emmet A. Francis
- grid.27860.3b0000 0004 1936 9684Department of Biomedical Engineering, University of California Davis, Davis, CA 95616 USA
| | - Jonathan Brand
- grid.27860.3b0000 0004 1936 9684Department of Biomedical Engineering, University of California Davis, Davis, CA 95616 USA
| | - Lay Heng Teng
- grid.27860.3b0000 0004 1936 9684Department of Biomedical Engineering, University of California Davis, Davis, CA 95616 USA
| | - Dennis J. Doorduijn
- grid.5477.10000000120346234Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Maartje Ruyken
- grid.5477.10000000120346234Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Remy M. Muts
- grid.5477.10000000120346234Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Christian Lehmann
- grid.5330.50000 0001 2107 3311Laboratory of Dendritic Cell Biology, Department of Dermatology, University Hospital of Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, 91052 Erlangen, Germany
| | - Admar Verschoor
- grid.15474.330000 0004 0477 2438Department of Otorhinolaryngology, Technische Universität München and Klinikum Rechts der Isar, 81675 Munich, Germany
| | - Kok P. M. van Kessel
- grid.5477.10000000120346234Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Volkmar Heinrich
- grid.27860.3b0000 0004 1936 9684Department of Biomedical Engineering, University of California Davis, Davis, CA 95616 USA
| | - Suzan H. M. Rooijakkers
- grid.5477.10000000120346234Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
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11
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Bechtler C, Koutsogiannaki S, Umnyakova E, Hamid A, Gautam A, Sarigiannis Y, Pouw RB, Lamers C, Rabbani S, Schmidt CQ, Lambris JD, Ricklin D. Complement-regulatory biomaterial coatings: Activity and selectivity profile of the factor H-binding peptide 5C6. Acta Biomater 2023; 155:123-138. [PMID: 36328123 DOI: 10.1016/j.actbio.2022.10.055] [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: 07/29/2022] [Revised: 10/06/2022] [Accepted: 10/25/2022] [Indexed: 11/15/2022]
Abstract
The use of biomaterials in modern medicine has enabled advanced drug delivery strategies and led to reduced morbidity and mortality in a variety of interventions such as transplantation or hemodialysis. However, immune-mediated reactions still present a serious complication of these applications. One of the drivers of such reactions is the complement system, a central part of humoral innate immunity that acts as a first-in-line defense system in its own right but also coordinates other host defense responses. A major regulator of the complement system is the abundant plasma protein factor H (FH), which impairs the amplification of complement responses. Previously, we could show that it is possible to recruit FH to biomedical surfaces using the phage display-derived cyclic peptide 5C6 and, consequently, reduce deposition of C3b, an activation product of the complement system. However, the optimal orientation of 5C6 on surfaces, structural determinants within the peptide for the binding, and the exact binding region on FH remained unknown. Here, we show that the cyclic core and C-terminal region of 5C6 are essential for its interaction with FH and that coating through its N-terminus strongly increases FH recruitment and reduces C3-mediated opsonization in a microparticle-based assay. Furthermore, we could demonstrate that 5C6 selectively binds to FH but not to related proteins. The observation that 5C6 also binds murine FH raises the potential for translational evaluation in animal models. This work provides important insight for the future development of 5C6 as a probe or therapeutic entity to reduce complement activation on biomaterials. STATEMENT OF SIGNIFICANCE: Biomaterials have evolved into core technologies critical to biomedical and drug delivery applications alike, yet their safe and efficient use may be adversely impacted by immune responses to the foreign materials. Taking inspiration from microbial immune evasion strategies, our group developed a peptide-based surface coating that recruits factor H (FH), a host regulator of the complement system, from plasma to the material surface and prevents unwanted activation of this innate immunity pathway. In this study, we identified the molecular determinants that define the interaction between FH and the coated peptide, developed tethering strategies with largely enhanced binding capacity and provided important insight into the target selectivity and species specificity of the FH-binding peptide, thereby paving the way for preclinical development steps.
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Affiliation(s)
- Clément Bechtler
- Molecular Pharmacy Group, Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland
| | - Sophia Koutsogiannaki
- Department of Pathology & Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, 422 Curie Blvd., Philadelphia, PA 19104, USA
| | - Ekaterina Umnyakova
- Molecular Pharmacy Group, Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland
| | - Amal Hamid
- Molecular Pharmacy Group, Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland
| | - Avneesh Gautam
- Department of Pathology & Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, 422 Curie Blvd., Philadelphia, PA 19104, USA
| | - Yiannis Sarigiannis
- Department of Pathology & Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, 422 Curie Blvd., Philadelphia, PA 19104, USA
| | - Richard B Pouw
- Molecular Pharmacy Group, Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland
| | - Christina Lamers
- Molecular Pharmacy Group, Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland
| | - Said Rabbani
- Molecular Pharmacy Group, Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland
| | - Christoph Q Schmidt
- Institute of Experimental and Clinical Pharmacology, Toxicology and Pharmacology of Natural Products, University of Ulm Medical Center, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - John D Lambris
- Department of Pathology & Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, 422 Curie Blvd., Philadelphia, PA 19104, USA.
| | - Daniel Ricklin
- Molecular Pharmacy Group, Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland.
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12
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Oskam N, Damelang T, Streutker M, Ooijevaar-de Heer P, Nouta J, Koeleman C, Van Coillie J, Wuhrer M, Vidarsson G, Rispens T. Factors affecting IgG4-mediated complement activation. Front Immunol 2023; 14:1087532. [PMID: 36776883 PMCID: PMC9910309 DOI: 10.3389/fimmu.2023.1087532] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 01/16/2023] [Indexed: 01/27/2023] Open
Abstract
Of the four human immunoglobulin G (IgG) subclasses, IgG4 is considered the least inflammatory, in part because it poorly activates the complement system. Regardless, in IgG4 related disease (IgG4-RD) and in autoimmune disorders with high levels of IgG4 autoantibodies, the presence of these antibodies has been linked to consumption and deposition of complement components. This apparent paradox suggests that conditions may exist, potentially reminiscent of in vivo deposits, that allow for complement activation by IgG4. Furthermore, it is currently unclear how variable glycosylation and Fab arm exchange may influence the ability of IgG4 to activate complement. Here, we used well-defined, glyco-engineered monoclonal preparations of IgG4 and determined their ability to activate complement in a controlled system. We show that IgG4 can activate complement only at high antigen and antibody concentrations, via the classical pathway. Moreover, elevated or reduced Fc galactosylation enhanced or diminished complement activation, respectively, with no apparent contribution from the lectin pathway. Fab glycans slightly reduced complement activation. Lastly, we show that bispecific, monovalent IgG4 resulting from Fab arm exchange is a less potent activator of complement than monospecific IgG4. Taken together, these results imply that involvement of IgG4-mediated complement activation in pathology is possible but unlikely.
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Affiliation(s)
- Nienke Oskam
- Sanquin Research and Landsteiner Laboratory, Department of Immunopathology, Academic Medical Center, Amsterdam, Netherlands
| | - Timon Damelang
- Sanquin Research and Landsteiner Laboratory, Department of Immunopathology, Academic Medical Center, Amsterdam, Netherlands.,Department of Immunohematology Experimental, Sanquin Research, Amsterdam, Netherlands.,Department of Biomolecular Mass Spectrometry and Proteomics, Utrecht Institute for Pharmaceutical Sciences and Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, Netherlands
| | - Marij Streutker
- Sanquin Research and Landsteiner Laboratory, Department of Immunopathology, Academic Medical Center, Amsterdam, Netherlands
| | - Pleuni Ooijevaar-de Heer
- Sanquin Research and Landsteiner Laboratory, Department of Immunopathology, Academic Medical Center, Amsterdam, Netherlands
| | - Jan Nouta
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, Netherlands
| | - Carolien Koeleman
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, Netherlands
| | - Julie Van Coillie
- Department of Immunohematology Experimental, Sanquin Research, Amsterdam, Netherlands.,Department of Biomolecular Mass Spectrometry and Proteomics, Utrecht Institute for Pharmaceutical Sciences and Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, Netherlands
| | - Manfred Wuhrer
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, Netherlands
| | - Gestur Vidarsson
- Department of Immunohematology Experimental, Sanquin Research, Amsterdam, Netherlands.,Department of Biomolecular Mass Spectrometry and Proteomics, Utrecht Institute for Pharmaceutical Sciences and Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, Netherlands
| | - Theo Rispens
- Sanquin Research and Landsteiner Laboratory, Department of Immunopathology, Academic Medical Center, Amsterdam, Netherlands
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13
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Zhang W, Chen Y, Pei H. C1q and central nervous system disorders. Front Immunol 2023; 14:1145649. [PMID: 37033981 PMCID: PMC10076750 DOI: 10.3389/fimmu.2023.1145649] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 03/07/2023] [Indexed: 04/11/2023] Open
Abstract
C1q is a crucial component of the complement system, which is activated through the classical pathway to perform non-specific immune functions, serving as the first line of defense against pathogens. C1q can also bind to specific receptors to carry out immune and other functions, playing a vital role in maintaining immune homeostasis and normal physiological functions. In the developing central nervous system (CNS), C1q functions in synapse formation and pruning, serving as a key player in the development and homeostasis of neuronal networks in the CNS. C1q has a close relationship with microglia and astrocytes, and under their influence, C1q may contribute to the development of CNS disorders. Furthermore, C1q can also have independent effects on neurological disorders, producing either beneficial or detrimental outcomes. Most of the evidence for these functions comes from animal models, with some also from human specimen studies. C1q is now emerging as a promising target for the treatment of a variety of diseases, and clinical trials are already underway for CNS disorders. This article highlights the role of C1q in CNS diseases, offering new directions for the diagnosis and treatment of these conditions.
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Affiliation(s)
- Wenjie Zhang
- Department of Emergency Intensive Care Unit, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
- Department of General Practice, Xingyang Sishui Central Health Center, Zhengzhou, China
| | - Yuan Chen
- Department of Neurology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Hui Pei
- Department of Emergency Intensive Care Unit, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
- *Correspondence: Hui Pei,
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14
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Anti-SARS-Cov-2 S-RBD IgG Formed after BNT162b2 Vaccination Can Bind C1q and Activate Complement. J Immunol Res 2022; 2022:7263740. [PMID: 36573216 PMCID: PMC9789906 DOI: 10.1155/2022/7263740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 11/19/2022] [Accepted: 12/07/2022] [Indexed: 12/23/2022] Open
Abstract
Background The ability of vaccine-induced antibodies to bind C1q could affect pathogen neutralization. In this study, we investigated C1q binding and subsequent complement activation by anti-spike (S) protein receptor-binding domain (RBD) specific antibodies produced following vaccination with either the mRNA vaccine BNT162b2 or the inactivated vaccine BBIBP-CorV. Methods Serum samples were collected in the period of July 2021-March 2022. Participants' demographic data, type of vaccine, date of vaccination, as well as adverse effects of the vaccine were recorded. The serum samples were incubated with S protein RBD-coated plates. Levels of human IgG, IgA, IgM, C1q, and mannose-binding lectin (MBL) that were bound to the plate, as well as formed C3d, and C5b-9 were compared between different groups of participants. Results A total of 151 samples were collected from vaccinated (n = 116) and nonvaccinated (n = 35) participants. Participants who received either one or two doses of BNT162b2 formed higher levels of anti-RBD IgG and IgA than participants who received BBIBP-CorV. The anti-RBD IgG formed following either vaccine bound C1q, but significantly more C1q binding was observed in participants who received BNT162b2. Subsequently, C5b-9 formation was significantly higher in participants who received BNT162b2, while no significant difference in C5b-9 formation was found between the nonvaccinated and BBIBP-CorV groups. The formation of C5b-9 was strongly correlated to C1q binding and not to MBL binding, additionally, the ratio of formed C5b-9/bound C1q was significantly higher in the BNT162b2 group. Conclusion Anti-RBD IgG formed following vaccination can bind C1q with subsequent complement activation, and the degree of terminal complement pathway activation differed between vaccines, which could play a role in the protection offered by COVID-19 vaccines. Further investigation into the correlation between vaccine protection and vaccine-induced antibodies' ability to activate complement is required.
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15
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Xiao K, Zhang S, Li C. The complement system and complement-like factors in sea cucumber. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2022; 136:104511. [PMID: 36029917 DOI: 10.1016/j.dci.2022.104511] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 07/31/2022] [Accepted: 08/04/2022] [Indexed: 06/15/2023]
Abstract
The complement system is an important part of innate immunity and plays an essential role in immune responses. Complement system consists of a series of proteins, its activation results in opsonization and phagocytosis of pathogens. Although the complement system has been studied extensively in vertebrates, considerably less is known about complement in invertebrates, especially in sea cucumber. Here, we reviewed the complement-like factors including Component 3 (C3), Complement factor B (Bf), Mannan-binding lectin (MBL) and globular Complement component 1q Receptor (gC1qR), which had been found in the complement system of sea cucumber. Furthermore, we compared the features of complement components among marine invertebrates and described the evolution of sea cucumber complement system obviously. This review can offer theoretical basis for disease control of the sea cucumber and will provide new insights into immune system of marine invertebrates. Meantime, the complete framework of sea cucumber complement may benefit the aquaculture industry.
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Affiliation(s)
- Ke Xiao
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, PR China
| | - Siyuan Zhang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, PR China.
| | - Chenghua Li
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, PR China; Collaborative Innovation Center for Zhejiang Marine High-efficiency and Healthy Aquaculture, Ningbo University, Ningbo, 315211, PR China.
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16
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Beudeker CR, Vijlbrief DC, van Montfrans J, Rooijakkers SH, van der Flier M. Neonatal sepsis and transient immunodeficiency: Potential for novel immunoglobulin therapies? Front Immunol 2022; 13:1016877. [PMID: 36330515 PMCID: PMC9623314 DOI: 10.3389/fimmu.2022.1016877] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 10/04/2022] [Indexed: 10/30/2023] Open
Abstract
Neonates, especially preterm neonates, have the highest risk of sepsis of all age groups. Transient immaturity of the neonatal immune system is an important risk factor. Neonates suffer from hypogammaglobulinemia as nor IgA nor IgM is transferred over the placenta and IgG is only transferred over the placenta late in gestation. In addition, neutrophil numbers and complement function are also decreased. This mini-review focuses on strategies to improve neonatal host-defense. Both clinical and preclinical studies have attempted to boost neonatal immunity to lower the incidence of sepsis and improve outcome. Recent advances in the development of (monoclonal) antibodies show promising results in preclinical studies but have yet to be tested in clinical trials. Strategies to increase complement activity seem efficient in vitro but potential disadvantages such as hyperinflammation have held back further clinical development. Increase of neutrophil numbers has been tested extensively in clinical trials but failed to show improvement in mortality. Future research should focus on clinical applicability of promising new prevention strategies for neonatal sepsis.
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Affiliation(s)
- Coco R. Beudeker
- Department of Pediatric Infectious Diseases and Immunology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Daniel C. Vijlbrief
- Department of Neonatology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Joris M. van Montfrans
- Department of Pediatric Infectious Diseases and Immunology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Suzan H.M. Rooijakkers
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Michiel van der Flier
- Department of Pediatric Infectious Diseases and Immunology, University Medical Center Utrecht, Utrecht, Netherlands
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17
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Monoclonal Antibodies for Bacterial Pathogens: Mechanisms of Action and Engineering Approaches for Enhanced Effector Functions. Biomedicines 2022; 10:biomedicines10092126. [PMID: 36140226 PMCID: PMC9496014 DOI: 10.3390/biomedicines10092126] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 08/04/2022] [Accepted: 08/11/2022] [Indexed: 11/17/2022] Open
Abstract
Monoclonal antibody (mAb) therapy has opened a new era in the pharmaceutical field, finding application in various areas of research, from cancer to infectious diseases. The IgG isoform is the most used therapeutic, given its long half-life, high serum abundance, and most importantly, the presence of the Fc domain, which can be easily engineered. In the infectious diseases field, there has been a rising interest in mAbs research to counteract the emerging crisis of antibiotic resistance in bacteria. Various pathogens are acquiring resistance mechanisms, inhibiting any chance of success of antibiotics, and thus may become critically untreatable in the near future. Therefore, mAbs represent a new treatment option which may complement or even replace antibiotics. However, very few antibacterial mAbs have succeeded clinical trials, and until now, only three mAbs have been approved by the FDA. These failures highlight the need of improving the efficacy of mAb therapeutic activity, which can also be achieved with Fc engineering. In the first part of this review, we will describe the mechanisms of action of mAbs against bacteria, while in the second part, we will discuss the recent advances in antibody engineering to increase efficacy of pre-existing anti-bacterial mAbs.
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18
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de Vor L, Beudeker CR, Flier A, Scheepmaker LM, Aerts PC, Vijlbrief DC, Bekker MN, Beurskens FJ, van Kessel KPM, de Haas CJC, Rooijakkers SHM, van der Flier M. Monoclonal antibodies effectively potentiate complement activation and phagocytosis of Staphylococcus epidermidis in neonatal human plasma. Front Immunol 2022; 13:933251. [PMID: 35967335 PMCID: PMC9372458 DOI: 10.3389/fimmu.2022.933251] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 06/29/2022] [Indexed: 12/12/2022] Open
Abstract
Central line associated bloodstream infections (CLABSI) with Staphylococcus epidermidis are a major cause of morbidity in neonates, who have an increased risk of infection because of their immature immune system. As especially preterm neonates suffer from antibody deficiency, clinical studies into preventive therapies have thus far focused on antibody supplementation with pooled intravenous immunoglobulins from healthy donors (IVIG) but with little success. Here we study the potential of monoclonal antibodies (mAbs) against S. epidermidis to induce phagocytic killing by human neutrophils. Nine different mAbs recognizing Staphylococcal surface components were cloned and expressed as human IgG1s. In binding assays, clones rF1, CR5133 and CR6453 showed the strongest binding to S. epidermidis ATCC14990 and CR5133 and CR6453 bound the majority of clinical isolates from neonatal sepsis (19 out of 20). To study the immune-activating potential of rF1, CR5133 and CR6453, bacteria were opsonized with mAbs in the presence or absence of complement. We observed that activation of the complement system is essential to induce efficient phagocytosis of S. epidermidis. Complement activation and phagocytic killing could be enhanced by Fc-mutations that improve IgG1 hexamerization on cellular surfaces. Finally, we studied the ability of the mAbs to activate complement in r-Hirudin neonatal plasma conditions. We show that classical pathway complement activity in plasma isolated from neonatal cord blood is comparable to adult levels. Furthermore, mAbs could greatly enhance phagocytosis of S. epidermidis in neonatal plasma. Altogether, our findings provide insights that are crucial for optimizing anti-S. epidermidis mAbs as prophylactic agents for neonatal CLABSI.
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Affiliation(s)
- Lisanne de Vor
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Coco R. Beudeker
- Department of Paediatric Infectious Diseases and Immunology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Anne Flier
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Lisette M. Scheepmaker
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Piet C. Aerts
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Daniel C. Vijlbrief
- Department of Neonatology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Mireille N. Bekker
- Department of Obstetrics, University Medical Center Utrecht, Utrecht, Netherlands
| | | | - Kok P. M. van Kessel
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Carla J. C. de Haas
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, Netherlands
| | | | - Michiel van der Flier
- Department of Paediatric Infectious Diseases and Immunology, University Medical Center Utrecht, Utrecht, Netherlands
- *Correspondence: Michiel van der Flier,
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19
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Dobó J, Kocsis A, Dani R, Gál P. Proprotein Convertases and the Complement System. Front Immunol 2022; 13:958121. [PMID: 35874789 PMCID: PMC9296861 DOI: 10.3389/fimmu.2022.958121] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 06/13/2022] [Indexed: 11/27/2022] Open
Abstract
Proteins destined for secretion - after removal of the signal sequence - often undergo further proteolytic processing by proprotein convertases (PCs). Prohormones are typically processed in the regulated secretory pathway, while most plasma proteins travel though the constitutive pathway. The complement system is a major proteolytic cascade in the blood, serving as a first line of defense against microbes and also contributing to the immune homeostasis. Several complement components, namely C3, C4, C5 and factor I (FI), are multi-chain proteins that are apparently processed by PCs intracellularly. Cleavage occurs at consecutive basic residues and probably also involves the action of carboxypeptidases. The most likely candidate for the intracellular processing of complement proteins is furin, however, because of the overlapping specificities of basic amino acid residue-specific proprotein convertases, other PCs might be involved. To our surprise, we have recently discovered that processing of another complement protein, mannan-binding lectin-associated serine protease-3 (MASP-3) occurs in the blood by PCSK6 (PACE4). A similar mechanism had been described for the membrane protease corin, which is also activated extracellularly by PCSK6. In this review we intend to point out that the proper functioning of the complement system intimately depends on the action of proprotein convertases. In addition to the non-enzymatic components (C3, C4, C5), two constitutively active complement proteases are directly activated by PCs either intracellularly (FI), or extracellularly (MASP-3), moreover indirectly, through the constitutive activation of pro-factor D by MASP-3, the activity of the alternative pathway also depends on a PC present in the blood.
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Affiliation(s)
| | | | | | - Péter Gál
- *Correspondence: József Dobó, ; Péter Gál,
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20
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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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21
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Khedraki R, Noguchi H, Baldwin WM. Balancing the View of C1q in Transplantation: Consideration of the Beneficial and Detrimental Aspects. Front Immunol 2022; 13:873479. [PMID: 35401517 PMCID: PMC8988182 DOI: 10.3389/fimmu.2022.873479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 03/07/2022] [Indexed: 11/29/2022] Open
Affiliation(s)
- Raneem Khedraki
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States.,Department of Biological, Geological, and Environmental Sciences, Cleveland State University, Cleveland, OH, United States
| | - Hirotsugu Noguchi
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
| | - William M Baldwin
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States.,Department of Biological, Geological, and Environmental Sciences, Cleveland State University, Cleveland, OH, United States
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22
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Boero E, Cruz AR, Pansegrau W, Giovani C, Rooijakkers SHM, van Kessel KPM, van Strijp JAG, Bagnoli F, Manetti AGO. Natural Human Immunity Against Staphylococcal Protein A Relies on Effector Functions Triggered by IgG3. Front Immunol 2022; 13:834711. [PMID: 35359919 PMCID: PMC8963248 DOI: 10.3389/fimmu.2022.834711] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 02/17/2022] [Indexed: 12/02/2022] Open
Abstract
Staphylococcal protein A (SpA) is a multifunctional, highly conserved virulence factor of Staphylococcus aureus. By binding the Fc portion of all human IgG subclasses apart from IgG3, SpA interferes with antibody and complement deposition on the bacterial surface, impairing staphylococcal clearance by phagocytosis. Because of its anti-opsonic properties, SpA is not investigated as a surface antigen to mediate bacterial phagocytosis. Herein we investigate human sera for the presence of SpA-opsonizing antibodies. The screening revealed that sera containing IgG3 against SpA were able to correctly opsonize the target and drive Fcγ receptor-mediated interactions and phagocytosis. We demonstrated that IgG3 Fc is significantly more efficient in inducing phagocytosis of SpA-expressing S. aureus as compared to IgG1 Fc in an assay resembling physiological conditions. Furthermore, we show that the capacity of SpA antibodies to induce phagocytosis depends on the specific epitope recognized by the IgGs on SpA molecules. Overall, our results suggest that anti-SpA IgG3 antibodies could favor the anti-staphylococcal response in humans, paving the way towards the identification of a correlate of protection against staphylococcal infections.
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Affiliation(s)
- Elena Boero
- GSK, Siena, Italy
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Ana Rita Cruz
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | | | | | - Suzan H. M. Rooijakkers
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Kok P. M. van Kessel
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Jos A. G. van Strijp
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
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23
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Quantitative Visualization of the Interaction between Complement Component C1 and Immunoglobulin G: The Effect of C H1 Domain Deletion. Int J Mol Sci 2022; 23:ijms23042090. [PMID: 35216207 PMCID: PMC8876274 DOI: 10.3390/ijms23042090] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Revised: 01/27/2022] [Accepted: 02/09/2022] [Indexed: 01/27/2023] Open
Abstract
Immunoglobulin G (IgG) adopts a modular multidomain structure that mediates antigen recognition and effector functions, such as complement-dependent cytotoxicity. IgG molecules are self-assembled into a hexameric ring on antigen-containing membranes, recruiting the complement component C1q. In order to provide deeper insights into the initial step of the complement pathway, we report a high-speed atomic force microscopy study for the quantitative visualization of the interaction between mouse IgG and the C1 complex composed of C1q, C1r, and C1s. The results showed that the C1q in the C1 complex is restricted regarding internal motion, and that it has a stronger binding affinity for on-membrane IgG2b assemblages than C1q alone, presumably because of the lower conformational entropy loss upon binding. Furthermore, we visualized a 1:1 stoichiometric interaction between C1/C1q and an IgG2a variant that lacks the entire CH1 domain in the absence of an antigen. In addition to the canonical C1q-binding site on Fc, their interactions are mediated through a secondary site on the CL domain that is cryptic in the presence of the CH1 domain. Our findings offer clues for novel-modality therapeutic antibodies.
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24
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Magda M, Bettoni S, Laabei M, Fairley D, Russo TA, Riesbeck K, Blom AM. Clinical Isolates of Acinetobacter spp. Are Highly Serum Resistant Despite Efficient Recognition by the Complement System. Front Immunol 2022; 13:814193. [PMID: 35173727 PMCID: PMC8841485 DOI: 10.3389/fimmu.2022.814193] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 01/13/2022] [Indexed: 11/13/2022] Open
Abstract
Gram-negative bacteria from the genus Acinetobacter are responsible for life-threating hospital-related infections such as pneumonia, septicemia, and meningitis, especially in immunocompromised patients. Worryingly, Acinetobacter have become multi- and extensively drug resistant (MDR/XDR) over the last few decades. The complement system is the first line of defense against microbes, thus it is highly important to increase our understanding of evasion mechanisms used by Acinetobacter spp. Here, we studied clinical isolates of Acinetobacter spp. (n=50), aiming to characterize their recognition by the complement system. Most isolates tested survived 1 h incubation in 30% serum, and only 8 isolates had a lower survival rate, yet none of those isolates were fully killed. Intriguingly, four isolates survived in human whole blood containing all cell component. Their survival was, however, significantly reduced. Flow cytometry analyses revealed that most of the isolates were detected by human IgG and IgM. Interestingly, we could not detect any significant concentration of deposited C1q, despite observing C4b deposition that was abolished in C1q-deficient serum, indicating transient binding of C1q to bacteria. Moreover, several isolates were recognized by MBL, with C4b deposition abolished in MBL-deficient serum. C3b was deposited on most isolates, but this was not, however, seen with respect to C5b and formation of the membrane attack complex (MAC), indicating that many isolates could avoid complement-mediated lysis. India ink staining showed that isolates were capsulated, and capsule thickness varied significantly between isolates. Studies performed on a wild-type strain and capsule mutant strains, demonstrated that the production of a capsular polysaccharide is one mechanism that mediates resistance to complement-mediated bactericidal activity by preventing MAC deposition and lysis. Our data showed that most clinical Acinetobacter spp. isolates are highly serum resistant despite being efficiently recognized by the complement system.
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Affiliation(s)
- Michal Magda
- Protein Chemistry, Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Serena Bettoni
- Protein Chemistry, Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Maisem Laabei
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - Derek Fairley
- Department of Microbiology, Belfast Health and Social Care Trust, Belfast, United Kingdom
| | - Thomas A. Russo
- Veterans Administration Western New York Healthcare System, Department of Medicine, Jacobs School of Medicine and Biomedical Sciences, University Buffalo, Buffalo, NY, United States
| | - Kristian Riesbeck
- Clinical Microbiology, Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Anna M. Blom
- Protein Chemistry, Department of Translational Medicine, Lund University, Malmö, Sweden
- *Correspondence: Anna M. Blom,
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25
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Tipping the balance: intricate roles of the complement system in disease and therapy. Semin Immunopathol 2021; 43:757-771. [PMID: 34698894 PMCID: PMC8547127 DOI: 10.1007/s00281-021-00892-7] [Citation(s) in RCA: 63] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 09/14/2021] [Indexed: 12/13/2022]
Abstract
The ability of the complement system to rapidly and broadly react to microbial intruders, apoptotic cells and other threats by inducing forceful elimination responses is indispensable for its role as host defense and surveillance system. However, the danger sensing versatility of complement may come at a steep price for patients suffering from various immune, inflammatory, age-related, or biomaterial-induced conditions. Misguided recognition of cell debris or transplants, excessive activation by microbial or damaged host cells, autoimmune events, and dysregulation of the complement response may all induce effector functions that damage rather than protect host tissue. Although complement has long been associated with disease, the prevalence, impact and complexity of complement’s involvement in pathological processes is only now becoming fully recognized. While complement rarely constitutes the sole driver of disease, it acts as initiator, contributor, and/or exacerbator in numerous disorders. Identifying the factors that tip complement’s balance from protective to damaging effects in a particular disease continues to prove challenging. Fortunately, however, molecular insight into complement functions, improved disease models, and growing clinical experience has led to a greatly improved understanding of complement’s pathological side. The identification of novel complement-mediated indications and the clinical availability of the first therapeutic complement inhibitors has also sparked a renewed interest in developing complement-targeted drugs, which meanwhile led to new approvals and promising candidates in late-stage evaluation. More than a century after its description, complement now has truly reached the clinic and the recent developments hold great promise for diagnosis and therapy alike.
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