1
|
Cheng J, Clayton JS, Acemel RD, Zheng Y, Taylor RL, Keleş S, Franke M, Boackle SA, Harley JB, Quail E, Gómez-Skarmeta JL, Ulgiati D. Regulatory Architecture of the RCA Gene Cluster Captures an Intragenic TAD Boundary, CTCF-Mediated Chromatin Looping and a Long-Range Intergenic Enhancer. Front Immunol 2022; 13:901747. [PMID: 35769482 PMCID: PMC9235356 DOI: 10.3389/fimmu.2022.901747] [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: 03/22/2022] [Accepted: 05/05/2022] [Indexed: 12/03/2022] Open
Abstract
The Regulators of Complement Activation (RCA) gene cluster comprises several tandemly arranged genes with shared functions within the immune system. RCA members, such as complement receptor 2 (CR2), are well-established susceptibility genes in complex autoimmune diseases. Altered expression of RCA genes has been demonstrated at both the functional and genetic level, but the mechanisms underlying their regulation are not fully characterised. We aimed to investigate the structural organisation of the RCA gene cluster to identify key regulatory elements that influence the expression of CR2 and other genes in this immunomodulatory region. Using 4C, we captured extensive CTCF-mediated chromatin looping across the RCA gene cluster in B cells and showed these were organised into two topologically associated domains (TADs). Interestingly, an inter-TAD boundary was located within the CR1 gene at a well-characterised segmental duplication. Additionally, we mapped numerous gene-gene and gene-enhancer interactions across the region, revealing extensive co-regulation. Importantly, we identified an intergenic enhancer and functionally demonstrated this element upregulates two RCA members (CR2 and CD55) in B cells. We have uncovered novel, long-range mechanisms whereby autoimmune disease susceptibility may be influenced by genetic variants, thus highlighting the important contribution of chromatin topology to gene regulation and complex genetic disease.
Collapse
Affiliation(s)
- Jessica Cheng
- School of Biomedical Sciences, The University of Western Australia, Crawley, WA, Australia
| | - Joshua S. Clayton
- Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, WA, Australia,Centre for Medical Research, The University of Western Australia, Crawley, WA, Australia
| | - Rafael D. Acemel
- Centro Andaluz de Biología del Desarrollo, Consejo Superior de Investigaciones Científicas/Universidad Pablo de Olavide, Sevilla, Spain
| | - Ye Zheng
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, United States,Department of Statistics, University of Wisconsin-Madison, Madison, WI, United States
| | - Rhonda L. Taylor
- Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, WA, Australia,Centre for Medical Research, The University of Western Australia, Crawley, WA, Australia
| | - Sündüz Keleş
- Department of Statistics, University of Wisconsin-Madison, Madison, WI, United States,Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, WI, United States
| | - Martin Franke
- Centro Andaluz de Biología del Desarrollo, Consejo Superior de Investigaciones Científicas/Universidad Pablo de Olavide, Sevilla, Spain
| | - Susan A. Boackle
- Department of Medicine, Division of Rheumatology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States,Rocky Mountain Regional Veterans Affairs Medical Center, Aurora, CO, United States
| | - John B. Harley
- Center for Autoimmune Genomics and Etiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States,US Department of Veterans Affairs Medical Centre, US Department of Veterans Affairs, Cincinnati, OH, United States
| | - Elizabeth Quail
- School of Biomedical Sciences, The University of Western Australia, Crawley, WA, Australia,School of Molecular Sciences, The University of Western Australia, Crawley, WA, Australia
| | - José Luis Gómez-Skarmeta
- Centro Andaluz de Biología del Desarrollo, Consejo Superior de Investigaciones Científicas/Universidad Pablo de Olavide, Sevilla, Spain
| | - Daniela Ulgiati
- School of Biomedical Sciences, The University of Western Australia, Crawley, WA, Australia,*Correspondence: Daniela Ulgiati,
| |
Collapse
|
2
|
Lim TKY, Ruthazer ES. Microglial trogocytosis and the complement system regulate axonal pruning in vivo. eLife 2021; 10:e62167. [PMID: 33724186 PMCID: PMC7963485 DOI: 10.7554/elife.62167] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Accepted: 02/28/2021] [Indexed: 12/14/2022] Open
Abstract
Partial phagocytosis-called trogocytosis-of axons by microglia has been documented in ex vivo preparations but has not been directly observed in vivo. The mechanisms that modulate microglial trogocytosis of axons and its function in neural circuit development remain poorly understood. Here, we directly observe axon trogocytosis by microglia in vivo in the developing Xenopus laevis retinotectal circuit. We show that microglia regulate pruning of retinal ganglion cell axons and are important for proper behavioral response to dark and bright looming stimuli. Using bioinformatics, we identify amphibian regulator of complement activation 3, a homolog of human CD46, as a neuronally expressed synapse-associated complement inhibitory molecule that inhibits trogocytosis and axonal pruning. Using a membrane-bound complement C3 fusion protein, we demonstrate that enhancing complement activity enhances axonal pruning. Our results support the model that microglia remodel axons via trogocytosis and that neurons can control this process through expression of complement inhibitory proteins.
Collapse
Affiliation(s)
- Tony KY Lim
- Department of Neurology & Neurosurgery, Montreal Neurological Institute-Hospital, McGill UniversityMontrealCanada
| | - Edward S Ruthazer
- Department of Neurology & Neurosurgery, Montreal Neurological Institute-Hospital, McGill UniversityMontrealCanada
| |
Collapse
|
3
|
Ojha H, Ghosh P, Singh Panwar H, Shende R, Gondane A, Mande SC, Sahu A. Spatially conserved motifs in complement control protein domains determine functionality in regulators of complement activation-family proteins. Commun Biol 2019; 2:290. [PMID: 31396570 PMCID: PMC6683126 DOI: 10.1038/s42003-019-0529-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 07/03/2019] [Indexed: 12/14/2022] Open
Abstract
Regulation of complement activation in the host cells is mediated primarily by the regulators of complement activation (RCA) family proteins that are formed by tandemly repeating complement control protein (CCP) domains. Functional annotation of these proteins, however, is challenging as contiguous CCP domains are found in proteins with varied functions. Here, by employing an in silico approach, we identify five motifs which are conserved spatially in a specific order in the regulatory CCP domains of known RCA proteins. We report that the presence of these motifs in a specific pattern is sufficient to annotate regulatory domains in RCA proteins. We show that incorporation of the lost motif in the fourth long-homologous repeat (LHR-D) in complement receptor 1 regains its regulatory activity. Additionally, the motif pattern also helped annotate human polydom as a complement regulator. Thus, we propose that the motifs identified here are the determinants of functionality in RCA proteins.
Collapse
Affiliation(s)
- Hina Ojha
- Complement Biology Laboratory, National Centre for Cell Science, S. P. Pune University campus, Pune, 411007 India
| | - Payel Ghosh
- Bioinformatics Centre, S. P. Pune University, Pune, 411007 India
| | - Hemendra Singh Panwar
- Complement Biology Laboratory, National Centre for Cell Science, S. P. Pune University campus, Pune, 411007 India
| | - Rajashri Shende
- Complement Biology Laboratory, National Centre for Cell Science, S. P. Pune University campus, Pune, 411007 India
| | | | - Shekhar C. Mande
- Structural Biology Laboratory, National Centre for Cell Science, S. P. Pune University campus, Pune, 411007 India
- Present Address: Council of Scientific and Industrial Research (CSIR), Anusandhan Bhawan, 2 Rafi Marg, New Delhi, 110001 India
| | - Arvind Sahu
- Complement Biology Laboratory, National Centre for Cell Science, S. P. Pune University campus, Pune, 411007 India
| |
Collapse
|
4
|
Hertz CE, Bayarri-Olmos R, Kirketerp-Møller N, van Putten S, Pilely K, Skjoedt MO, Garred P. Chimeric Proteins Containing MAP-1 and Functional Domains of C4b-Binding Protein Reveal Strong Complement Inhibitory Capacities. Front Immunol 2018; 9:1945. [PMID: 30210498 PMCID: PMC6120983 DOI: 10.3389/fimmu.2018.01945] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 08/07/2018] [Indexed: 01/23/2023] Open
Abstract
The complement system is a tightly regulated network of proteins involved in defense against pathogens, inflammatory processes, and coordination of the innate and adaptive immune responses. Dysregulation of the complement cascade is associated with many inflammatory disorders. Thus, inhibition of the complement system has emerged as an option for treatment of a range of different inflammatory diseases. MAP-1 is a pattern recognition molecule (PRM)-associated inhibitor of the lectin pathway of the complement system, whereas C4b-binding protein (C4BP) regulates both the classical and lectin pathways. In this study we generated chimeric proteins consisting of MAP-1 and the first five domains of human C4BP (C4BP1−5) in order to develop a targeted inhibitor acting at different levels of the complement cascade. Two different constructs were designed and expressed in CHO cells where MAP-1 was fused with C4BP1−5 in either the C- or N-terminus. The functionality of the chimeric proteins was assessed using different in vitro complement activation assays. Both chimeric proteins displayed the characteristic Ca2+-dependent dimerization and binding to PRMs of native MAP-1, as well as the co-factor activity of native C4BP. In ELISA-based complement activation assays they could effectively inhibit the lectin and classical pathways. Notably, MAP-1:C4BP1−5 was five times more effective than rMAP-1 and rC4BP1−5 applied at the same time, emphasizing the advantage of a single inhibitor containing both functional domains. The MAP-1/C4BP chimeras exert unique complement inhibitory properties and represent a novel therapeutic approach targeting both upstream and central complement activation.
Collapse
Affiliation(s)
- Cecilie E Hertz
- Laboratory of Molecular Medicine, Department of Clinical Immunology Section, Rigshospitalet, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Rafael Bayarri-Olmos
- Laboratory of Molecular Medicine, Department of Clinical Immunology Section, Rigshospitalet, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nikolaj Kirketerp-Møller
- Laboratory of Molecular Medicine, Department of Clinical Immunology Section, Rigshospitalet, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Sander van Putten
- Finsen Laboratory, Rigshospitalet, Biotech Research and Innovation Center (BRIC), Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Katrine Pilely
- Laboratory of Molecular Medicine, Department of Clinical Immunology Section, Rigshospitalet, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mikkel-Ole Skjoedt
- Laboratory of Molecular Medicine, Department of Clinical Immunology Section, Rigshospitalet, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Peter Garred
- Laboratory of Molecular Medicine, Department of Clinical Immunology Section, Rigshospitalet, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| |
Collapse
|
5
|
Kolev M, Kemper C. Keeping It All Going-Complement Meets Metabolism. Front Immunol 2017; 8:1. [PMID: 28149297 PMCID: PMC5241319 DOI: 10.3389/fimmu.2017.00001] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 01/03/2017] [Indexed: 01/22/2023] Open
Abstract
The complement system is an evolutionary old and crucial component of innate immunity, which is key to the detection and removal of invading pathogens. It was initially discovered as a liver-derived sentinel system circulating in serum, the lymph, and interstitial fluids that mediate the opsonization and lytic killing of bacteria, fungi, and viruses and the initiation of the general inflammatory responses. Although work performed specifically in the last five decades identified complement also as a critical instructor of adaptive immunity—indicating that complement’s function is likely broader than initially anticipated—the dominant opinion among researchers and clinicians was that the key complement functions were in principle defined. However, there is now a growing realization that complement activity goes well beyond “classic” immune functions and that this system is also required for normal (neuronal) development and activity and general cell and tissue integrity and homeostasis. Furthermore, the recent discovery that complement activation is not confined to the extracellular space but occurs within cells led to the surprising understanding that complement is involved in the regulation of basic processes of the cell, particularly those of metabolic nature—mostly via novel crosstalks between complement and intracellular sensor, and effector, pathways that had been overlooked because of their spatial separation. These paradigm shifts in the field led to a renaissance in complement research and provide new platforms to now better understand the molecular pathways underlying the wide-reaching effects of complement functions in immunity and beyond. In this review, we will cover the current knowledge about complement’s emerging relationship with the cellular metabolism machinery with a focus on the functional differences between serum-circulating versus intracellularly active complement during normal cell survival and induction of effector functions. We will also discuss how taking a closer look into the evolution of key complement components not only made the functional connection between complement and metabolism rather “predictable” but how it may also give clues for the discovery of additional roles for complement in basic cellular processes.
Collapse
Affiliation(s)
- Martin Kolev
- Division of Transplant Immunology and Mucosal Biology, MRC Centre for Transplantation, King's College London, Guy's Hospital , London , UK
| | - Claudia Kemper
- Division of Transplant Immunology and Mucosal Biology, MRC Centre for Transplantation, King's College London, Guy's Hospital, London, UK; Laboratory of Molecular Immunology, The Immunology Center, National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health (NIH), Bethesda, MD, USA
| |
Collapse
|
6
|
Ermert D, Blom AM. C4b-binding protein: The good, the bad and the deadly. Novel functions of an old friend. Immunol Lett 2015; 169:82-92. [PMID: 26658464 DOI: 10.1016/j.imlet.2015.11.014] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Revised: 11/26/2015] [Accepted: 11/27/2015] [Indexed: 01/29/2023]
Abstract
C4b-binding protein (C4BP) is best known as a potent soluble inhibitor of the classical and lectin pathways of the complement system. This large 500 kDa multimeric plasma glycoprotein is expressed mainly in the liver but also in lung and pancreas. It consists of several identical 75 kDa α-chains and often also one 40 kDa β-chain, both of which are mainly composed of complement control protein (CCP) domains. Structure-function studies revealed that one crucial binding site responsible for inhibition of complement is located to CCP1-3 of the α-chain. Binding of anticoagulant protein S to the CCP1 of the β-chain provides C4BP with the ability to strongly bind apoptotic and necrotic cells in order to prevent inflammation arising from activation of complement by these cells. Further, C4BP interacts strongly with various types of amyloid and enhances fibrillation of islet amyloid polypeptide secreted from pancreatic beta cells, which may attenuate pro-inflammatory and cytotoxic effects of this amyloid. Full deficiency of C4BP has not been identified but non-synonymous alterations in its sequence have been found in haemolytic uremic syndrome and recurrent pregnancy loss. Furthermore, C4BP is bound by several bacterial pathogens, notably Streptococcus pyogenes, which due to inhibition of complement and enhancement of bacterial adhesion to endothelial cells provides these bacteria with a survival advantage in the host. Thus, depending on the context, C4BP has a protective or detrimental role in the organism.
Collapse
Affiliation(s)
- David Ermert
- Lund University, Department of Translational Medicine, Division of Medical Protein Chemistry, Inga Marie Nilssons Street 53, Malmö, 20502, Sweden.
| | - Anna M Blom
- Lund University, Department of Translational Medicine, Division of Medical Protein Chemistry, Inga Marie Nilssons Street 53, Malmö, 20502, Sweden.
| |
Collapse
|
7
|
Sato H, Oshiumi H, Takaki H, Hikono H, Seya T. Evolution of the DEAD box helicase family in chicken: chickens have no DHX9 ortholog. Microbiol Immunol 2015; 59:633-40. [DOI: 10.1111/1348-0421.12322] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 09/09/2015] [Accepted: 09/14/2015] [Indexed: 11/28/2022]
Affiliation(s)
- Haruko Sato
- Department of Microbiology and Immunology; Hokkaido University Graduate School of Medicine; Kita-ku Sapporo 060-8638
| | - Hiroyuki Oshiumi
- Department of Microbiology and Immunology; Hokkaido University Graduate School of Medicine; Kita-ku Sapporo 060-8638
| | - Hiromi Takaki
- Department of Microbiology and Immunology; Hokkaido University Graduate School of Medicine; Kita-ku Sapporo 060-8638
| | - Hirokazu Hikono
- National Institute of Animal Health; National Agriculture and Food Research Organization (NARO); Tsukuba 305-8642 Japan
| | - Tsukasa Seya
- Department of Microbiology and Immunology; Hokkaido University Graduate School of Medicine; Kita-ku Sapporo 060-8638
| |
Collapse
|
8
|
Tsujikura M, Nagasawa T, Ichiki S, Nakamura R, Somamoto T, Nakao M. A CD46-like molecule functional in teleost fish represents an ancestral form of membrane-bound regulators of complement activation. THE JOURNAL OF IMMUNOLOGY 2014; 194:262-72. [PMID: 25452563 DOI: 10.4049/jimmunol.1303179] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In the complement system, the regulators of complement activation (RCA) play crucial roles in controlling excessive complement activation and in protecting host cell from misdirected attack of complement. Several members of RCA family have been cloned from cyclostome and bony fish species and classified into soluble and membrane-bound type as in mammalian RCA factors. Complement-regulatory functions have been described only for soluble RCA of lamprey and barred sand bass; however, little is known on the biological function of the membrane-bound RCA proteins in the lower vertebrates. In this study, a membrane-bound RCA protein, designated teleost complement-regulatory membrane protein (Tecrem), was cloned and characterized for its complement-regulatory roles. Carp Tecrem, an ortholog of a zebrafish type 2 RCA, ZCR1, consists of four short consensus repeat modules, a serine/threonine/proline-rich domain, a transmembrane region, and a cytoplasmic domain, from the N terminus, as does mammalian CD46. Tecrem showed a ubiquitous mRNA expression in carp tissues, agreeing well with the putative regulatory role in complement activation. A recombinant Chinese hamster ovary cell line bearing carp Tecrem showed a significantly higher tolerance against lytic activity of carp complement and less deposition of C3-S, the major C3 isotypes acting on the target cell, than control Chinese hamster ovary (mock transfectant). Anti-Tecrem mAb enhanced the depositions of carp C3 and two C4 isotypes on autologous erythrocytes. Thus, the present findings provide the evidence of complement regulation by a membrane-bound group 2 RCA in bony fish, implying the host-cell protection is an evolutionarily conserved mechanism in regulation of the complement system.
Collapse
Affiliation(s)
- Masakazu Tsujikura
- Laboratory of Marine Biochemistry, Department of Bioscience and Biotechnology, Kyushu University, Hakozaki, Fukuoka 812-8581, Japan
| | - Takahiro Nagasawa
- Laboratory of Marine Biochemistry, Department of Bioscience and Biotechnology, Kyushu University, Hakozaki, Fukuoka 812-8581, Japan
| | - Satoko Ichiki
- Laboratory of Marine Biochemistry, Department of Bioscience and Biotechnology, Kyushu University, Hakozaki, Fukuoka 812-8581, Japan
| | - Ryota Nakamura
- Laboratory of Marine Biochemistry, Department of Bioscience and Biotechnology, Kyushu University, Hakozaki, Fukuoka 812-8581, Japan
| | - Tomonori Somamoto
- Laboratory of Marine Biochemistry, Department of Bioscience and Biotechnology, Kyushu University, Hakozaki, Fukuoka 812-8581, Japan
| | - Miki Nakao
- Laboratory of Marine Biochemistry, Department of Bioscience and Biotechnology, Kyushu University, Hakozaki, Fukuoka 812-8581, Japan
| |
Collapse
|
9
|
Incorporation of host complement regulatory proteins into Newcastle disease virus enhances complement evasion. J Virol 2012; 86:12708-16. [PMID: 22973037 DOI: 10.1128/jvi.00886-12] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Newcastle disease virus (NDV), an avian paramyxovirus, is inherently tumor selective and is currently being considered as a clinical oncolytic virus and vaccine vector. In this study, we analyzed the effect of complement on the neutralization of NDV purified from embryonated chicken eggs, a common source for virus production. Fresh normal human serum (NHS) neutralized NDV by multiple pathways of complement activation, independent of neutralizing antibodies. Neutralization was associated with C3 deposition and the activation of C2, C3, C4, and C5 components. Interestingly, NDV grown in mammalian cell lines was resistant to complement neutralization by NHS. To confirm whether the incorporation of regulators of complement activity (RCA) into the viral envelope afforded complement resistance, we grew NDV in CHO cells stably transfected with CD46 or HeLa cells, which strongly express CD46 and CD55. NDV grown in RCA-expressing cells was resistant to complement by incorporating CD46 and CD55 on virions. Mammalian CD46 and CD55 molecules on virions exhibited homologous restriction, since chicken sera devoid of neutralizing antibodies to NDV were able to effectively neutralize these virions. The incorporation of chicken RCA into NDV produced in embryonated eggs similarly provided species specificity toward chicken sera.
Collapse
|
10
|
Wu J, Li H, Zhang S. Regulator of complement activation (RCA) group 2 gene cluster in zebrafish: identification, expression, and evolution. Funct Integr Genomics 2012; 12:367-77. [DOI: 10.1007/s10142-012-0262-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Revised: 12/18/2011] [Accepted: 01/01/2012] [Indexed: 10/14/2022]
|
11
|
Regulator of complement activation (RCA) gene cluster in Xenopus tropicalis. Immunogenetics 2009; 61:371-84. [DOI: 10.1007/s00251-009-0368-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2009] [Accepted: 03/16/2009] [Indexed: 11/27/2022]
|
12
|
The oligomerization domain of C4-binding protein (C4bp) acts as an adjuvant, and the fusion protein comprised of the 19-kilodalton merozoite surface protein 1 fused with the murine C4bp domain protects mice against malaria. Infect Immun 2008; 76:3817-23. [PMID: 18474650 DOI: 10.1128/iai.01369-07] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Highly purified protein antigens are usually poor immunogens; in practice, adjuvants are needed to obtain satisfactory immune responses. Plasmodium yoelii 19-kDa merozoite surface protein 1 (MSP1(19)) is a weak antigen, but mice vaccinated with this antigen in strong adjuvants can survive an otherwise lethal parasite challenge. Fusion proteins comprising this antigen fused to the oligomerization domain of the murine complement inhibitor C4-binding protein (C4bp) and a series of homologues have been produced. These C4bp domains acted as adjuvants for the fused antigen; the MSP1(19)-murine C4bp fusion protein induced protective immunity in BALB/c mice. Because this fusion protein also induced antibodies against circulating murine C4bp, distantly related C4bp oligomerization domains fused to the same antigen were tested. These homologous domains did not induce antibodies against murine C4bp and, surprisingly, induced higher antibody titers against the antigen than the murine C4bp domain induced. These results demonstrate a new adjuvantlike effect of C4bp oligomerization domains.
Collapse
|
13
|
Nonaka M, Kimura A. Genomic view of the evolution of the complement system. Immunogenetics 2006; 58:701-13. [PMID: 16896831 PMCID: PMC2480602 DOI: 10.1007/s00251-006-0142-1] [Citation(s) in RCA: 192] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2006] [Accepted: 06/19/2006] [Indexed: 12/31/2022]
Abstract
The recent accumulation of genomic information of many representative animals has made it possible to trace the evolution of the complement system based on the presence or absence of each complement gene in the analyzed genomes. Genome information from a few mammals, chicken, clawed frog, a few bony fish, sea squirt, fruit fly, nematoda and sea anemone indicate that bony fish and higher vertebrates share practically the same set of complement genes. This suggests that most of the gene duplications that played an essential role in establishing the mammalian complement system had occurred by the time of the teleost/mammalian divergence around 500 million years ago (MYA). Members of most complement gene families are also present in ascidians, although they do not show a one-to-one correspondence to their counterparts in higher vertebrates, indicating that the gene duplications of each gene family occurred independently in vertebrates and ascidians. The C3 and factor B genes, but probably not the other complement genes, are present in the genome of the cnidaria and some protostomes, indicating that the origin of the central part of the complement system was established more than 1,000 MYA.
Collapse
Affiliation(s)
- Masaru Nonaka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Tokyo, Japan.
| | | |
Collapse
|