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Ilse V, Scholz R, Wermann M, Naumann M, Staege MS, Roßner S, Cynis H. Immunogenicity of the Envelope Surface Unit of Human Endogenous Retrovirus K18 in Mice. Int J Mol Sci 2022; 23:ijms23158330. [PMID: 35955468 PMCID: PMC9369184 DOI: 10.3390/ijms23158330] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 07/21/2022] [Accepted: 07/25/2022] [Indexed: 02/06/2023] Open
Abstract
The triggers for the development of multiple sclerosis (MS) have not been fully understood to date. One hypothesis proposes a viral etiology. Interestingly, viral proteins from human endogenous retroviruses (HERVs) may play a role in the pathogenesis of MS. Allelic variants of the HERV-K18 env gene represent a genetic risk factor for MS, and the envelope protein is considered to be an Epstein–Barr virus-trans-activated superantigen. To further specify a possible role for HERV-K18 in MS, the present study examined the immunogenicity of the purified surface unit (SU). HERV-K18(SU) induced envelope-specific plasma IgG in immunized mice and triggered proliferation of T cells isolated from these mice. It did not trigger phenotypic changes in a mouse model of experimental autoimmune encephalomyelitis. Further studies are needed to investigate the underlying mechanisms of HERV-K18 interaction with immune system regulators in more detail.
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Affiliation(s)
- Victoria Ilse
- Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Weinbergweg 22, 06120 Halle, Germany; (V.I.); (R.S.); (M.W.); (M.N.)
| | - Rebekka Scholz
- Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Weinbergweg 22, 06120 Halle, Germany; (V.I.); (R.S.); (M.W.); (M.N.)
| | - Michael Wermann
- Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Weinbergweg 22, 06120 Halle, Germany; (V.I.); (R.S.); (M.W.); (M.N.)
| | - Marcel Naumann
- Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Weinbergweg 22, 06120 Halle, Germany; (V.I.); (R.S.); (M.W.); (M.N.)
| | - Martin S. Staege
- Department of Surgical and Conservative Pediatrics and Adolescent Medicine, Medical Faculty, Martin Luther University Halle-Wittenberg, Ernst-Grube-Str. 40, 06097 Halle, Germany;
| | - Steffen Roßner
- Paul Flechsig Institute for Brain Research, Leipzig University, Liebigstraße 19, 04103 Leipzig, Germany;
| | - Holger Cynis
- Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Weinbergweg 22, 06120 Halle, Germany; (V.I.); (R.S.); (M.W.); (M.N.)
- Correspondence: ; Tel.: +49-345-13142835; Fax: +49-345-13142801
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Tartaglione AM, Cipriani C, Chiarotti F, Perrone B, Balestrieri E, Matteucci C, Sinibaldi-Vallebona P, Calamandrei G, Ricceri L. Early Behavioral Alterations and Increased Expression of Endogenous Retroviruses Are Inherited Across Generations in Mice Prenatally Exposed to Valproic Acid. Mol Neurobiol 2018; 56:3736-3750. [DOI: 10.1007/s12035-018-1328-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 08/22/2018] [Indexed: 12/12/2022]
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Gröger V, Cynis H. Human Endogenous Retroviruses and Their Putative Role in the Development of Autoimmune Disorders Such as Multiple Sclerosis. Front Microbiol 2018; 9:265. [PMID: 29515547 PMCID: PMC5826199 DOI: 10.3389/fmicb.2018.00265] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 02/05/2018] [Indexed: 12/13/2022] Open
Abstract
Human endogenous retroviruses (HERVs) are remnants of retroviral germ line infections of human ancestors and make up ~8% of the human genome. Under physiological conditions, these elements are frequently inactive or non-functional due to deactivating mutations and epigenetic control. However, they can be reactivated under certain pathological conditions and produce viral transcripts and proteins. Several disorders, like multiple sclerosis or amyotrophic lateral sclerosis are associated with increased HERV expression. Although their detailed contribution to individual diseases has yet to be elucidated, an increasing number of studies in vitro and in vivo suggest HERVs as potent modulators of the immune system. They are able to affect the transcription of other immune-related genes, interact with pattern recognition receptors, and influence the positive and negative selection of developing thymocytes. Interestingly, HERV envelope proteins can both stimulate and suppress immune responses based on different mechanisms. In the light of HERV proteins becoming an emerging drug target for autoimmune-related disorders and cancer, we will provide an overview on recent findings of the complex interactions between HERVs and the human immune system with a focus on autoimmunity.
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Affiliation(s)
| | - Holger Cynis
- Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Halle, Germany
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Frank JA, Feschotte C. Co-option of endogenous viral sequences for host cell function. Curr Opin Virol 2017; 25:81-89. [PMID: 28818736 DOI: 10.1016/j.coviro.2017.07.021] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 06/13/2017] [Accepted: 07/23/2017] [Indexed: 01/26/2023]
Abstract
Eukaryotic genomes are littered with sequences of diverse viral origins, termed endogenous viral elements (EVEs). Here we used examples primarily drawn from mammalian endogenous retroviruses to document how the influx of EVEs has provided a source of prefabricated coding and regulatory sequences that were formerly utilized for viral infection and replication, but have been occasionally repurposed for cellular function. While EVE co-option has benefited a variety of host biological functions, there appears to be a disproportionate contribution to immunity and antiviral defense. The mammalian embryo and placenta offer opportunistic routes of viral transmission to the next host generation and as such they represent hotbeds for EVE cooption. Based on these observations, we propose that EVE cooption is initially driven as a mean to mitigate conflicts between host and viruses, which in turn acts as a stepping-stone toward the evolution of cellular innovations serving host physiology and development.
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Affiliation(s)
- John A Frank
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Cédric Feschotte
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.
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Kassiotis G, Stoye JP. Immune responses to endogenous retroelements: taking the bad with the good. Nat Rev Immunol 2016; 16:207-19. [PMID: 27026073 DOI: 10.1038/nri.2016.27] [Citation(s) in RCA: 165] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The ultimate form of parasitism and evasion of host immunity is for the parasite genome to enter the germ line of the host species. Retroviruses have invaded the host germ line on the grandest scale, and this is evident in the extraordinary abundance of endogenous retroelements in the genome of all vertebrate species that have been studied. Many of these endogenous retroelements have retained viral characteristics; some also the capacity to replicate and, consequently, the potential to trigger host innate and adaptive immune responses. However, although retroelements are mainly recognized for their pathogenic potential, recent evidence suggests that this 'enemy within' may also have beneficial roles in tuning host immune reactivity. In this Review, we discuss how the immune system recognizes and is shaped by endogenous retroelements.
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Affiliation(s)
- George Kassiotis
- Retroviral Immunology, the Francis Crick Institute, Mill Hill Laboratory, London NW7 1AA, UK.,Department of Medicine, Faculty of Medicine, Imperial College London, London W2 1PG, UK
| | - Jonathan P Stoye
- Department of Medicine, Faculty of Medicine, Imperial College London, London W2 1PG, UK.,Retrovirus-Host Interactions, the Francis Crick Institute, Mill Hill Laboratory, London NW7 1AA, UK
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Dreyfus DH. Gene sharing between Epstein–Barr virus and human immune response genes. Immunol Res 2016; 65:37-45. [DOI: 10.1007/s12026-016-8814-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Thorborn G, Young GR, Kassiotis G. Effective T helper cell responses against retroviruses: are all clonotypes equal? J Leukoc Biol 2014; 96:27-37. [PMID: 24737804 DOI: 10.1189/jlb.2ri0613-347r] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The critical importance of CD4(+) T cells in coordinating innate and adaptive immune responses is evidenced by the susceptibility to various pathogenic and opportunistic infections that arises from primary or acquired CD4(+) T cell immunodeficiency, such as following HIV-1 infection. However, despite the clearly defined roles of cytotoxic CD8(+) T cells and antibodies in host protection from retroviruses, the ability of CD4(+) T cells to exert a similar function remains unclear. Recent studies in various settings have drawn attention to the complexity of the T cell response within and between individuals. Distinct TCR clonotypes within an individual differ substantially in their response to the same epitope. Functionally similar, "public" TCR clonotypes can also dominate the response of different individuals. TCR affinity for antigen directly influences expansion and differentiation of responding T cells, also likely affecting their ultimate protective capacity. With this increasing understanding of the parameters that determine the magnitude and effector type of the T cell response, we are now better equipped to address the protective capacity against retroviruses of CD4(+) T cell clonotypes induced by natural infection or vaccination.
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Affiliation(s)
| | - George R Young
- Divisions of Immunoregulation and Virology, Medical Research Council National Institute for Medical Research, The Ridgeway, London, United Kingdom; and
| | - George Kassiotis
- Divisions of Immunoregulation and Department of Medicine, Faculty of Medicine, Imperial College London, United Kingdom
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Kassiotis G. Endogenous retroviruses and the development of cancer. THE JOURNAL OF IMMUNOLOGY 2014; 192:1343-9. [PMID: 24511094 DOI: 10.4049/jimmunol.1302972] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Mammalian genomes include a considerable number of endogenous retroviruses (ERVs), relics of ancestral infectious retroviruses, whose proviruses have invaded the germ-line. The documented ability of infectious retroviruses to cause cancer has greatly contributed to the discovery of ERVs. It also reinforced the concept that ERVs are causative agents of many cancers, a notion that historically has not always stood up to experimental scrutiny. The recent greater appreciation of the complexity of ERV biology and the identification of dedicated host mechanisms controlling ERV activity have revealed novel interactions between ERVs and their hosts, with the potential to cause or contribute to disease. In this review, the involvement of ERVs in cancer initiation and progression is discussed, as well as their contribution to our understanding of the process of transformation and to the invention of innovative preventive and therapeutic cancer treatments.
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Affiliation(s)
- George Kassiotis
- Division of Immunoregulation, Medical Research Council National Institute for Medical Research, London NW7 1AA, United Kingdom
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Young GR, Stoye JP, Kassiotis G. Are human endogenous retroviruses pathogenic? An approach to testing the hypothesis. Bioessays 2013; 35:794-803. [PMID: 23864388 PMCID: PMC4352332 DOI: 10.1002/bies.201300049] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A number of observations have led researchers to postulate that, despite being replication-defective, human endogenous retroviruses (HERVs) may have retained the potential to cause or contribute to disease. However, mechanisms of HERV pathogenicity might differ substantially from those of modern infectious retroviruses or of the infectious precursors of HERVs. Therefore, novel pathways of HERV involvement in disease pathogenesis should be investigated. Recent technological advances in sequencing and bioinformatics are making this task increasingly feasible. The accumulating knowledge of HERV biology may also facilitate the definition and general acceptance of criteria that establish HERV pathogenicity. Here, we explore possible mechanisms whereby HERVs may cause disease and examine the evidence that either has been or should be obtained in order to decisively address the pathogenic potential of HERVs.
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Affiliation(s)
- George R Young
- Division of Virology, MRC National Institute for Medical Research, London, UK
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Autoimmune disease: A role for new anti-viral therapies? Autoimmun Rev 2011; 11:88-97. [DOI: 10.1016/j.autrev.2011.08.005] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2011] [Accepted: 08/11/2011] [Indexed: 12/30/2022]
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Evans AG, Moser JM, Krug LT, Pozharskaya V, Mora AL, Speck SH. A gammaherpesvirus-secreted activator of Vbeta4+ CD8+ T cells regulates chronic infection and immunopathology. J Exp Med 2008; 205:669-84. [PMID: 18332178 PMCID: PMC2275388 DOI: 10.1084/jem.20071135] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2007] [Accepted: 02/07/2008] [Indexed: 11/23/2022] Open
Abstract
Little is known about herpesvirus modulation of T cell activation in latently infected individuals or the implications of such for chronic immune disorders. Murine gammaherpesvirus 68 (MHV68) elicits persistent activation of CD8(+) T cells bearing a Vbeta4(+) T cell receptor (TCR) by a completely unknown mechanism. We show that a novel MHV68 protein encoded by the M1 gene is responsible for Vbeta4(+) CD8(+) T cell stimulation in a manner reminiscent of a viral superantigen. During infection, M1 expression induces a Vbeta4(+) effector T cell response that resists functional exhaustion and appears to suppress virus reactivation from peritoneal cells by means of long-term interferon-gamma (IFNgamma) production. Mice lacking an IFNgamma receptor (IFNgammaR(-/-)) fail to control MHV68 replication, and Vbeta4(+) and CD8(+) T cell activation by M1 instead contributes to severe inflammation and multiorgan fibrotic disease. Thus, M1 manipulates the host CD8(+) T cell response in a manner that facilitates latent infection in an immunocompetent setting, but promotes disease during a dysregulated immune response. Identification of a viral pathogenecity determinant with superantigen-like activity for CD8(+) T cells broadens the known repertoire of viral immunomodulatory molecules, and its function illustrates the delicate balance achieved between persistent viruses and the host immune response.
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Affiliation(s)
- Andrew G Evans
- Emory Vaccine Center, Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322, USA
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Voisset C, Weiss RA, Griffiths DJ. Human RNA "rumor" viruses: the search for novel human retroviruses in chronic disease. Microbiol Mol Biol Rev 2008; 72:157-96, table of contents. [PMID: 18322038 PMCID: PMC2268285 DOI: 10.1128/mmbr.00033-07] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Retroviruses are an important group of pathogens that cause a variety of diseases in humans and animals. Four human retroviruses are currently known, including human immunodeficiency virus type 1, which causes AIDS, and human T-lymphotropic virus type 1, which causes cancer and inflammatory disease. For many years, there have been sporadic reports of additional human retroviral infections, particularly in cancer and other chronic diseases. Unfortunately, many of these putative viruses remain unproven and controversial, and some retrovirologists have dismissed them as merely "human rumor viruses." Work in this field was last reviewed in depth in 1984, and since then, the molecular techniques available for identifying and characterizing retroviruses have improved enormously in sensitivity. The advent of PCR in particular has dramatically enhanced our ability to detect novel viral sequences in human tissues. However, DNA amplification techniques have also increased the potential for false-positive detection due to contamination. In addition, the presence of many families of human endogenous retroviruses (HERVs) within our DNA can obstruct attempts to identify and validate novel human retroviruses. Here, we aim to bring together the data on "novel" retroviral infections in humans by critically examining the evidence for those putative viruses that have been linked with disease and the likelihood that they represent genuine human infections. We provide a background to the field and a discussion of potential confounding factors along with some technical guidelines. In addition, some of the difficulties associated with obtaining formal proof of causation for common or ubiquitous agents such as HERVs are discussed.
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Affiliation(s)
- Cécile Voisset
- CNRS-UMR8161, Institut de Biologie de Lille et Institut Pasteur de Lille, Lille, France
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Hsiao FC, Lin M, Tai A, Chen G, Huber BT. Cutting Edge: Epstein-Barr Virus Transactivates the HERV-K18 Superantigen by Docking to the Human Complement Receptor 2 (CD21) on Primary B Cells. THE JOURNAL OF IMMUNOLOGY 2006; 177:2056-60. [PMID: 16887963 DOI: 10.4049/jimmunol.177.4.2056] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
EBV, a ubiquitous human herpesvirus, is the causative agent of infectious mononucleosis and is associated with many carcinomas. We have previously shown that the EBV latent genes LMP-1 and LMP-2A (for latent membrane proteins 1 and 2A), transactivate a human endogenous retrovirus (HERV), HERV-K18, in infected B lymphocytes. The envelope (Env) protein of HERV-K18 encodes a superantigen that strongly stimulates a large number of T cells. In this study we report that HERV-K18 env is transactivated even earlier in the infection process, before the establishment of latency; namely, we found that EBV, through its interaction with its cellular receptor CD21, induces the HERV-K18 env gene in resting B lymphocytes. This transactivation is direct and immediate, as up-regulation of transcripts can be detected within 30 min after EBV exposure. Thus, EBV binding to human CD21 on resting B cells triggers the expression of an endogenous superantigen. The biological significance of this superantigen expression for the EBV life cycle is discussed.
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Affiliation(s)
- Francis C Hsiao
- Department of Pathology, Tufts University School of Medicine, 150 Harrison Avenue, Boston, MA 02111, USA
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