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Casper C, Corey L, Cohen JI, Damania B, Gershon AA, Kaslow DC, Krug LT, Martin J, Mbulaiteye SM, Mocarski ES, Moore PS, Ogembo JG, Phipps W, Whitby D, Wood C. KSHV (HHV8) vaccine: promises and potential pitfalls for a new anti-cancer vaccine. NPJ Vaccines 2022; 7:108. [PMID: 36127367 PMCID: PMC9488886 DOI: 10.1038/s41541-022-00535-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 09/02/2022] [Indexed: 01/25/2023] Open
Abstract
Seven viruses cause at least 15% of the total cancer burden. Viral cancers have been described as the "low-hanging fruit" that can be potentially prevented or treated by new vaccines that would alter the course of global human cancer. Kaposi sarcoma herpesvirus (KSHV or HHV8) is the sole cause of Kaposi sarcoma, which primarily afflicts resource-poor and socially marginalized populations. This review summarizes a recent NIH-sponsored workshop's findings on the epidemiology and biology of KSHV as an overlooked but potentially vaccine-preventable infection. The unique epidemiology of this virus provides opportunities to prevent its cancers if an effective, inexpensive, and well-tolerated vaccine can be developed and delivered.
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Affiliation(s)
- Corey Casper
- Infectious Disease Research Institute, 1616 Eastlake Ave. East, Suite 400, Seattle, WA, 98102, USA
| | - Lawrence Corey
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, Seattle, WA, 98109, USA
| | - Jeffrey I Cohen
- Laboratory of Infectious Diseases, National Institutes of Health, Bldg. 50, Room 6134, 50 South Drive, MSC8007, Bethesda, MD, 20892-8007, USA
| | - Blossom Damania
- Lineberger Comprehensive Cancer Center & Department of Microbiology and Immunology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, US
| | - Anne A Gershon
- Department of Pediatrics, Vagelos College of Physicians & Surgeons, Columbia University, 630 West 168th Street, New York, NY10032, US
| | - David C Kaslow
- PATH Essential Medicines, PATH, 2201 Westlake Avenue, Suite 200, Seattle, WA, USA
| | - Laurie T Krug
- HIV and AIDS Malignancy Branch, National Cancer Institute, Bethesda, MD, 20892, USA
| | - Jeffrey Martin
- Department of Epidemiology and Biostatistics, University of California, San Francisco, CA, USA
| | - Sam M Mbulaiteye
- Division of Cancer Epidemiology & Genetics, National Cancer Institute, NIH, HHS, 9609 Medical Center Dr, Rm. 6E118 MSC 3330, Bethesda, MD, 20892, USA
| | | | - Patrick S Moore
- Cancer Virology Program, Hillman Cancer Center, University of Pittsburgh, Pittsburgh, PA, 15213, USA.
| | - Javier Gordon Ogembo
- Department of Immuno-Oncology, Beckman Research Institute of City of Hope, Duarte, CA, 91010, USA
| | - Warren Phipps
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center; Department of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Seattle, WA, USA
| | - Denise Whitby
- AIDS and Cancer Virus Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Charles Wood
- Department of Interdisciplinary Oncology, Louisiana State University Health Sciences Center, New Orleans, LA, 70112, USA
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2
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Yunis J, Redwood AJ, Belz GT, Stevenson PG. Membrane association of a model CD4 + T-cell vaccine antigen confers enhanced yet incomplete protection against murid herpesvirus-4 infection. Immunol Cell Biol 2020; 98:332-343. [PMID: 31997396 DOI: 10.1111/imcb.12319] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 01/20/2020] [Accepted: 01/27/2020] [Indexed: 12/14/2022]
Abstract
Vaccination against γ-herpesviruses has proved difficult. CD4+ T cells are essential to contain infection, but how best to prime them and whether this can reduce viral loads remain unclear. To address these questions, we used ovalbumin (OVA) as a model antigen, delivering it with murine cytomegalovirus (MCMV) to protect mice against OVA-expressing murine herpesvirus-4 (MuHV-4). Membrane-associated OVA (mOVA) was more effective than soluble OVA, both to prime CD4+ T cells and as an effector target. It was also a better target than an OVA epitope limited to infected cells, suggesting that protective CD4+ T cells recognize infected cell debris rather than infected cells themselves. While MCMV-mOVA protected acutely against MuHV-4-mOVA, long-term protection was incomplete, even when OVA-specific CD8+ T cells and B cells were also primed. Thus, even optimized single-target vaccines may poorly reduce long-term γ-herpesvirus infections.
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Affiliation(s)
- Joseph Yunis
- School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, QLD, Australia
| | - Alec J Redwood
- Faculty of Health and Medical Sciences, University of Western Australia, Perth, WA, Australia
| | - Gabrielle T Belz
- Molecular Immunology, Walter and Eliza Hall Institute, Melbourne, VIC, Australia
| | - Philip G Stevenson
- School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, QLD, Australia
- Royal Children's Hospital, Brisbane, QLD, Australia
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3
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O'Grady T, Feswick A, Hoffman BA, Wang Y, Medina EM, Kara M, van Dyk LF, Flemington EK, Tibbetts SA. Genome-wide Transcript Structure Resolution Reveals Abundant Alternate Isoform Usage from Murine Gammaherpesvirus 68. Cell Rep 2019; 27:3988-4002.e5. [PMID: 31242428 PMCID: PMC7071827 DOI: 10.1016/j.celrep.2019.05.086] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 02/27/2019] [Accepted: 05/22/2019] [Indexed: 12/18/2022] Open
Abstract
The gammaherpesviruses, including Epstein-Barr virus (EBV), Kaposi's sarcoma-associated herpesvirus (KSHV), and murine gammaherpesvirus 68 (MHV68, MuHV-4, γHV68), are etiologic agents of a wide range of lymphomas and non-hematological malignancies. These viruses possess large and highly dense dsDNA genomes that feature >80 bidirectionally positioned open reading frames (ORFs). The abundance of overlapping transcripts and extensive splicing throughout these genomes have until now prohibited high throughput-based resolution of transcript structures. Here, we integrate the capabilities of long-read sequencing with the accuracy of short-read platforms to globally resolve MHV68 transcript structures using the transcript resolution through integration of multi-platform data (TRIMD) pipeline. This approach reveals highly complex features, including: (1) pervasive overlapping transcript structures; (2) transcripts containing intra-gene or trans-gene splices that yield chimeric ORFs; (3) antisense and intergenic transcripts containing ORFs; and (4) noncoding transcripts. This work sheds light on the underappreciated complexity of gammaherpesvirus transcription and provides an extensively revised annotation of the MHV68 transcriptome.
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Affiliation(s)
- Tina O'Grady
- Laboratory of Gene Expression and Cancer, GIGA-R (MBD), University of Liège, Liège, Belgium
| | - April Feswick
- Department of Molecular Genetics & Microbiology, UF Health Cancer Center, University of Florida, Gainesville, FL, USA
| | - Brett A Hoffman
- Department of Molecular Genetics & Microbiology, UF Health Cancer Center, University of Florida, Gainesville, FL, USA
| | - Yiping Wang
- Department of Molecular Genetics & Microbiology, UF Health Cancer Center, University of Florida, Gainesville, FL, USA
| | - Eva M Medina
- Department of Immunology and Microbiology, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, USA
| | - Mehmet Kara
- Department of Molecular Genetics & Microbiology, UF Health Cancer Center, University of Florida, Gainesville, FL, USA
| | - Linda F van Dyk
- Department of Immunology and Microbiology, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, USA
| | - Erik K Flemington
- Department of Pathology, Tulane Cancer Center, Tulane University, New Orleans, LA, USA.
| | - Scott A Tibbetts
- Department of Molecular Genetics & Microbiology, UF Health Cancer Center, University of Florida, Gainesville, FL, USA.
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4
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Bortz E, Wu TT, Patel P, Whitelegge JP, Sun R. Proteomics of Bronchoalveolar Lavage Fluid Reveals a Lung Oxidative Stress Response in Murine Herpesvirus-68 Infection. Viruses 2018; 10:v10120670. [PMID: 30486363 PMCID: PMC6316452 DOI: 10.3390/v10120670] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 11/15/2018] [Accepted: 11/20/2018] [Indexed: 12/25/2022] Open
Abstract
Murine herpesvirus-68 (MHV-68) productively infects mouse lungs, exhibiting a complex pathology characteristic of both acute viral infections and chronic respiratory diseases. We sought to discover proteins differentially expressed in bronchoalveolar lavage (BAL) from mice infected with MHV-68. Mice were infected intranasally with MHV-68. After nine days, as the lytic phase of infection resolved, differential BAL proteins were identified by two-dimensional (2D) electrophoresis and mass spectrometry. Of 23 unique proteins, acute phase proteins, vitamin A transport, and oxidative stress response factors Pdx6 and EC-SOD (Sod3) were enriched. Correspondingly, iNOS2 was induced in lung tissue by seven days post-infection. Oxidative stress was partly a direct result of MHV-68 infection, as reactive oxygen species (ROS) were induced in cultured murine NIH3T3 fibroblasts and human lung A549 cells infected with MHV-68. Finally, mice infected with a recombinant MHV-68 co-expressing inflammatory cytokine murine interleukin 6 (IL6) showed exacerbated oxidative stress and soluble type I collagen characteristic of tissue recovery. Thus, oxidative stress appears to be a salient feature of MHV-68 pathogenesis, in part caused by lytic replication of the virus and IL6. Proteins and small molecules in lung oxidative stress networks therefore may provide new therapeutic targets to ameliorate respiratory virus infections.
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Affiliation(s)
- Eric Bortz
- Department of Biological Sciences, University of Alaska Anchorage, Anchorage, AK 99508, USA.
| | - Ting-Ting Wu
- Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.
| | - Parthive Patel
- Center for Molecular Biology and German Cancer Research Center (DKFZ), University of Heidelberg (ZMBH), 69120 Heidelberg, Germany.
| | - Julian P Whitelegge
- The Pasarow Mass Spectrometry Laboratory & the Jane and Terry Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.
| | - Ren Sun
- Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.
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5
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The Major Envelope Glycoprotein of Murid Herpesvirus 4 Promotes Sexual Transmission. J Virol 2017; 91:JVI.00235-17. [PMID: 28424280 DOI: 10.1128/jvi.00235-17] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 04/10/2017] [Indexed: 12/25/2022] Open
Abstract
Gammaherpesviruses are important human and animal pathogens. Infection control has proven difficult because the key process of transmission is ill understood. Murid herpesvirus 4 (MuHV-4), a gammaherpesvirus of mice, is transmitted sexually. We show that this depends on the major virion envelope glycoprotein gp150. gp150 is redundant for host entry, and in vitro, it regulates rather than promotes cell binding. We show that gp150-deficient MuHV-4 reaches and replicates normally in the female genital tract after nasal infection but is poorly released from vaginal epithelial cells and fails to pass from the female to the male genital tract during sexual contact. Thus, we show that the regulation of virion binding is a key component of spontaneous gammaherpesvirus transmission.IMPORTANCE Gammaherpesviruses are responsible for many important diseases in both animals and humans. Some important aspects of their life cycle are still poorly understood. Key among these is viral transmission. Here we show that the major envelope glycoprotein of murid herpesvirus 4 functions not in entry or dissemination but in virion release to allow sexual transmission to new hosts.
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Gram AM, Oosenbrug T, Lindenbergh MFS, Büll C, Comvalius A, Dickson KJI, Wiegant J, Vrolijk H, Lebbink RJ, Wolterbeek R, Adema GJ, Griffioen M, Heemskerk MHM, Tscharke DC, Hutt-Fletcher LM, Wiertz EJHJ, Hoeben RC, Ressing ME. The Epstein-Barr Virus Glycoprotein gp150 Forms an Immune-Evasive Glycan Shield at the Surface of Infected Cells. PLoS Pathog 2016; 12:e1005550. [PMID: 27077376 PMCID: PMC4831753 DOI: 10.1371/journal.ppat.1005550] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 03/14/2016] [Indexed: 12/15/2022] Open
Abstract
Cell-mediated immunity plays a key role in host control of viral infection. This is exemplified by life-threatening reactivations of e.g. herpesviruses in individuals with impaired T-cell and/or iNKT cell responses. To allow lifelong persistence and virus production in the face of primed immunity, herpesviruses exploit immune evasion strategies. These include a reduction in viral antigen expression during latency and a number of escape mechanisms that target antigen presentation pathways. Given the plethora of foreign antigens expressed in virus-producing cells, herpesviruses are conceivably most vulnerable to elimination by cell-mediated immunity during the replicative phase of infection. Here, we show that a prototypic herpesvirus, Epstein-Barr virus (EBV), encodes a novel, broadly acting immunoevasin, gp150, that is expressed during the late phase of viral replication. In particular, EBV gp150 inhibits antigen presentation by HLA class I, HLA class II, and the non-classical, lipid-presenting CD1d molecules. The mechanism of gp150-mediated T-cell escape does not depend on degradation of the antigen-presenting molecules nor does it require gp150’s cytoplasmic tail. Through its abundant glycosylation, gp150 creates a shield that impedes surface presentation of antigen. This is an unprecedented immune evasion mechanism for herpesviruses. In view of its likely broader target range, gp150 could additionally have an impact beyond escape of T cell activation. Importantly, B cells infected with a gp150-null mutant EBV displayed rescued levels of surface antigen presentation by HLA class I, HLA class II, and CD1d, supporting an important role for iNKT cells next to classical T cells in fighting EBV infection. At the same time, our results indicate that EBV gp150 prolongs the timespan for producing viral offspring at the most vulnerable stage of the viral life cycle. The human herpesvirus Epstein-Barr virus (EBV) is an important human pathogen involved in infectious mononucleosis and several malignant tumors, including lymphomas in the immunosuppressed. Upon primary infection, a balance between virus and host is established, to which EBV’s capacity to dodge T cell-mediated attack contributes. Here we identify the late protein EBV gp150 as a novel immunoevasin, frustrating antigen presentation by HLA class I, class II, and CD1d molecules. EBV gp150’s many sialoglycans create a shield impeding surface detection of presented antigen. Interestingly, exploiting glycan shielding as a mechanism to mask surface exposed proteins on infected cells could permit EBV to additionally modulate other aspects of host antiviral defense. B cells producing wild-type EBV escaped immune recognition more efficiently than those infected with a gp150-null virus, pointing towards a role for gp150 in natural infection. Our results reveal a novel, broadly active strategy by which a herpesvirus glycoprotein, EBV gp150, blocks antigen presentation to T cells through glycan shielding, a new paradigm in herpesvirus immune evasion.
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Affiliation(s)
- Anna M. Gram
- Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Timo Oosenbrug
- Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Christian Büll
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Anouskha Comvalius
- Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - Kathryn J. I. Dickson
- John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Joop Wiegant
- Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - Hans Vrolijk
- Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - Robert Jan Lebbink
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Ron Wolterbeek
- Department of Medical Statistics & Bioinformatics, Leiden University Medical Center, Leiden, The Netherlands
| | - Gosse J. Adema
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Marieke Griffioen
- Department of Hematology, Leiden University Medical Center, Leiden, The Netherlands
| | | | - David C. Tscharke
- John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Lindsey M. Hutt-Fletcher
- Department of Microbiology and Immunology, Louisiana State University Health Sciences Center, Shreveport, Louisiana, United States of America
| | | | - Rob C. Hoeben
- Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - Maaike E. Ressing
- Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands
- * E-mail:
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7
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Arias C, Weisburd B, Stern-Ginossar N, Mercier A, Madrid AS, Bellare P, Holdorf M, Weissman JS, Ganem D. KSHV 2.0: a comprehensive annotation of the Kaposi's sarcoma-associated herpesvirus genome using next-generation sequencing reveals novel genomic and functional features. PLoS Pathog 2014; 10:e1003847. [PMID: 24453964 PMCID: PMC3894221 DOI: 10.1371/journal.ppat.1003847] [Citation(s) in RCA: 221] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Accepted: 10/20/2013] [Indexed: 01/08/2023] Open
Abstract
Productive herpesvirus infection requires a profound, time-controlled remodeling of the viral transcriptome and proteome. To gain insights into the genomic architecture and gene expression control in Kaposi's sarcoma-associated herpesvirus (KSHV), we performed a systematic genome-wide survey of viral transcriptional and translational activity throughout the lytic cycle. Using mRNA-sequencing and ribosome profiling, we found that transcripts encoding lytic genes are promptly bound by ribosomes upon lytic reactivation, suggesting their regulation is mainly transcriptional. Our approach also uncovered new genomic features such as ribosome occupancy of viral non-coding RNAs, numerous upstream and small open reading frames (ORFs), and unusual strategies to expand the virus coding repertoire that include alternative splicing, dynamic viral mRNA editing, and the use of alternative translation initiation codons. Furthermore, we provide a refined and expanded annotation of transcription start sites, polyadenylation sites, splice junctions, and initiation/termination codons of known and new viral features in the KSHV genomic space which we have termed KSHV 2.0. Our results represent a comprehensive genome-scale image of gene regulation during lytic KSHV infection that substantially expands our understanding of the genomic architecture and coding capacity of the virus. Kaposi's sarcoma-associated herpesvirus (KSHV) is a cancer-causing agent in immunocompromised patients that establishes long-lasting infections in its hosts. Initially described in 1994 and extensively studied ever since, KSHV molecular biology is understood in broad outline, but many detailed questions are still to be resolved. After almost two decades, specific aspects pertaining to the organization of the KSHV genome as well as the fate of the viral transcripts during the productive stages of infection remain unexplored. Here we use a systematic genome-wide approach to investigate changes in gene and protein expression during the productive stage of infection known as the lytic cycle. We found that the viral genome has a large coding capacity, capable of generating at least 45% more products than initially anticipated by bioinformatic analyses alone, and that it uses multiple strategies to expand its coding capacity well beyond what is determined solely by the DNA sequence of its genome. We also provide an expanded and highly detailed annotation of known and new genomic features in KSHV. We have termed this new architectural and functional annotation KSHV 2.0. Our results indicate that viral genomes are more complex than anticipated, and that they are subject to tight mechanisms of regulation to ensure correct gene expression.
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Affiliation(s)
- Carolina Arias
- Novartis Institute for Biomedical Research, Department of Infectious Diseases, Emeryville, California, United States of America
- * E-mail:
| | - Ben Weisburd
- Novartis Vaccines and Diagnostics, Bioinformatics, Emeryville, California, United States of America
| | - Noam Stern-Ginossar
- Department of Cellular and Molecular Pharmacology, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, California, United States of America
| | - Alexandre Mercier
- Novartis Institute for Biomedical Research, Department of Infectious Diseases, Emeryville, California, United States of America
| | - Alexis S. Madrid
- Novartis Institute for Biomedical Research, Department of Infectious Diseases, Emeryville, California, United States of America
| | - Priya Bellare
- Novartis Institute for Biomedical Research, Department of Infectious Diseases, Emeryville, California, United States of America
| | - Meghan Holdorf
- Novartis Institute for Biomedical Research, Department of Infectious Diseases, Emeryville, California, United States of America
| | - Jonathan S. Weissman
- Department of Cellular and Molecular Pharmacology, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, California, United States of America
| | - Don Ganem
- Novartis Institute for Biomedical Research, Department of Infectious Diseases, Emeryville, California, United States of America
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8
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Frederico B, Milho R, May JS, Gillet L, Stevenson PG. Myeloid infection links epithelial and B cell tropisms of Murid Herpesvirus-4. PLoS Pathog 2012; 8:e1002935. [PMID: 23028329 PMCID: PMC3447751 DOI: 10.1371/journal.ppat.1002935] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Accepted: 08/14/2012] [Indexed: 11/18/2022] Open
Abstract
Gamma-herpesviruses persist in lymphocytes and cause disease by driving their proliferation. Lymphocyte infection is therefore a key pathogenetic event. Murid Herpesvirus-4 (MuHV-4) is a rhadinovirus that like the related Kaposi's Sarcoma-associated Herpesvirus persists in B cells in vivo yet infects them poorly in vitro. Here we used MuHV-4 to understand how virion tropism sets the path to lymphocyte colonization. Virions that were highly infectious in vivo showed a severe post-binding block to B cell infection. Host entry was accordingly an epithelial infection and B cell infection a secondary event. Macrophage infection by cell-free virions was also poor, but improved markedly when virion binding improved or when macrophages were co-cultured with infected fibroblasts. Under the same conditions B cell infection remained poor; it improved only when virions came from macrophages. This reflected better cell penetration and correlated with antigenic changes in the virion fusion complex. Macrophages were seen to contact acutely infected epithelial cells, and cre/lox-based virus tagging showed that almost all the virus recovered from lymphoid tissue had passed through lysM+ and CD11c+ myeloid cells. Thus MuHV-4 reached B cells in 3 distinct stages: incoming virions infected epithelial cells; infection then passed to myeloid cells; glycoprotein changes then allowed B cell infection. These data identify new complexity in rhadinovirus infection and potentially also new vulnerability to intervention. Rhadinoviruses cause lymphocytic cancers. Their infection of lymphocytes is therefore an important therapeutic target. How this occurs is unclear. One prevalent hypothesis has been that virions directly infect lymphocytes when they enter new hosts. Here we show that host entry by Murid Herpesvirus-4, a close relative of the Kaposi's Sarcoma-associated Herpesvirus, is an epithelial rather than a lymphocyte infection: the mucosal lymphoid colonization typical of acute infectious mononucleosis only occurred later. Macrophages were closely associated with the acutely infected epithelium, and most if not all of the virus reaching B cells showed evidence of previous myeloid cell infection. Macrophage-derived virions showed a greatly enhanced capacity for lymphocyte infection that was associated with antigenic changes in the viral fusion proteins. Thus host colonization required epithelial and myeloid infections before there was lymphocyte infection. The implication is that each of these infection events could be independently targeted to limit viral persistence.
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Affiliation(s)
| | | | | | | | - Philip G. Stevenson
- Division of Virology, Department of Pathology, University of Cambridge, Addenbrookes Hospital, Cambridge, United Kingdom
- * E-mail:
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9
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Sathish N, Wang X, Yuan Y. Tegument Proteins of Kaposi's Sarcoma-Associated Herpesvirus and Related Gamma-Herpesviruses. Front Microbiol 2012; 3:98. [PMID: 22435068 PMCID: PMC3304090 DOI: 10.3389/fmicb.2012.00098] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Accepted: 02/28/2012] [Indexed: 12/12/2022] Open
Abstract
A herpesvirus virion is composed of a viral genomic DNA-containing capsid surrounded by a viral envelope with glycoprotein spikes on its surface. Located between the capsid and the outer viral envelope is the virion tegument layer. Though the majority of the virion proteins are located in the tegument, this layer is less studied and was thought to be an amorphous structure. Over the last decade, a number of studies have indicated the presence of organized tegument structures across the spectrum of herpesviruses, implicating tegument components in critical steps governing the viral life cycle. In the case of Kaposi’s sarcoma-associated herpesvirus (KSHV), the etiological agent of Kaposi’s sarcoma, several functions exerted by tegument proteins at different stages of the viral life cycle, inclusive of primary de novo infection and virion assembly, have been identified over the last several years. In this review, KSHV tegument components are cataloged and the occurrence of organized tegument structures in KSHV, built through interactions amongst the different virion proteins, is discussed in depth. The significant functional roles of the KSHV tegument proteins at different stages of the viral life cycle are elaborated under separate headings. Definitive functional roles exerted by tegument proteins of related gamma-herpesviruses are also discussed. Since tegument proteins play key roles during viral assembly, viral entry, and represent an important interface for virus–host interactions, further research in this area should provide detailed insights into the functional capacity of the KSHV tegument, resulting in a better understanding of the viral life cycle.
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Affiliation(s)
- Narayanan Sathish
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal Bhopal, Madhya Pradesh, India
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10
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Tiled microarray identification of novel viral transcript structures and distinct transcriptional profiles during two modes of productive murine gammaherpesvirus 68 infection. J Virol 2012; 86:4340-57. [PMID: 22318145 DOI: 10.1128/jvi.05892-11] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
We applied a custom tiled microarray to examine murine gammaherpesvirus 68 (MHV68) polyadenylated transcript expression in a time course of de novo infection of fibroblast cells and following phorbol ester-mediated reactivation from a latently infected B cell line. During de novo infection, all open reading frames (ORFs) were transcribed and clustered into four major temporal groups that were overlapping yet distinct from clusters based on the phorbol ester-stimulated B cell reactivation time course. High-density transcript analysis at 2-h intervals during de novo infection mapped gene boundaries with a 20-nucleotide resolution, including a previously undefined ORF73 transcript and the MHV68 ORF63 homolog of Kaposi's sarcoma-associated herpesvirus vNLRP1. ORF6 transcript initiation was mapped by tiled array and confirmed by 5' rapid amplification of cDNA ends. The ∼1.3-kb region upstream of ORF6 was responsive to lytic infection and MHV68 RTA, identifying a novel RTA-responsive promoter. Transcription in intergenic regions consistent with the previously defined expressed genomic regions was detected during both types of productive infection. We conclude that the MHV68 transcriptome is dynamic and distinct during de novo fibroblast infection and upon phorbol ester-stimulated B cell reactivation, highlighting the need to evaluate further transcript structure and the context-dependent molecular events that govern viral gene expression during chronic infection.
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11
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Gaspar M, May JS, Sukla S, Frederico B, Gill MB, Smith CM, Belz GT, Stevenson PG. Murid herpesvirus-4 exploits dendritic cells to infect B cells. PLoS Pathog 2011; 7:e1002346. [PMID: 22102809 PMCID: PMC3213091 DOI: 10.1371/journal.ppat.1002346] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Accepted: 09/15/2011] [Indexed: 11/19/2022] Open
Abstract
Dendritic cells (DCs) play a central role in initiating immune responses. Some persistent viruses infect DCs and can disrupt their functions in vitro. However, these viruses remain strongly immunogenic in vivo. Thus what role DC infection plays in the pathogenesis of persistent infections is unclear. Here we show that a persistent, B cell-tropic gamma-herpesvirus, Murid Herpesvirus-4 (MuHV-4), infects DCs early after host entry, before it establishes a substantial infection of B cells. DC-specific virus marking by cre-lox recombination revealed that a significant fraction of the virus latent in B cells had passed through a DC, and a virus attenuated for replication in DCs was impaired in B cell colonization. In vitro MuHV-4 dramatically altered the DC cytoskeleton, suggesting that it manipulates DC migration and shape in order to spread. MuHV-4 therefore uses DCs to colonize B cells. We detect invading viruses with dendritic cells and eliminate them with lymphocytes. A key interaction is lymphocyte activation by dendritic cells presenting viral antigens. Not all viruses can be eliminated, and some that persist deliberately colonize lymphocytes and dendritic cells, such that parasitism and host defence co-exist within the same sites. Once established, these infections are very hard to eliminate. Therefore to vaccinate against them we must determine how infection first occurs. Here we show that a gamma-herpesvirus relation of the Kaposi's Sarcoma-associated Herpesvirus and Epstein-Barr virus - B cell-tropic human pathogens that cause cancers - uses dendritic cells to reach and infect B lymphocytes. Dendritic cells were infected before B cells; viruses marked genetically in dendritic cells were recovered from B cells; and a virus unable to replicate in dendritic cells infected B cells poorly. Thus dendritic cells not only present viral antigens to lymphocytes, but can be exploited by evasive viruses to infect lymphocytes. Therefore targeting dendritic cell infection could be an effective means of vaccine-primed host defence.
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Affiliation(s)
- Miguel Gaspar
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Janet S. May
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Soumi Sukla
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Bruno Frederico
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Michael B. Gill
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Christopher M. Smith
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Gabrielle T. Belz
- Division of Immunology, The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia
| | - Philip G. Stevenson
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
- * E-mail:
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12
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May JS, Stevenson PG. Vaccination with murid herpesvirus-4 glycoprotein B reduces viral lytic replication but does not induce detectable virion neutralization. J Gen Virol 2010; 91:2542-52. [PMID: 20519454 PMCID: PMC3052599 DOI: 10.1099/vir.0.023085-0] [Citation(s) in RCA: 21] [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: 04/26/2010] [Accepted: 05/31/2010] [Indexed: 01/17/2023] Open
Abstract
Herpesviruses characteristically disseminate from immune hosts. Therefore in the context of natural infection, antibody neutralizes them poorly. Murid herpesvirus-4 (MuHV-4) provides a tractable model with which to understand gammaherpesvirus neutralization. MuHV-4 virions blocked for cell binding by immune sera remain infectious for IgG-Fc receptor(+) myeloid cells, so broadly neutralizing antibodies must target the virion fusion complex - glycoprotein B (gB) or gH/gL. While gB-specific neutralizing antibodies are rare, its domains I+II (gB-N) contain at least one potent neutralization epitope. Here, we tested whether immunization with recombinant gB presenting this epitope could induce neutralizing antibodies in naive mice and protect them against MuHV-4 challenge. Immunizing with the full-length gB extracellular domain induced a strong gB-specific antibody response and reduced MuHV-4 lytic replication but did not induce detectable neutralization. gB-N alone, which more selectively displayed pre-fusion epitopes including neutralization epitopes, also failed to induce neutralizing responses, and while viral lytic replication was again reduced this depended completely on IgG Fc receptors. gB and gB-N also boosted neutralizing responses in only a minority of carrier mice. Therefore, it appears that neutralizing epitopes on gB are intrinsically difficult for the immune response to target.
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Affiliation(s)
- Janet S May
- Division of Virology, Department of Pathology, University of Cambridge, UK
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13
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Johnson LS, Willert EK, Virgin HW. Redefining the genetics of murine gammaherpesvirus 68 via transcriptome-based annotation. Cell Host Microbe 2010; 7:516-26. [PMID: 20542255 DOI: 10.1016/j.chom.2010.05.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Revised: 02/24/2010] [Accepted: 04/06/2010] [Indexed: 11/25/2022]
Abstract
Viral genetic studies typically focus on large open reading frames (ORFs) identified during genome annotation (ORF-based annotation). Here we describe tools for examining viral gene expression nucleotide by nucleotide across the genome. Using these tools on the 119,450 base pair (bp) genome of murine gammaherpesvirus 68 (gammaHV68) allowed us to establish that gammaHV68 RNA expression was significantly more complex than predicted from ORF-based annotation, including over 73,000 nucleotides of unexpected transcription within 30 expressed genomic regions (EGRs). Approximately 90% of this RNA expression was antisense to genomic regions containing known large ORFs. We verified the existence of previously undefined transcripts in three EGRs and determined which parts of the transcriptome depend on protein or viral DNA synthesis. This study redefines the genetic map of gammaHV68, indicating that herpesviruses contain significantly more genetic complexity than predicted from ORF-based genome annotations, and provides alternative tools and approaches for viral genetic studies.
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Affiliation(s)
- L Steven Johnson
- Department of Pathology and Immunology, Midwest Regional Center of Excellence for Biodefense and Emerging Infectious Diseases Research, Washington University School of Medicine, St Louis, MO 63110, USA
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14
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Wright DE, Colaco S, Colaco C, Stevenson PG. Antibody limits in vivo murid herpesvirus-4 replication by IgG Fc receptor-dependent functions. J Gen Virol 2009; 90:2592-2603. [PMID: 19625459 PMCID: PMC2885036 DOI: 10.1099/vir.0.014266-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2009] [Accepted: 07/17/2009] [Indexed: 12/11/2022] Open
Abstract
Antibody is an important antiviral defence. However, it is considered to do little against human gamma-herpesviruses, which establish predominantly latent infections regulated by T cells. One limitation on analysing these infections has been that latency is already well-established at clinical presentation; early infection may still be accessible to antibody. Here, using murid herpesvirus-4 (MuHV-4), we tested the impact of adoptively transferred antibody on early gamma-herpesvirus infection. Immune sera and neutralizing and non-neutralizing monoclonal antibodies (mAbs) all reduced acute lytic MuHV-4 replication. The reductions, even by neutralizing mAbs, were largely or completely dependent on host IgG Fc receptors. Therefore, passive antibody can blunt acute gamma-herpesvirus lytic infection, and does this principally by IgG Fc-dependent functions rather than by neutralization.
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Affiliation(s)
- Debbie E. Wright
- Division of Virology, Department of Pathology, University of Cambridge, UK
| | - Susanna Colaco
- Division of Virology, Department of Pathology, University of Cambridge, UK
| | - Camilo Colaco
- Immunobiology Ltd, Babraham Research Campus, Cambridge, UK
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15
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Gillet L, May JS, Stevenson PG. In vivo importance of heparan sulfate-binding glycoproteins for murid herpesvirus-4 infection. J Gen Virol 2009; 90:602-613. [PMID: 19218205 PMCID: PMC2885066 DOI: 10.1099/vir.0.005785-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2008] [Accepted: 11/27/2008] [Indexed: 11/18/2022] Open
Abstract
Many herpesviruses bind to heparan sulfate (HS). Murid herpesvirus-4 (MuHV-4) does so via its envelope glycoproteins gp70 and gH/gL. MuHV-4 gp150 further regulates an HS-independent interaction to make that HS-dependent too. Cell binding by MuHV-4 virions is consequently strongly HS-dependent. Gp70 and gH/gL show some in vitro redundancy: an antibody-mediated blockade of HS binding by one is well tolerated, whereas a blockade of both severely impairs infection. In order to understand the importance of HS binding for MuHV-4 in vivo, we generated mutants lacking both gL and gp70. As expected, gL(-)gp70(-) MuHV-4 showed very poor cell binding. It infected mice at high dose but not at low dose, indicating defective host entry. But once entry occurred, host colonization, which for MuHV-4 is relatively independent of the infection dose, was remarkably normal. The gL(-)gp70(-) entry deficit was much greater than that of gL(-) or gp70(-) single knockouts. And gp150 disruption, which allows HS-independent cell binding, largely rescued the gL(-)gp70(-) cell binding and host entry deficits. Thus, it appeared that MuHV-4 HS binding is important in vivo, principally for efficient host entry.
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Affiliation(s)
- Laurent Gillet
- Division of Virology, Department of Pathology, University of Cambridge, UK
| | - Janet S May
- Division of Virology, Department of Pathology, University of Cambridge, UK
| | - Philip G Stevenson
- Division of Virology, Department of Pathology, University of Cambridge, UK
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16
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Milho R, Smith CM, Marques S, Alenquer M, May JS, Gillet L, Gaspar M, Efstathiou S, Simas JP, Stevenson PG. In vivo imaging of murid herpesvirus-4 infection. J Gen Virol 2009; 90:21-32. [PMID: 19088269 PMCID: PMC2885022 DOI: 10.1099/vir.0.006569-0] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2008] [Accepted: 10/06/2008] [Indexed: 12/27/2022] Open
Abstract
Luciferase-based imaging allows a global view of microbial pathogenesis. We applied this technique to gammaherpesvirus infection by inserting a luciferase expression cassette into the genome of murine herpesvirus-4 (MuHV-4). The recombinant virus strongly expressed luciferase in lytically infected cells without significant attenuation. We used it to compare different routes of virus inoculation. After intranasal infection of anaesthetized mice, luciferase was expressed in the nose and lungs for 7-10 days and in lymphoid tissue, most consistently the superficial cervical lymph nodes, for up to 30 days. Gastrointestinal infection was not observed. Intraperitoneal infection was very different to intranasal, with strong luciferase expression in the liver, kidneys, intestines, reproductive tract and spleen, but none in the nose or lungs. The nose has not previously been identified as a site of MuHV-4 infection. After intranasal infection of non-anaesthetized mice, it was the only site of non-lymphoid luciferase expression. Nevertheless, lymphoid colonization and persistence were still established, even at low inoculation doses. In contrast, virus delivered orally was very poorly infectious. Inoculation route therefore had a major impact on pathogenesis. Low dose intranasal infection without anaesthesia seems most likely to mimic natural transmission, and may therefore be particularly informative about normal viral gene functions.
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Affiliation(s)
- Ricardo Milho
- Division of Virology, Department of Pathology, University of Cambridge, UK
| | | | - Sofia Marques
- Instituto de Microbiologia e Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Portugal
| | - Marta Alenquer
- Instituto de Microbiologia e Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Portugal
| | - Janet S. May
- Division of Virology, Department of Pathology, University of Cambridge, UK
| | - Laurent Gillet
- Division of Virology, Department of Pathology, University of Cambridge, UK
| | - Miguel Gaspar
- Division of Virology, Department of Pathology, University of Cambridge, UK
| | - Stacey Efstathiou
- Division of Virology, Department of Pathology, University of Cambridge, UK
| | - J. Pedro Simas
- Instituto de Microbiologia e Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Portugal
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17
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Gillet L, Colaco S, Stevenson PG. Glycoprotein B switches conformation during murid herpesvirus 4 entry. J Gen Virol 2008; 89:1352-1363. [PMID: 18474550 PMCID: PMC2886948 DOI: 10.1099/vir.0.83519-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2007] [Accepted: 02/07/2008] [Indexed: 11/18/2022] Open
Abstract
Herpesviruses are ancient pathogens that infect all vertebrates. The most conserved component of their entry machinery is glycoprotein B (gB), yet how gB functions is unclear. A striking feature of the murid herpesvirus 4 (MuHV-4) gB is its resistance to neutralization. Here, we show by direct visualization of infected cells that the MuHV-4 gB changes its conformation between extracellular virions and those in late endosomes, where capsids are released. Specifically, epitopes on its N-terminal cell-binding domain become inaccessible, whilst non-N-terminal epitopes are revealed, consistent with structural changes reported for the vesicular stomatitis virus glycoprotein G. Inhibitors of endosomal acidification blocked the gB conformation switch. They also blocked capsid release and the establishment of infection, implying that the gB switch is a key step in entry. Neutralizing antibodies could only partially inhibit the switch. Their need to engage a less vulnerable, upstream form of gB, because its fusion form is revealed only in endosomes, helps to explain why gB-directed MuHV-4 neutralization is so difficult.
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Affiliation(s)
- Laurent Gillet
- Division of Virology, Department of Pathology, University of Cambridge, UK
| | - Susanna Colaco
- Division of Virology, Department of Pathology, University of Cambridge, UK
| | - Philip G Stevenson
- Division of Virology, Department of Pathology, University of Cambridge, UK
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18
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May JS, Smith CM, Gill MB, Stevenson PG. An essential role for the proximal but not the distal cytoplasmic tail of glycoprotein M in murid herpesvirus 4 infection. PLoS One 2008; 3:e2131. [PMID: 18461133 PMCID: PMC2329910 DOI: 10.1371/journal.pone.0002131] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2008] [Accepted: 03/31/2008] [Indexed: 01/08/2023] Open
Abstract
Murid herpesvirus-4 (MuHV-4) provides a tractable model with which to define common, conserved features of gamma-herpesvirus biology. The multi-membrane spanning glycoprotein M (gM) is one of only 4 glycoproteins that are essential for MuHV-4 lytic replication. gM binds to gN and is thought to function mainly secondary envelopment and virion egress, for which several predicted trafficking motifs in its C-terminal cytoplasmic tail could be important. We tested the contribution of the gM cytoplasmic tail to MuHV-4 lytic replication by making recombinant viruses with varying C-terminal deletions. Removing an acidic cluster and a distal YXXΦ motif altered the capsid distribution somewhat in infected cells but had little effect on virus replication, either in vitro or in vivo. In contrast, removing a proximal YXXΦ motif as well completely prevented productive replication. gM was still expressed, but unlike its longer forms showed only limited colocalization with co-transfected gN, and in the context of whole virus appeared to support gN expression less well. We conclude that some elements of the gM cytoplasmic tail are dispensible for MuHV-4 replication, but the tail as a whole is not.
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Affiliation(s)
- Janet S May
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
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19
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Abstract
Herpesviruses use multiple virion glycoproteins to enter cells. How these work together is not well understood: some may act separately or they may form a single complex. Murine gammaherpesvirus 68 (MHV-68) gB, gH, gL, and gp150 all participate in entry. gB and gL are involved in binding, gB and gH are conserved fusion proteins, and gp150 inhibits cell binding until glycosaminoglycans are engaged. Here we show that a gH-specific antibody coprecipitates gB and thus that gH and gB are associated in the virion membrane. A gH/gL-specific antibody also coprecipitated gB, implying a tripartite complex of gL/gH/gB, although the gH/gB association did not require gL. The association was also independent of gp150, and gp150 was not demonstrably bound to gB or gH. However, gp150 incorporation into virions was partly gL dependent, suggesting that it too contributes to a single entry complex. gp150- and gL- gp150- mutants bound better than the wild type to B cells and readily colonized B cells in vivo. Thus, gp150 and gL appear to be epithelial cell-adapted accessories of a core gB/gH entry complex. The cell binding revealed by gp150 disruption did not require gL and therefore seemed most likely to involve gB.
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Affiliation(s)
- Laurent Gillet
- Division of Virology, Department of Pathology, Tennis Court Road, Cambridge CB2 1QP, United Kingdom
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20
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Gillet L, May JS, Colaco S, Stevenson PG. The murine gammaherpesvirus-68 gp150 acts as an immunogenic decoy to limit virion neutralization. PLoS One 2007; 2:e705. [PMID: 17684552 PMCID: PMC1931612 DOI: 10.1371/journal.pone.0000705] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Accepted: 07/05/2007] [Indexed: 11/19/2022] Open
Abstract
Herpesviruses maintain long-term infectivity without marked antigenic variation. They must therefore evade neutralization by other means. Immune sera block murine gammaherpesvirus-68 (MHV-68) infection of fibroblasts, but fail to block and even enhance its infection of IgG Fc receptor-bearing cells, suggesting that the antibody response to infection is actually poor at ablating virion infectivity completely. Here we analyzed this effect further by quantitating the glycoprotein-specific antibody response of MHV-68 carrier mice. Gp150 was much the commonest glycoprotein target and played a predominant role in driving Fc receptor-dependent infection: when gp150-specific antibodies were boosted, Fc receptor-dependent infection increased; and when gp150-specific antibodies were removed, Fc receptor-dependent infection was largely lost. Neither gp150-specific monoclonal antibodies nor gp150-specific polyclonal sera gave significant virion neutralization. Gp150 therefore acts as an immunogenic decoy, distorting the MHV-68-specific antibody response to promote Fc receptor-dependent infection and so compromise virion neutralization. This immune evasion mechanism may be common to many non-essential herpesvirus glycoproteins.
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Affiliation(s)
- Laurent Gillet
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Janet S. May
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Susanna Colaco
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Philip G. Stevenson
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
- * To whom correspondence should be addressed. E-mail:
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21
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Gillet L, Adler H, Stevenson PG. Glycosaminoglycan interactions in murine gammaherpesvirus-68 infection. PLoS One 2007; 2:e347. [PMID: 17406671 PMCID: PMC1829177 DOI: 10.1371/journal.pone.0000347] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2007] [Accepted: 03/14/2007] [Indexed: 11/19/2022] Open
Abstract
Glycosaminoglycans (GAGs) commonly participate in herpesvirus entry. They are thought to provide a reversible attachment to cells that promotes subsequent receptor binding. Murine gamma-herpesvirus-68 (MHV-68) infection of fibroblasts and epithelial cells is highly GAG-dependent. This is a function of the viral gp150, in that gp150-deficient mutants are much less GAG-dependent than wild-type. Here we show that the major MHV-68 GAG-binding protein is not gp150 but gp70, a product of ORF4. Surprisingly, ORF4-deficient MHV-68 showed normal cell binding and was more sensitive than wild-type to inhibition by soluble heparin rather than less. Thus, the most obvious viral GAG interaction made little direct contribution to infection. Indeed, a large fraction of the virion gp70 had its GAG-binding domain removed by post-translational cleavage. ORF4 may therefore act mainly to absorb soluble GAGs and prevent them from engaging gp150 prematurely. In contrast to gp70, gp150 bound poorly to GAGs, implying that it provides little in the way of adhesion. We hypothesize that it acts instead as a GAG-sensitive switch that selectively activates MHV-68 entry at cell surfaces.
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Affiliation(s)
- Laurent Gillet
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Heiko Adler
- GSF-Research Center for Environment and Health, Institute of Molecular Immunology, Clinical Cooperation Group Hematopoietic Cell Transplantation, Munich, Germany
| | - Philip G. Stevenson
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
- * To whom correspondence should be addressed. E-mail:
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22
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Hart J, Ackermann M, Jayawardane G, Russell G, Haig DM, Reid H, Stewart JP. Complete sequence and analysis of the ovine herpesvirus 2 genome. J Gen Virol 2007; 88:28-39. [PMID: 17170433 DOI: 10.1099/vir.0.82284-0] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Ovine herpesvirus 2 (OvHV-2) is endemic in sheep populations worldwide and causes malignant catarrhal fever (MCF), a lymphoproliferative disease, in cattle, bison and deer. OvHV-2 has been placed in the gammaherpesvirus subfamily and is related closely to Alcelaphine herpesvirus 1 (AlHV-1). Here, the cloning, sequencing and analysis of the complete OvHV-2 genome derived from a lymphoblastoid cell line from an affected cow (BJ1035) are reported. The unique portion of the genome consists of 130,930 bp, with a mean G+C content of 52 mol%. The unique DNA is flanked by multiple copies of terminal repeat elements 4205 bp in length, with a mean G+C content of 72 mol%. Analysis revealed 73 open reading frames (ORFs), the majority (62) of which showed homology to other gammaherpesvirus genes. A further subset of nine ORFs is shared with only the related AlHV-1. Three ORFs are entirely unique to OvHV-2, including a spliced homologue of cellular interleukin-10 that retains the exon structure of the cellular gene. The sequence of OvHV-2 is a critical first step in the study of the pathogenesis and treatment of MCF.
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Affiliation(s)
- Jane Hart
- Department of Veterinary Pathology, University of Edinburgh, Edinburgh, UK
| | | | - Gamini Jayawardane
- Division of Medical Microbiology, School of Infection and Host Defence, University of Liverpool, Duncan Building, Daulby Street, Liverpool L69 3GA, UK
| | - George Russell
- Division of Virology, Moredun Research Institute, Edinburgh, UK
| | - David M Haig
- Division of Virology, Moredun Research Institute, Edinburgh, UK
| | - Hugh Reid
- Division of Virology, Moredun Research Institute, Edinburgh, UK
| | - James P Stewart
- Division of Medical Microbiology, School of Infection and Host Defence, University of Liverpool, Duncan Building, Daulby Street, Liverpool L69 3GA, UK
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Krug LT, Moser JM, Dickerson SM, Speck SH. Inhibition of NF-kappaB activation in vivo impairs establishment of gammaherpesvirus latency. PLoS Pathog 2007; 3:e11. [PMID: 17257062 PMCID: PMC1781481 DOI: 10.1371/journal.ppat.0030011] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2006] [Accepted: 12/13/2006] [Indexed: 12/20/2022] Open
Abstract
A critical determinant in chronic gammaherpesvirus infections is the ability of these viruses to establish latency in a lymphocyte reservoir. The nuclear factor (NF)-κB family of transcription factors represent key players in B-cell biology and are targeted by gammaherpesviruses to promote host cell survival, proliferation, and transformation. However, the role of NF-κB signaling in the establishment of latency in vivo has not been addressed. Here we report the generation and in vivo characterization of a recombinant murine gammaherpesvirus 68 (γHV68) that expresses a constitutively active form of the NF-κB inhibitor, IκBαM. Inhibition of NF-κB signaling upon infection with γHV68-IκBαM did not affect lytic replication in cell culture or in the lung following intranasal inoculation. However, there was a substantial decrease in the frequency of latently infected lymphocytes in the lung (90% reduction) and spleens (97% reduction) 16 d post intranasal inoculation. Importantly, the defect in establishment of latency in lung B cells could not be overcome by increasing the dose of virus 100-fold. The observed decrease in establishment of viral latency correlated with a loss of activated, CD69hi B cells in both the lungs and spleen at day 16 postinfection, which was not apparent by 6 wk postinfection. Constitutive expression of Bcl-2 in B cells did not rescue the defect in the establishment of latency observed with γHV68-IκBαM, indicating that NF-κB–mediated functions apart from Bcl-2–mediated B-cell survival are critical for the efficient establishment of gammaherpesvirus latency in vivo. In contrast to the results obtained following intranasal inoculation, infection of mice with γHV68-IκBαM by the intraperitoneal route had only a modest impact on splenic latency, suggesting that route of inoculation may alter requirements for establishment of virus latency in B cells. Finally, analyses of the pathogenesis of γHV68-IκBαM provides evidence that NF-κB signaling plays an important role during multiple stages of γHV68 infection in vivo and, as such, represents a key host regulatory pathway that is likely manipulated by the virus to establish latency in B cells. A central aspect of chronic infection of a host by herpesviruses is the ability of these viruses to establish a quiescent infection (latent infection) in some cell type(s) in which there is only intermittent production of progeny virus (virus reactivation). The establishment of a latent infection in the antibody producing cells of the host immune system (B lymphocytes) is critical for life-long persistence of gammaherpesviruses, as well as the development of virus-associated lymphoproliferative diseases (e.g., B-cell lymphomas). Nuclear factor (NF)-κB transcription factors are a family of cellular proteins that play an important role regulating gene expression in B cells, and it has been shown that gammaherpesviruses have evolved multiple strategies for manipulating NF-κB activity. However, to date there has been no reported examination of the role of NF-κB in the establishment of chronic gammaherpesvirus infection in vivo. Murine gammaherpesvirus 68 (γHV68) infects rodents and shares genetic and biologic properties with the human gammaherpesviruses, Epstein-Barr virus and Kaposi sarcoma–associated herpesvirus. To selectively block the function of NF-κB in infected cells, we engineered a transgenic virus that expresses a repressor of NF-κB activation (IκBαM). Notably, this recombinant virus was defective in the establishment of latency in B cells in the lungs and spleen following intranasal inoculation. We also observed that the decrease in B-cell infection could not be rescued by forced expression of the cellular Bcl-2 protein, which is normally upregulated by NF-κB and serves to protect B cells from some forms of cell death. Thus, we conclude that NF-κB is an important host factor for the successful establishment of a chronic infection by gammaherpesviruses, and likely requires functions of NF-κB apart from its role in B-cell survival.
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Affiliation(s)
- Laurie T Krug
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, United States of America
- The Emory Vaccine Center, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Janice M Moser
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, United States of America
- The Emory Vaccine Center, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Shelley M Dickerson
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, United States of America
- The Emory Vaccine Center, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Samuel H Speck
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, United States of America
- The Emory Vaccine Center, Emory University School of Medicine, Atlanta, Georgia, United States of America
- * To whom correspondence should be addressed. E-mail:
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Gillet L, Gill MB, Colaco S, Smith CM, Stevenson PG. Murine gammaherpesvirus-68 glycoprotein B presents a difficult neutralization target to monoclonal antibodies derived from infected mice. J Gen Virol 2006; 87:3515-3527. [PMID: 17098966 PMCID: PMC2884974 DOI: 10.1099/vir.0.82313-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Persistent viruses disseminate from immune hosts. They must therefore resist neutralization by antibody. Murine gammaherpesvirus-68 (MHV-68) represents an accessible model with which to address how resistance to neutralization is achieved and how overcoming it might improve infection control. The MHV-68 glycoprotein B (gB), like that of other herpesviruses, is a virion protein that is essential for infectivity. As such, it presents a potential neutralization target. In order to test whether virus-induced antibodies reduce virion infectivity by binding to gB, monoclonal antibodies (mAbs) were derived from MHV-68-infected mice. gB-specific mAbs were common, but only an IgM specific for the gB N terminus reduced virion infectivity significantly. It inhibited MHV-68 entry into BHK-21 cells at a post-binding step that was linked closely to membrane fusion. Reducing the mAb to IgM monomers compromised neutralization severely, suggesting that a pentameric structure was crucial to its function. Antibody treatment never blocked BHK-21 cell infection completely and blocked the infection of NMuMG epithelial cells hardly at all. Virions saturated with antibody also remained infectious to mice. Thus, the MHV-68 gB presents at best a very difficult target for antibody-mediated neutralization.
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Affiliation(s)
- Laurent Gillet
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Michael B Gill
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Susanna Colaco
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Christopher M Smith
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Philip G Stevenson
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
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Smith CM, Rosa GTL, May JS, Bennett NJ, Mount AM, Belz GT, Stevenson PG. CD4+ T cells specific for a model latency-associated antigen fail to control a gammaherpesvirusin vivo. Eur J Immunol 2006; 36:3186-97. [PMID: 17109468 DOI: 10.1002/eji.200636164] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
CD4(+) T cells play a major role in containing herpesvirus infections. However, their cellular targets remain poorly defined. In vitro CD4(+) T cells have been reported to kill B cells that harbor a latent gammaherpesvirus. We used the B cell-tropic murine gammaherpesvirus-68 (MHV-68) to test whether this also occurred in vivo. MHV-68 that expressed cytoplasmic ovalbumin (OVA) in tandem with its episome maintenance protein, ORF73, stimulated CD8(+) T cells specific for the H2-K(b)-restricted OVA epitope SIINFEKL and was rapidly eliminated from C57BL/6 (H2(b)) mice. However, the same virus failed to stimulate CD4(+) T cells specific for the I-A(d)/I-A(b)-restricted OVA(323-339) epitope. We overcame any barrier to the MHC class II-restricted presentation of an endogenous epitope by substituting OVA(323-339) for the CLIP peptide of the invariant chain (ORF73-IRES-Ii-OVA), again expressed in tandem with ORF73. This virus presented OVA(323-339) but showed little or no latency deficit in either BALB/c (H2(d)) or C57BL/6 mice. Latent antigen-specific CD4(+) T cells therefore either failed to recognize key virus-infected cell populations in vivo or lacked the effector functions required to control them.
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Affiliation(s)
- Christopher M Smith
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, UK
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Gill MB, Gillet L, Colaco S, May JS, de Lima BD, Stevenson PG. Murine gammaherpesvirus-68 glycoprotein H-glycoprotein L complex is a major target for neutralizing monoclonal antibodies. J Gen Virol 2006; 87:1465-1475. [PMID: 16690911 DOI: 10.1099/vir.0.81760-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Herpesviruses characteristically persist in immune hosts as latent genomes, but to transmit infection they must reactivate and replicate lytically. The interaction between newly formed virions and pre-existing antibody is therefore likely to be a crucial determinant of viral fitness. Murine gammaherpesvirus-68 (MHV-68) behaves as a natural pathogen of conventional, inbred mice and consequently allows such interactions to be analysed experimentally in a relatively realistic setting. Here, monoclonal antibodies (mAbs) were derived from MHV-68-infected mice and all those recognizing infected-cell surfaces were tested for their capacity to neutralize MHV-68 virions. All of the neutralizing mAbs identified were specific for the viral glycoprotein H (gH)-gL heterodimer and required both gH and gL to reproduce their cognate epitopes. Based on antibody interference, there appeared to be two major neutralization epitopes on gH-gL. Analysis of a representative mAb indicated that it blocked infection at a post-binding step--either virion endocytosis or membrane fusion.
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Affiliation(s)
- Michael B Gill
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Laurent Gillet
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Susanna Colaco
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Janet S May
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Brigitte D de Lima
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Philip G Stevenson
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
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Abstract
The murine gamma-herpesvirus-68 (MHV-68) is a relative of the Kaposi's sarcoma-associated herpesvirus (KSHV) and Epstein-Barr virus (EBV) that infects mice. All these gamma-herpesviruses are subject to immune control, but limit the impact of this control through immune evasion. Molecular evasion mechanisms have been described in abundance. However, we can only speculate what EBV and KSHV immune evasion contributes to the viral lifecycle. With MHV-68, we can analyze in vivo the contribution of immunological and virological gene expression to pathogenesis. While the physiology of infection seems quite well conserved between these viruses, the pathologies associated with immune suppression are obviously very different. MHV-68 is therefore more suited to uncovering the basic biology of gamma-herpesvirus infection than to testing disease interventions. Nevertheless, it may make some useful predictions about effective strategies of vaccination and infection control. This review aims to outline our current state of knowledge and to highlight some limitations of the MHV-68 model as it stands, in the hope of stimulating constructive progress.
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Affiliation(s)
- Philip G Stevenson
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK.
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May JS, de Lima BD, Colaco S, Stevenson PG. Intercellular gamma-herpesvirus dissemination involves co-ordinated intracellular membrane protein transport. Traffic 2005; 6:780-93. [PMID: 16101681 DOI: 10.1111/j.1600-0854.2005.00316.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The murine gamma-herpesvirus-68 (MHV-68) ORF27 encodes gp48, a type 2 transmembrane glycoprotein that contributes to intercellular viral spread. Gp48 is expressed on the surface of infected cells but is retained intracellularly after transfection. In this study, we show that the multimembrane spanning ORF58 gene product is both necessary and sufficient for gp48 to reach the cell surface. ORF58-deficient MHV-68 expressed ORF27 in normal amounts, but retained it in the endoplasmic reticulum (ER). Transfected ORF27 also remained in ER, whereas green fluorescent protein-tagged ORF58 localized to the ER and trans-Golgi network. When ORF27 and ORF58 were co-transfected, they formed a protein complex and reached the cell surface. Surprisingly, ORF58 rather than ORF27 mediated cell binding via a small extracellular loop. The heavily glycosylated ORF27 component of the complex may, therefore, act mainly to protect this loop against antibody. The interdependent transport of ORF27 and ORF58 transport ensures that such protection is always present.
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Affiliation(s)
- Janet S May
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, UK
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