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Lv W, Li Z, Wang S, He J, Zhang L. A role for tunneling nanotubes in virus spread. Front Microbiol 2024; 15:1356415. [PMID: 38435698 PMCID: PMC10904554 DOI: 10.3389/fmicb.2024.1356415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 01/30/2024] [Indexed: 03/05/2024] Open
Abstract
Tunneling nanotubes (TNTs) are actin-rich intercellular conduits that mediate distant cell-to-cell communication and enable the transfer of various cargos, including proteins, organelles, and virions. They play vital roles in both physiological and pathological processes. In this review, we focus on TNTs in different types of viruses, including retroviruses such as HIV, HTLV, influenza A, herpesvirus, paramyxovirus, alphavirus and SARS-CoV-2. We summarize the viral proteins responsible for inducing TNT formation and explore how these virus-induced TNTs facilitate intercellular communication, thereby promoting viral spread. Furthermore, we highlight other virus infections that can induce TNT-like structures, facilitating the dissemination of viruses. Moreover, TNTs promote intercellular spread of certain viruses even in the presence of neutralizing antibodies and antiviral drugs, posing significant challenges in combating viral infections. Understanding the mechanisms underlying viral spread via TNTs provides valuable insights into potential drug targets and contributes to the development of effective therapies for viral infections.
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Affiliation(s)
- Weimiao Lv
- Department of Clinical Laboratory Medicine, The First Affiliated Hospital of Shandong First Medical University and Shandong Provincial Qianfoshan Hospital, Jinan, Shandong, China
- Department of Pathogen Biology, School of Clinical and Basic Medical Sciences, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, Shandong, China
- Medical Science and Technology Innovation Center, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, Shandong, China
| | - Zichen Li
- Department of Pathogen Biology, School of Clinical and Basic Medical Sciences, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, Shandong, China
- Medical Science and Technology Innovation Center, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, Shandong, China
| | - Shule Wang
- School of Clinical Medicine, Shandong Second Medical University, Weifang, Shandong, China
| | - Jingyi He
- Department of Pathogen Biology, School of Clinical and Basic Medical Sciences, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, Shandong, China
| | - Leiliang Zhang
- Department of Clinical Laboratory Medicine, The First Affiliated Hospital of Shandong First Medical University and Shandong Provincial Qianfoshan Hospital, Jinan, Shandong, China
- Department of Pathogen Biology, School of Clinical and Basic Medical Sciences, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, Shandong, China
- Medical Science and Technology Innovation Center, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, Shandong, China
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2
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Szabó-Meleg E. Intercellular Highways in Transport Processes. Results Probl Cell Differ 2024; 73:173-201. [PMID: 39242380 DOI: 10.1007/978-3-031-62036-2_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/09/2024]
Abstract
Communication among cells is vital in multicellular organisms. Various structures and mechanisms have evolved over time to achieve the intricate flow of material and information during this process. One such way of communication is through tunnelling membrane nanotubes (TNTs), which were initially described in 2004. These TNTs are membrane-bounded actin-rich cellular extensions, facilitating direct communication between distant cells. They exhibit remarkable diversity in terms of structure, morphology, and function, in which cytoskeletal proteins play an essential role. Biologically, TNTs play a crucial role in transporting membrane components, cell organelles, and nucleic acids, and they also present opportunities for the efficient transmission of bacteria and viruses, furthermore, may contribute to the dissemination of misfolded proteins in certain neurodegenerative diseases. Convincing results of studies conducted both in vitro and in vivo indicate that TNTs play roles in various biomedical processes, including cell differentiation, tissue regeneration, neurodegenerative diseases, immune response and function, as well as tumorigenesis.
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Affiliation(s)
- Edina Szabó-Meleg
- Department of Biophysics, Medical School, University of Pécs, Pécs, Hungary.
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3
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Kapoor D, Sharma P, Siani A, Azhar E, Elste J, Kohlmeir EK, Shukla D, Tiwari V. Tunneling Nanotubes: The Cables for Viral Spread and Beyond. Results Probl Cell Differ 2024; 73:375-417. [PMID: 39242387 DOI: 10.1007/978-3-031-62036-2_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/09/2024]
Abstract
Multicellular organisms require cell-to-cell communication to maintain homeostasis and thrive. For cells to communicate, a network of filamentous, actin-rich tunneling nanotubes (TNTs) plays a pivotal role in facilitating efficient cell-to-cell communication by connecting the cytoplasm of adjacent or distant cells. Substantial documentation indicates that diverse cell types employ TNTs in a sophisticated and intricately organized fashion for both long and short-distance communication. Paradoxically, several pathogens, including viruses, exploit the structural integrity of TNTs to facilitate viral entry and rapid cell-to-cell spread. These pathogens utilize a "surfing" mechanism or intracellular transport along TNTs to bypass high-traffic cellular regions and evade immune surveillance and neutralization. Although TNTs are present across various cell types in healthy tissue, their magnitude is increased in the presence of viruses. This heightened induction significantly amplifies the role of TNTs in exacerbating disease manifestations, severity, and subsequent complications. Despite significant advancements in TNT research within the realm of infectious diseases, further studies are imperative to gain a precise understanding of TNTs' roles in diverse pathological conditions. Such investigations are essential for the development of novel therapeutic strategies aimed at leveraging TNT-associated mechanisms for clinical applications. In this chapter, we emphasize the significance of TNTs in the life cycle of viruses, showcasing the potential for a targeted approach to impede virus-host cell interactions during the initial stages of viral infections. This approach holds promise for intervention and prevention strategies.
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Affiliation(s)
- Divya Kapoor
- Department of Microbiology and Immunology, Department of Ophthalmology and Visual Sciences, University of Illinois, Chicago, IL, USA
| | - Pankaj Sharma
- Department of Microbiology and Immunology, Department of Ophthalmology and Visual Sciences, University of Illinois, Chicago, IL, USA
| | - Akash Siani
- Hinsdale Central High School, Hinsdale, IL, USA
| | - Eisa Azhar
- Department of Microbiology and Immunology, Chicago College of Osteopathic Medicine, Midwestern University, Downers Grove, IL, USA
| | - James Elste
- Department of Microbiology and Immunology, Chicago College of Osteopathic Medicine, Midwestern University, Downers Grove, IL, USA
| | | | - Deepak Shukla
- Department of Microbiology and Immunology, Department of Ophthalmology and Visual Sciences, University of Illinois, Chicago, IL, USA
| | - Vaibhav Tiwari
- Department of Microbiology and Immunology, Chicago College of Osteopathic Medicine, Midwestern University, Downers Grove, IL, USA.
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The Epstein-Barr Virus Glycoprotein BDLF2 Is Essential for Efficient Viral Spread in Stratified Epithelium. J Virol 2023; 97:e0152822. [PMID: 36688650 PMCID: PMC9972961 DOI: 10.1128/jvi.01528-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Epstein-Barr virus (EBV) is a ubiquitous human pathogen that infects the majority of the adult population regardless of socioeconomic status or geographical location. EBV primarily infects B and epithelial cells and is associated with different cancers of these cell types, such as Burkitt lymphoma and nasopharyngeal carcinoma. While the life cycle of EBV in B cells is well understood, EBV infection within epithelium is not, largely due to the inability to model productive replication in epithelium in vitro. Organotypic cultures generated from primary human keratinocytes can model many aspects of EBV infection, including productive replication in the suprabasal layers. The EBV glycoprotein BDLF2 is a positional homologue of the murine gammaherpesvirus-68 protein gp48, which plays a role in intercellular spread of viral infection, though sequence homology is limited. To determine the role that BDLF2 plays in EBV infection, we generated a recombinant EBV in which the BDLF2 gene has been replaced with a puromycin resistance gene. The ΔBDLF2 recombinant virus infected both B cell and HEK293 cell lines and was able to immortalize primary B cells. However, the loss of BDLF2 resulted in substantially fewer infected cells in organotypic cultures compared to wild-type virus. While numerous clusters of infected cells representing a focus of infection are observed in wild-type-infected organotypic cultures, the majority of cells observed in the absence of BDLF2 were isolated cells, suggesting that the EBV glycoprotein BDLF2 plays a major role in intercellular viral spread in stratified epithelium. IMPORTANCE The ubiquitous herpesvirus Epstein-Barr virus (EBV) is associated with cancers of B lymphocytes and epithelial cells and is primarily transmitted in saliva. While several models exist for analyzing the life cycle of EBV in B lymphocytes, models of EBV infection in the epithelium have more recently been established. Using an organotypic culture model of epithelium that we previously determined accurately reflects EBV infection in situ, we have ascertained that the loss of the viral envelope protein BDLF2 had little effect on the EBV life cycle in B cells but severely restricted the number of infected cells in organotypic cultures. Loss of BDLF2 has a substantial impact on the size of infected areas, suggesting that BDLF2 plays a specific role in the spread of infection in stratified epithelium.
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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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Tiwari V, Koganti R, Russell G, Sharma A, Shukla D. Role of Tunneling Nanotubes in Viral Infection, Neurodegenerative Disease, and Cancer. Front Immunol 2021; 12:680891. [PMID: 34194434 PMCID: PMC8236699 DOI: 10.3389/fimmu.2021.680891] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 05/26/2021] [Indexed: 12/14/2022] Open
Abstract
The network of tunneling nanotubes (TNTs) represents the filamentous (F)-actin rich tubular structure which is connected to the cytoplasm of the adjacent and or distant cells to mediate efficient cell-to-cell communication. They are long cytoplasmic bridges with an extraordinary ability to perform diverse array of function ranging from maintaining cellular physiology and cell survival to promoting immune surveillance. Ironically, TNTs are now widely documented to promote the spread of various pathogens including viruses either during early or late phase of their lifecycle. In addition, TNTs have also been associated with multiple pathologies in a complex multicellular environment. While the recent work from multiple laboratories has elucidated the role of TNTs in cellular communication and maintenance of homeostasis, this review focuses on their exploitation by the diverse group of viruses such as retroviruses, herpesviruses, influenza A, human metapneumovirus and SARS CoV-2 to promote viral entry, virus trafficking and cell-to-cell spread. The later process may aggravate disease severity and the associated complications due to widespread dissemination of the viruses to multiple organ system as observed in current coronavirus disease 2019 (COVID-19) patients. In addition, the TNT-mediated intracellular spread can be protective to the viruses from the circulating immune surveillance and possible neutralization activity present in the extracellular matrix. This review further highlights the relevance of TNTs in ocular and cardiac tissues including neurodegenerative diseases, chemotherapeutic resistance, and cancer pathogenesis. Taken together, we suggest that effective therapies should consider precise targeting of TNTs in several diseases including virus infections.
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Affiliation(s)
- Vaibhav Tiwari
- Department of Microbiology & Immunology, Chicago College of Osteopathic Medicine, Midwestern University, Downers Grove, IL, United States
| | - Raghuram Koganti
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, United States
| | - Greer Russell
- Department of Biomedical Sciences, College of Graduate Studies, Midwestern University, Downers Grove, IL, United States
| | - Ananya Sharma
- Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Deepak Shukla
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, United States.,Department of Microbiology and Immunology, University of Illinois at Chicago, Chicago, IL, United States
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7
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Field Observations and Genetic Characterization of Sheep-Associated Malignant Catarrhal Fever in Egypt, 2018. Vet Sci 2020; 7:vetsci7040201. [PMID: 33322397 PMCID: PMC7768452 DOI: 10.3390/vetsci7040201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 11/27/2020] [Accepted: 12/11/2020] [Indexed: 11/29/2022] Open
Abstract
Ovine gammaherpesvirus-2 (OvHV-2) causes a lethal disease in cattle and some wild ruminants called malignant catarrhal fever (MCF), which affects the epithelial and lymphoid tissues of the respiratory and digestive tracts and has an important impact on the livestock industry. In this study, MCF was diagnosed in 18 of 427 cattle from different sites in Egypt by its typical clinical signs, found in all 18 animals: corneal opacity, fever, erosions in the buccal cavity, lymphadenitis, and purulent nasal discharge. All affected cattle had been reared in contact with clinically inconspicuous sheep. Of the 18 clinically ill cattle, 13 succumbed to the disease, resulting in estimated morbidity and case fatality rates of 4.2% and 72.2%, respectively. Five samples collected from the affected cattle were positive for OvHV-2 by real-time PCR and were used for sequencing of an 832-bp fragment of the ORF27/gp48 gene. The ORF27 nucleotide sequence of all Egyptian samples was identical, but distinct from viruses found in other parts of Africa and the Mediterranean.
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8
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Abstract
Tunneling nanotubes (TNTs) are actin-based intercellular conduits that connect distant cells and allow intercellular transfer of molecular information, including genetic information, proteins, lipids, and even organelles. Besides providing a means of intercellular communication, TNTs may also be hijacked by pathogens, particularly viruses, to facilitate their spread. Viruses of many different families, including retroviruses, herpesviruses, orthomyxoviruses, and several others have been reported to trigger the formation of TNTs or TNT-like structures in infected cells and use these structures to efficiently spread to uninfected cells. In the current review, we give an overview of the information that is currently available on viruses and TNT-like structures, and we discuss some of the standing questions in this field.
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9
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Multiple Roles of the Cytoplasmic Domain of Herpes Simplex Virus 1 Envelope Glycoprotein D in Infected Cells. J Virol 2016; 90:10170-10181. [PMID: 27581980 DOI: 10.1128/jvi.01396-16] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 08/23/2016] [Indexed: 01/27/2023] Open
Abstract
Herpes simplex virus 1 (HSV-1) envelope glycoprotein D (gD) plays an essential role in viral entry. The functional regions of gD responsible for viral entry have been mapped to its extracellular domain, whereas the gD cytoplasmic domain plays no obvious role in viral entry. Thus far, the role(s) of the gD cytoplasmic domain in HSV-1 replication has remained to be elucidated. In this study, we show that ectopic expression of gD induces microvillus-like tubular structures at the plasma membrane which resemble the reported projection structures of the plasma membrane induced in HSV-1-infected cells. Mutations in the arginine cluster (residues 365 to 367) in the gD cytoplasmic domain greatly reduced gD-induced plasma membrane remodeling. In agreement with this, the mutations in the arginine cluster in the gD cytoplasmic domain reduced the number of microvillus-like tubular structures at the plasma membrane in HSV-1-infected cells. In addition, the mutations produced an accumulation of unenveloped nucleocapsids in the cytoplasm and reduced viral replication and cell-cell spread. These results suggest that the arginine cluster in the gD cytoplasmic domain is required for the efficient induction of plasma membrane projections and viral final envelopment, and these functions of the gD domain may lead to efficient viral replication and cell-cell spread. IMPORTANCE The cytoplasmic domain of HSV-1 gD, an envelope glycoprotein essential for viral entry, was reported to promote viral replication and cell-cell spread, but the role(s) of the domain during HSV-1 infection has remained unknown. In this study, we clarify two functions of the arginine cluster in the HSV-1 gD cytoplasmic domain, both of which require host cell membrane remodeling, i.e., the formation of microvillus-like projections at the plasma membrane and viral final envelopment in HSV-1-infected cells. We also show that the gD arginine cluster is required for efficient HSV-1 replication and cell-cell spread. This is the first report clarifying not only the functions of the gD cytoplasmic domain but also identifying the gD arginine cluster to be the HSV-1 factor responsible for the induction of plasma membrane projections in HSV-1-infected cells. Our results elucidate some of the functions of this multifunctional envelope glycoprotein during HSV-1 infection.
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10
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Cieniewicz B, Santana AL, Minkah N, Krug LT. Interplay of Murine Gammaherpesvirus 68 with NF-kappaB Signaling of the Host. Front Microbiol 2016; 7:1202. [PMID: 27582728 PMCID: PMC4987367 DOI: 10.3389/fmicb.2016.01202] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 07/19/2016] [Indexed: 11/13/2022] Open
Abstract
Herpesviruses establish a chronic infection in the host characterized by intervals of lytic replication, quiescent latency, and reactivation from latency. Murine gammaherpesvirus 68 (MHV68) naturally infects small rodents and has genetic and biologic parallels with the human gammaherpesviruses (gHVs), Kaposi's sarcoma-associated herpesvirus and Epstein-Barr virus. The murine gammaherpesvirus model pathogen system provides a platform to apply cutting-edge approaches to dissect the interplay of gammaherpesvirus and host determinants that enable colonization of the host, and that shape the latent or lytic fate of an infected cell. This knowledge is critical for the development of novel therapeutic interventions against the oncogenic gHVs. The nuclear factor kappa B (NF-κB) signaling pathway is well-known for its role in the promotion of inflammation and many aspects of B cell biology. Here, we review key aspects of the virus lifecycle in the host, with an emphasis on the route that the virus takes to gain access to the B cell latency reservoir. We highlight how the murine gammaherpesvirus requires components of the NF-κB signaling pathway to promote replication, latency establishment, and maintenance of latency. These studies emphasize the complexity of gammaherpesvirus interactions with NF-κB signaling components that direct innate and adaptive immune responses of the host. Importantly, multiple facets of NF-κB signaling have been identified that might be targeted to reduce the burden of gammaherpesvirus-associated diseases.
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Affiliation(s)
- Brandon Cieniewicz
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook NY, USA
| | - Alexis L Santana
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook NY, USA
| | - Nana Minkah
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook NY, USA
| | - Laurie T Krug
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook NY, USA
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11
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Abstract
Glycoproteins are critical to virus entry, to spread within and between hosts and can modify the behavior of cells. Many viruses carry only a few, most found in the virion envelope. EBV makes more than 12, providing flexibility in how it colonizes its human host. Some are dedicated to getting the virus through the cell membrane and on toward the nucleus of the cell, some help guide the virus back out and on to the next cell in the same or a new host. Yet others undermine host defenses helping the virus persist for a lifetime, maintaining a presence that is mostly tolerated and serves to perpetuate EBV as one of the most common infections of man.
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Affiliation(s)
- Lindsey M Hutt-Fletcher
- Department of Microbiology & Immunology, Feist-Weiller Cancer Center and Center for Molecular & Tumor Virology, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, LA 71130, USA; Tel.: +1 318 675 4948
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12
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Frederico B, Chao B, May JS, Belz GT, Stevenson PG. A murid gamma-herpesviruses exploits normal splenic immune communication routes for systemic spread. Cell Host Microbe 2015; 15:457-70. [PMID: 24721574 DOI: 10.1016/j.chom.2014.03.010] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2013] [Revised: 12/05/2013] [Accepted: 02/03/2014] [Indexed: 12/12/2022]
Abstract
Gamma-herpesviruses (γHVs) are widespread oncogenic pathogens that chronically infect circulating lymphocytes. How they subvert the immune check-point function of the spleen to promote persistent infection is not clear. We show that Murid Herpesvirus-4 (MuHV-4) enters the spleen by infecting marginal zone (MZ) macrophages, which provided a conduit to MZ B cells. Relocation of MZ B cells to the white pulp allowed virus transfer to follicular dendritic cells. From here the virus reached germinal center B cells to establish persistent infection. Mice lacking MZ B cells, or treated with a sphingosine-1-phosphate receptor agonist to dislocate them, were protected against MuHV-4 colonization. MuHV-4 lacking ORF27, which encodes a glycoprotein necessary for efficient intercellular spread, could infect MZ macrophages but was impaired in long-term infection. Thus, MuHV-4, a γHV, exploits normal immune communication routes to spread by serial lymphoid/myeloid exchange.
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Affiliation(s)
- Bruno Frederico
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge CB2 2QQ, UK
| | - Brittany Chao
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge CB2 2QQ, UK
| | - Janet S May
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge CB2 2QQ, UK
| | - Gabrielle T Belz
- Molecular Immunology, Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria 3052, Australia
| | - Philip G Stevenson
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge CB2 2QQ, UK; Sir Albert Sakzewski Virus Research Centre and Queensland Children's Medical Research Institute, University of Queensland, Brisbane, Queensland 4029, Australia.
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13
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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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14
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Vidick S, Leroy B, Palmeira L, Machiels B, Mast J, François S, Wattiez R, Vanderplasschen A, Gillet L. Proteomic characterization of murid herpesvirus 4 extracellular virions. PLoS One 2013; 8:e83842. [PMID: 24386290 PMCID: PMC3875534 DOI: 10.1371/journal.pone.0083842] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 11/18/2013] [Indexed: 12/18/2022] Open
Abstract
Gammaherpesvirinae, such as the human Epstein-Barr virus (EBV) and the Kaposi’s sarcoma associated herpesvirus (KSHV) are highly prevalent pathogens that have been associated with several neoplastic diseases. As EBV and KSHV are host-range specific and replicate poorly in vitro, animal counterparts such as Murid herpesvirus-4 (MuHV-4) have been widely used as models. In this study, we used MuHV-4 in order to improve the knowledge about proteins that compose gammaherpesviruses virions. To this end, MuHV-4 extracellular virions were isolated and structural proteins were identified using liquid chromatography tandem mass spectrometry-based proteomic approaches. These analyses allowed the identification of 31 structural proteins encoded by the MuHV-4 genome which were classified as capsid (8), envelope (9), tegument (13) and unclassified (1) structural proteins. In addition, we estimated the relative abundance of the identified proteins in MuHV-4 virions by using exponentially modified protein abundance index analyses. In parallel, several host proteins were found in purified MuHV-4 virions including Annexin A2. Although Annexin A2 has previously been detected in different virions from various families, its role in the virion remains controversial. Interestingly, despite its relatively high abundance in virions, Annexin A2 was not essential for the growth of MuHV-4 in vitro. Altogether, these results extend previous work aimed at determining the composition of gammaherpesvirus virions and provide novel insights for understanding MuHV-4 biology.
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Affiliation(s)
- Sarah Vidick
- Department of Infectious Diseases, Faculty of Veterinary Medicine, University of Liège, Liège, Belgium
| | - Baptiste Leroy
- Department of Proteomics and Microbiology, Research Institute for Biosciences Interdisciplinary Mass Spectrometry Center (CISMa), University of Mons, Mons, Belgium
| | - Leonor Palmeira
- Department of Infectious Diseases, Faculty of Veterinary Medicine, University of Liège, Liège, Belgium
| | - Bénédicte Machiels
- Department of Infectious Diseases, Faculty of Veterinary Medicine, University of Liège, Liège, Belgium
| | - Jan Mast
- Electron Microscopy Unit, Veterinary and Agrochemical Research Centre, Brussels, Belgium
| | - Sylvie François
- Department of Infectious Diseases, Faculty of Veterinary Medicine, University of Liège, Liège, Belgium
| | - Ruddy Wattiez
- Department of Proteomics and Microbiology, Research Institute for Biosciences Interdisciplinary Mass Spectrometry Center (CISMa), University of Mons, Mons, Belgium
| | - Alain Vanderplasschen
- Department of Infectious Diseases, Faculty of Veterinary Medicine, University of Liège, Liège, Belgium
| | - Laurent Gillet
- Department of Infectious Diseases, Faculty of Veterinary Medicine, University of Liège, Liège, Belgium
- * E-mail:
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15
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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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16
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Richerioux N, Blondeau C, Wiedemann A, Rémy S, Vautherot JF, Denesvre C. Rho-ROCK and Rac-PAK signaling pathways have opposing effects on the cell-to-cell spread of Marek's Disease Virus. PLoS One 2012; 7:e44072. [PMID: 22952878 PMCID: PMC3428312 DOI: 10.1371/journal.pone.0044072] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 07/31/2012] [Indexed: 01/11/2023] Open
Abstract
Marek's Disease Virus (MDV) is an avian alpha-herpesvirus that only spreads from cell-to-cell in cell culture. While its cell-to-cell spread has been shown to be dependent on actin filament dynamics, the mechanisms regulating this spread remain largely unknown. Using a recombinant BAC20 virus expressing an EGFPVP22 tegument protein, we found that the actin cytoskeleton arrangements and cell-cell contacts differ in the center and periphery of MDV infection plaques, with cells in the latter areas showing stress fibers and rare cellular projections. Using specific inhibitors and activators, we determined that Rho-ROCK pathway, known to regulate stress fiber formation, and Rac-PAK, known to promote lamellipodia formation and destabilize stress fibers, had strong contrasting effects on MDV cell-to-cell spread in primary chicken embryo skin cells (CESCs). Inhibition of Rho and its ROCKs effectors led to reduced plaque sizes whereas inhibition of Rac or its group I-PAKs effectors had the adverse effect. Importantly, we observed that the shape of MDV plaques is related to the semi-ordered arrangement of the elongated cells, at the monolayer level in the vicinity of the plaques. Inhibition of Rho-ROCK signaling also resulted in a perturbation of the cell arrangement and a rounding of plaques. These opposing effects of Rho and Rac pathways in MDV cell-to-cell spread were validated for two parental MDV recombinant viruses with different ex vivo spread efficiencies. Finally, we demonstrated that Rho/Rac pathways have opposing effects on the accumulation of N-cadherin at cell-cell contact regions between CESCs, and defined these contacts as adherens junctions. Considering the importance of adherens junctions in HSV-1 cell-to-cell spread in some cell types, this result makes of adherens junctions maintenance one potential and attractive hypothesis to explain the Rho/Rac effects on MDV cell-to-cell spread. Our study provides the first evidence that MDV cell-to-cell spread is regulated by Rho/Rac signaling.
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Affiliation(s)
- Nicolas Richerioux
- INRA, UMR1282, Infectious Diseases and Public Health, ISP, BIOVA team, Nouzilly, France
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17
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Abstract
Gammaherpesviruses are important pathogens in human and animal populations. During early events of infection, these viruses manipulate preexisting host cell signaling pathways to allow successful infection. The different proteins that compose viral particles are therefore likely to have critical functions not only in viral structures and in entry into target cell but also in evasion of the host's antiviral response. In this study, we analyzed the protein composition of bovine herpesvirus 4 (BoHV-4), a close relative of the human Kaposi's sarcoma-associated herpesvirus. Using mass spectrometry-based approaches, we identified 37 viral proteins associated with extracellular virions, among which 24 were resistant to proteinase K treatment of intact virions. Analysis of proteins associated with purified capsid-tegument preparations allowed us to define protein localization. In parallel, in order to identify some previously undefined open reading frames, we mapped peptides detected in whole virion lysates onto the six frames of the BoHV-4 genome to generate a proteogenomic map of BoHV-4 virions. Furthermore, we detected important glycosylation of three envelope proteins: gB, gH, and gp180. Finally, we identified 38 host proteins associated with BoHV-4 virions; 15 of these proteins were resistant to proteinase K treatment of intact virions. Many of these have important functions in different cellular pathways involved in virus infection. This study extends our knowledge of gammaherpesvirus virions composition and provides new insights for understanding the life cycle of these viruses.
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18
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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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19
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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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20
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Van den Broeke C, Favoreel HW. Actin' up: herpesvirus interactions with Rho GTPase signaling. Viruses 2011; 3:278-92. [PMID: 21994732 PMCID: PMC3185701 DOI: 10.3390/v3040278] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Revised: 03/15/2011] [Accepted: 03/16/2011] [Indexed: 01/06/2023] Open
Abstract
Herpesviruses constitute a very large and diverse family of DNA viruses, which can generally be subdivided in alpha-, beta- and gammaherpesvirus subfamilies. Increasing evidence indicates that many herpesviruses interact with cytoskeleton-regulating Rho GTPase signaling pathways during different phases of their replication cycle. Because of the large differences between herpesvirus subfamilies, the molecular mechanisms and specific consequences of individual herpesvirus interactions with Rho GTPase signaling may differ. However, some evolutionary distinct but similar general effects on Rho GTPase signaling and the cytoskeleton have also been reported. Examples of these include Rho GTPase-mediated nuclear translocation of virus during entry in a host cell and Rho GTPase-mediated viral cell-to-cell spread during later stages of infection. The current review gives an overview of both general and individual interactions of herpesviruses with Rho GTPase signaling.
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Affiliation(s)
- Céline Van den Broeke
- Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium.
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21
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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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22
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Xiao J, Palefsky JM, Herrera R, Sunshine C, Tugizov SM. EBV-positive human sera contain antibodies against the EBV BMRF-2 protein. Virology 2009; 393:151-9. [PMID: 19698968 DOI: 10.1016/j.virol.2009.07.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2009] [Revised: 06/19/2009] [Accepted: 07/22/2009] [Indexed: 12/21/2022]
Abstract
We previously showed that the EBV glycoprotein BMRF-2 contains a functional integrin-binding Arg-Gly-Asp (RGD) domain that plays an important role in viral infection and cell-to-cell spread of progeny virions in oral epithelial cells. In this study, we found that EBV-seropositive human sera contain antibodies against BMRF-2. The inhibitory effect of EBV-positive sera on EBV infection of oral epithelial cells was substantially reduced by pre-incubation of serum samples with the BMRF-2 RGD peptide, suggesting that anti-BMRF-2 human antibodies possess neutralizing activity. EBV-specific sera reacted strongly with the BMRF-2 extracellular domain (170-213 aa) containing the RGD motif, whereas they reacted only weakly or not at all with a mutated form of the BMRF-2 extracellular domain containing AAA instead of RGD. These data indicate that RGD motif of BMRF-2 is part of an immunodominant antigenic determinant within the extracellular domain of BMRF-2 that may contribute to EBV neutralization during EBV reactivation.
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Affiliation(s)
- Jianqiao Xiao
- Department of Medicine, University of California, San Francisco, CA 94143-0654, USA
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23
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Xiao J, Palefsky JM, Herrera R, Berline J, Tugizov SM. EBV BMRF-2 facilitates cell-to-cell spread of virus within polarized oral epithelial cells. Virology 2009; 388:335-43. [PMID: 19394065 DOI: 10.1016/j.virol.2009.03.030] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Revised: 03/20/2009] [Accepted: 03/21/2009] [Indexed: 12/12/2022]
Abstract
We previously reported that the Epstein-Barr virus (EBV) BMRF-2 protein plays an important role in EBV infection of polarized oral epithelial cells by interacting with beta1 and alphav family integrins. Here we show that infection of polarized oral epithelial cells with B27-BMRF-2(low) recombinant virus, expressing a low level of BMRF-2, resulted in significantly smaller plaques compared with infection by parental B95-8 virus. BMRF-2 localized in the trans-Golgi network (TGN) and basolateral sorting vesicles and was transported to the basolateral membranes of polarized epithelial cells. Mutation of the tyrosine- and dileucine-containing basolateral sorting signal, YLLV, in the cytoplasmic domain of BMRF-2 led to the failure of its accumulation in the TGN and its basolateral transport. These data show that BMRF-2 may play an important role in promoting the spread of EBV progeny virions through lateral membranes of oral epithelial cells.
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Affiliation(s)
- Jianqiao Xiao
- Department of Medicine, University of California, San Francisco, USA
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24
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Loesing JB, Di Fiore S, Ritter K, Fischer R, Kleines M. Epstein-Barr virus BDLF2-BMRF2 complex affects cellular morphology. J Gen Virol 2009; 90:1440-1449. [PMID: 19264620 DOI: 10.1099/vir.0.009571-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Herpesvirus glycoproteins often form specific heterodimers that can fulfil functions that cannot be carried out by either of the partners acting alone. This study showed that interactions between the Epstein-Barr virus (EBV) multi-spanning transmembrane envelope protein BMRF2 and type II membrane protein BDLF2 influence the way in which these proteins are trafficked in the cell, and hence the subcellular compartment in which they accumulate. When expressed transiently in mammalian cells, BDLF2 accumulated in the endoplasmic reticulum (ER), whereas BMRF2 accumulated in the ER and Golgi apparatus. However, when the two proteins were co-expressed, BDLF2 was transported with BMRF2 to the Golgi apparatus and from there to the plasma membrane, where the proteins co-localized extensively. The distribution of the two proteins at the plasma membrane was reproducibly associated with dramatic changes in cellular morphology, including the formation of enlarged membrane protrusions and cellular processes whose adhesion extremities were organized by the actin cytoskeleton. A dominant-active form of the small GTPase RhoA was epistatic to this morphological phenotype, suggesting that RhoA is a central component of the signalling pathway that reorganizes the cytoskeleton in response to BDLF2-BMRF2. It was concluded that EBV produces a glycoprotein heterodimer that induces changes in cellular morphology through reorganization of the actin cytoskeleton and may facilitate virion spread between cells.
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Affiliation(s)
- Jens-Bernhard Loesing
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Forckenbeckstr. 6, 52074 Aachen, Germany.,Division of Virology, Department of Medical Microbiology, UK Aachen, RWTH Aachen, Pauwelsstr. 30, 52074 Aachen, Germany
| | - Stefano Di Fiore
- Institute for Molecular Biotechnology (IMB), RWTH Aachen, Worringerweg 1, 52074 Aachen, Germany
| | - Klaus Ritter
- Division of Virology, Department of Medical Microbiology, UK Aachen, RWTH Aachen, Pauwelsstr. 30, 52074 Aachen, Germany
| | - Rainer Fischer
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Forckenbeckstr. 6, 52074 Aachen, Germany
| | - Michael Kleines
- Division of Virology, Department of Medical Microbiology, UK Aachen, RWTH Aachen, Pauwelsstr. 30, 52074 Aachen, Germany
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25
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Gore M, Hutt-Fletcher LM. The BDLF2 protein of Epstein-Barr virus is a type II glycosylated envelope protein whose processing is dependent on coexpression with the BMRF2 protein. Virology 2008; 383:162-7. [PMID: 18995876 DOI: 10.1016/j.virol.2008.10.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2008] [Revised: 09/30/2008] [Accepted: 10/03/2008] [Indexed: 01/12/2023]
Abstract
Epstein-Barr virus has been documented to encode for ten envelope glycoproteins, gB, gH, gL, gM, gN, gp350, gp42, gp78, gp150 and BMRF2. The BDLF2 open reading frame is also predicted to encode a type II membrane protein but, although found in the virion, it has been described as a component of the tegument. We show here that, as predicted, it is the eleventh envelope glycoprotein of the virus. The full length 65 kDa glycoprotein formed a complex with BMRF2 and, as its homologs in other gammaherpesviruses, was dependent on BMRF2, for authentic processing and transport. Two cleavage products of BDLF2 were also identified in cells and in purified virion particles, one corresponding approximately to the aminoterminal half of the protein, that remained associated with the full length form, and one corresponding to the carboxyterminal glycosylated portion of the protein which did not.
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Affiliation(s)
- Mindy Gore
- Department of Microbiology and Immunology, Center for Molecular and Tumor Virology and Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, LA 71130, USA
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26
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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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27
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Gill MB, Edgar R, May JS, Stevenson PG. A gamma-herpesvirus glycoprotein complex manipulates actin to promote viral spread. PLoS One 2008; 3:e1808. [PMID: 18350146 PMCID: PMC2262946 DOI: 10.1371/journal.pone.0001808] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2008] [Accepted: 02/10/2008] [Indexed: 11/19/2022] Open
Abstract
Viruses lack self-propulsion. To move in multi-cellular hosts they must therefore manipulate infected cells. Herpesviruses provide an archetype for many aspects of host manipulation, but only for alpha-herpesviruses in is there much information about they move. Other herpesviruses are not necessarily the same. Here we show that Murine gamma-herpesvirus-68 (MHV-68) induces the outgrowth of long, branched plasma membrane fronds to create an intercellular network for virion traffic. The fronds were actin-based and RhoA-dependent. Time-lapse imaging showed that the infected cell surface became highly motile and that virions moved on the fronds. This plasma membrane remodelling was driven by the cytoplasmic tail of gp48, a MHV-68 glycoprotein previously implicated in intercellular viral spread. The MHV-68 ORF58 was also required, but its role was simply transporting gp48 to the plasma membrane, since a gp48 mutant exported without ORF58 did not require ORF58 to form membrane fronds either. Together, gp48/ORF58 were sufficient to induce fronds in transfected cells, as were the homologous BDLF2/BMRF2 of Epstein-Barr virus. Gp48/ORF58 therefore represents a conserved module by which gamma-herpesviruses rearrange cellular actin to increase intercellular contacts and thereby promote their spread.
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Affiliation(s)
- Michael B. Gill
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Rachel Edgar
- 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
| | - 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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28
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Abstract
The gammaherpesvirus alcelaphine herpesvirus 1 (AlHV-1) causes malignant catarrhal fever in susceptible ungulates but infects its natural host, wildebeest, without obvious clinical signs. In tissue culture, AlHV-1 is initially predominantly cell associated and virulent but on extended culture becomes cell-free and attenuated. We wanted to determine what changes in protein composition had taken place during the transition from virulent to attenuated virus in culture. Purified virus preparations were fractionated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and proteins were analyzed by liquid chromatography-electrospray ionization-tandem mass spectrometry. Peptides were identified in serial gel slices by using MASCOT software to interrogate virus-specific and nonredundant sequence databases. Twenty-three AlHV-1-encoded proteins and six cellular proteins were identified in the attenuated and virulent viruses. Two polypeptides were detected in only the virulent virus preparations, while one other protein was found in only the attenuated virus. Two of these virus-specific proteins were identified by a single peptide, suggesting that these may be low-abundance virion proteins rather than markers of attenuation or pathogenesis. The results suggest that attenuation of AlHV-1 is not the result of gross changes in the composition of the virus particle but probably due to altered viral gene expression in the infected cell.
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Kayhan B, Yager EJ, Lanzer K, Cookenham T, Jia Q, Wu TT, Woodland DL, Sun R, Blackman MA. A replication-deficient murine gamma-herpesvirus blocked in late viral gene expression can establish latency and elicit protective cellular immunity. THE JOURNAL OF IMMUNOLOGY 2008; 179:8392-402. [PMID: 18056385 DOI: 10.4049/jimmunol.179.12.8392] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The human gamma-herpesviruses, EBV and Kaposi's sarcoma-associated herpesvirus, are widely disseminated and are associated with the onset of a variety of malignancies. Thus, the development of prophylactic and therapeutic vaccination strategies is an important goal. The experimental mouse gamma-herpesvirus, gammaHV68 (or MHV-68), has provided an in vivo model for studying immune control of these persistent viruses. In the current studies, we have examined infectivity, immunogenicity, and protective efficacy following infection with a replication-deficient gammaHV68 blocked in late viral gene expression, ORF31STOP. The data show that ORF31STOP was able to latently infect B cells. However, the anatomical site and persistence of the infection depended on the route of inoculation, implicating a role for viral replication in viral spread but not the infectivity per se. Furthermore, i.p. infection with ORF31STOP elicited strong cellular immunity but a non-neutralizing Ab response. In contrast, intranasal infection was poorly immunogenic. Consistent with this, mice infected i.p. had enhanced control of both the lytic and latent viral loads following challenge with wild-type gammaHV68, whereas intranasal infected mice were not protected. These data provide important insight into mechanisms of infection and protective immunity for the gamma-herpesviruses and demonstrate the utility of replication-deficient mutant viruses in direct testing of "proof of principal" vaccination strategies.
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30
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Dai W, Jia Q, Bortz E, Shah S, Liu J, Atanasov I, Li X, Taylor KA, Sun R, Zhou ZH. Unique structures in a tumor herpesvirus revealed by cryo-electron tomography and microscopy. J Struct Biol 2007; 161:428-38. [PMID: 18096403 DOI: 10.1016/j.jsb.2007.10.010] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2007] [Revised: 10/12/2007] [Accepted: 10/13/2007] [Indexed: 11/17/2022]
Abstract
Gammaherpesviruses, including the human pathogens Epstein-Barr virus and Kaposi's sarcoma-associated herpesvirus, are causative agents of lymphomas and other malignancies. The structural characterization of these viruses has been limited due to difficulties in obtaining adequate amount of virion particles. Here we report the first three-dimensional structural characterization of a whole gammaherpesvirus virion by an emerging integrated approach of cryo-electron tomography combined with single-particle cryo-electron microscopy, using murine gammaherpesvirus-68 (MHV-68) as a model system. We found that the MHV-68 virion consists of distinctive envelope and tegument compartments, and a highly conserved nucleocapsid. Two layers of tegument are identified: an inner tegument layer tethered to the underlying capsid and an outer, flexible tegument layer conforming to the overlying, pleomorphic envelope, consistent with the sequential viral tegumentation process inside host cells. Surprisingly, comparison of the MHV-68 virion and capsid reconstructions shows that the interactions between the capsid and inner tegument proteins are completely different from those observed in alpha and betaherpesviruses. These observations support the notion that the inner layer tegument across different subfamilies of herpesviruses has evolved significantly to confer specific characteristics related to viral-host interactions, in contrast to a highly conserved capsid for genome encapsidation and protection.
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Affiliation(s)
- Wei Dai
- Department of Pathology and Laboratory Medicine, University of Texas Medical School at Houston, Houston, TX 77030, USA
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31
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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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32
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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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33
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Rosa GT, Gillet L, Smith CM, de Lima BD, Stevenson PG. IgG fc receptors provide an alternative infection route for murine gamma-herpesvirus-68. PLoS One 2007; 2:e560. [PMID: 17593961 PMCID: PMC1891442 DOI: 10.1371/journal.pone.0000560] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2007] [Accepted: 05/30/2007] [Indexed: 01/22/2023] Open
Abstract
Background Herpesviruses can be neutralized in vitro but remain infectious in immune hosts. One difference between these settings is the availability of immunoglobulin Fc receptors. The question therefore arises whether a herpesvirus exposed to apparently neutralizing antibody can still infect Fc receptor+ cells. Principal Findings Immune sera blocked murine gamma-herpesvirus-68 (MHV-68) infection of fibroblasts, but failed to block and even enhanced its infection of macrophages and dendritic cells. Viral glycoprotein-specific monoclonal antibodies also enhanced infection. MHV-68 appeared to be predominantly latent in macrophages regardless of whether Fc receptors were engaged, but the infection was not abortive and new virus production soon overwhelmed infected cultures. Lytically infected macrophages down-regulated MHC class I-restricted antigen presentation, endocytosis and their response to LPS. Conclusions IgG Fc receptors limit the neutralization of gamma-herpesviruses such as MHV-68.
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MESH Headings
- Animals
- Antibodies, Monoclonal/immunology
- Antibodies, Neutralizing/immunology
- Antigen Presentation
- Cells, Cultured
- Cytomegalovirus/genetics
- DNA, Viral/genetics
- Fibroblasts/immunology
- Fibroblasts/metabolism
- Fibroblasts/pathology
- Flow Cytometry
- Fluorescent Antibody Technique
- Glycoproteins/immunology
- Green Fluorescent Proteins/metabolism
- Herpesviridae Infections/immunology
- Herpesviridae Infections/metabolism
- Herpesviridae Infections/pathology
- Immediate-Early Proteins/genetics
- Macrophages, Peritoneal/immunology
- Macrophages, Peritoneal/metabolism
- Macrophages, Peritoneal/pathology
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Neutralization Tests
- Promoter Regions, Genetic/genetics
- Receptors, Fc/immunology
- Receptors, IgG/immunology
- Rhadinovirus/immunology
- Tumor Virus Infections/immunology
- Tumor Virus Infections/metabolism
- Tumor Virus Infections/pathology
- Virion/immunology
- Virus Replication
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Affiliation(s)
- Gustavo T. Rosa
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Laurent Gillet
- 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
| | - Brigitte D. de Lima
- 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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34
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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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35
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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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36
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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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37
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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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