1
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Sheng Q, Sun Y, Zhai R, Fan X, Ying Y, Liu Z, Kong X. Murine cytomegalovirus localization and uveitic cell infiltration might both contribute to trabecular meshwork impairment in Posner-Schlossman syndrome: Evidence from an open-angle rat model. Exp Eye Res 2023; 231:109477. [PMID: 37137438 DOI: 10.1016/j.exer.2023.109477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/22/2023] [Accepted: 04/16/2023] [Indexed: 05/05/2023]
Abstract
As a special type of glaucoma, Posner-Schlossman syndrome (PSS) is characterized by elevated intraocular pressure (IOP) and anterior uveitis. Cytomegalovirus (CMV) anterior chamber infection has now been considered the leading cause of PSS. We used murine CMV (MCMV) intracameral injection to establish a rat model manifested in IOP elevation and mild anterior uveitis, much like PSS; viral localization and gene expression at various time points and inflammatory cell infiltration derived from innate and adaptive immunity were investigated, as well as pathogenetic changes of the trabecular meshwork (TM). The IOP and uveitic manifestations peaked at 24 h post-infection (p.i.) and returned to normal after 96 h; the iridocorneal angle remained open consistently. At 24 h p.i., leucocytes gathered at the chamber angle. Maximum transcription of MCMV immediate early 1 (IE1) was reached at 24 h in the cornea and 48 h in the iris and ciliary body. MCMV localized in aqueous humor outflow facilities and the iris from 24 h to 28 d p.i. and was detected by in situ hybridization, though it did not transcribe after 7 d p.i. TM and iris pigment epithelial cells harboring viral inclusion bodies and autophagosomes were present at 28 d p.i. These findings shed light on how and where innate and adaptive immunity reacted after MCMV was found and transcribed in a highly ordered cascade, as well as pathogenetic changes in TM as a result of virus and uveitis behaviors.
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Affiliation(s)
- Qilian Sheng
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, 200031, China; National Health Commission Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, China; Shanghai Key Laboratory of Visual Impairment and Restoration, 83 Fenyang Rd., 200031, Shanghai, China
| | - Yanan Sun
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, 200031, China; National Health Commission Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, China; Shanghai Key Laboratory of Visual Impairment and Restoration, 83 Fenyang Rd., 200031, Shanghai, China
| | - Ruyi Zhai
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, 200031, China; National Health Commission Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, China; Shanghai Key Laboratory of Visual Impairment and Restoration, 83 Fenyang Rd., 200031, Shanghai, China
| | - Xintong Fan
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, 200031, China; National Health Commission Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, China; Shanghai Key Laboratory of Visual Impairment and Restoration, 83 Fenyang Rd., 200031, Shanghai, China
| | - Yue Ying
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, 200031, China; National Health Commission Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, China; Shanghai Key Laboratory of Visual Impairment and Restoration, 83 Fenyang Rd., 200031, Shanghai, China
| | - Zhijun Liu
- Department of Medical Microbiology, Weifang Medical University, Weifang, 261053, China.
| | - Xiangmei Kong
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, 200031, China; National Health Commission Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, China; Shanghai Key Laboratory of Visual Impairment and Restoration, 83 Fenyang Rd., 200031, Shanghai, China.
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2
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Štimac I, Jug Vučko N, Blagojević Zagorac G, Marcelić M, Mahmutefendić Lučin H, Lučin P. Dynamin Inhibitors Prevent the Establishment of the Cytomegalovirus Assembly Compartment in the Early Phase of Infection. Life (Basel) 2021; 11:876. [PMID: 34575026 PMCID: PMC8469281 DOI: 10.3390/life11090876] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/21/2021] [Accepted: 08/23/2021] [Indexed: 12/30/2022] Open
Abstract
Cytomegalovirus (CMV) infection initiates massive rearrangement of cytoplasmic organelles to generate assembly compartment (AC). The earliest events, the establishment of the preAC, are initiated in the early phase as an extensive reorganization of early endosomes (EEs), endosomal recycling compartment (ERC), trans-Golgi network (TGN), and the Golgi. Here, we demonstrate that dynamin inhibitors (Dynasore, Dyngo-4a, MiTMAB, and Dynole-34-2) block the establishment of the preAC in murine CMV (MCMV) infected cells. In this study, we extensively analyzed the effect of Dynasore on the Golgi reorganization sequence into the outer preAC. We also monitored the development of the inner preAC using a set of markers that define EEs (Rab5, Vps34, EEA1, and Hrs), the EE-ERC interface (Rab10), the ERC (Rab11, Arf6), three layers of the Golgi (GRASP65, GM130, Golgin97), and late endosomes (Lamp1). Dynasore inhibited the pericentriolar accumulation of all markers that display EE-ERC-TGN interface in the inner preAC and prevented Golgi unlinking and dislocation to the outer preAC. Furthermore, in pulse-chase experiments, we demonstrated that the presence of dynasore only during the early phase of MCMV infection (4-14 hpi) is sufficient to prevent not only AC formation but also the synthesis of late-phase proteins and virion production. Therefore, our results indicate that dynamin-2 acts as a part of the machinery required for AC generation and rearrangement of EE/ERC/Golgi membranes in the early phase of CMV infection.
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Affiliation(s)
- Igor Štimac
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia; (I.Š.); (N.J.V.); (G.B.Z.); (M.M.); (P.L.)
| | - Natalia Jug Vučko
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia; (I.Š.); (N.J.V.); (G.B.Z.); (M.M.); (P.L.)
| | - Gordana Blagojević Zagorac
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia; (I.Š.); (N.J.V.); (G.B.Z.); (M.M.); (P.L.)
- Nursing Department, University North, University Center Varaždin, Jurja Križanića 31b, 42000 Varaždin, Croatia
| | - Marina Marcelić
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia; (I.Š.); (N.J.V.); (G.B.Z.); (M.M.); (P.L.)
| | - Hana Mahmutefendić Lučin
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia; (I.Š.); (N.J.V.); (G.B.Z.); (M.M.); (P.L.)
- Nursing Department, University North, University Center Varaždin, Jurja Križanića 31b, 42000 Varaždin, Croatia
| | - Pero Lučin
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia; (I.Š.); (N.J.V.); (G.B.Z.); (M.M.); (P.L.)
- Nursing Department, University North, University Center Varaždin, Jurja Križanića 31b, 42000 Varaždin, Croatia
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Zhang LL, Zhang XY, Lu YY, Bi YD, Liu XL, Fang F. The Role of Autophagy in Murine Cytomegalovirus Hepatitis. Viral Immunol 2021; 34:241-255. [PMID: 33566740 DOI: 10.1089/vim.2020.0024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Autophagy is involved in the pathogenesis of multiple pathogen infection. Previous studies have reported that human cytomegalovirus (CMV) activates autophagy in the early stage of infection and then inhibits autophagy. Little is known about the role of autophagy in murine CMV (MCMV) infection, especially in MCMV-induced hepatitis. The purpose of this study is to investigate the role of autophagy in MCMV hepatitis. BALB/c mice were infected with MCMV and a series of experiments involving western blot, immunofluorescence, immunohistochemistry, H&E (Hematoxylin and Eosin) staining and quantitative real-time polymerase chain reaction were performed in this study. The expression of SQSTM1/p62, PI3K, the ratio of phosphorylated Akt to total Akt, and the ratio of phosphorylated mammalian target of rapamycin (mTOR) to total mTOR were increased, and the expression of light-chain 3 (LC3)-II were decreased in the livers of infected mice on days 3 and 7 postinfection (p.i.). Compared with the untreated infected group, increased transcription level of MCMV glycoprotein B (gB), increased expression levels of interleukin1-β (IL-1β), aspartate aminotransferase (AST) and alanine aminotransferase (ALT), decreased expression level of type I interferon α (IFN-α), as well as aggravated liver pathological injury were detected in starvation-treated infected group on days 3 and 7 p.i.; whereas decreased transcription level of MCMV gB, decreased expression levels of IL-1β, AST and ALT, increased expression level of type I IFN-α, as well as alleviated liver pathological injury were detected in chloroquine (CQ)-treated infected group on day 3 p.i. In conclusion, autophagy is inhibited through activating the PI3K/Akt/mTOR pathway in the liver of BALB/c mice during MCMV infection, and autophagy may promote MCMV replication and aggravate liver pathological damage and inflammation. Further understanding of the interactions between autophagy and MCMV infection and its potential mechanism may bring new important cues to the control of MCMV infection and antiviral therapy.
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Affiliation(s)
- Lin-Lin Zhang
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xin-Yan Zhang
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yuan-Yuan Lu
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yi-Dan Bi
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xing-Lou Liu
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Feng Fang
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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4
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Mouse Cytomegalovirus Differentially Exploits Cell Surface Glycosaminoglycans in a Cell Type-Dependent and MCK-2-Independent Manner. Viruses 2019; 12:v12010031. [PMID: 31892128 PMCID: PMC7019585 DOI: 10.3390/v12010031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 12/17/2019] [Accepted: 12/24/2019] [Indexed: 12/12/2022] Open
Abstract
Many viruses initiate interaction with target cells by binding to cell surface glycosaminoglycans (GAGs). Heparan sulfate (HS) appears to be particularly important in fibroblasts, epithelial cells and endothelial cells, where it represents the dominant GAG. How GAGs influence viral infectivity in HS-poor target cells such as macrophages has not been clearly defined. Here, we show that mouse cytomegalovirus (MCMV) targets HS in susceptible fibroblasts and cultured salivary gland acinar cells (SGACs), but not in macrophage cell lines and primary bone marrow-derived macrophages, where chondroitin sulfate was the dominant virus-binding GAG. MCK-2, an MCMV-encoded GAG-binding chemokine that promotes infection of macrophages as part of a gH/gL/MCK-2 entry complex, was dispensable for MCMV attachment to the cell surface and for direct infection of SGACs. Thus, MCMV tropism for target cells is markedly influenced by differential GAG expression, suggesting that the specificity of anti-GAG peptides now under development as HCMV therapeutics may need to be broadened for effective application as anti-viral agents.
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5
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Čížková D, Baird SJE, Těšíková J, Voigt S, Ľudovít Ď, Piálek J, Goüy de Bellocq J. Host subspecific viral strains in European house mice: Murine cytomegalovirus in the Eastern (Mus musculus musculus) and Western house mouse (Mus musculus domesticus). Virology 2018; 521:92-98. [PMID: 29894896 DOI: 10.1016/j.virol.2018.05.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 05/27/2018] [Accepted: 05/28/2018] [Indexed: 01/14/2023]
Abstract
Murine cytomegalovirus (MCMV) has been reported from house mice (Mus musculus) worldwide, but only recently from Eastern house mice (M. m. musculus), of particular interest because they form a semi-permeable species barrier in Europe with Western house mice, M. m. domesticus. Here we report genome sequences of EastMCMV (from Eastern mice), and set these in the context of MCMV genomes from genus Mus hosts. We show EastMCMV and WestMCMV are genetically distinct. Phylogeny splitting analyses show a genome wide (94%) pattern consistent with no West-East introgression, the major exception (3.8%) being a genome-terminal region of duplicated genes involved in host immune system evasion. As expected from its function, this is a region of maintenance of ancestral polymorphism: The lack of clear splitting signal cannot be interpreted as evidence of introgression. The EastMCMV genome sequences reported here can therefore serve as a well-described resource for exploration of murid MCMV diversity.
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Affiliation(s)
- Dagmar Čížková
- Institute of Vertebrate Biology of the Czech Academy of Sciences, Brno, Czech Republic.
| | - Stuart J E Baird
- Institute of Vertebrate Biology of the Czech Academy of Sciences, Brno, Czech Republic
| | - Jana Těšíková
- Institute of Vertebrate Biology of the Czech Academy of Sciences, Brno, Czech Republic; Department of Botany and Zoology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Sebastian Voigt
- Department of Pediatric Oncology/Hematology/Stem Cell Transplantation, Charité-Universitätsmedizin, Berlin, Germany; Department of Infectious Diseases, Robert Koch Institute, Berlin, Germany
| | - Ďureje Ľudovít
- Institute of Vertebrate Biology of the Czech Academy of Sciences, Brno, Czech Republic
| | - Jaroslav Piálek
- Institute of Vertebrate Biology of the Czech Academy of Sciences, Brno, Czech Republic
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Le-Trilling VTK, Trilling M. Mouse newborn cells allow highly productive mouse cytomegalovirus replication, constituting a novel convenient primary cell culture system. PLoS One 2017; 12:e0174695. [PMID: 28339479 PMCID: PMC5365124 DOI: 10.1371/journal.pone.0174695] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 03/13/2017] [Indexed: 12/13/2022] Open
Abstract
Mammalian cell culture is indispensable for most aspects of current biomedical research. Immortalized cell lines are very convenient, but transforming principles (e.g. oncogenic viruses or their oncogenes) can heavily influence the experimental outcome. Primary cells do not share this apparent disadvantage but are more laborious to generate. Certain viruses (e.g. mouse cytomegalovirus) do not replicate efficiently in most transformed cell lines. In the past, such viruses have been routinely propagated on primary mouse embryonic fibroblasts (MEF) established around day 17 (d17) of gestation. According to new regulations of the European Union, experiments using gravid mammals and/or their embryos in the last trimester (>d14 in the case of mice) of gestation do require explicit permission of the local authorities responsible for animal care and use. Applying for such permission is time-consuming and often inflexible. Embryonic fibroblasts could also be produced at earlier time points of pregnancy from younger and smaller embryos. Obviously, this approach consumes more pregnant mice and embryos. Newborn mice are larger thus yielding more cells per sacrificed animal and the new Directive (2010/63/EU) excludes the killing of animals solely for the use of their organs or tissues. We established a convenient protocol to generate adherent mouse newborn cells (MNC). A direct comparison of MNC with MEF revealed that MNC fully recapitulate all tested aspects of a broad panel of virological parameters (plaque size, final titers, viral replication kinetics, viral gene expression, drug and interferon susceptibility as well as species specificity). The herein described approach allows researchers the legal use of primary cells and contributes to the 3R (replace, reduce, refine) guiding principles-especially the 'reduce' aspect-for the use of animals in scientific research. Additionally, it offers the option to directly compare in vitro and in vivo experiments when MNC are generated from littermates of animals included in the in vivo experiments.
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Affiliation(s)
- Vu Thuy Khanh Le-Trilling
- Institute for Virology, University Hospital Essen, University Duisburg-Essen, Essen, Germany
- * E-mail: (MT); (VTKL-T)
| | - Mirko Trilling
- Institute for Virology, University Hospital Essen, University Duisburg-Essen, Essen, Germany
- * E-mail: (MT); (VTKL-T)
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Peggs KS. Cytomegalovirus following stem cell transplantation: from pharmacologic to immunologic therapy. Expert Rev Anti Infect Ther 2014; 2:559-73. [PMID: 15482220 DOI: 10.1586/14787210.2.4.559] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Human cytomegalovirus is a large DNA virus that is well-equipped to evade both innate and adaptive host immune responses and to establish lifelong latency. It is a major opportunistic pathogen in immunocompromised hosts. Following allogeneic transplantation, immune responses are often inadequate to inhibit viral reactivation, resulting in progressive tissue damage, manifesting as overt human cytomegalovirus disease that usually presents as pneumonitis, colitis or hepatitis. Currently available antiviral pharmacotherapies are limited by toxicities if used prophylactically, and by a lack of efficacy in established human cytomegalovirus disease. Efforts have therefore focused on molecular diagnostic surveillance protocols that allow earlier intervention and the development of adoptive immunotherapeutic strategies to hasten host immune reconstitution.
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Affiliation(s)
- Karl S Peggs
- Department of Hematology, Royal Free and University College London Medical School, 98 Chenies Mews, London, WC1E 6HX, UK.
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Tsen SWD, Chapa T, Beatty W, Tsen KT, Yu D, Achilefu S. Inactivation of enveloped virus by laser-driven protein aggregation. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:128002. [PMID: 23224114 PMCID: PMC3518210 DOI: 10.1117/1.jbo.17.12.128002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Ultrafast lasers in the visible and near-infrared range have emerged as a potential new method for pathogen reduction of blood products and pharmaceuticals. However, the mechanism of enveloped virus inactivation by this method is unknown. We report the inactivation as well as the molecular and structural effects caused by visible (425 nm) femtosecond laser irradiation on murine cytomegalovirus (MCMV), an enveloped, double-stranded DNA virus. Our results show that laser irradiation (1) caused a 5-log reduction in MCMV titer, (2) did not cause significant changes to the global structure of MCMV virions including membrane and capsid, as assessed by electron microscopy, (3) produced no evidence of double-strand breaks or crosslinking in MCMV genomic DNA, and (4) caused selective aggregation of viral capsid and tegument proteins. We propose a model in which ultrafast laser irradiation induces partial unfolding of viral proteins by disrupting hydrogen bonds and/or hydrophobic interactions, leading to aggregation of closely associated viral proteins and inactivation of the virus. These results provide new insight into the inactivation of enveloped viruses by visible femtosecond lasers at the molecular level, and help pave the way for the development of a new ultrafast laser technology for pathogen reduction.
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Affiliation(s)
- Shaw-Wei D. Tsen
- Washington University School of Medicine, Department of Radiology, St. Louis, Missouri 63110
| | - Travis Chapa
- Washington University School of Medicine, Department of Molecular Microbiology, St. Louis, Missouri 63110
| | - Wandy Beatty
- Washington University School of Medicine, Department of Molecular Microbiology, St. Louis, Missouri 63110
| | - Kong-Thon Tsen
- Arizona State University, Department of Physics, Tempe, Arizona 85287
- Arizona State University, Center for Biophysics, Tempe, Arizona 85287
- Address correspondence to: Samuel Achilefu, Washington University School of Medicine, Department of Radiology, St. Louis, Missouri 63110. Tel: 314-362-8599; Fax: 314-747-5191; E-mail: , or Kong-Thon Tsen, Arizona State University, Department of Physics, Tempe, Arizona 85287. Tel: 480-965-5206; Fax: 480-965-7954;
| | - Dong Yu
- Washington University School of Medicine, Department of Molecular Microbiology, St. Louis, Missouri 63110
| | - Samuel Achilefu
- Washington University School of Medicine, Department of Radiology, St. Louis, Missouri 63110
- Washington University School of Medicine, Department of Biochemistry and Molecular Biophysics, St. Louis, Missouri 63110
- Washington University School of Medicine, Department of Biomedical Engineering, St. Louis, Missouri 63110
- Address correspondence to: Samuel Achilefu, Washington University School of Medicine, Department of Radiology, St. Louis, Missouri 63110. Tel: 314-362-8599; Fax: 314-747-5191; E-mail: , or Kong-Thon Tsen, Arizona State University, Department of Physics, Tempe, Arizona 85287. Tel: 480-965-5206; Fax: 480-965-7954;
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9
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Schröer D, Veits J, Keil G, Römer-Oberdörfer A, Weber S, Mettenleiter TC. Efficacy of Newcastle disease virus recombinant expressing avian influenza virus H6 hemagglutinin against Newcastle disease and low pathogenic avian influenza in chickens and turkeys. Avian Dis 2011; 55:201-11. [PMID: 21793434 DOI: 10.1637/9539-092710-reg.1] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
A recombinant Newcastle disease virus (NDV) expressing H6 hemagglutinin (HA) of a low pathogenic avian influenza virus (LPAIV) was generated by reverse genetics (NDVH6). The H6 open reading frame was inserted as an additional transcription unit between the fusion and hemagglutinin-neuraminidase (HN) gene of lentogenic NDV clone 30. Expression of the foreign gene was demonstrated by northern blot, western blot, and indirect immunofluorescence analyses. The protective efficacy against Newcastle disease and avian influenza of subtype H6 was evaluated in 3-wk-old chickens and turkeys. A single vaccination protected specific-pathogen-free (SPF) chickens against a subsequent lethal NDV infection and prevented shedding of AIV after homologous H6 LPAIV infection. Furthermore, vaccinated and AIV-infected animals could be differentiated by detection of AIV nucleoprotein-specific antibodies. Three-week-old commercial turkeys, exhibiting NDV-specific maternal antibodies, were partially protected against a lethal NDV challenge infection. The mortality rate of NDVH6-immunized turkeys was reduced to 40% compared to 90% in unvaccinated birds. After H6 LPAIV infection, shedding in NDVH6-immunized turkeys was only marginally reduced compared to NDV-immunized control birds. We previously described HA-expressing NDV recombinants as potent bivalent vaccines against Newcastle disease and highly pathogenic avian influenza of subtype H5 or H7. The results presented here are in contrast to the high protective efficacy in SPF chickens, as a single vaccination with NDVH6 was insufficient in turkeys in the presence of maternal antibodies against NDV. Therefore, the vector virus has to be improved to overcome these limitations.
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Affiliation(s)
- Diana Schröer
- Institute of Molecular Biology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, D-17493 Greifswald-Insel Riems, Germany
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10
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Lacaze P, Forster T, Ross A, Kerr LE, Salvo-Chirnside E, Lisnic VJ, López-Campos GH, García-Ramírez JJ, Messerle M, Trgovcich J, Angulo A, Ghazal P. Temporal profiling of the coding and noncoding murine cytomegalovirus transcriptomes. J Virol 2011; 85:6065-76. [PMID: 21471238 PMCID: PMC3126304 DOI: 10.1128/jvi.02341-10] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Accepted: 03/28/2011] [Indexed: 12/20/2022] Open
Abstract
The global transcriptional program of murine cytomegalovirus (MCMV), involving coding, noncoding, and antisense transcription, remains unknown. Here we report an oligonucleotide custom microarray platform capable of measuring both coding and noncoding transcription on a genome-wide scale. By profiling MCMV wild-type and immediate-early mutant strains in fibroblasts, we found rapid activation of the transcriptome by 6.5 h postinfection, with absolute dependency on ie3, but not ie1 or ie2, for genomic programming of viral gene expression. Evidence is also presented to show, for the first time, genome-wide noncoding and bidirectional transcription at late stages of MCMV infection.
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Affiliation(s)
- Paul Lacaze
- Division of Pathway Medicine, The University of Edinburgh, The Chancellor's Building, College of Medicine, 49 Little France Crescent, Edinburgh, United Kingdom
| | - Thorsten Forster
- Division of Pathway Medicine, The University of Edinburgh, The Chancellor's Building, College of Medicine, 49 Little France Crescent, Edinburgh, United Kingdom
| | - Alan Ross
- Division of Pathway Medicine, The University of Edinburgh, The Chancellor's Building, College of Medicine, 49 Little France Crescent, Edinburgh, United Kingdom
| | - Lorraine E. Kerr
- Centre for Systems Biology at Edinburgh, The University of Edinburgh, Darwin Building, King's Buildings Campus, Mayfield Road, Edinburgh, United Kingdom
| | - Eliane Salvo-Chirnside
- Centre for Systems Biology at Edinburgh, The University of Edinburgh, Darwin Building, King's Buildings Campus, Mayfield Road, Edinburgh, United Kingdom
| | - Vanda Juranic Lisnic
- Department of Histology and Embryology, Faculty of Medicine, Rijeka University, Croatia
| | | | - José J. García-Ramírez
- Department of Inorganic and Organic Chemistry and Biochemistry, Medical School, Regional Center for Biomedical Research, University of Castilla—La Mancha, Avenida de Almansa 14, 02006 Albacete, Spain
| | - Martin Messerle
- Department of Virology, Hannover Medical School, Hannover, Germany
| | - Joanne Trgovcich
- Department of Pathology, The Ohio State University, Columbus, Ohio 43210
| | - Ana Angulo
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Peter Ghazal
- Division of Pathway Medicine, The University of Edinburgh, The Chancellor's Building, College of Medicine, 49 Little France Crescent, Edinburgh, United Kingdom
- Centre for Systems Biology at Edinburgh, The University of Edinburgh, Darwin Building, King's Buildings Campus, Mayfield Road, Edinburgh, United Kingdom
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11
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Human cytomegalovirus immunity and immune evasion. Virus Res 2010; 157:151-60. [PMID: 21056604 DOI: 10.1016/j.virusres.2010.10.031] [Citation(s) in RCA: 193] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Revised: 10/27/2010] [Accepted: 10/28/2010] [Indexed: 02/02/2023]
Abstract
Human cytomegalovirus (HCMV) infection induces both innate immune responses including Natural Killer cells as well as adaptive humoral and cell mediated (CD4+ helper, CD8+ cytotoxic and γδ T cell) responses which lead to the resolution of acute primary infection. Despite such a robust primary immune response, HCMV is still able to establish latency. Long term memory T cell responses are maintained at high frequency and are thought to prevent clinical disease following periodic reactivation of the virus. As such, a balance is established between the immune response and viral reactivation. Loss of this balance in the immunocompromised host can lead to unchecked viral replication following reactivation of latent virus, with consequent disease and mortality. HCMV encodes multiple immune evasion mechanisms that target both the innate and acquired immune system. This article describes the current understanding of Natural killer cell, antibody and T cell mediated immune responses and the mechanisms that the virus utilizes to subvert these responses.
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The m74 gene product of murine cytomegalovirus (MCMV) is a functional homolog of human CMV gO and determines the entry pathway of MCMV. J Virol 2010; 84:4469-80. [PMID: 20181688 DOI: 10.1128/jvi.02441-09] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The glycoprotein gO (UL74) of human cytomegalovirus (HCMV) forms a complex with gH/gL. Virus mutants with a deletion of gO show a defect in secondary envelopment with the consequence that virus spread is restricted to a cell-associated pathway. Here we report that the positional homolog of HCMV gO, m74 of mouse CMV (MCMV), codes for a glycosylated protein which also forms a complex with gH (M75). m74 knockout mutants of MCMV show the same spread phenotype as gO knockout mutants of HCMV, namely, a shift from supernatant-driven to cell-associated spread. We could show that this phenotype is due to a reduction of infectious virus particles in cell culture supernatants. m74 knockout mutants enter fibroblasts via an energy-dependent and pH-sensitive pathway, whereas in the presence of an intact m74 gene product, entry is neither energy dependent nor pH sensitive. This entry phenotype is shared by HCMV expressing or lacking gO. Our data indicate that the m74 and UL74 gene products both codetermine CMV spread and CMV entry into cells. We postulate that MCMV, like HCMV, expresses alternative gH/gL complexes which govern cell-to-cell spread of the virus.
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13
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Abstract
Cytomegalovirus (CMV) infection in patients receiving hematopoietic stem cell transplants (HSCT) is associated with morbidity and mortality. Adoptive T cell immunotherapy has been used to treat viral reactivation but is hardly feasible in high-risk constellations of CMV-positive HSCT patients and CMV-negative stem cell donors. We endowed human effector T cells with a chimeric immunoreceptor (cIR) directed against CMV glycoprotein B. These cIR-engineered primary T cells mediated antiviral effector functions such as cytokine production and cytolysis. This first description of cIR-redirected CMV-specific T cells opens up a new perspective for HLA-independent immunotherapy of CMV infection in high-risk patients.
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15
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Systematic review: cytomegalovirus infection in inflammatory bowel disease. J Gastroenterol 2009; 43:735-40. [PMID: 18958541 DOI: 10.1007/s00535-008-2246-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Accepted: 07/01/2008] [Indexed: 02/04/2023]
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16
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Pavlova SP, Veits J, Keil GM, Mettenleiter TC, Fuchs W. Protection of chickens against H5N1 highly pathogenic avian influenza virus infection by live vaccination with infectious laryngotracheitis virus recombinants expressing H5 hemagglutinin and N1 neuraminidase. Vaccine 2008; 27:773-85. [PMID: 19041677 DOI: 10.1016/j.vaccine.2008.11.033] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2008] [Revised: 10/20/2008] [Accepted: 11/03/2008] [Indexed: 11/18/2022]
Abstract
Attenuated vaccine strains of the alphaherpesvirus causing infectious laryngotracheitis of chickens (ILTV, gallid herpesvirus 1) can be used for mass application. Previously, we showed that live virus vaccination with recombinant ILTV expressing hemagglutinin of highly pathogenic avian influenza viruses (HPAIV) protected chickens against ILT and fowl plague caused by HPAIV carrying the corresponding hemagglutinin subtypes [Lüschow D, Werner O, Mettenleiter TC, Fuchs W. Protection of chickens from lethal avian influenza A virus infection by live-virus vaccination with infectious laryngotracheitis virus recombinants expressing the hemagglutinin (H5) gene. Vaccine 2001;19(30):4249-59; Veits J, Lüschow D, Kindermann K, Werner O, Teifke JP, Mettenleiter TC, et al. Deletion of the non-essential UL0 gene of infectious laryngotracheitis (ILT) virus leads to attenuation in chickens, and UL0 mutants expressing influenza virus haemagglutinin (H7) protect against ILT and fowl plague. J Gen Virol 2003;84(12):3343-52]. However, protection against H5N1 HPAIV was not satisfactory. Therefore, a newly designed dUTPase-negative ILTV vector was used for rapid insertion of the H5-hemagglutinin, or N1-neuraminidase genes of a recent H5N1 HPAIV isolate. Compared to our previous constructs, protein expression was considerably enhanced by insertion of synthetic introns downstream of the human cytomegalovirus immediate-early promoter within the 5'-nontranslated region of the transgenes. Deletion of the viral dUTPase gene did not affect in vitro replication of the ILTV recombinants, but led to sufficient attenuation in vivo. After a single ocular immunization, all chickens developed H5- or N1-specific serum antibodies. Nevertheless, animals immunized with N1-ILTV died after subsequent H5N1 HPAIV challenge, although survival times were prolonged compared to non-vaccinated controls. In contrast, all chickens vaccinated with either H5-ILTV alone, or H5- and N1-ILTV simultaneously, survived without showing any clinical signs. Real-time RT-PCR indicated limited challenge virus replication after vaccination with H5-ILTV only, which was completely blocked after coimmunization with N1-ILTV. Thus, chickens can be protected from H5N1 HPAIV-induced disease by live vaccination with an attenuated hemagglutinin-expressing ILTV recombinant, and efficacy can be further increased by coadministration of an ILTV mutant expressing neuraminidase. Furthermore, chickens vaccinated with ILTV vectors can be easily differentiated from influenza virus-infected animals by the absence of serum antibodies against the AIV nucleoprotein.
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Affiliation(s)
- Sophia P Pavlova
- Institute of Molecular Biology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
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17
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Britt W. Manifestations of human cytomegalovirus infection: proposed mechanisms of acute and chronic disease. Curr Top Microbiol Immunol 2008; 325:417-70. [PMID: 18637519 DOI: 10.1007/978-3-540-77349-8_23] [Citation(s) in RCA: 232] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Infections with human cytomegalovirus (HCMV) are a major cause of morbidity and mortality in humans with acquired or developmental deficits in innate and adaptive immunity. In the normal immunocompetent host, symptoms rarely accompany acute infections, although prolonged virus shedding is frequent. Virus persistence is established in all infected individuals and appears to be maintained by both a chronic productive infections as well as latency with restricted viral gene expression. The contributions of the each of these mechanisms to the persistence of this virus in the individual is unknown but frequent virus shedding into the saliva and genitourinary tract likely accounts for the near universal incidence of infection in most populations in the world. The pathogenesis of disease associated with acute HCMV infection is most readily attributable to lytic virus replication and end organ damage either secondary to virus replication and cell death or from host immunological responses that target virus-infected cells. Antiviral agents limit the severity of disease associated with acute HCMV infections, suggesting a requirement for virus replication in clinical syndromes associated with acute infection. End organ disease secondary to unchecked virus replication can be observed in infants infected in utero, allograft recipients receiving potent immunosuppressive agents, and patients with HIV infections that exhibit a loss of adaptive immune function. In contrast, diseases associated with chronic or persistent infections appear in normal individuals and in the allografts of the transplant recipient. The manifestations of these infections appear related to chronic inflammation, but it is unclear if poorly controlled virus replication is necessary for the different phenotypic expressions of disease that are reported in these patients. Although the relationship between HCMV infection and chronic allograft rejection is well known, the mechanisms that account for the role of this virus in graft loss are not well understood. However, the capacity of this virus to persist in the midst of intense inflammation suggests that its persistence could serve as a trigger for the induction of host-vs-graft responses or alternatively host responses to HCMV could contribute to the inflammatory milieu characteristic of chronic allograft rejection.
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Affiliation(s)
- W Britt
- Department of Pediatrics, University of Alabama School of Medicine, Childrens Hospital, Harbor Bldg. 104, 1600 7th Ave. South Birmingham, AL 35233, USA.
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18
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Hossain MS, Roback JD, Wang F, Waller EK. Host and donor immune responses contribute to antiviral effects of amotosalen-treated donor lymphocytes following early posttransplant cytomegalovirus infection. THE JOURNAL OF IMMUNOLOGY 2008; 180:6892-902. [PMID: 18453610 DOI: 10.4049/jimmunol.180.10.6892] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We have previously shown that amotosalen-treated splenocytes rescued allorecipients from a lethal dose of mouse CMV (MCMV) administered on day 0 in experimental parent C57BL/6-->CB6F1 allogeneic bone marrow transplant. In this study, we investigated the mechanism of antiviral activity of amotosalen-treated donor splenocytes when sublethal MCMV infections were administered 7 days posttransplant. Recipients of 3 x 10(6) untreated splenocytes were used as control. Following MCMV infection, recipients of untreated splenocytes had 40% early mortality due to acute graft-vs-host disease compared with no deaths among recipients of 10 x 10(6) treated splenocytes. However, recipients of both types of donor splenocytes effectively cleared MCMV from their liver. Like the untreated CD8(+) T cells, amotosalen-treated CD8(+) T cells equally retained their in vivo CTL activity against MCMV early peptide-pulsed targets and expressed similar levels of granzyme B within 11 days of infection. In contrast to full donor chimerism in recipients of untreated splenocytes, recipients of amotosalen-treated splenocytes showed mixed chimerism with both donor spleen- and host-derived anti-MCMV CD8(+) T cells in their blood and lymphoid organs, with significantly higher numbers of host-derived CD4(-)CD8(-) (double negative) T cells in the spleens of recipients of treated splenocytes compared with the recipients of untreated splenocytes. Additionally, recipients of amotosalen-treated splenocytes had lower levels of serum IFN-gamma and TNF-alpha in response to MCMV infection compared with untreated recipients. Thus, adoptive immunotherapy with treated T cells is a novel therapeutic approach that facilitates hematopoietic engraftment and permits antiviral immunity of both donor and host T cells without graft-vs-host disease.
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Affiliation(s)
- Mohammad S Hossain
- Department of Hematology and Oncology, Division of Stem Cell and Bone Marrow Transplantation, Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA 30322, USA
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19
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Abstract
Murine cytomegalovirus (MCMV) is a well-studied model of natural beta-herpesvirus infection. However, many questions remain regarding its control by and evasion of the immune response it generates. CD8 and CD4 T cells have both unique and redundant roles in control of the virus that differ based on the immunocompetence of the infected mice. MCMV encodes major histocompatibility complex (MHC) class I immune evasion genes that can have an impact in vitro, but their role in infection of immunocompetent mice has been difficult to identify. This review addresses the evidence for their in vivo function and suggests why they may be evolutionarily conserved.
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Affiliation(s)
- Carmen M Doom
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA
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20
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Wilson SR, Wilson JH, Buonocore L, Palin A, Rose JK, Reuter JD. Intranasal immunization with recombinant vesicular stomatitis virus expressing murine cytomegalovirus glycoprotein B induces humoral and cellular immunity. Comp Med 2008; 58:129-139. [PMID: 18524170 PMCID: PMC2703170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Revised: 11/10/2007] [Accepted: 11/29/2007] [Indexed: 05/26/2023]
Abstract
Cytomegalovirus is a leading cause of morbidity and mortality among neonatal and immunocompromised patients. The use of vaccine prophylaxis continues to be an effective approach to reducing viral infections and their associated diseases. Murine cytomegalovirus (mCMV) has proven to be a valuable animal model in determining the efficacy of newly developed vaccine strategies in vivo. Live recombinant vesicular stomatitis viruses (rVSV) have successfully been used as vaccine vectors for several viruses to induce strong humoral and cellular immunity. We tested the ability of intranasal immunization with an rVSV expressing the major envelope protein of mCMV, glycoprotein B (gB), to protect against challenge with mCMV in a mouse model. rVSV-gB-infected cells showed strong cytoplasmic and cell surface expression of gB, and neutralizing antibodies to gB were present in mice after a single intranasal vaccination of VSV-gB. After challenge with mCMV, recovery of live virus and viral DNA was significantly reduced in immunized mice. In addition, primed splenocytes produced a CD8+ IFNgamma response to gB. The ability to induce an immune response to a gene product through mucosal vaccination with rVSV-gB represents a potentially effective approach to limiting CMV-induced disease.
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Affiliation(s)
- Steven R Wilson
- Section of Comparative Medicine, Yale University School of Medicine, New Haven, CT, USA.
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21
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Mouse cytomegalovirus microRNAs dominate the cellular small RNA profile during lytic infection and show features of posttranscriptional regulation. J Virol 2007; 81:13771-82. [PMID: 17942535 DOI: 10.1128/jvi.01313-07] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
MicroRNAs (miRNAs) are small, noncoding RNA molecules that regulate gene expression at the posttranscriptional level. Originally identified in a variety of organisms ranging from plants to mammals, miRNAs have recently been identified in several viruses. Viral miRNAs may play a role in modulating both viral and host gene expression. Here, we report on the identification and characterization of 18 viral miRNAs from mouse fibroblasts lytically infected with the murine cytomegalovirus (MCMV). The MCMV miRNAs are expressed at early times of infection and are scattered in small clusters throughout the genome with up to four distinct miRNAs processed from a single transcript. No significant homologies to human CMV-encoded miRNAs were found. Remarkably, as soon as 24 h after infection, MCMV miRNAs constituted about 35% of the total miRNA pool, and at 72 h postinfection, this proportion was increased to more than 60%. However, despite the abundance of viral miRNAs during the early phase of infection, the expression of some MCMV miRNAs appeared to be regulated. Hence, for three miRNAs we observed polyuridylation of their 3' end, coupled to subsequent degradation. Individual knockout mutants of two of the most abundant MCMV miRNAs, miR-m01-4 and miR-M44-1, or a double knockout mutant of miR-m21-1 and miR-M23-2, incurred no or only a very mild growth deficit in murine embryonic fibroblasts in vitro.
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22
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Wang X, Zhang X, Chen S, Zhu G, Ai J. The effects of murine cytomegalovirus on the maturation, fertilization, cleavage and blastula formation of mouse oocytes in vitro. JOURNAL OF HUAZHONG UNIVERSITY OF SCIENCE AND TECHNOLOGY. MEDICAL SCIENCES = HUA ZHONG KE JI DA XUE XUE BAO. YI XUE YING DE WEN BAN = HUAZHONG KEJI DAXUE XUEBAO. YIXUE YINGDEWEN BAN 2007; 27:468-70. [PMID: 17828514 DOI: 10.1007/s11596-007-0431-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2006] [Indexed: 10/22/2022]
Abstract
To study the effects of mouse cytomegalovirus (MCMV) on the in vitro maturation, fertilization, cleavage and blastula formation of mouse oocytes, the immature oocytes were infected in vitro by MCMVs of different dosages (100 TCID(50), 10 TCID(50) and 1 TCID(50)). The oocytes were then observed for in vitro maturation, fertilization, cleavage and blastula formation and the ultrastructural changes after the culture with the viruses. Our results showed that no significant differences were found in IVM, IVF, cleavage and blastula formation among the groups treated with of virus of various dosages. And ultrastructural abnormality was observed in the oocytes treated by 100 TCID(50) of viruses. It is concluded that MCMV did not have any conspicuous effects on IVM, IVF, cleavage and blastula formation of murine immature oocytes.
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Affiliation(s)
- Xinrong Wang
- Department of Gynecology & Obstetrics, Huazhong University of Science and Technology, Wuhan 430030, China.
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23
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Abstract
Human cytomegalovirus (HCMV) disease is a major cause of morbidity and mortality in neonates and immunocompromised populations, such as transplant recipients and HIV-infected patients. The development of a vaccine to prevent HCMV infection or disease has been assigned the highest priority by the US Institute of Medicine. Although, after 30 years of intensive study, a clinically licensed vaccine is still not available, significant progress has been made in the field of HCMV vaccine development, along with greater understanding of HCMV immunology, molecular biology and pathology. In recent years, new vaccine strategies have been developed that have shown promising results in preclinical studies and are able to induce HCMV-specific immune responses in clinical studies, although efficacy data are not yet available. Here we review the history of HCMV vaccine development and the current strategies in the development of new HCMV vaccines. We propose that research should focus on the development of a vaccine to prevent or control HCMV-related disease rather than to prevent infection, and that discerning strategies should be used for targeting HCMV disease in different clinical settings.
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Affiliation(s)
- Jie Zhong
- Australian Centre for Vaccine Development, Queensland Institute of Medical Research, Tumour Immunology Laboratory, Division of Infectious Diseases and Immunology, Brisbane, Australia
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24
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Valchanova RS, Picard-Maureau M, Budt M, Brune W. Murine cytomegalovirus m142 and m143 are both required to block protein kinase R-mediated shutdown of protein synthesis. J Virol 2006; 80:10181-90. [PMID: 17005695 PMCID: PMC1617306 DOI: 10.1128/jvi.00908-06] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2006] [Accepted: 07/21/2006] [Indexed: 11/20/2022] Open
Abstract
Cytomegaloviruses carry the US22 family of genes, which have common sequence motifs but diverse functions. Only two of the 12 US22 family genes of murine cytomegalovirus (MCMV) are essential for virus replication, but their functions have remained unknown. In the present study, we deleted the essential US22 family genes, m142 and m143, from the MCMV genome and propagated the mutant viruses on complementing cells. The m142 and the m143 deletion mutants were both unable to replicate in noncomplementing cells at low and high multiplicities of infection. In cells infected with the deletion mutants, viral immediate-early and early proteins were expressed, but viral DNA replication and synthesis of the late-gene product glycoprotein B were inhibited, even though mRNAs of late genes were present. Global protein synthesis was impaired in these cells, which correlated with phosphorylation of the double-stranded RNA-dependent protein kinase R (PKR) and its target protein, the eukaryotic translation initiation factor 2alpha, suggesting that m142 and m143 are necessary to block the PKR-mediated shutdown of protein synthesis. Replication of the m142 and m143 knockout mutants was partially restored by expression of the human cytomegalovirus TRS1 gene, a known double-stranded-RNA-binding protein that inhibits PKR activation. These results indicate that m142 and m143 are both required for inhibition of the PKR-mediated host antiviral response.
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Affiliation(s)
- Ralitsa S Valchanova
- Robert Koch-Institut, Fachgebiet Virale Infektionen, Nordufer 20, 13353 Berlin, Germany
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25
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Schleiss MR, Heineman TC. Progress toward an elusive goal: current status of cytomegalovirus vaccines. Expert Rev Vaccines 2006; 4:381-406. [PMID: 16026251 DOI: 10.1586/14760584.4.3.381] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Although infection with human cytomegalovirus (CMV) is ubiquitous and generally asymptomatic in most individuals, certain patient populations are at high risk for CMV-associated disease. These include HIV-infected individuals with AIDS, transplant patients, and newborn infants with congenital CMV infection. Immunity to CMV infection, both in the transplant setting and among women of childbearing age, plays a vital role in the control of CMV-induced injury and disease. Although immunity induced by CMV infection is not completely protective against reinfection, there is nevertheless a sound basis on which to believe that vaccination could help control CMV disease in high-risk patient populations. Evidence from several animal models of CMV infection indicates that a variety of vaccine strategies are capable of inducing immune responses sufficient to protect against CMV-associated illness following viral challenge. Vaccination has also proven effective in improving pregnancy outcomes following CMV challenge of pregnant guinea pigs, providing a 'proof-of-principle' relevant to human clinical trials of CMV vaccines. Although there are no licensed vaccines currently available for human CMV, progress toward this goal has been made, as evidenced by ongoing clinical trial testing of a number of immunization strategies. CMV vaccines currently in various stages of preclinical and clinical testing include: protein subunit vaccines; DNA vaccines; vectored vaccines using viral vectors, such as attenuated pox- and alphaviruses; peptide vaccines; and live attenuated vaccines. This review summarizes some of the obstacles that must be overcome in development of a CMV vaccine, and provides an overview of the current state of preclinical and clinical trial evaluation of vaccines for this important public health problem.
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Affiliation(s)
- Mark R Schleiss
- University of Minnesota School of Medicine, 420 Delaware Street SE, MMC 296, Minneapolis, MN 55455, USA.
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26
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Rouvio O, Dvorkin T, Amir-Kroll H, Atias D, Cohen IR, Rager-Zisman B, Porgador A. Self HSP60 peptide serves as an immunogenic carrier for a CTL epitope against persistence of murine cytomegalovirus in the salivary gland. Vaccine 2005; 23:3508-18. [PMID: 15855009 DOI: 10.1016/j.vaccine.2005.02.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2004] [Revised: 12/20/2004] [Accepted: 02/01/2005] [Indexed: 01/25/2023]
Abstract
Murine cytomegalovirus (MCMV) infection is associated with persistence of virus in the salivary glands, despite relatively rapid clearance of virus from the spleen. An effective immunization against MCMV should prevent such viral persistence. We previously reported that a peptide (p458) from the sequence of the 60 kDa heat shock protein (HSP60) molecule in a conjugate vaccine can provide T cell help for the induction of protecting antibody against bacterial capsular polysaccharides. We now report that the p458 peptide as a carrier peptide can also enhance the immunogenicity of a dominant CTL epitope of the MCMV pp89 antigen-89pep. We synthesized a linear combined peptide: chimeric p458-89pep. We immunized young BALB/c mice and challenged them with MCMV. We found that the p458-89pep chimeric peptide was more effective than the 89pep in inducing 89pep-specific IFN(gamma) secretion and specific CTL activity. Moreover, the p458-89pep chimeric peptide induced sustained IFN(gamma) secretion in the salivary gland specific to 89pep and only this immunization was associated with clearance of virus from the salivary gland. These results suggest that a peptide epitope of HSP60 may be advantageous as a T cell carrier peptide in the induction of specific T cell immunity against infectious agents.
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Affiliation(s)
- Ory Rouvio
- Department of Microbiology and Immunology, Faculty of Health Sciences and the Cancer Research Center, Ben Gurion University of the Negev, Beer Sheva 84105, Israel
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27
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Brocchieri L, Kledal TN, Karlin S, Mocarski ES. Predicting coding potential from genome sequence: application to betaherpesviruses infecting rats and mice. J Virol 2005; 79:7570-96. [PMID: 15919911 PMCID: PMC1143683 DOI: 10.1128/jvi.79.12.7570-7596.2005] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Prediction of protein-coding regions and other features of primary DNA sequence have greatly contributed to experimental biology. Significant challenges remain in genome annotation methods, including the identification of small or overlapping genes and the assessment of mRNA splicing or unconventional translation signals in expression. We have employed a combined analysis of compositional biases and conservation together with frame-specific G+C representation to reevaluate and annotate the genome sequences of mouse and rat cytomegaloviruses. Our analysis predicts that there are at least 34 protein-coding regions in these genomes that were not apparent in earlier annotation efforts. These include 17 single-exon genes, three new exons of previously identified genes, a newly identified four-exon gene for a lectin-like protein (in rat cytomegalovirus), and 10 probable frameshift extensions of previously annotated genes. This expanded set of candidate genes provides an additional basis for investigation in cytomegalovirus biology and pathogenesis.
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Affiliation(s)
- Luciano Brocchieri
- Department of Mathematics, Stanford University, Stanford, CA 94305-2125, USA.
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28
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Britt WJ, Boppana S. Human cytomegalovirus virion proteins. Hum Immunol 2005; 65:395-402. [PMID: 15172437 DOI: 10.1016/j.humimm.2004.02.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2003] [Revised: 01/15/2004] [Accepted: 02/03/2004] [Indexed: 12/16/2022]
Abstract
Human cytomegalovirus (HCMV) is the largest member of the family of human herpesviruses. The number of virus encoded proteins and the complexity of their functions in the life cycle of this virus are reflected in the size of its genome. There continues to be some controversy surrounding the exact protein coding capacity of the virus with estimates ranging from 160 open reading frames to more than 200 open reading frames. Very recent studies using mass spectrometry to determine the viral proteome suggests that the number of viral proteins may be even greater than previous estimates. The proteins of the virion capsid have readily identifiable homologous proteins in the capsid of the more extensively studied herpes simplex virus, likely because of similar capsid structure and assembly pathways. In contrast, the tegument and the envelope of HCMV contain a significant number of proteins that lack structural homology to proteins found in either alpha or gamma-herpesviruses. This brief overview discusses some of the general features and possible functions of the HCMV virion structural proteins in the replicative cycle of this virus.
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Affiliation(s)
- William J Britt
- Department of Pediatrics, University of Alabama at Birmingham, AL, USA.
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29
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Scalzo AA, Dallas PB, Forbes CA, Mikosza ASJ, Fleming P, Lathbury LJ, Lyons PA, Laferté S, Craggs MM, Loh LC. The murine cytomegalovirus M73.5 gene, a member of a 3' co-terminal alternatively spliced gene family, encodes the gp24 virion glycoprotein. Virology 2005; 329:234-50. [PMID: 15518804 DOI: 10.1016/j.virol.2004.08.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2004] [Revised: 06/08/2004] [Accepted: 08/05/2004] [Indexed: 10/26/2022]
Abstract
We have identified a novel family of five 3' co-terminal transcripts in murine cytomegalovirus (MCMV) arranged in a tail-to-tail orientation with respect to the MCMV glycoprotein H (gH) gene M75. They share the same exon 2 sequence but possess different exon 1 sequences. Two of these spliced transcripts (M73) encode the MCMV homolog of glycoprotein N (gN) entirely within exon 1. Two other transcripts designated M73.5 encode a previously described virion glycoprotein gp24 that shares its first 20 amino acids with gN, but which has another 64 amino acids encoded within exon 2. The fifth transcript, designated m60, has an 80-bp exon 1 near the MCMV oriLyt region 10.8 kb upstream of exon 2. Both MCMV M73.5 and m60 encode type II glycoproteins expressed at the cell surface. Their shared exon 2 coding sequences likely represent the highly conserved region of an as yet unidentified betaherpesvirus-specific glycoprotein species.
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Affiliation(s)
- Anthony A Scalzo
- Immunology and Virology Program, Centre for Ophthalmology and Visual Science, The University of Western Australia, Nedlands, WA 6009, Australia.
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30
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Morello CS, Ye M, Hung S, Kelley LA, Spector DH. Systemic priming-boosting immunization with a trivalent plasmid DNA and inactivated murine cytomegalovirus (MCMV) vaccine provides long-term protection against viral replication following systemic or mucosal MCMV challenge. J Virol 2005; 79:159-75. [PMID: 15596812 PMCID: PMC538742 DOI: 10.1128/jvi.79.1.159-175.2005] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2004] [Accepted: 08/23/2004] [Indexed: 11/20/2022] Open
Abstract
We previously demonstrated that vaccination of BALB/c mice with a pool of 13 plasmid DNAs (pDNAs) expressing murine cytomegalovirus (MCMV) genes followed by formalin-inactivated MCMV (FI-MCMV) resulted in complete protection against viral replication in the spleen and salivary glands following sublethal intraperitoneal (i.p.) challenge. Here, we found that following intranasal (i.n.) challenge, titers of virus in the lungs of the immunized mice were reduced approximately 1,000-fold relative to those for mock-immunized controls. We next sought to extend these results and to determine whether similar protection levels could be achieved by priming with a pool of three pDNAs containing three key plasmids (IE1, M84, and gB). We found that the three-pDNA priming elicited IE1- and M84-p65-specific CD8+ T lymphocytes and, following FI-MCMV boost, high levels of virion-specific immunoglobulin G (IgG) and virus-neutralizing antibodies. When mice were i.n. challenged 4 months after the last boost, titers of virus in the lungs of immunized mice were reduced 1,000- to 2,000-fold from those for controls during the peak of viral replication. Additionally, titers of virus were either at or below the detection limits for the salivary glands, liver, and spleen of the majority of the immunized mice. Following sublethal i.p. challenge, virus was undetectable in all of the above target organs of the immunized mice. Virion-specific IgA in the lungs was consistently detected by day 6 post-i.n. challenge for the immunized mice and by day 14 for controls. These results demonstrate the immunity and high levels of protection of the priming-boosting vaccination against both systemic and mucosal challenge.
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Affiliation(s)
- Christopher S Morello
- Section of Molecular Biology and Center for Molecular Genetics, University of California, San Diego, La Jolla, California 92093-0366, USA
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Gandhi MK, Khanna R. Human cytomegalovirus: clinical aspects, immune regulation, and emerging treatments. THE LANCET. INFECTIOUS DISEASES 2004; 4:725-38. [PMID: 15567122 DOI: 10.1016/s1473-3099(04)01202-2] [Citation(s) in RCA: 387] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
After initial infection, human cytomegalovirus remains in a persistent state with the host. Immunity against the virus controls replication, although intermitent viral shedding can still take place in the seropositive immunocompetent person. Replication of cytomegalovirus in the absence of an effective immune response is central to the pathogenesis of disease. Therefore, complications are primarily seen in individuals whose immune system is immature, or is suppressed by drug treatment or coinfection with other pathogens. Although our increasing knowledge of the host-virus relationship has lead to the development of new pharmacological strategies for cytomegalovirus-associated infections, these strategies all have limitations-eg, drug toxicities, development of resistance, poor oral bioavailability, and low potency. Immune-based therapies to complement pharmacological strategies for the successful treatment of virus-associated complications should be prospectively investigated.
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Affiliation(s)
- Maher K Gandhi
- Tumour Immunology Laboratory at the Queensland Institute of Medical Research, Brisbane, Australia
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Deyde V, Rizvanov A, Otteson E, Brandt S, Bego M, Pari G, Kozel T, St Jeor S. Identification of a monoclonal antibody from Peromyscus maniculatus (deer mouse) cytomegalovirus (PCMV) which binds to a protein with homology to the human CMV matrix protein HCMV pp71. J Virol Methods 2004; 123:9-15. [PMID: 15582693 DOI: 10.1016/j.jviromet.2004.08.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2004] [Accepted: 08/16/2004] [Indexed: 11/20/2022]
Abstract
In this study we identified and characterized a monoclonal antibody against the matrix protein of a cytomegalovirus isolated from the common deer mouse (Peromyscus maniculatus) (PCMV). The monoclonal antibody was isolated using previously described technology which could be applied to the production of monoclonal antibodies against zoonotic disease. The antibody was found to react with a protein homologous to the human cytomegalovirus (HCMV) matrix protein (pp71), the product of the UL82 open reading frame (ORF). mAbs were generated from heterologous fusion of spleen cells from PCMV-positive mice and Balb/C P3X63-Ag8.653 myeloma cells. Using this approach, four monoclonal antibodies: B8C4, C12E8, G6A2 and P4E5 were generated. Antibody G6A2 reacted strongly with PCMV-infected cells as well as purified virions on ELISA and immunofluorescence. Western blot analysis, using sucrose gradient-purified virions, demonstrated that this mAb reacted specifically to a single protein with an apparent molecular weight of 71 kDa. The protein band was excised from the gel, purified and subjected to trypsin digestion followed by mass spectrometry. The protein sequences obtained were found to have identity to HCMV UL82 gene product. Sequence analysis indicated that it is the putative HCMV pp71 protein homolog of PCMV. G6A2 mAb did not cross-react with either human or murine recombinant pp71 proteins expressed in mammalian cells.
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Affiliation(s)
- Varough Deyde
- Cell and Molecular Biology Program, University of Nevada-Reno 1664, North Virginia St., Reno, NV 89557, USA
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33
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Kattenhorn LM, Mills R, Wagner M, Lomsadze A, Makeev V, Borodovsky M, Ploegh HL, Kessler BM. Identification of proteins associated with murine cytomegalovirus virions. J Virol 2004; 78:11187-97. [PMID: 15452238 PMCID: PMC521832 DOI: 10.1128/jvi.78.20.11187-11197.2004] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Proteins associated with the murine cytomegalovirus (MCMV) viral particle were identified by a combined approach of proteomic and genomic methods. Purified MCMV virions were dissociated by complete denaturation and subjected to either separation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and in-gel digestion or treated directly by in-solution tryptic digestion. Peptides were separated by nanoflow liquid chromatography and analyzed by tandem mass spectrometry (LC-MS/MS). The MS/MS spectra obtained were searched against a database of MCMV open reading frames (ORFs) predicted to be protein coding by an MCMV-specific version of the gene prediction algorithm GeneMarkS. We identified 38 proteins from the capsid, tegument, glycoprotein, replication, and immunomodulatory protein families, as well as 20 genes of unknown function. Observed irregularities in coding potential suggested possible sequence errors in the 3'-proximal ends of m20 and M31. These errors were experimentally confirmed by sequencing analysis. The MS data further indicated the presence of peptides derived from the unannotated ORFs ORF(c225441-226898) (m166.5) and ORF(105932-106072). Immunoblot experiments confirmed expression of m166.5 during viral infection.
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Affiliation(s)
- Lisa M Kattenhorn
- Pathology Functional Proteomics Center, Department of Pathology, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA
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Jones TR, Lee SW, Johann SV, Razinkov V, Visalli RJ, Feld B, Bloom JD, O'Connell J. Specific inhibition of human cytomegalovirus glycoprotein B-mediated fusion by a novel thiourea small molecule. J Virol 2004; 78:1289-300. [PMID: 14722284 PMCID: PMC321382 DOI: 10.1128/jvi.78.3.1289-1300.2004] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A novel small molecule inhibitor of human cytomegalovirus (HCMV) was identified as the result of screening a chemical library by using a whole-virus infected-cell assay. Synthetic chemistry efforts yielded the analog designated CFI02, a compound whose potency had been increased about 100-fold over an initial inhibitor. The inhibitory concentration of CFI02 in various assays is in the low nanomolar range. CFI02 is a selective and potent inhibitor of HCMV; it has no activity against other CMVs, alphaherpesviruses, or unrelated viruses. Mechanism-of-action studies indicate that CFI02 acts very early in the replication cycle, inhibiting virion envelope fusion with the cell plasma membrane. Mutants resistant to CFI02 have mutations in the abundant virion envelope glycoprotein B that are sufficient to confer resistance. Taken together, the data suggest that CFI02 inhibits glycoprotein B-mediated HCMV virion fusion. Furthermore, CFI02 inhibits the cell-cell spread of HCMV. This is the first study of a potent and selective small molecule inhibitor of CMV fusion and cell-cell spread.
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Affiliation(s)
- Thomas R Jones
- Infectious Disease Section, Wyeth Research, Pearl River, New York 10965, USA.
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35
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Abstract
Human cytomegalovirus (HCMV), a betaherpesvirus, represents the major infectious cause of birth defects, as well as an important pathogen for immunocompromised individuals. The viral nucleocapsid containing a linear double-stranded DNA of 230 kb is surrounded by a proteinaceous tegument, which is itself enclosed by a loosely applied lipid bilayer. Expression of the HCMV genome is controlled by a cascade of transcriptional events that leads to the synthesis of three categories of viral proteins designated as immediate-early, early, and late. Clinical manifestations can be seen following primary infection, reinfection, or reactivation. About 10% of infants are infected by the age of 6 months following transmission from their mothers via the placenta, during delivery, or by breastfeeding. HCMV is a significant post-allograft pathogen and contributes to graft loss independently from graft rejection. Histopathologic examination of necropsy tissues demonstrates that the virus enters via the epithelium of the upper alimentary, respiratory, or genitourinary tracts. Hematogenous spreading is typically followed by infection of ductal epithelial cells. Infections are kept under control by the immune system. However, total HCMV clearance is rarely achieved, and the viral genome remains at selected sites in a latent state. Virological and molecular detection of HCMV, as well as serological demonstration of a specific immune response, are used for diagnosis. Treatment of HCMV infections is difficult because there are few options. The presently available drugs produced a significant clinical improvement, but suffer from poor oral bioavailability, low potency, development of resistance in clinical practice, and dose-limiting toxicities.
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Affiliation(s)
- Santo Landolfo
- Department of Public Health and Microbiology, University of Turin, Via Santena 9, 10126 Turin, Italy.
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36
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Schleiss MR, Jensen NJ. Cloning and expression of the guinea pig cytomegalovirus glycoprotein B (gB) in a recombinant baculovirus: utility for vaccine studies for the prevention of experimental infection. J Virol Methods 2003; 108:59-65. [PMID: 12565154 DOI: 10.1016/s0166-0934(02)00258-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The guinea pig cytomegalovirus (GPCMV) is unique among the cytomegaloviruses of small mammals, insofar as during pregnancy it crosses the placenta, causing infection of the fetus. Although the guinea pig model is well suited to vaccine studies, the lack of cloned, recombinant forms of immunogenic GPCMV proteins, such as envelope glycoproteins, has hindered experimental evaluations of subunit immunization for prevention of fetal disease. Since the glycoprotein B (gB) is a major target of neutralizing antibody responses, the GPCMV gB was cloned and expressed in a recombinant baculovirus. A recombinant was generated which expressed gB, truncated at codon 692, upstream of the putative transmembrane domain. Processing and expression of the recombinant protein, designated Bac-gB, was assessed, and the protein was characterized immunologically. Anti-gB antibodies were immunoreactive with Bac-gB by enzyme linked immunosorbent assay (ELISA) and immunoblot assay. Immunoprecipitation with polyclonal anti-GPCMV antisera identified protein species of 120, 80 and 30 kDa by reducing SDS-PAGE, suggesting that authentic cleavage and processing of Bac-gB occurred in insect cells. Sera from guinea pigs immunized with lectin-column purified native glycoproteins had high ELISA titers to Bac-gB. Recombinant GPCMV gB expressed in insect cells should prove useful in defining correlates of protective immunity in the GPCMV congenital infection model.
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Affiliation(s)
- Mark R Schleiss
- Division of Infectious Diseases, Children's Hospital Research Foundation, 3333 Burnet Avenue, Cincinnati, OH 45229, USA.
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37
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Wagner M, Gutermann A, Podlech J, Reddehase MJ, Koszinowski UH. Major histocompatibility complex class I allele-specific cooperative and competitive interactions between immune evasion proteins of cytomegalovirus. J Exp Med 2002; 196:805-16. [PMID: 12235213 PMCID: PMC2194048 DOI: 10.1084/jem.20020811] [Citation(s) in RCA: 149] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2002] [Revised: 07/11/2002] [Accepted: 08/07/2002] [Indexed: 11/30/2022] Open
Abstract
Cytomegaloviruses (CMVs) deploy a set of genes for interference with antigen presentation in the major histocompatibility complex (MHC) class I pathway. In murine CMV (MCMV), three genes were identified so far: m04/gp34, m06/gp48, and m152/gp40. While their function as immunoevasins was originally defined after their selective expression, this may not necessarily reflect their biological role during infection. The three immunoevasins might act synergistically, but they might also compete for their common substrate, the MHC class I complexes. To approach this question in a systematic manner, we have generated a complete set of mutant viruses with deletions of the three genes in all seven possible combinations. Surface expression of a set of MHC class I molecules specified by haplotypes H-2(d) (K(d), D(d), and L(d)) and H-2(b) (K(b) and D(b)) was the parameter for evaluation of the interference with class I trafficking. The data show the following: first, there exists no additional MCMV gene of major influence on MHC class I surface expression; second, the strength of the inhibitory effect of immunoevasins shows an allele-specific hierarchy; and third, the immunoevasins act not only synergistically but can, in certain combinations, interact antagonistically. In essence, this work highlights the importance of studying the immunosubversive mechanisms of cytomegaloviruses in the context of gene expression during the viral replicative cycle in infected cells.
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Affiliation(s)
- Markus Wagner
- Max von Pettenkofer Institute, Department for Virology, Ludwig-Maximilians-Universität München, 80336 Munich, Germany
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38
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Lenzo JC, Fairweather D, Cull V, Shellam GR, James Lawson CM. Characterisation of murine cytomegalovirus myocarditis: cellular infiltration of the heart and virus persistence. J Mol Cell Cardiol 2002; 34:629-40. [PMID: 12054850 DOI: 10.1006/jmcc.2002.2003] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Myocarditis triggered by a viral infection has integral viral and immunological aspects associated with the pathogenesis of disease. The present study was performed to analyse the cellular inflammatory response in the heart and cytomegalovirus replication during the development of myocarditis in vivo. We examined murine cytomegalovirus in an animal model of myocarditis using both susceptible BALB/c and resistant C57BL/6 mice. The heart infiltrating cells of BALB/c mice were found to comprise predominantly CD8+ T cells, with other cells of the CD4+ T cell, macrophage, B cell and neutrophil phenotype. Infectious MCMV titres in the heart were low and replicative virus could not be isolated beyond the first week post-infection (p.i.). Direct viral lysis of myocytes in vitro and apoptosis of cardiac cells in vivo was observed. Furthermore, viral DNA was detected in the heart of both mouse strains throughout the development of chronic disease. Viral gB RNA was detected during the first 35 days p.i. However, viral transcript for ie1 RNA but not gB RNA was found in the heart during the late stage of disease, suggesting latent viral infection of the heart. Our findings suggest that maintenance of the chronic phase of myocarditis involving post-viral immunological responses can occur in the presence of little infectious virus replication in the heart.
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Affiliation(s)
- Jason C Lenzo
- Department of Microbiology, The University of Western Australia, Australia
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Holtappels R, Pahl-Seibert MF, Thomas D, Reddehase MJ. Enrichment of immediate-early 1 (m123/pp89) peptide-specific CD8 T cells in a pulmonary CD62L(lo) memory-effector cell pool during latent murine cytomegalovirus infection of the lungs. J Virol 2000; 74:11495-503. [PMID: 11090146 PMCID: PMC112429 DOI: 10.1128/jvi.74.24.11495-11503.2000] [Citation(s) in RCA: 181] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2000] [Accepted: 09/19/2000] [Indexed: 11/20/2022] Open
Abstract
Interstitial cytomegalovirus (CMV) pneumonia is a clinically relevant complication in recipients of bone marrow transplantation (BMT). Recent data for a model of experimental syngeneic BMT and concomitant infection of BALB/c mice with murine CMV (mCMV) have documented the persistence of tissue-resident CD8 T cells after clearance of productive infection of the lungs (J. Podlech, R. Holtappels, M.-F. Pahl-Seibert, H.-P. Steffens, and M. J. Reddehase, J. Virol. 74:7496-7507, 2000). It was proposed that these cells represent antiviral "standby" memory cells whose functional role might be to help prevent reactivation of latent virus. The pool of pulmonary CD8 T cells was composed of two subsets defined by the T-cell activation marker L-selectin (CD62L): a CD62L(hi) subset of quiescent memory cells, and a CD62L(lo) subset of recently resensitized memory-effector cells. In this study, we have continued this line of investigation by quantitating CD8 T cells specific for the three currently published antigenic peptides of mCMV: peptide YPHFMPTNL processed from the immediate-early protein IE1 (pp89), and peptides YGPSLYRRF and AYAGLFTPL, derived from the early proteins m04 (gp34) and M84 (p65), respectively. IE1-specific CD8 T cells dominated in acute-phase pulmonary infiltrates and were selectively enriched in latently infected lungs. Notably, most IE1-specific CD8 T cells were found to belong to the CD62L(lo) subset representing memory-effector cells. This finding is in accordance with the interpretation that IE1-specific CD8 T cells are frequently resensitized during latent infection of the lungs and may thus be involved in the maintenance of mCMV latency.
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Affiliation(s)
- R Holtappels
- Institute for Virology, Johannes Gutenberg University, 55101 Mainz, Germany
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40
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Angulo A, Ghazal P, Messerle M. The major immediate-early gene ie3 of mouse cytomegalovirus is essential for viral growth. J Virol 2000; 74:11129-36. [PMID: 11070009 PMCID: PMC113196 DOI: 10.1128/jvi.74.23.11129-11136.2000] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The significance of the major immediate-early gene ie3 of mouse cytomegalovirus (MCMV) and that of the corresponding ie2 gene of human cytomegalovirus to viral replication are not known. To investigate the function of the MCMV IE3 regulatory protein, we generated two different MCMV recombinants that contained a large deletion in the IE3 open reading frame (ORF). The mutant genomes were constructed by the bacterial artificial chromosome mutagenesis technique, and MCMV ie3 deletion mutants were reconstituted on a mouse fibroblast cell line that expresses the MCMV major immediate-early genes. The ie3 deletion mutants failed to replicate on normal mouse fibroblasts even when a high multiplicity of infection was used. The replication defect was rescued when the IE3 protein was provided in trans by a complementing cell line. A revertant virus in which the IE3 ORF was restored was able to replicate with wild-type kinetics in normal mouse fibroblasts, providing evidence that the defective growth phenotype of the ie3 mutants was due to disruption of the ie3 gene. To characterize the point of restriction in viral replication that is controlled by ie3, we analyzed the pattern of expression of selective early (beta) and late (gamma) genes. While we could detect transcripts for the immediate-early gene ie1 in cells infected with the ie3 mutants, we failed to detect transcripts for representative beta and gamma genes. These data demonstrate that the MCMV transactivator IE3 plays an indispensable role during viral replication in tissue culture, implicating a similar role for the human CMV ie2 gene product. To our knowledge, the ie3 deletion mutants represent the first MCMV recombinants isolated that contain a disruption of an essential gene.
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Affiliation(s)
- A Angulo
- Department of Immunology and Molecular Biology, Division of Virology, The Scripps Research Institute, La Jolla, California 92037, USA.
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41
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Palmon A, Tel-or S, Shai E, Rager-Zisman B, Burstein Y. Development of a highly sensitive quantitative competitive PCR assay for the detection of murine cytomegalovirus DNA. J Virol Methods 2000; 86:107-14. [PMID: 10785285 DOI: 10.1016/s0166-0934(00)00141-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Viral persistence and molecular latency are characteristic of infection by the human cytomegalovirus (HCMV). Using the murine cytomegalovirus (MCMV) as a model for human infection, a quantitative-competitive polymerase chain reaction (QC-PCR) assay was developed to detect and quantify MCMV-DNA in the salivary glands of infected mice. The QC-PCR detected high numbers of MCMV DNA copies in the absence of infectious virus. By comparing the DNA content and the results obtained from a standard semiquantitative plaque assay, it is concluded that 1 plaque-forming unit (pfu) is the equivalent of approximately 1500 viral genomes. By day 42-post infection (pi) 4x10(3) copies of DNA/1 mg tissue were sufficient to reactivate infectious virions after cyclophosphamide immunosupression. By day 90 pi, however, when the DNA load was decreased to <1.2x10(2), reactivation was not observed. These results indicate that viral reactivation will occur when the number of infectious DNA copies is equivalent about 2-3 pfu. This quantitative test may therefore help to detect CMV and the risk of reactivation in immunosupressed patients.
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Affiliation(s)
- A Palmon
- Department of Oral Biology, Faculty of Dental Medicine, Hebrew University, Jerusalem, Israel.
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42
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Abstract
Human cytomegalovirus is ubiquitous, yet causes little illness in immunocompetent individuals. Disease is evident in immunodeficient groups such as neonates, transplant recipients and AIDS patients either following a primary infection or reactivation of a latent infection. Little is known of the mechanisms underlying the pathogenicity of the virus. The recent determination of the nucleotide sequence of both human cytomegalovirus (strain AD169) and murine cytomegalovirus (murine cytomegalovirus strain Smith) has allowed an analysis of the biological importance of several virus genes. Studies with human cytomegalovirus have indicated that many viral genes are non-essential for replication in vitro which are thus assumed to be important in the pathogenesis of the virus. This is being examined in the murine model where the role of the gene and its product in disease can be directly examined in vivo using viral mutants in which the relevant gene has been interrupted or deleted. Current information on the role of cytomegalovirus genes in tissue tropism, immune evasion, latency, reactivation from latency and damage is described.
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Affiliation(s)
- C Sweet
- School of Biological Sciences, University of Birmingham, UK.
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Klein M, Schoppel K, Amvrossiadis N, Mach M. Strain-specific neutralization of human cytomegalovirus isolates by human sera. J Virol 1999; 73:878-86. [PMID: 9882288 PMCID: PMC103907 DOI: 10.1128/jvi.73.2.878-886.1999] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/1998] [Accepted: 10/29/1998] [Indexed: 11/20/2022] Open
Abstract
Induction of an effective antibody response against human cytomegalovirus (HCMV) is an important defense mechanism since it is potentially capable of neutralizing infectious viruses. We have analyzed the extent of HCMV strain-specific neutralization capacity in human sera. Nine recent HCMV isolates and their corresponding sera were investigated in cross-neutralization assays. We observed differences, independent of the overall neutralization capacity, in the 50% neutralization titers of the sera against individual strains, differences that ranged from 8-fold to more than 60-fold. For one isolate, complete resistance to neutralization by two human sera was observed. The neutralization capacity of human sera was not influenced by the presence of various concentrations (up to 100-fold excess) of noninfectious envelope glycoproteins, an inherent contamination of virus preparations from recent HCMV isolates. This indicated that the decisive parameter for neutralization is the titer of the neutralizing antibodies and that neutralization is largely independent of the concentration of virus. Analysis with transplant patients revealed that during primary infection strain-specific and strain-common antibodies are produced asynchronously. Thus, our data demonstrate that the induction of strain-specific neutralizing antibodies is a common event during infection with HCMV and that it might have important implications for the course of the infection and the development of anti-HCMV vaccines.
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Affiliation(s)
- M Klein
- Institut für Klinische und Molekulare Virologie, Universität Erlangen-Nurnberg, 91054 Erlangen, Germany
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Kurz SK, Rapp M, Steffens HP, Grzimek NK, Schmalz S, Reddehase MJ. Focal transcriptional activity of murine cytomegalovirus during latency in the lungs. J Virol 1999; 73:482-94. [PMID: 9847354 PMCID: PMC103855 DOI: 10.1128/jvi.73.1.482-494.1999] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Interstitial pneumonia is a frequent and critical manifestation of human cytomegalovirus (CMV) disease in immunocompromised patients, in particular in recipients of bone marrow transplantation. Previous work in the murine CMV infection model has identified the lungs as a major organ site of CMV latency and recurrence. It was open to question whether the viral genome is transcriptionally silent or active during latency. Transcription could be latency associated and thus be part of the latency phenotype. Alternatively, transcriptional activity could reflect episodes of reactivation. We demonstrate here that transcription of the immediate-early (IE) transcription unit ie1-ie3 selectively generates ie1-specific transcripts during latency. Notably, while the latent viral DNA was found to be evenly distributed in the lungs, transcription was focal and randomly distributed. This finding indicates that IE transcription is not a feature inherent to murine CMV latency but rather reflects foci of primordial reactivation. However, this reactivation did not initiate productive infection, since ie3 gene mRNA specifying the essential transactivator IE3 of murine CMV early gene expression was not detectable. Accordingly, transcripts encoding gB were absent during latency. By contrast, during induced virus recurrence, IE-phase transcription switched from focal to generalized and ie3-specific transcripts were generated. These data imply that latency and recurrence are regulated not only at the IE promoter-enhancer and that there exists an additional checkpoint at the level of precursor RNA splicing. We propose that focal transcription reflects random episodes of nonproductive reactivation that get terminated before IE3 is expressed and ignites the productive cycle.
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Affiliation(s)
- S K Kurz
- Institute for Virology, Johannes Gutenberg-University, Mainz, Germany
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45
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Steffens HP, Kurz S, Holtappels R, Reddehase MJ. Preemptive CD8 T-cell immunotherapy of acute cytomegalovirus infection prevents lethal disease, limits the burden of latent viral genomes, and reduces the risk of virus recurrence. J Virol 1998; 72:1797-804. [PMID: 9499030 PMCID: PMC109469 DOI: 10.1128/jvi.72.3.1797-1804.1998] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
In the immunocompetent host, primary cytomegalovirus (CMV) infection is resolved by the immune response without causing overt disease. The viral genome, however, is not cleared but is maintained in a latent state that entails a risk of virus recurrence and consequent organ disease. By using murine CMV as a model, we have shown previously that multiple organs harbor latent CMV and that reactivation occurs with an incidence that is determined by the viral DNA load in the respective organ (M. J. Reddehase, M. Balthesen, M. Rapp, S. Jonjic, I. Pavic, and U. H. Koszinowski. J. Exp. Med. 179:185-193, 1994). This predicts that a therapeutic intervention capable of limiting the load of latent viral genome should also reduce the risk of virus recurrence. Here we demonstrate the benefits and the limits of a preemptive CD8 T-cell immunotherapy of CMV infection in the immunocompromised bone marrow transplantation recipient. Antiviral CD8 T cells prevented CMV disease and accelerated the resolution of productive infection. The therapy also resulted in a lower load of latent CMV DNA in organs and consequently reduced the incidence of recurrence. The data thus provide a further supporting argument for clinical trials of preemptive cytoimmunotherapy of human CMV disease with CD8 T cells. However, CD8 T cells failed to clear the viral DNA. The therapy-susceptible portion of the DNA load differed between organs and was highest in the lungs. The existence of an invariant, therapy-resistant load suggests a role for immune system evasion mechanisms in the establishment of CMV latency.
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Affiliation(s)
- H P Steffens
- Institute for Virology, Johannes Gutenberg-University, Mainz, Germany
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Mayer A, Podlech J, Kurz S, Steffens HP, Maiberger S, Thalmeier K, Angele P, Dreher L, Reddehase MJ. Bone marrow failure by cytomegalovirus is associated with an in vivo deficiency in the expression of essential stromal hemopoietin genes. J Virol 1997; 71:4589-98. [PMID: 9151853 PMCID: PMC191681 DOI: 10.1128/jvi.71.6.4589-4598.1997] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Bone marrow (BM) failure associated with cytomegalovirus (CMV) infection is a feared complication after clinical BM transplantation. Experiments in long-term BM cultures have indicated that BM stromal cells (BMSC) are targets of productive CMV infection, but an in situ infection of BM stroma remained to be documented, and the pathomechanism is open to question. Here we describe a murine in vivo model of lethal CMV aplastic anemia (CMV-AA). The reconstitution of hematopoietic progenitor cells expressing stem cell factor (SCF) receptor was found to be defective in CMV-AA. While murine CMV replication in permissive parenchymal tissues is cytolytic, the hematopoietic cord was found to be a site of very limited virus production with foci of reticular BMSC expressing the intranuclear viral IE1 protein, but with only a few BMSC positive for viral genome in the in situ hybridization. XX-XY BM chimeras were established in order to quantitate Y-chromosome-tagged BMSC by a PCR specific for the male-sex-determining gene Tdy. This approach revealed that murine CMV infection is not associated with a significant loss of BMSC. Despite the physical integrity of the stromal network, the functional integrity of the stroma was impaired. While housekeeping genes were expressed normally in BMSC of infected mice, the expression of genes encoding the essential hemopoietins SCF, granulocyte colony-stimulating factor, and interleukin-6 was markedly reduced. In conclusion, the mechanism of BM failure is not a stromal lesion but an insufficient stromal function. These findings explain CMV-AA as a manifestation of multiple hemopoietin deficiency.
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Affiliation(s)
- A Mayer
- Institute for Virology, Johannes Gutenberg-University, Mainz, Germany
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47
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Masse MJ, Messerle M, Mocarski ES. The location and sequence composition of the murine cytomegalovirus replicator (oriLyt). Virology 1997; 230:350-60. [PMID: 9143291 DOI: 10.1006/viro.1997.8473] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
DNA replication during human or simian cytomegalovirus (CMV) infection has been shown to be under control of a replicator region referred to as oriLyt. The murine CMV oriLyt has been mapped to a region of the genome located upstream of the gene encoding the herpesvirus-conserved single-stranded DNA binding protein, analogous to human and simian CMV oriLyts. A minimal oriLyt of approximately 1.7 kbp has been identified using a transient replication system. Like occurs with human and simian CMV counterparts, addition of flanking sequences to this minimal origin-stimulated replication efficiency. Analysis of the DNA sequence in this region shows that murine CMV oriLyt is complex and exhibits an asymmetric distribution of nucleotides as well as many repeat sequence elements, including distinct AT- and GC-rich regions and region with arrays of closely spaced direct repeats. Despite similarities in organization of all three CMV oriLyts, no sequence identity and only limited DNA sequence similarity was detectable. Consistent with this sequence divergence, the human and murine CMV oriLyts were unable to substitute for one another in transient replication assays.
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Affiliation(s)
- M J Masse
- Department of Microbiology and Immunology, Stanford University, California 94305-5402, USA
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48
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Abstract
The complete DNA sequence of the Smith strain of murine cytomegalovirus (MCMV) was determined from virion DNA by using a whole-genome shotgun approach. The genome has an overall G+C content of 58.7%, consists of 230,278 bp, and is arranged as a single unique sequence with short (31-bp) terminal direct repeats and several short internal repeats. Significant similarity to the genome of the sequenced human cytomegalovirus (HCMV) strain AD169 is evident, particularly for 78 open reading frames encoded by the central part of the genome. There is a very similar distribution of G+C content across the two genomes. Sequences toward the ends of the MCMV genome encode tandem arrays of homologous glycoproteins (gps) arranged as two gene families. The left end encodes 15 gps that represent one family, and the right end encodes a different family of 11 gps. A homolog (m144) of cellular major histocompatibility complex (MHC) class I genes is located at the end of the genome opposite the HCMV MHC class I homolog (UL18). G protein-coupled receptor (GCR) homologs (M33 and M78) occur in positions congruent with two (UL33 and UL78) of the four putative HCMV GCR homologs. Counterparts of all of the known enzyme homologs in HCMV are present in the MCMV genome, including the phosphotransferase gene (M97), whose product phosphorylates ganciclovir in HCMV-infected cells, and the assembly protein (M80).
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Affiliation(s)
- W D Rawlinson
- Laboratory of Molecular Biology, Cambridge, United Kingdom.
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49
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Palmon A, Blagerman S, Tel-Or S, Pecht M, Trainin N, Burstein Y, Rager-Zisman B. Treatment of murine cytomegalovirus salivary-gland infection by combined therapy with ganciclovir and thymic humoral factor gamma 2. Antiviral Res 1996; 33:55-64. [PMID: 8955853 DOI: 10.1016/s0166-3542(96)00996-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
An optimal therapeutic regimen against primary CMV salivary-gland infection has not yet been developed. We used a murine CMV (MCMV) model system to assess the ability of combined thymic humoral factor THF-gamma 2 immunotherapy and ganciclovir (GCV) antiviral chemotherapy to eliminate detectable viral DNA from salivary glands of infected animals. Mice in different experimental groups were inoculated intraperitoneally with MCMV, treated, and then sacrificed either 2 weeks or 3 months later. To amplify and detect MCMV DNA in infected salivary-gland tissue, we developed a sensitive polymerase chain reaction (PCR) using a glycoprotein B gene primer pair that amplifies a 356 bp segment. During the acute phase of the infection, the detection of high titers of infectious virus in the salivary glands correlated with a strong PCR amplification signal. Although active virions could not be recovered from untreated animals 3 months after viral inoculation, the PCR assay detected a latent MCMV genome. Treatment with either GCV alone or THF-gamma 2 alone had little or no effect on the presence of MCMV DNA. By contrast, combined treatment with THF-gamma 2 and GCV significantly reduced the amount of salivary-gland MCMV DNA to below the limit of PCR detection. The results presented here, and experimental data from previous MCMV research in our laboratories, imply that elimination of the virus from the salivary glands could be due in part to THF-gamma 2 restoration of the various MCMV-suppressed, cell mediated immune-responses. Combining THF-gamma 2 immunotherapy and GCV antiviral chemotherapy may be an important step toward an effective therapeutic regimen that has the potential to prevent the establishment of viral latency ensuing from primary MCMV salivary-gland infection.
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Affiliation(s)
- A Palmon
- Department of Oral Biology, Faculty of Dental Medicine, Hebrew University, Jerusalem, Israel
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50
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Norais N, Tang D, Kaur S, Chamberlain SH, Masiarz FR, Burke RL, Marcus F. Disulfide bonds of herpes simplex virus type 2 glycoprotein gB. J Virol 1996; 70:7379-87. [PMID: 8892856 PMCID: PMC190805 DOI: 10.1128/jvi.70.11.7379-7387.1996] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Glycoprotein B (gB) is the most highly conserved envelope glycoprotein of herpesviruses. The gB protein is required for virus infectivity and cell penetration. Recombinant forms of gB being used for the development of subunit vaccines are able to induce virus-neutralizing antibodies and protective efficacy in animal models. To gain structural information about the protein, we have determined the location of the disulfide bonds of a 696-amino-acid residue truncated, recombinant form of herpes simplex virus type 2 glycoprotein gB (HSV gB2t) produced by expression in Chinese hamster ovary cells. The purified protein, which contains virtually the entire extracellular domain of herpes simplex virus type 2 gB, was digested with trypsin under nonreducing conditions, and peptides were isolated by reversed-phase high-performance liquid chromatography (HPLC). The peptides were characterized by using mass spectrometry and amino acid sequence analysis. The conditions of cleavage (4 M urea, pH 7) induced partial carbamylation of the N termini of the peptides, and each disulfide peptide was found with two or three different HPLC retention times (peptides with and without carbamylation of either one or both N termini). The 10 cysteines of the molecule were found to be involved in disulfide bridges. These bonds were located between Cys-89 (C1) and Cys-548 (C8), Cys-106 (C2) and Cys-504 (C7), Cys-180 (C3) and Cys-244 (C4), Cys-337 (C5) and Cys-385 (C6), and Cys-571 (C9) and Cys-608 (C10). These disulfide bonds are anticipated to be similar in the corresponding gBs from other herpesviruses because the 10 cysteines listed above are always conserved in the corresponding protein sequences.
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Affiliation(s)
- N Norais
- Chiron Corporation, Emeryville, California 94608, USA
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