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Abstract
Human cytomegalovirus (HCMV) is a betaherpesvirus that establishes lifelong infection in its host and can cause severe comorbidities in individuals with suppressed or compromised immune systems. The lifecycle of HCMV consists of lytic and latent phases, largely dependent upon the cell type infected and whether transcription from the major immediate early locus can ensue. Control of this locus, which acts as a critical "switch" region from where the lytic gene expression cascade originates, as well as regulation of the additional ~235 kilobases of virus genome, occurs through chromatinization with cellular histone proteins after infection. Upon infection of a host cell, an initial intrinsic antiviral response represses gene expression from the incoming genome, which is relieved in permissive cells by viral and host factors in concert. Latency is established in a subset of hematopoietic cells, during which viral transcription is largely repressed while the genome is maintained. As these latently infected cells differentiate, the cellular milieu and epigenetic modifications change, giving rise to the initial stages of virus reactivation from latency. Thus, throughout the cycle of infection, chromatinization, chromatin modifiers, and the recruitment of specific transcription factors influence the expression of genes from the HCMV genome. In this review, we discuss epigenetic regulation of the HCMV genome during the different phases of infection, with an emphasis on recent reports that add to our current perspective.
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Affiliation(s)
- Stephen M. Matthews
- Infection Biology, Global Center for Pathogen and Human Health Research, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Ian J. Groves
- Infection Biology, Global Center for Pathogen and Human Health Research, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
- Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland Clinic, Cleveland, Ohio, USA
| | - Christine M. O'Connor
- Infection Biology, Global Center for Pathogen and Human Health Research, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
- Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland Clinic, Cleveland, Ohio, USA
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Human Immunodeficiency Virus (HIV) and Human Cytomegalovirus (HCMV) Coinfection of Infant Tonsil Epithelium May Synergistically Promote both HIV-1 and HCMV Spread and Infection. J Virol 2021; 95:e0092121. [PMID: 34232730 DOI: 10.1128/jvi.00921-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Mother-to-child transmission (MTCT) of human immunodeficiency virus type 1 (HIV-1) and human cytomegalovirus (HCMV) may occur during pregnancy, labor, or breastfeeding. These viruses from amniotic fluid, cervicovaginal secretions, and breast milk may simultaneously interact with oropharyngeal and tonsil epithelia; however, the molecular mechanism of HIV-1 and HCMV cotransmission through the oral mucosa and its role in MTCT are poorly understood. To study the molecular mechanism of HIV-1 and HCMV MTCT via oral epithelium, we established polarized infant tonsil epithelial cells and polarized-oriented ex vivo tonsil tissue explants. Using these models, we showed that cell-free HIV-1 and its proteins gp120 and tat induce the disruption of tonsil epithelial tight junctions and increase paracellular permeability, which facilitates HCMV spread within the tonsil mucosa. Inhibition of HIV-1 gp120-induced upregulation of mitogen-activated protein kinase (MAPK) and NF-κB signaling in tonsil epithelial cells, reduces HCMV infection, indicating that HIV-1-activated MAPK and NF-κB signaling may play a critical role in HCMV infection of tonsil epithelium. HCMV infection of tonsil epithelial cells also leads to the disruption of tight junctions and increases paracellular permeability, facilitating HIV-1 paracellular spread into tonsil mucosa. HCMV-promoted paracellular spread of HIV-1 increases its accessibility to tonsil CD4 T lymphocytes, macrophages, and dendritic cells. HIV-1-enhanced HCMV paracellular spread and infection of epithelial cells subsequently leads to the spread of HCMV to tonsil macrophages and dendritic cells. Our findings revealed that HIV-1- and HCMV-induced disruption of infant tonsil epithelial tight junctions promotes MTCT of these viruses through tonsil mucosal epithelium, and therapeutic intervention for both HIV-1 and HCMV infection may substantially reduce their MTCT. IMPORTANCE Most HIV-1 and HCMV MTCT occurs in infancy, and the cotransmission of these viruses may occur via infant oropharyngeal and tonsil epithelia, which are the first biological barriers for viral pathogens. We have shown that HIV-1 and HCMV disrupt epithelial junctions, reducing the barrier functions of epithelia and thus allowing paracellular penetration of both viruses via mucosal epithelia. Subsequently, HCMV infects epithelial cells, macrophages, and dendritic cells, and HIV-1 infects CD4+ lymphocytes, macrophages, and dendritic cells. Infection of these cells in HCMV- and HIV-1-coinfected tonsil tissues is much higher than that by HCMV or HIV-1 infection alone, promoting their MTCT at its initial stages via infant oropharyngeal and tonsil epithelia.
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HCMV Infection and Apoptosis: How Do Monocytes Survive HCMV Infection? Viruses 2018; 10:v10100533. [PMID: 30274264 PMCID: PMC6213175 DOI: 10.3390/v10100533] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 09/10/2018] [Accepted: 09/26/2018] [Indexed: 12/11/2022] Open
Abstract
Human cytomegalovirus (HCMV) infection of peripheral blood monocytes plays a key role in the hematogenous dissemination of the virus to multiple organ systems following primary infection or reactivation of latent virus in the bone marrow. Monocytes have a short life span of 1⁻3 days in circulation; thus, HCMV must alter their survival and differentiation to utilize these cells and their differentiated counterparts-macrophages-for dissemination and long term viral persistence. Because monocytes are not initially permissive for viral gene expression and replication, HCMV must control host-derived factors early during infection to prevent apoptosis or programmed cell death prior to viral induced differentiation into naturally long-lived macrophages. This review provides a short overview of HCMV infection of monocytes and describes how HCMV has evolved to utilize host cell anti-apoptotic pathways to allow infected monocytes to bridge the 48⁻72 h viability gate so that differentiation into a long term stable mature cell can occur. Because viral gene expression is delayed in monocytes following initial infection and only occurs (begins around two to three weeks post infection in our model) following what appears to be complete differentiation into mature macrophages or dendritic cells, or both; virally-encoded anti-apoptotic gene products cannot initially control long term infected cell survival. Anti-apoptotic viral genes are discussed in the second section of this review and we argue they would play an important role in long term macrophage or dendritic cell survival following infection-induced differentiation.
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Crawford LB, Streblow DN, Hakki M, Nelson JA, Caposio P. Humanized mouse models of human cytomegalovirus infection. Curr Opin Virol 2015; 13:86-92. [PMID: 26118890 DOI: 10.1016/j.coviro.2015.06.006] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 06/10/2015] [Indexed: 02/07/2023]
Abstract
The generation of humanized mouse models in which immune deficient mice are engrafted with human tissues allows for the direct in vivo investigation of human-restricted viruses. These humanized mouse models have been developed and improved over the past 30 years. It is now possible to achieve high levels of human cell engraftment producing human myeloid and lymphoid lineage cells. Humanized mouse models have been increasingly utilized in the study of human cytomegalovirus (HCMV), a human-specific beta-herpesvirus that infects myeloprogenitor cells and establishes a life-long latency in the infected host. This review focuses on the strengths and limitations of the current humanized mouse models used to study HCMV replication, pathogenesis and treatment.
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Affiliation(s)
| | - Daniel N Streblow
- VGTI, OHSU West Campus, 505 NW 185th Avenue, Beaverton, OR 97006, USA
| | - Morgan Hakki
- Division of Infectious Diseases, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA
| | - Jay A Nelson
- VGTI, OHSU West Campus, 505 NW 185th Avenue, Beaverton, OR 97006, USA
| | - Patrizia Caposio
- VGTI, OHSU West Campus, 505 NW 185th Avenue, Beaverton, OR 97006, USA.
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Poole E, Juss JK, Krishna B, Herre J, Chilvers ER, Sinclair J. Alveolar Macrophages Isolated Directly From Human Cytomegalovirus (HCMV)-Seropositive Individuals Are Sites of HCMV Reactivation In Vivo. J Infect Dis 2015; 211:1936-42. [PMID: 25552371 PMCID: PMC4442624 DOI: 10.1093/infdis/jiu837] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 12/15/2014] [Indexed: 12/27/2022] Open
Abstract
Human cytomegalovirus (HCMV) causes significant morbidity in the immunocompromised host. Following primary infection, the virus establishes latent infection in progenitor cells of the myeloid lineage. These cells exhibit limited viral gene transcription and no evidence of de novo virion production. It is well recognized that differentiation of latently infected myeloid progenitor cells to dendritic or macrophage-like cells permits viral reactivation in vitro. This has been used to support the concept that viral reactivation in HCMV carriers routinely occurs from such terminally differentiated myeloid cells in vivo. However, to date this has not been shown for in vivo-differentiated macrophages. This study is the first to demonstrate that alveolar macrophages from HCMV carriers express immediate early lytic genes and produce infectious virus. This supports the view, until now based on in vitro data, that terminally differentiated myeloid cells in vivo are sites of HCMV reactivation and potential centers of viral dissemination in latently infected individuals with no evidence of virus disease or dissemination.
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Affiliation(s)
| | | | | | - Jurgen Herre
- Department of Medicine,University of Cambridge,United Kingdom
| | | | - John Sinclair
- Department of Medicine,University of Cambridge,United Kingdom
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Stevenson EV, Collins-McMillen D, Kim JH, Cieply SJ, Bentz GL, Yurochko AD. HCMV reprogramming of infected monocyte survival and differentiation: a Goldilocks phenomenon. Viruses 2014; 6:782-807. [PMID: 24531335 PMCID: PMC3939482 DOI: 10.3390/v6020782] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 02/04/2014] [Accepted: 02/04/2014] [Indexed: 12/14/2022] Open
Abstract
The wide range of disease pathologies seen in multiple organ sites associated with human cytomegalovirus (HCMV) infection results from the systemic hematogenous dissemination of the virus, which is mediated predominately by infected monocytes. In addition to their role in viral spread, infected monocytes are also known to play a key role in viral latency and life-long persistence. However, in order to utilize infected monocytes for viral spread and persistence, HCMV must overcome a number of monocyte biological hurdles, including their naturally short lifespan and their inability to support viral gene expression and replication. Our laboratory has shown that HCMV is able to manipulate the biology of infected monocytes in order to overcome these biological hurdles by inducing the survival and differentiation of infected monocytes into long-lived macrophages capable of supporting viral gene expression and replication. In this current review, we describe the unique aspects of how HCMV promotes monocyte survival and differentiation by inducing a “finely-tuned” macrophage cell type following infection. Specifically, we describe the induction of a uniquely polarized macrophage subset from infected monocytes, which we argue is the ideal cellular environment for the initiation of viral gene expression and replication and, ultimately, viral spread and persistence within the infected host.
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Affiliation(s)
- Emily V Stevenson
- Department of Microbiology and Immunology, Louisiana State University Health Sciences Center-Shreveport, Shreveport, LA 71130, USA.
| | - Donna Collins-McMillen
- Department of Microbiology and Immunology, Louisiana State University Health Sciences Center-Shreveport, Shreveport, LA 71130, USA.
| | - Jung Heon Kim
- Department of Microbiology and Immunology, Louisiana State University Health Sciences Center-Shreveport, Shreveport, LA 71130, USA.
| | - Stephen J Cieply
- Department of Microbiology and Immunology, Louisiana State University Health Sciences Center-Shreveport, Shreveport, LA 71130, USA.
| | - Gretchen L Bentz
- Department of Microbiology and Immunology, Louisiana State University Health Sciences Center-Shreveport, Shreveport, LA 71130, USA.
| | - Andrew D Yurochko
- Department of Microbiology and Immunology, Louisiana State University Health Sciences Center-Shreveport, Shreveport, LA 71130, USA.
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Gredmark-Russ S, Söderberg-Nauclér C. Dendritic cell biology in human cytomegalovirus infection and the clinical consequences for host immunity and pathology. Virulence 2012; 3:621-34. [PMID: 23076329 PMCID: PMC3545944 DOI: 10.4161/viru.22239] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Human cytomegalovirus (HCMV), a member of the herpesvirus family, establishes life-long persistence and latency after primary infection and can be reactivated later in life. In immunosuppressed patients, it is an important pathogen that can cause severe disease. HCMV is also thought to play a causative role in inflammatory diseases and cancer. The virus can infect different immune cells, including dendritic cells (DCs) and can take advantage of host immune functions to avoid immune recognition. These characteristics have sparked major interest in understanding HCMV and its interaction with immune cells and their relevance to disease pathogenesis. In this review, we focus on the complex host-pathogen relationship between HCMV and DCs, including the persistence of the virus in these cells, their function in the immune response to HCMV infection and the potential clinical consequences of HCMV infection in DCs.
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Affiliation(s)
- Sara Gredmark-Russ
- Center for Infectious Medicine, Department of Medicine, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden.
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Giusti P, Frascaroli G, Tammik C, Gredmark-Russ S, Söderberg-Nauclér C, Varani S. The novel anti-rheumatic compound Rabeximod impairs differentiation and function of human pro-inflammatory dendritic cells and macrophages. Immunobiology 2011; 216:243-50. [PMID: 20494473 DOI: 10.1016/j.imbio.2010.04.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2009] [Revised: 03/14/2010] [Accepted: 04/21/2010] [Indexed: 12/31/2022]
Affiliation(s)
- Pablo Giusti
- Department of Medicine, Solna, Karolinska Institutet, Stockholm, Sweden
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Makler O, Oved K, Netzer N, Wolf D, Reiter Y. Direct visualization of the dynamics of antigen presentation in human cells infected with cytomegalovirus revealed by antibodies mimicking TCR specificity. Eur J Immunol 2010; 40:1552-65. [PMID: 20306470 DOI: 10.1002/eji.200939875] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
There are no direct means to study class I MHC presentation in human normal or diseased cells. Using CMV-infected human cells and applying novel mAb that mimic T-cell receptor specificity directed toward the immunogenic epitope of the viral pp65 protein presented on HLA-A2 molecules, we directly imaged the dynamics of Ag presentation in infected cells. We demonstrate that following infection large intracellular pools of HLA-A2/pp65 complexes are localized to the Golgi. These HLA-A2/pp65 pools account for the majority of total HLA-A2 molecules in infected cells. Interestingly, these large pools are sequestered inside infected cells and only a small portion of them are exported to the cell surface. Virus-induced class I MHC down-regulation did not affect the intracellular pool of HLA-A2/pp65 complexes. Our data also suggest that proteasome function influences the release of class I complexes to the membrane. We present herein a new and direct molecular tool to study the dynamics of viral Ag presentation that may further elucidate the balance between immune response versus viral escape.
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Affiliation(s)
- Oryan Makler
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel
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Buckner AE, Dix RD. Nicotine Treatment Alters NF-κB Expression in Human Cytomegalovirus-Infected ARPE-19 Cells. Curr Eye Res 2009; 31:191-8. [PMID: 16500770 DOI: 10.1080/02713680500514651] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
PURPOSE To test if nicotine counteracts the dampening effect of human cytomegalovirus (HCMV) infection of NF-kappaB in retinal pigment epithelial (RPE) cells, thereby increasing the permissiveness of RPE cells for HCMV replication. METHODS Human ARPE-19 cells were transfected with NF-kappaB luciferase DNA, inoculated with HCMV at 24 hr post-transfection, and maintained in the absence or presence of a physiologic dose of nicotine at 1 hr prior to HCMV inoculation. RESULTS Whereas HCMV-infected ARPE-19 cells without nicotine treatment showed a dramatic decrease in NF-kappaB levels, nicotine treatment reduced this decrease but did not abolish it completely. Nicotine treatment of uninfected ARPE-19 cells had no effect on baseline NF-kappaB levels. CONCLUSIONS Treatment of HCMV-infected ARPE-19 cells with nicotine at a physiologic dose dampened the downregulation of NF-kappaB observed in HCMV-infected ARPE-19 cells without nicotine treatment. We conclude that nicotine can serve as a cofactor to stimulate productive, lytic replication of HCMV.
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Affiliation(s)
- Anissa E Buckner
- Department of Ophthalmology, Harvey & Bernice Jones Eye Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA.
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HCMV infection of PDCs deviates the NK cell response into cytokine-producing cells unable to perform cytotoxicity. Immunobiology 2009; 214:331-41. [PMID: 19152985 DOI: 10.1016/j.imbio.2008.10.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2008] [Accepted: 10/30/2008] [Indexed: 11/24/2022]
Abstract
Plasmacytoid dendritic cells (PDCs) are thought to induce natural killer (NK) cell CD69 expression, cytotoxicity, and cytokine secretion. Since human cytomegalovirus (HCMV) interferes with multiple functions of infected cells, we investigated whether the HCMV infection of PDCs affects NK cell activation. Human PDCs infected with HCMV strain VR1814 at multiplicity of infection (MOI) 10 or stimulated with control CpG-A were cocultured with human NK cells in an autologous system. As expected, CpG-stimulation of PDCs increased expression of the NK cell activation marker CD69, enhanced cytotoxicity and stimulated secretion of tumor necrosis factor (TNF)-alpha and IFN-alpha, but not IFN-gamma, and induced NK cell migration. In contrast, incubation with HCMV-infected PDCs induced CD69 expression, migration and elevated production of both TNF-alpha and IFN-gamma by NK cells, but these cells did not exhibit enhanced cytotoxicity. Also, HCMV-infected PDCs were unable to induce increased intracellular perforin levels. Thus, HCMV infection of PDCs induce NK cells to increase CD69 expression and produce inflammatory cytokines, but infected PDCs are unable to induce NK cell cytotoxicity. This NK cell phenotype with impaired killing abilities, but enhanced production of inflammatory cytokines may instead facilitate reactivation and replication of HCMV. This data indicate that HCMV can target PDCs through novel dual strategies that may result in evasion of the innate immune response at the same time as facilitating virus reactivation and replication early in the infection, through enhanced inflammation.
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Keller MJ, Wu AW, Andrews JI, McGonagill PW, Tibesar EE, Meier JL. Reversal of human cytomegalovirus major immediate-early enhancer/promoter silencing in quiescently infected cells via the cyclic AMP signaling pathway. J Virol 2007; 81:6669-81. [PMID: 17301150 PMCID: PMC1900132 DOI: 10.1128/jvi.01524-06] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2006] [Accepted: 02/02/2007] [Indexed: 11/20/2022] Open
Abstract
The human cytomegalovirus (HCMV) major immediate-early (MIE) enhancer contains five functional cyclic AMP (cAMP) response elements (CRE). Because the CRE in their native context do not contribute appreciably to MIE enhancer/promoter activity in lytically infected human fibroblasts and NTera2 (NT2)-derived neurons, we postulated that they might have a role in MIE enhancer/promoter reactivation in quiescently infected cells. Here, we show that stimulation of the cAMP signaling pathway by treatment with forskolin (FSK), an adenylyl cyclase activator, greatly alleviates MIE enhancer/promoter silencing in quiescently infected NT2 neuronal precursors. The effect is immediate, independent of de novo protein synthesis, associated with the phosphorylation of ATF-1 serine 63 and CREB serine 133, dependent on protein kinase A (PKA) and the enhancer's CRE, and linked to viral-lytic-cycle advancement. Coupling of FSK treatment with the inhibition of either histone deacetylases or protein synthesis synergistically activates MIE gene expression in a manner suggesting that MIE enhancer/promoter silencing is optimally relieved by an interplay of multiple regulatory mechanisms. In contrast, MIE enhancer/promoter silence is not overcome by stimulation of the gamma interferon (IFN-gamma) signaling pathway, despite the enhancer having two IFN-gamma-activated-site-like elements. We conclude that stimulation of the cAMP/PKA signaling pathway drives CRE-dependent MIE enhancer/promoter activation in quiescently infected cells, thus exposing a potential mode of regulation in HCMV reactivation.
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Affiliation(s)
- Michael J Keller
- Department of Internal Medicine, University of Iowa Carver College of Medicine, and Veterans Affairs Medical Center, Iowa City, Iowa 52242, USA
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Tugizov S, Herrera R, Veluppillai P, Greenspan J, Greenspan D, Palefsky JM. Epstein-Barr virus (EBV)-infected monocytes facilitate dissemination of EBV within the oral mucosal epithelium. J Virol 2007; 81:5484-96. [PMID: 17376918 PMCID: PMC1900306 DOI: 10.1128/jvi.00171-07] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Epstein-Barr virus (EBV) causes hairy leukoplakia (HL), a benign lesion of oral epithelium that occurs primarily in the setting of human immunodeficiency virus (HIV)-associated immunodeficiency. However, the mechanisms of EBV infection of oral epithelium are poorly understood. Analysis of HL tissues shows a small number of EBV-positive intraepithelial macrophages and dendritic/Langerhans cells. To investigate a role for these cells in spreading EBV to epithelial cells, we used tongue and buccal explants infected ex vivo with EBV. We showed that EBV first infects submucosal CD14(+) monocytes, which then migrate into the epithelium and spread virus to oral epithelial cells, initiating productive viral infection within the terminally differentiated spinosum and granulosum layers. Incubation of EBV-infected monocytes and oral explants with antibodies to CCR2 receptor and monocyte chemotactic protein 1 prevented entry of monocytes into the epithelium and inhibited EBV infection of keratinocytes. B lymphocytes played little part in the spread of EBV to keratinocytes in our explant model. However, cocultivation of EBV-infected B lymphocytes with uninfected monocytes in vitro showed that EBV may spread from B lymphocytes to monocytes. Circulating EBV-positive monocytes were detected in most HIV-infected individuals, consistent with a model in which EBV may be spread from B lymphocytes to monocytes, which then enter the epithelium and initiate productive viral infection of keratinocytes.
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Affiliation(s)
- Sharof Tugizov
- Department of Medicine, University of California San Francisco, 513 Parnassus Ave., San Francisco, CA 94143-0512, USA.
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Gredmark S, Strååt K, Homman-Loudiyi M, Kannisto K, Söderberg-Nauclér C. Human cytomegalovirus downregulates expression of receptors for platelet-derived growth factor by smooth muscle cells. J Virol 2007; 81:5112-20. [PMID: 17344284 PMCID: PMC1900217 DOI: 10.1128/jvi.02197-06] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Infection by human cytomegalovirus (HCMV) is associated with the development of vascular diseases and may cause severe brain damage in infected fetuses. Platelet-derived growth factor receptors alpha and beta (PDGFR-alpha and -beta) control important cellular processes associated with atherosclerosis and fetal development. In the present investigation, our goal was to determine whether infection by HCMV can influence the expression of PDGFR-alpha and -beta in human smooth muscle cells (SMCs). In connection with HCMV infection in vitro the levels of PDGFR-alpha and -beta at the cell surface and in the total cellular protein of SMCs were reduced in parallel with decreases in the levels of the corresponding mRNAs. These effects were dependent on immediate-early (IE) or early (E) HCMV gene products, since inhibition of late genes did not prevent HCMV from affecting the expression of PDGFR-alpha and -beta. The downregulation of PDGFR caused by HCMV was dose dependent. Furthermore, confocal microscopy revealed that the localization of PDGFR-beta was altered in HCMV-infected cells, in which this protein colocalized with proteins associated with endosomes (Rab4 and -5) and lysosomes (Lamp1 and -2), indicating entrance into pathways for protein degradation. Altogether these observations indicate that an IE and/or E HCMV protein(s) downregulates the expression of PDGFR-alpha and -beta in SMCs. This phenomenon may disrupt cellular processes of importance in connection with cellular differentiation, migration, and/or proliferation. These observations may explain why congenital infection with HCMV can cause fetal brain damage.
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Affiliation(s)
- Sara Gredmark
- Department of Medicine, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
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Abstract
Innate immunity was believed originally to serve simply as the first-line defense against infection and malignancy, with adaptive immunity imposing specificity and ensuring that appropriate responses are mounted against chronic or reoccurring challenges. In this model of immunity, innate and adaptive immune responses are sequential, essentially non-overlapping, and interactions between components of each response limited or non-existent. Over the last 5 years, it has become increasingly evident that interactions between elements of the innate and adaptive immune systems are common. Indeed, it is now clear that the generation and maintenance of effective immunity require an extensive array of interactions between multiple components of the immune system. This review discusses recent advances in this area with particular emphasis on the role of natural killer cells in shaping the adaptive immune response to viral infection.
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Affiliation(s)
- Christopher E Andoniou
- Immunology and Virology Program, Centre for Ophthalmology and Visual Science, the University of Western Australia, Crawley, Western Australia, Australia
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16
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Kis Z, Pallinger E, Endresz V, Burian K, Falus A, Berencsi G, Gonczol E. A soluble factor(s) released by MRC-5 cells early and late after human cytomegalovirus infection induces maturation of monocyte-derived dendritic cells. Arch Virol 2006; 151:2277-87. [PMID: 16773236 DOI: 10.1007/s00705-006-0799-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2005] [Accepted: 05/09/2006] [Indexed: 12/01/2022]
Abstract
A human cytomegalovirus (HCMV) strain passaged 10 times on MRC-5 human fibroblast cells failed to express immediate early (IE) antigens in immature dendritic cells (iDCs) after infection. However, both the early and the late HCMV conditioning medium, harvested from MRC-5 cells at 24 h or 7-9 days after infection, respectively, induced a higher ratio of DCs expressing maturation markers (CD40, CD83, CD86 and HLA-DR) on the surface of the cells. HCMV conditioning medium, ultracentrifuged to remove virus particles, exhibited a similarly enhanced expression of DC maturation markers. DCs treated with HCMV conditioning medium harvested late after infection increased the percentages of autologous CD4+ and CD8+ cells of seropositive donors to produce IFN-gamma and stimulated HCMV-specific lymphoproliferative responses. The early HCMC conditioning medium was also able to induce the functional maturation of DCs, as demonstrated by supplementing this medium with a Chlamydia pneumoniae antigen.
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Affiliation(s)
- Z Kis
- Division of Virology, National Center for Epidemiology, Budapest, Hungary
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Bosnjak L, Jones CA, Abendroth A, Cunningham AL. Dendritic cell biology in herpesvirus infections. Viral Immunol 2005; 18:419-33. [PMID: 16212521 DOI: 10.1089/vim.2005.18.419] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Lidija Bosnjak
- Centre for Virus Research, Westmead Millennium Institute, Darcy Road, Westmead, NSW 2145, Australia
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Noda S, Aguirre SA, Bitmansour A, Brown JM, Sparer TE, Huang J, Mocarski ES. Cytomegalovirus MCK-2 controls mobilization and recruitment of myeloid progenitor cells to facilitate dissemination. Blood 2005; 107:30-8. [PMID: 16046529 PMCID: PMC1895360 DOI: 10.1182/blood-2005-05-1833] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Murine cytomegalovirus encodes a secreted, pro-inflammatory chemokine-like protein, MCK-2, that recruits leukocytes and facilitates viral dissemination. We have shown that MCK-2-enhanced recruitment of myelomonocytic leukocytes with an immature phenotype occurs early during infection and is associated with efficient viral dissemination. Expression of MCK-2 drives the mobilization of a population of leukocytes from bone marrow that express myeloid marker Mac-1 (CD11b), intermediate levels of Gr-1 (Ly6 G/C), platelet-endothelial-cell adhesion molecule-1 (PECAM-1, CD31), together with heterogeneous levels of stem-cell antigen-1 (Sca-1, Ly-6 A /E). Recombinant MCK-2 mediates recruitment of this population even in the absence of viral infection. Recruitment of this cell population and viral dissemination via the bloodstream to salivary glands proceeds normally in mice that lack CCR2 and MCP-1 (CCL2), suggesting that recruitment of macrophages is not a requisite component of pathogenesis. Thus, a systemic impact of MCK-2 enhances the normal host response and causes a marked increase in myelomonocytic recruitment with an immature phenotype to initial sites of infection. Mobilization influences levels of virus dissemination via the bloodstream to salivary glands and is dependent on a myelomonocytic cell type other than mature macrophages.
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Affiliation(s)
- Satoshi Noda
- Department of Microbiology and Immunology, Stanford University School of Medicine, Fairchild Science Bldg, 299 Campus Dr, Stanford, CA 94305-5124, USA
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19
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Netterwald J, Yang S, Wang W, Ghanny S, Cody M, Soteropoulos P, Tian B, Dunn W, Liu F, Zhu H. Two gamma interferon-activated site-like elements in the human cytomegalovirus major immediate-early promoter/enhancer are important for viral replication. J Virol 2005; 79:5035-46. [PMID: 15795289 PMCID: PMC1069560 DOI: 10.1128/jvi.79.8.5035-5046.2005] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human cytomegalovirus (HCMV) infection directly initiates a signal transduction pathway that leads to activation of a large number of cellular interferon-stimulated genes (ISGs). Our previous studies demonstrated that two interferon response elements, the interferon-stimulated response element and gamma interferon-activated site (GAS), in the ISG promoters serve as HCMV response sites (VRS). Interestingly, two GAS-like VRS elements (VRS1) were also present in the HCMV major immediate-early promoter-enhancer (MIEP/E). In this study, the importance of these VRS elements in viral replication was investigated. We demonstrate that the expression of the major IE genes, IE1 and IE2, is interferon inducible. To understand the biological significance of this signal transduction pathway in HCMV major IE expression, the two VRS1 in the MIEP/E were mutated. Mutant HCMVs in which the VRS elements were deleted or that contained point mutations grew dramatically more slowly than wild-type virus at a low multiplicity of infection (MOI). Insertion of wild-type VRS1 into the mutant viral genome rescued the slow growth phenotype. Furthermore, the expression levels of major IE RNAs and proteins were greatly reduced during infection with the VRS mutants at a low MOI. HCMV microarray analysis indicated that infection of host cells with the VRS mutant virus resulted in a global reduction in the expression of viral genes. Collectively, these data demonstrate that the two VRS elements in the MIEP/E are necessary for efficient viral gene expression and replication. This study suggests that although the HCMV-initiated signal transduction pathway results in induction of cellular antiviral genes, it also functions to stimulate viral major IE gene expression. This might be a new viral strategy in which the pathway is used to regulate gene expression and play a role in reactivation.
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Affiliation(s)
- James Netterwald
- Department of Microbiology and Molecular Genetics, UMDNJ-New Jersey Medical School, 225 Warren St., Newark, NJ 07101-1709, USA
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20
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Chang WLW, Baumgarth N, Yu D, Barry PA. Human cytomegalovirus-encoded interleukin-10 homolog inhibits maturation of dendritic cells and alters their functionality. J Virol 2004; 78:8720-31. [PMID: 15280480 PMCID: PMC479089 DOI: 10.1128/jvi.78.16.8720-8731.2004] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Interleukin-10 (IL-10) suppresses the maturation and cytokine production of dendritic cells (DCs), key regulators of adaptive immunity, and prevents the activation and polarization of naïve T cells towards protective gamma interferon-producing effectors. We hypothesized that human cytomegalovirus (HCMV) utilizes its viral IL-10 homolog (cmvIL-10) to attenuate DC functionality, thereby subverting the efficient induction of antiviral immune responses. RNA and protein analyses demonstrated that the cmvIL-10 gene was expressed with late gene kinetics. Treatment of immature DCs (iDCs) with supernatant from HCMV-infected cultures inhibited both the lipopolysaccharide-induced DC maturation and proinflammatory cytokine production. These inhibitory effects were specifically mediated through the IL-10 receptor and were not observed when DCs were treated with supernatant of cells infected with a cmvIL-10-knockout mutant. Incubation of iDCs with recombinant cmvIL-10 recapitulated the inhibition of maturation. Furthermore, cmvIL-10 had pronounced long-term effects on those DCs that could overcome this inhibition of maturation. It enhanced the migration of mature DCs (mDCs) towards the lymph node homing chemokine but greatly reduced their cytokine production. The inability of mDCs to secrete IL-12 was maintained, even when they were restimulated by the activated T-cell signal CD40 ligand in the absence of cmvIL-10. Importantly, cmvIL-10 potentiates these anti-inflammatory effects, at least partially, by inducing endogenous cellular IL-10 expression in DCs. Collectively, we show that cmvIL-10 causes long-term functional alterations at all stages of DC activation.
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Affiliation(s)
- W L William Chang
- Center for Comparative Medicine, University of California, Davis, County Road 98 and Hutchison Drive, Davis, CA 95616, USA.
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21
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Hertel L, Lacaille VG, Strobl H, Mellins ED, Mocarski ES. Susceptibility of immature and mature Langerhans cell-type dendritic cells to infection and immunomodulation by human cytomegalovirus. J Virol 2003; 77:7563-74. [PMID: 12805456 PMCID: PMC164783 DOI: 10.1128/jvi.77.13.7563-7574.2003] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Human cytomegalovirus (CMV) infection initiates in mucosal epithelia and disseminates via leukocytes throughout the body. Langerhans cells (LCs), the immature dendritic cells (DCs) that reside in epithelial tissues, are among the first cells to encounter virus and may play important roles in the immune response, as well as in pathogenesis as hosts for viral replication and as vehicles for dissemination. Here, we demonstrate that CD34(+) progenitor cell-derived LC-type DCs exhibit a differentiation state-dependent susceptibility to CMV infection. In contrast to the small percentage (3 to 4%) of the immature LCs that supported infection, a high percentage (48 to 74%) of mature, LC-derived DCs were susceptible to infection with endotheliotropic strains (TB40/E or VHL/E) of CMV. These cells were much less susceptible to viral strains AD169varATCC, TownevarRIT(3), and Toledo. When exposed to endotheliotropic strains, viral gene expression (IE1/IE2 and other viral gene products) and viral replication proceeded efficiently in LC-derived mature DCs (mDCs). Productive infection was associated with downmodulation of cell surface CD83, CD1a, CD80, CD86, ICAM-1, major histocompatibility complex (MHC) class I, and MHC class II on these cells. In addition, the T-cell proliferative response to allogeneic LC-derived mDCs was attenuated when CMV-infected cultures were used as stimulators. This investigation revealed important characteristics of the interaction between CMV and the LC lineage of DCs, suggesting that LC-derived mDCs are important to viral pathogenesis and immunity through their increased susceptibility to virus replication and virus-mediated immune escape.
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Affiliation(s)
- Laura Hertel
- Departments of Microbiology and Immunology. Pediatrics, Stanford University School of Medicine, Stanford, California 94305, USA
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22
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Tamura K, Oka T, Ohsawa K, Koji T, Watanabe Y, Katamine S, Sato H, Ayabe H. Allogeneic cell stimulation enhances cytomegalovirus replication in the early period of primary infection in an experimental rat model. J Heart Lung Transplant 2003; 22:452-9. [PMID: 12681423 DOI: 10.1016/s1053-2498(02)01156-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Cytomegalovirus (CMV) diseases commonly occur in allograft recipients in the early post-transplant period. However, factors responsible for the high incidence of CMV diseases during this period are not yet fully defined. METHODS Wistar-Furth (WF; RT-1(u)) rats were inoculated with 10(4) plaque-forming units (PFU) of rat CMV (RCMV) intraperitoneally, and then transplanted with allogeneic lungs from Dark Agouti (DA; RT-1avl) rats or stimulated with 10(7) mitomycin C-treated spleen cells from DA rats by daily sub-cutaneous injections for 2 weeks. No immunosuppressive agent was used. Naive WF rats and WF rats grafted with syngeneic lungs or cells were used as controls. The level of RCMV replication in rats was assessed by infectious virus titers in tissues. RESULTS The virus titers in salivary glands of allogeneic and syngeneic lung graft recipients were significantly higher than in naive WF rats. The level of RCMV replication in rats stimulated with allogeneic spleen cells was significantly higher than in the syngeneic recipient rats: virus titers in the salivary gland of allogeneic and syngeneic recipients reached 4.61 +/- 0.33 and 4.00 +/- 0.37 log(10) PFU/g tissue, respectively, at 14 days post-infection (p = 0.015). The augmented viral replication in allogeneic recipients was confirmed by an increase in the number of RCMV antigen-positive macrophages present in tissue sections of the salivary gland. CONCLUSIONS Acute lung allograft rejection and allogeneic spleen cell stimulation enhance CMV replication in the salivary gland of rats. Various responses to allogeneic antigens occurring in the process of acute allograft rejection could be risk factors for post-transplant CMV replication and infection.
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Affiliation(s)
- Kazuki Tamura
- First Department of Surgery, Nagasaki University School of Medicine, Nagasaki, Japan
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23
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Johnson DC, Hegde NR. Inhibition of the MHC class II antigen presentation pathway by human cytomegalovirus. Curr Top Microbiol Immunol 2002; 269:101-15. [PMID: 12224504 DOI: 10.1007/978-3-642-59421-2_7] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Human cytomegalovirus (HCMV) causes serious disease in immunocompromised individuals. Normally, anti-HCMV immune response controls virus replication following reactivation from latency. However, HCMV, like other large herpesviruses, encodes immune evasion proteins that allow the virus to replicate, for a time or in specific tissues, and produce viral progeny in the face of robust host immunity. HCMV glycoproteins US2, US3, US6 and US11 all inhibit different stages of the MHC class I antigen presentation pathway and can reduce recognition by CD8+ T lymphocytes. Here, we discuss two novel inhibitors of the MHC class II antigen presentation pathway, HCMV glycoproteins US2 and US3. Both US2 and US3 can inhibit presentation of exogenous protein antigens to CD4+ T lymphocytes in in vitro assays. US2 causes degradation of MHC class II molecules: HLA-DR-alpha and HLA-DM-alpha, as well as class I heavy chain (HC), but does not affect DR-beta or DM-beta chains. Mutant forms of US2 have been constructed that can bind to DR-alpha and class I HC but do not cause their degradation, separating the binding step from other processes that precede degradation. We also found evidence that US2-induced degradation of class I and II proteins involves a cellular component, other than Sec61, that is limiting in quantity. Unlike US2, US3 binds newly synthesized class II alpha/beta complexes, reducing the association with the invariant chain (Ii) and causing mislocalization of class II complexes in cells. US3 expression reduces accumulation of class II complexes in peptide-loading compartments and loading of peptides. Since US2 and US3 are expressed solely within HCMV-infected cells, it appears that these viral proteins have evolved to inhibit presentation of endogenous, intracellular viral antigens to anti-HCMV CD4+ T cells. This is different from how the MHC class II pathway is normally viewed, as a pathway for presentation of exogenous, extracellular proteins. The existence of these proteins indicates the importance of class II-mediated presentation of endogenous antigens in signalling virus infection to CD4+ T cells.
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Affiliation(s)
- D C Johnson
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, OR 97201, USA
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24
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Le Roy E, Baron M, Faigle W, Clément D, Lewinsohn DM, Streblow DN, Nelson JA, Amigorena S, Davignon JL. Infection of APC by human cytomegalovirus controlled through recognition of endogenous nuclear immediate early protein 1 by specific CD4(+) T lymphocytes. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 169:1293-301. [PMID: 12133951 DOI: 10.4049/jimmunol.169.3.1293] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Infections by human CMV are controlled by cellular immune responses. Professional APC such as monocytes and macrophages can be infected in vivo and are considered as a reservoir of virus. However, CMV-specific CD4(+) responses against infected APC have not been reported. To develop a model of CD4-infected APC interaction, we have transfected the U373MG astrocytoma cell line with the class II transactivator (CIITA). Confocal microscopy experiments showed that U373MG-CIITA cells expressed markers characteristic of APC. Functional assays demonstrated that infected U373MG-CIITA APC processed and presented both exogenous and endogenously neosynthesized nuclear immediate early (IE) protein 1 through the MHC class II pathway. More importantly, endogenous presentation of IE1 by infected APC lead to efficient control of CMV infection as revealed by decreased viral titer. Thus, these results describe the endogenous presentation of a nuclear viral protein by the MHC class II pathway and suggest that IE1-specific CD4(+) T cells may play an important role in CMV infection by directly acting against infected APC.
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Affiliation(s)
- Emmanuelle Le Roy
- Institut National de la Santé et de la Recherche Médicale, Toulouse, France
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25
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Rehm A, Engelsberg A, Tortorella D, Körner IJ, Lehmann I, Ploegh HL, Höpken UE. Human cytomegalovirus gene products US2 and US11 differ in their ability to attack major histocompatibility class I heavy chains in dendritic cells. J Virol 2002; 76:5043-50. [PMID: 11967320 PMCID: PMC136120 DOI: 10.1128/jvi.76.10.5043-5050.2002] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human cytomegalovirus (HCMV) encodes several proteins that inhibit major histocompatibility complex (MHC) class I-dependent antigen presentation. The HCMV products US2 and US11 are each sufficient for causing the dislocation of human and murine MHC class I heavy chains from the lumen of the endoplasmic reticulum to the cytosol, where the heavy chains are readily degraded. The apparent redundancy of US2 and US11 has been probed predominantly in cultured cell lines, where differences in their specificities were shown for murine and human MHC class I locus products. Here, we expressed US11 and US2 via adenovirus vectors and show that US11 exhibits a superior ability to degrade MHC class I molecules in primary human dendritic cells. MHC class II complexes are unaffected by US2- and US11-mediated attack. We suggest that multiple HCMV-encoded immunoevasions have evolved complementary functions in response to diverse host cell types and tissues.
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Affiliation(s)
- Armin Rehm
- Robert-Rössle-Klinik, Department of Hematology, Oncology and Tumorimmunology, Universitätsklinikum Charite, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
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26
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Moutaftsi M, Mehl AM, Borysiewicz LK, Tabi Z. Human cytomegalovirus inhibits maturation and impairs function of monocyte-derived dendritic cells. Blood 2002; 99:2913-21. [PMID: 11929782 DOI: 10.1182/blood.v99.8.2913] [Citation(s) in RCA: 176] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Dendritic cells (DCs) play a pivotal role in the generation of virus-specific cytotoxic T-cell responses, but some viruses can render DCs inefficient in stimulating T cells. We studied whether infection of DCs with human cytomegalovirus (HCMV) results in a suppression of DC function which may assist HCMV in establishing persistence. The effect of HCMV infection on the phenotype and function of monocyte-derived DCs and on their ability to mature following infection with an endothelial cell-adapted clinical HCMV isolate were studied. HCMV infection induced no maturation of DCs; instead, it efficiently down-regulated the expression of surface major histocompatibility complex (MHC) class I, CD40, and CD80 molecules. Slight down-regulation of MHC class II and CD86 molecules was also observed. Lipopolysaccharide (LPS)-induced maturation of infected DCs was strongly inhibited, as indicated by lower levels of surface expression of MHC class I, class II, costimulatory, and CD83 molecules. The down-regulation or inhibition of these surface markers occurred only in HCMV antigen-positive DCs. DCs produced no interleukin 12 (IL-12) and only low levels of tumor necrosis factor alpha (TNF-alpha) upon HCMV infection. Furthermore, cytokine production upon stimulation with LPS or CD40L was significantly impaired. Inhibition of cytokine production did not depend on viral gene expression as UV-irradiated HCMV resulted in the same effect. Proliferation and cytotoxicity of T cells specific to a recall antigen presented by DCs were also reduced when DCs were HCMV infected. This study shows that HCMV inhibits DC function, revealing a powerful viral strategy to delay or prevent the generation of virus-specific cytotoxic T cells.
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Affiliation(s)
- Magdalena Moutaftsi
- Section of Infection and Immunity, University of Wales College of Medicine, Cardiff, United Kingdom
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27
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Beisser PS, Laurent L, Virelizier JL, Michelson S. Human cytomegalovirus chemokine receptor gene US28 is transcribed in latently infected THP-1 monocytes. J Virol 2001; 75:5949-57. [PMID: 11390596 PMCID: PMC114310 DOI: 10.1128/jvi.75.13.5949-5957.2001] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The human cytomegalovirus (HCMV) US28 gene product, pUS28, is a G protein-coupled receptor that interacts with both CC and CX(3)C chemokines. To date, the role of pUS28 in immune evasion and cell migration has been studied only in cell types that can establish productive HCMV infection. We show that HCMV can latently infect THP-1 monocytes and that during latency US28 is transcribed. We also show that the transcription is sustained during differentiation of the THP-1 monocytes. Since cells expressing pUS28 were previously shown to adhere to immobilized CX(3)C chemokines (C. A. Haskell, M. D. Cleary, and I. F. Charo, J. Biol. Chem. 275:34183-34189, 2000), we hypothesize that latently infected circulating monocytes express pUS28, thereby enabling adhesion of these cells to CX(3)C-exposing endothelium. Consequently, the US28-encoded chemokine receptor may play an important role in dissemination of latent HCMV.
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Affiliation(s)
- P S Beisser
- Unité d'Immunologie Virale, Institut Pasteur, 75274 Paris Cedex 15, France.
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28
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Martinez A, Castro A, Gil C, Perez C. Recent strategies in the development of new human cytomegalovirus inhibitors. Med Res Rev 2001; 21:227-44. [PMID: 11301412 DOI: 10.1002/med.1008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Human cytomegalovirus (HCMV) is one of the most common opportunistic infections in immunucompromised individuals, such as AIDS patients and organ transplant recipients, and is the most frequent congenital viral infection in humans. Despite a reduction of the incidence of AIDS-related opportunistic infections in patients under highly active antiretroviral treatment, attention should be paid to the HCMV risk factor in these individuals. Furthermore, HCMV may have an important role in atherosclerosis. Existing antiviral treatments for the HCMV infection suffer from poor bioavailability, toxicity, and limited effectiveness, mainly due to the development of drug resistance. Fortunately there are novel and potentially very effective new compounds undergoing pre-clinical and clinical evaluation. This review provides an overview in the last five years of new HCMV inhibitors (chemical structures, SAR, and new mechanisms of action) with the aim to provide new clues for the development of future drugs against this opportunistic virus.
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Affiliation(s)
- A Martinez
- Instituto de Química Médica (CSIC), Juan de la Cierva 3, 28006 Madrid, Spain.
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29
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Tabi Z, Moutaftsi M, Borysiewicz LK. Human cytomegalovirus pp65- and immediate early 1 antigen-specific HLA class I-restricted cytotoxic T cell responses induced by cross-presentation of viral antigens. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 166:5695-703. [PMID: 11313411 DOI: 10.4049/jimmunol.166.9.5695] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Dendritic cells (DCs) play a pivotal role in the development of anti-viral CD8(+) CTL responses. This is straightforward if they are directly infected with virus, but is less clear in response to viruses that cannot productively infect DCS: Human CMV (HCMV) shows strain-specific cell tropism: fibroblast (Fb)-adapted laboratory strains (AD169) and recent clinical isolates do not infect DCs, whereas endothelial cell-adapted strains (TB40/E) result in productive lytic DC infection. However, we show here that uninfected DCs induce CD8(+) T cell cytotoxicity and IFN-gamma production against HCMV pp65 and immediate early 1 Ags following in vitro coculture with HCMV-AD169-infected Fbs, regardless of the HLA type of these FBS: CD8(+) T cell stimulation was inhibited by pretreatment of DCs with cytochalasin B or brefeldin A, indicating a phagosome/endosome to cytosol pathway. HCMV-infected Fbs were not apoptotic as measured by annexin V binding, and induction of apoptosis of infected Fbs in vitro did not augment CTL induction by DCs, suggesting a mechanism other than apoptosis in the initiation of cross-presentation. Furthermore, HCMV-infected Fbs provided a maturation signal for immature DCs during coculture, as evidenced by increased CD83 and HLA class II expression. Cross-presentation of HCMV Ags by host DCs enables these professional APCs to bypass some of the evasion mechanisms HCMV has developed to avoid T cell recognition. It may also serve to explain the presence of immediate early 1 Ag-specific CTLs in the face of pp65-induced inhibition of Ag presentation at the level of the infected cell.
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MESH Headings
- Amino Acid Sequence
- Antigen Presentation/drug effects
- Antigen Presentation/genetics
- Antigens, Viral/biosynthesis
- Antigens, Viral/genetics
- Antigens, Viral/immunology
- Antigens, Viral/metabolism
- Apoptosis/immunology
- Brefeldin A/pharmacology
- Cell Count
- Cell Differentiation/immunology
- Cell Line
- Cells, Cultured
- Coculture Techniques
- Cytochalasin B/pharmacology
- Cytomegalovirus/genetics
- Cytomegalovirus/immunology
- Cytotoxicity, Immunologic/drug effects
- Dendritic Cells/cytology
- Dendritic Cells/drug effects
- Dendritic Cells/immunology
- Dendritic Cells/virology
- Epitopes, T-Lymphocyte/immunology
- Fibroblasts/cytology
- Fibroblasts/immunology
- Fibroblasts/virology
- Gene Expression Regulation, Viral/immunology
- Green Fluorescent Proteins
- HLA Antigens/immunology
- Histocompatibility Antigens Class I/immunology
- Humans
- Immediate-Early Proteins/biosynthesis
- Immediate-Early Proteins/genetics
- Immediate-Early Proteins/immunology
- Immunosuppressive Agents/pharmacology
- Luminescent Proteins/biosynthesis
- Luminescent Proteins/genetics
- Lymphocyte Activation/drug effects
- Molecular Sequence Data
- Phosphoproteins/immunology
- Signal Transduction/immunology
- T-Lymphocytes, Cytotoxic/immunology
- T-Lymphocytes, Cytotoxic/metabolism
- T-Lymphocytes, Cytotoxic/virology
- Viral Matrix Proteins/immunology
- Viral Proteins
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Affiliation(s)
- Z Tabi
- Department of Medicine, University of Wales, College of Medicine, Cardiff, United Kingdom.
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30
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Generation of Cytotoxic T Lymphocytes Specific for Human Cytomegalovirus Using Dendritic Cells In Vitro. J Immunother 2001. [DOI: 10.1097/00002371-200105000-00008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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31
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Arrode G, Boccaccio C, Lulé J, Allart S, Moinard N, Abastado JP, Alam A, Davrinche C. Incoming human cytomegalovirus pp65 (UL83) contained in apoptotic infected fibroblasts is cross-presented to CD8(+) T cells by dendritic cells. J Virol 2000; 74:10018-24. [PMID: 11024130 PMCID: PMC102040 DOI: 10.1128/jvi.74.21.10018-10024.2000] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human cytomegalovirus (HCMV) infection is well controlled mainly by cytotoxic CD8(+) T lymphocytes (CTL) directed against the matrix protein pp65 despite the numerous immune escape mechanisms developed by the virus. Dendritic cells (DCs) are key antigen-presenting cells for the generation of an immune response which have the capacity to acquire antigens via endocytosis of apoptotic cells and thus present peptides to major histocompatibility complex class I-restricted T cells. We examined whether this mechanism could contribute to the activation of anti-pp65 CTL. In this study, we show that infection by HCMV AD169 induced sensitization of MRC5 fibroblasts to tumor necrosis factor alpha-mediated apoptosis very early after virus inoculation and that pp65 contained in apoptotic cells came from the delivery of the matrix protein into the cell. We observed that immature DCs derived from peripheral monocytes were not permissive to HCMV AD169 infection but were able to internalize pp65-positive apoptotic infected MRC5 cells. We then demonstrated that following exposure to these apoptotic bodies, DCs could activate HLA-A2- or HLA-B35-restricted anti-pp65 CTL, suggesting that they acquired and processed properly fibroblast-derived pp65. Together, our data suggest that cross-presentation of incoming pp65 contained in apoptotic cells may provide a quick and efficient way to prime anti-HCMV CD8(+) T cells.
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Affiliation(s)
- G Arrode
- INSERM U395, IFR 30, UPS, CNRS, CHU, 31024 Toulouse Cédex, France
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32
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Riegler S, Hebart H, Einsele H, Brossart P, Jahn G, Sinzger C. Monocyte-derived dendritic cells are permissive to the complete replicative cycle of human cytomegalovirus. J Gen Virol 2000; 81:393-9. [PMID: 10644837 DOI: 10.1099/0022-1317-81-2-393] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The susceptibility of monocyte-derived immature dendritic cells (DC) to infection by various strains of human cytomegalovirus (HCMV) was analysed. Immature DC were generated by incubation of peripheral blood monocytes with interleukin-4 and granulocyte-macrophage colony-stimulating factor for 7 days and were characterized by a CD1a+/CD40+/CD80+/CD86+/HLA-DR+/CD14- phenotype. Viral antigen expression and production of infectious progeny virus were analysed in infected immature DC cultures. Immature DC were 80-90 % susceptible to HCMV strains that had been propagated in endothelial cell culture, whereas the infection rate was negligible with fibroblast-adapted HCMV strains. Immature DC infection resulted in expression of viral immediate early, early and late genes. Productive infection was proven by the detection of infectious virus in single-step growth curves and in infectious centre assays. It is concluded that HCMV might interfere with the host immune reaction by permissive, lytic infection of immature DC.
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Affiliation(s)
- S Riegler
- Department of Medical Virology, University of Tübingen, Calwerstrasse 7/6, D-72076 Tübingen, Germany
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