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Twigg CAI, Haugo-Crooks A, Roller RJ. Extragenic suppression of an HSV-1 UL34 nuclear egress mutant reveals role for pUS9 as an inhibitor of epithelial cell-to-cell spread. J Virol 2023; 97:e0083623. [PMID: 37787529 PMCID: PMC10617574 DOI: 10.1128/jvi.00836-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 08/16/2023] [Indexed: 10/04/2023] Open
Abstract
IMPORTANCE Herpesviruses are able to disseminate in infected hosts despite development of a strong immune response. Their ability to do this relies on a specialized process called cell-to-cell spread in which newly assembled virus particles are trafficked to plasma membrane surfaces that abut adjacent uninfected cells. The mechanism of cell-to-cell spread is obscure, and little is known about whether or how it is regulated in different cells. We show here that a viral protein with a well-characterized role in promoting spread from neurons has an opposite, inhibitory role in other cells.
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Affiliation(s)
- Carly A. I. Twigg
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Alison Haugo-Crooks
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Richard J. Roller
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
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2
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The Epstein-Barr Virus Glycoprotein BDLF2 Is Essential for Efficient Viral Spread in Stratified Epithelium. J Virol 2023; 97:e0152822. [PMID: 36688650 PMCID: PMC9972961 DOI: 10.1128/jvi.01528-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Epstein-Barr virus (EBV) is a ubiquitous human pathogen that infects the majority of the adult population regardless of socioeconomic status or geographical location. EBV primarily infects B and epithelial cells and is associated with different cancers of these cell types, such as Burkitt lymphoma and nasopharyngeal carcinoma. While the life cycle of EBV in B cells is well understood, EBV infection within epithelium is not, largely due to the inability to model productive replication in epithelium in vitro. Organotypic cultures generated from primary human keratinocytes can model many aspects of EBV infection, including productive replication in the suprabasal layers. The EBV glycoprotein BDLF2 is a positional homologue of the murine gammaherpesvirus-68 protein gp48, which plays a role in intercellular spread of viral infection, though sequence homology is limited. To determine the role that BDLF2 plays in EBV infection, we generated a recombinant EBV in which the BDLF2 gene has been replaced with a puromycin resistance gene. The ΔBDLF2 recombinant virus infected both B cell and HEK293 cell lines and was able to immortalize primary B cells. However, the loss of BDLF2 resulted in substantially fewer infected cells in organotypic cultures compared to wild-type virus. While numerous clusters of infected cells representing a focus of infection are observed in wild-type-infected organotypic cultures, the majority of cells observed in the absence of BDLF2 were isolated cells, suggesting that the EBV glycoprotein BDLF2 plays a major role in intercellular viral spread in stratified epithelium. IMPORTANCE The ubiquitous herpesvirus Epstein-Barr virus (EBV) is associated with cancers of B lymphocytes and epithelial cells and is primarily transmitted in saliva. While several models exist for analyzing the life cycle of EBV in B lymphocytes, models of EBV infection in the epithelium have more recently been established. Using an organotypic culture model of epithelium that we previously determined accurately reflects EBV infection in situ, we have ascertained that the loss of the viral envelope protein BDLF2 had little effect on the EBV life cycle in B cells but severely restricted the number of infected cells in organotypic cultures. Loss of BDLF2 has a substantial impact on the size of infected areas, suggesting that BDLF2 plays a specific role in the spread of infection in stratified epithelium.
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3
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The Major Envelope Glycoprotein of Murid Herpesvirus 4 Promotes Sexual Transmission. J Virol 2017; 91:JVI.00235-17. [PMID: 28424280 DOI: 10.1128/jvi.00235-17] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 04/10/2017] [Indexed: 12/25/2022] Open
Abstract
Gammaherpesviruses are important human and animal pathogens. Infection control has proven difficult because the key process of transmission is ill understood. Murid herpesvirus 4 (MuHV-4), a gammaherpesvirus of mice, is transmitted sexually. We show that this depends on the major virion envelope glycoprotein gp150. gp150 is redundant for host entry, and in vitro, it regulates rather than promotes cell binding. We show that gp150-deficient MuHV-4 reaches and replicates normally in the female genital tract after nasal infection but is poorly released from vaginal epithelial cells and fails to pass from the female to the male genital tract during sexual contact. Thus, we show that the regulation of virion binding is a key component of spontaneous gammaherpesvirus transmission.IMPORTANCE Gammaherpesviruses are responsible for many important diseases in both animals and humans. Some important aspects of their life cycle are still poorly understood. Key among these is viral transmission. Here we show that the major envelope glycoprotein of murid herpesvirus 4 functions not in entry or dissemination but in virion release to allow sexual transmission to new hosts.
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4
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Wu Y, Prager A, Boos S, Resch M, Brizic I, Mach M, Wildner S, Scrivano L, Adler B. Human cytomegalovirus glycoprotein complex gH/gL/gO uses PDGFR-α as a key for entry. PLoS Pathog 2017; 13:e1006281. [PMID: 28403202 PMCID: PMC5389851 DOI: 10.1371/journal.ppat.1006281] [Citation(s) in RCA: 119] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 03/08/2017] [Indexed: 01/05/2023] Open
Abstract
Herpesvirus gH/gL envelope glycoprotein complexes are key players in virus entry as ligands for host cell receptors and by promoting fusion of viral envelopes with cellular membranes. Human cytomegalovirus (HCMV) has two alternative gH/gL complexes, gH/gL/gO and gH/gL/UL128,130,131A which both shape the HCMV tropism. By studying binding of HCMV particles to fibroblasts, we could for the first time show that virion gH/gL/gO binds to platelet-derived growth factor-α (PDGFR-α) on the surface of fibroblasts and that gH/gL/gO either directly or indirectly recruits gB to this complex. PDGFR-α functions as an entry receptor for HCMV expressing gH/gL/gO, but not for HCMV mutants lacking the gH/gL/gO complex. PDGFR-α-dependent entry is not dependent on activation of PDGFR-α. We could also show that the gH/gL/gO—PDGFR-α interaction starts the predominant entry pathway for infection of fibroblasts with free virus. Cell-associated virus spread is either driven by gH/gL/gO interacting with PDGFR-α or by the gH/gL/UL128,130,131A complex. PDGFR-α-positive cells may thus be preferred first target cells for infections with free virus which might have implications for the design of future HCMV vaccines or anti-HCMV drugs. The identification of cellular receptors recognized by viral glycoproteins promoting entry is central for understanding virus pathogenesis and transmission for any virus. Although the roles of alternative gH/gL complexes of HCMV in cell tropism and virus spread have been extensively studied in cell culture, transfer to HCMV tropism in vivo is a controversial issue. Our characterization of the PDGFR-α –gH/gL/gO interaction offers an explanation for the tropism of HCMV for cells and tissues with high levels of surface PDGFR-α in vivo. Discrepant findings, when similar cell types were analyzed in culture, may retrospectively be attributed to a culture-dependent loss or up-regulation of PDGFR-α protein levels. Our finding that the PDGFR-α—gH/gL/gO interaction starts the predominant entry pathway for infection with free virus moves the gH/gL/gO complex in the center of interest for vaccines designed to prevent horizontal or vertical transmission and also for the development of CMV vaccine or gene therapy vectors.
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Affiliation(s)
- Yiquan Wu
- Max von Pettenkofer-Institute, Department of Virology, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Adrian Prager
- Max von Pettenkofer-Institute, Department of Virology, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Simone Boos
- Max von Pettenkofer-Institute, Department of Virology, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Moritz Resch
- Max von Pettenkofer-Institute, Department of Virology, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Ilija Brizic
- Max von Pettenkofer-Institute, Department of Virology, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Michael Mach
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Sabrina Wildner
- Max von Pettenkofer-Institute, Department of Virology, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Laura Scrivano
- Max von Pettenkofer-Institute, Department of Virology, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Barbara Adler
- Max von Pettenkofer-Institute, Department of Virology, Ludwig-Maximilians-University Munich, Munich, Germany
- * E-mail:
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5
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Vidick S, Leroy B, Palmeira L, Machiels B, Mast J, François S, Wattiez R, Vanderplasschen A, Gillet L. Proteomic characterization of murid herpesvirus 4 extracellular virions. PLoS One 2013; 8:e83842. [PMID: 24386290 PMCID: PMC3875534 DOI: 10.1371/journal.pone.0083842] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 11/18/2013] [Indexed: 12/18/2022] Open
Abstract
Gammaherpesvirinae, such as the human Epstein-Barr virus (EBV) and the Kaposi’s sarcoma associated herpesvirus (KSHV) are highly prevalent pathogens that have been associated with several neoplastic diseases. As EBV and KSHV are host-range specific and replicate poorly in vitro, animal counterparts such as Murid herpesvirus-4 (MuHV-4) have been widely used as models. In this study, we used MuHV-4 in order to improve the knowledge about proteins that compose gammaherpesviruses virions. To this end, MuHV-4 extracellular virions were isolated and structural proteins were identified using liquid chromatography tandem mass spectrometry-based proteomic approaches. These analyses allowed the identification of 31 structural proteins encoded by the MuHV-4 genome which were classified as capsid (8), envelope (9), tegument (13) and unclassified (1) structural proteins. In addition, we estimated the relative abundance of the identified proteins in MuHV-4 virions by using exponentially modified protein abundance index analyses. In parallel, several host proteins were found in purified MuHV-4 virions including Annexin A2. Although Annexin A2 has previously been detected in different virions from various families, its role in the virion remains controversial. Interestingly, despite its relatively high abundance in virions, Annexin A2 was not essential for the growth of MuHV-4 in vitro. Altogether, these results extend previous work aimed at determining the composition of gammaherpesvirus virions and provide novel insights for understanding MuHV-4 biology.
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Affiliation(s)
- Sarah Vidick
- Department of Infectious Diseases, Faculty of Veterinary Medicine, University of Liège, Liège, Belgium
| | - Baptiste Leroy
- Department of Proteomics and Microbiology, Research Institute for Biosciences Interdisciplinary Mass Spectrometry Center (CISMa), University of Mons, Mons, Belgium
| | - Leonor Palmeira
- Department of Infectious Diseases, Faculty of Veterinary Medicine, University of Liège, Liège, Belgium
| | - Bénédicte Machiels
- Department of Infectious Diseases, Faculty of Veterinary Medicine, University of Liège, Liège, Belgium
| | - Jan Mast
- Electron Microscopy Unit, Veterinary and Agrochemical Research Centre, Brussels, Belgium
| | - Sylvie François
- Department of Infectious Diseases, Faculty of Veterinary Medicine, University of Liège, Liège, Belgium
| | - Ruddy Wattiez
- Department of Proteomics and Microbiology, Research Institute for Biosciences Interdisciplinary Mass Spectrometry Center (CISMa), University of Mons, Mons, Belgium
| | - Alain Vanderplasschen
- Department of Infectious Diseases, Faculty of Veterinary Medicine, University of Liège, Liège, Belgium
| | - Laurent Gillet
- Department of Infectious Diseases, Faculty of Veterinary Medicine, University of Liège, Liège, Belgium
- * E-mail:
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6
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Jochmann R, Pfannstiel J, Chudasama P, Kuhn E, Konrad A, Stürzl M. O-GlcNAc transferase inhibits KSHV propagation and modifies replication relevant viral proteins as detected by systematic O-GlcNAcylation analysis. Glycobiology 2013; 23:1114-30. [PMID: 23580777 DOI: 10.1093/glycob/cwt028] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
O-GlcNAcylation is an inducible, highly dynamic and reversible post-translational modification, mediated by a unique enzyme named O-linked N-acetyl-d-glucosamine (O-GlcNAc) transferase (OGT). In response to nutrients, O-GlcNAc levels are differentially regulated on many cellular proteins involved in gene expression, translation, immune reactions, protein degradation, protein-protein interaction, apoptosis and signal transduction. In contrast to eukaryotic cells, little is known about the role of O-GlcNAcylation in the viral life cycle. Here, we show that the overexpression of the OGT reduces the replication efficiency of Kaposi's sarcoma-associated herpesvirus (KSHV) in a dose-dependent manner. In order to investigate the global impact of O-GlcNAcylation in the KSHV life cycle, we systematically analyzed the 85 annotated KSHV-encoded open reading frames for O-GlcNAc modification. For this purpose, an immunoprecipitation (IP) strategy with three different approaches was carried out and the O-GlcNAc signal of the identified proteins was properly controlled for specificity. Out of the 85 KSHV-encoded proteins, 18 proteins were found to be direct targets for O-GlcNAcylation. Selected proteins were further confirmed by mass spectrometry for O-GlcNAc modification. Correlation of the functional annotation and the O-GlcNAc status of KSHV proteins showed that the predominant targets were proteins involved in viral DNA synthesis and replication. These results indicate that O-GlcNAcylation plays a major role in the regulation of KSHV propagation.
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Affiliation(s)
- Ramona Jochmann
- Division of Molecular and Experimental Surgery, University Medical Center Erlangen, Friedrich-Alexander University of Erlangen-Nuremberg, Schwabachanlage 10, 91054 Erlangen, Germany
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7
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Frederico B, Milho R, May JS, Gillet L, Stevenson PG. Myeloid infection links epithelial and B cell tropisms of Murid Herpesvirus-4. PLoS Pathog 2012; 8:e1002935. [PMID: 23028329 PMCID: PMC3447751 DOI: 10.1371/journal.ppat.1002935] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Accepted: 08/14/2012] [Indexed: 11/18/2022] Open
Abstract
Gamma-herpesviruses persist in lymphocytes and cause disease by driving their proliferation. Lymphocyte infection is therefore a key pathogenetic event. Murid Herpesvirus-4 (MuHV-4) is a rhadinovirus that like the related Kaposi's Sarcoma-associated Herpesvirus persists in B cells in vivo yet infects them poorly in vitro. Here we used MuHV-4 to understand how virion tropism sets the path to lymphocyte colonization. Virions that were highly infectious in vivo showed a severe post-binding block to B cell infection. Host entry was accordingly an epithelial infection and B cell infection a secondary event. Macrophage infection by cell-free virions was also poor, but improved markedly when virion binding improved or when macrophages were co-cultured with infected fibroblasts. Under the same conditions B cell infection remained poor; it improved only when virions came from macrophages. This reflected better cell penetration and correlated with antigenic changes in the virion fusion complex. Macrophages were seen to contact acutely infected epithelial cells, and cre/lox-based virus tagging showed that almost all the virus recovered from lymphoid tissue had passed through lysM+ and CD11c+ myeloid cells. Thus MuHV-4 reached B cells in 3 distinct stages: incoming virions infected epithelial cells; infection then passed to myeloid cells; glycoprotein changes then allowed B cell infection. These data identify new complexity in rhadinovirus infection and potentially also new vulnerability to intervention. Rhadinoviruses cause lymphocytic cancers. Their infection of lymphocytes is therefore an important therapeutic target. How this occurs is unclear. One prevalent hypothesis has been that virions directly infect lymphocytes when they enter new hosts. Here we show that host entry by Murid Herpesvirus-4, a close relative of the Kaposi's Sarcoma-associated Herpesvirus, is an epithelial rather than a lymphocyte infection: the mucosal lymphoid colonization typical of acute infectious mononucleosis only occurred later. Macrophages were closely associated with the acutely infected epithelium, and most if not all of the virus reaching B cells showed evidence of previous myeloid cell infection. Macrophage-derived virions showed a greatly enhanced capacity for lymphocyte infection that was associated with antigenic changes in the viral fusion proteins. Thus host colonization required epithelial and myeloid infections before there was lymphocyte infection. The implication is that each of these infection events could be independently targeted to limit viral persistence.
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Affiliation(s)
| | | | | | | | - Philip G. Stevenson
- Division of Virology, Department of Pathology, University of Cambridge, Addenbrookes Hospital, Cambridge, United Kingdom
- * E-mail:
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8
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Abstract
Gammaherpesviruses are important pathogens in human and animal populations. During early events of infection, these viruses manipulate preexisting host cell signaling pathways to allow successful infection. The different proteins that compose viral particles are therefore likely to have critical functions not only in viral structures and in entry into target cell but also in evasion of the host's antiviral response. In this study, we analyzed the protein composition of bovine herpesvirus 4 (BoHV-4), a close relative of the human Kaposi's sarcoma-associated herpesvirus. Using mass spectrometry-based approaches, we identified 37 viral proteins associated with extracellular virions, among which 24 were resistant to proteinase K treatment of intact virions. Analysis of proteins associated with purified capsid-tegument preparations allowed us to define protein localization. In parallel, in order to identify some previously undefined open reading frames, we mapped peptides detected in whole virion lysates onto the six frames of the BoHV-4 genome to generate a proteogenomic map of BoHV-4 virions. Furthermore, we detected important glycosylation of three envelope proteins: gB, gH, and gp180. Finally, we identified 38 host proteins associated with BoHV-4 virions; 15 of these proteins were resistant to proteinase K treatment of intact virions. Many of these have important functions in different cellular pathways involved in virus infection. This study extends our knowledge of gammaherpesvirus virions composition and provides new insights for understanding the life cycle of these viruses.
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9
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Xiao J, Palefsky JM, Herrera R, Sunshine C, Tugizov SM. EBV-positive human sera contain antibodies against the EBV BMRF-2 protein. Virology 2009; 393:151-9. [PMID: 19698968 DOI: 10.1016/j.virol.2009.07.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2009] [Revised: 06/19/2009] [Accepted: 07/22/2009] [Indexed: 12/21/2022]
Abstract
We previously showed that the EBV glycoprotein BMRF-2 contains a functional integrin-binding Arg-Gly-Asp (RGD) domain that plays an important role in viral infection and cell-to-cell spread of progeny virions in oral epithelial cells. In this study, we found that EBV-seropositive human sera contain antibodies against BMRF-2. The inhibitory effect of EBV-positive sera on EBV infection of oral epithelial cells was substantially reduced by pre-incubation of serum samples with the BMRF-2 RGD peptide, suggesting that anti-BMRF-2 human antibodies possess neutralizing activity. EBV-specific sera reacted strongly with the BMRF-2 extracellular domain (170-213 aa) containing the RGD motif, whereas they reacted only weakly or not at all with a mutated form of the BMRF-2 extracellular domain containing AAA instead of RGD. These data indicate that RGD motif of BMRF-2 is part of an immunodominant antigenic determinant within the extracellular domain of BMRF-2 that may contribute to EBV neutralization during EBV reactivation.
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Affiliation(s)
- Jianqiao Xiao
- Department of Medicine, University of California, San Francisco, CA 94143-0654, USA
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10
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Xiao J, Palefsky JM, Herrera R, Berline J, Tugizov SM. EBV BMRF-2 facilitates cell-to-cell spread of virus within polarized oral epithelial cells. Virology 2009; 388:335-43. [PMID: 19394065 DOI: 10.1016/j.virol.2009.03.030] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Revised: 03/20/2009] [Accepted: 03/21/2009] [Indexed: 12/12/2022]
Abstract
We previously reported that the Epstein-Barr virus (EBV) BMRF-2 protein plays an important role in EBV infection of polarized oral epithelial cells by interacting with beta1 and alphav family integrins. Here we show that infection of polarized oral epithelial cells with B27-BMRF-2(low) recombinant virus, expressing a low level of BMRF-2, resulted in significantly smaller plaques compared with infection by parental B95-8 virus. BMRF-2 localized in the trans-Golgi network (TGN) and basolateral sorting vesicles and was transported to the basolateral membranes of polarized epithelial cells. Mutation of the tyrosine- and dileucine-containing basolateral sorting signal, YLLV, in the cytoplasmic domain of BMRF-2 led to the failure of its accumulation in the TGN and its basolateral transport. These data show that BMRF-2 may play an important role in promoting the spread of EBV progeny virions through lateral membranes of oral epithelial cells.
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Affiliation(s)
- Jianqiao Xiao
- Department of Medicine, University of California, San Francisco, USA
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11
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Loesing JB, Di Fiore S, Ritter K, Fischer R, Kleines M. Epstein-Barr virus BDLF2-BMRF2 complex affects cellular morphology. J Gen Virol 2009; 90:1440-1449. [PMID: 19264620 DOI: 10.1099/vir.0.009571-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Herpesvirus glycoproteins often form specific heterodimers that can fulfil functions that cannot be carried out by either of the partners acting alone. This study showed that interactions between the Epstein-Barr virus (EBV) multi-spanning transmembrane envelope protein BMRF2 and type II membrane protein BDLF2 influence the way in which these proteins are trafficked in the cell, and hence the subcellular compartment in which they accumulate. When expressed transiently in mammalian cells, BDLF2 accumulated in the endoplasmic reticulum (ER), whereas BMRF2 accumulated in the ER and Golgi apparatus. However, when the two proteins were co-expressed, BDLF2 was transported with BMRF2 to the Golgi apparatus and from there to the plasma membrane, where the proteins co-localized extensively. The distribution of the two proteins at the plasma membrane was reproducibly associated with dramatic changes in cellular morphology, including the formation of enlarged membrane protrusions and cellular processes whose adhesion extremities were organized by the actin cytoskeleton. A dominant-active form of the small GTPase RhoA was epistatic to this morphological phenotype, suggesting that RhoA is a central component of the signalling pathway that reorganizes the cytoskeleton in response to BDLF2-BMRF2. It was concluded that EBV produces a glycoprotein heterodimer that induces changes in cellular morphology through reorganization of the actin cytoskeleton and may facilitate virion spread between cells.
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Affiliation(s)
- Jens-Bernhard Loesing
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Forckenbeckstr. 6, 52074 Aachen, Germany.,Division of Virology, Department of Medical Microbiology, UK Aachen, RWTH Aachen, Pauwelsstr. 30, 52074 Aachen, Germany
| | - Stefano Di Fiore
- Institute for Molecular Biotechnology (IMB), RWTH Aachen, Worringerweg 1, 52074 Aachen, Germany
| | - Klaus Ritter
- Division of Virology, Department of Medical Microbiology, UK Aachen, RWTH Aachen, Pauwelsstr. 30, 52074 Aachen, Germany
| | - Rainer Fischer
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Forckenbeckstr. 6, 52074 Aachen, Germany
| | - Michael Kleines
- Division of Virology, Department of Medical Microbiology, UK Aachen, RWTH Aachen, Pauwelsstr. 30, 52074 Aachen, Germany
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12
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Gillet L, May JS, Stevenson PG. In vivo importance of heparan sulfate-binding glycoproteins for murid herpesvirus-4 infection. J Gen Virol 2009; 90:602-613. [PMID: 19218205 PMCID: PMC2885066 DOI: 10.1099/vir.0.005785-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2008] [Accepted: 11/27/2008] [Indexed: 11/18/2022] Open
Abstract
Many herpesviruses bind to heparan sulfate (HS). Murid herpesvirus-4 (MuHV-4) does so via its envelope glycoproteins gp70 and gH/gL. MuHV-4 gp150 further regulates an HS-independent interaction to make that HS-dependent too. Cell binding by MuHV-4 virions is consequently strongly HS-dependent. Gp70 and gH/gL show some in vitro redundancy: an antibody-mediated blockade of HS binding by one is well tolerated, whereas a blockade of both severely impairs infection. In order to understand the importance of HS binding for MuHV-4 in vivo, we generated mutants lacking both gL and gp70. As expected, gL(-)gp70(-) MuHV-4 showed very poor cell binding. It infected mice at high dose but not at low dose, indicating defective host entry. But once entry occurred, host colonization, which for MuHV-4 is relatively independent of the infection dose, was remarkably normal. The gL(-)gp70(-) entry deficit was much greater than that of gL(-) or gp70(-) single knockouts. And gp150 disruption, which allows HS-independent cell binding, largely rescued the gL(-)gp70(-) cell binding and host entry deficits. Thus, it appeared that MuHV-4 HS binding is important in vivo, principally for efficient host entry.
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Affiliation(s)
- Laurent Gillet
- Division of Virology, Department of Pathology, University of Cambridge, UK
| | - Janet S May
- Division of Virology, Department of Pathology, University of Cambridge, UK
| | - Philip G Stevenson
- Division of Virology, Department of Pathology, University of Cambridge, UK
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13
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Milho R, Smith CM, Marques S, Alenquer M, May JS, Gillet L, Gaspar M, Efstathiou S, Simas JP, Stevenson PG. In vivo imaging of murid herpesvirus-4 infection. J Gen Virol 2009; 90:21-32. [PMID: 19088269 PMCID: PMC2885022 DOI: 10.1099/vir.0.006569-0] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2008] [Accepted: 10/06/2008] [Indexed: 12/27/2022] Open
Abstract
Luciferase-based imaging allows a global view of microbial pathogenesis. We applied this technique to gammaherpesvirus infection by inserting a luciferase expression cassette into the genome of murine herpesvirus-4 (MuHV-4). The recombinant virus strongly expressed luciferase in lytically infected cells without significant attenuation. We used it to compare different routes of virus inoculation. After intranasal infection of anaesthetized mice, luciferase was expressed in the nose and lungs for 7-10 days and in lymphoid tissue, most consistently the superficial cervical lymph nodes, for up to 30 days. Gastrointestinal infection was not observed. Intraperitoneal infection was very different to intranasal, with strong luciferase expression in the liver, kidneys, intestines, reproductive tract and spleen, but none in the nose or lungs. The nose has not previously been identified as a site of MuHV-4 infection. After intranasal infection of non-anaesthetized mice, it was the only site of non-lymphoid luciferase expression. Nevertheless, lymphoid colonization and persistence were still established, even at low inoculation doses. In contrast, virus delivered orally was very poorly infectious. Inoculation route therefore had a major impact on pathogenesis. Low dose intranasal infection without anaesthesia seems most likely to mimic natural transmission, and may therefore be particularly informative about normal viral gene functions.
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Affiliation(s)
- Ricardo Milho
- Division of Virology, Department of Pathology, University of Cambridge, UK
| | | | - Sofia Marques
- Instituto de Microbiologia e Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Portugal
| | - Marta Alenquer
- Instituto de Microbiologia e Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Portugal
| | - Janet S. May
- Division of Virology, Department of Pathology, University of Cambridge, UK
| | - Laurent Gillet
- Division of Virology, Department of Pathology, University of Cambridge, UK
| | - Miguel Gaspar
- Division of Virology, Department of Pathology, University of Cambridge, UK
| | - Stacey Efstathiou
- Division of Virology, Department of Pathology, University of Cambridge, UK
| | - J. Pedro Simas
- Instituto de Microbiologia e Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Portugal
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Gore M, Hutt-Fletcher LM. The BDLF2 protein of Epstein-Barr virus is a type II glycosylated envelope protein whose processing is dependent on coexpression with the BMRF2 protein. Virology 2008; 383:162-7. [PMID: 18995876 DOI: 10.1016/j.virol.2008.10.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2008] [Revised: 09/30/2008] [Accepted: 10/03/2008] [Indexed: 01/12/2023]
Abstract
Epstein-Barr virus has been documented to encode for ten envelope glycoproteins, gB, gH, gL, gM, gN, gp350, gp42, gp78, gp150 and BMRF2. The BDLF2 open reading frame is also predicted to encode a type II membrane protein but, although found in the virion, it has been described as a component of the tegument. We show here that, as predicted, it is the eleventh envelope glycoprotein of the virus. The full length 65 kDa glycoprotein formed a complex with BMRF2 and, as its homologs in other gammaherpesviruses, was dependent on BMRF2, for authentic processing and transport. Two cleavage products of BDLF2 were also identified in cells and in purified virion particles, one corresponding approximately to the aminoterminal half of the protein, that remained associated with the full length form, and one corresponding to the carboxyterminal glycosylated portion of the protein which did not.
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Affiliation(s)
- Mindy Gore
- Department of Microbiology and Immunology, Center for Molecular and Tumor Virology and Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, LA 71130, USA
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15
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Gillet L, Colaco S, Stevenson PG. The Murid Herpesvirus-4 gL regulates an entry-associated conformation change in gH. PLoS One 2008; 3:e2811. [PMID: 18665235 PMCID: PMC2481400 DOI: 10.1371/journal.pone.0002811] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2008] [Accepted: 07/02/2008] [Indexed: 11/18/2022] Open
Abstract
The glycoprotein H (gH)/gL heterodimer is crucial for herpesvirus membrane fusion. Yet how it functions is not well understood. The Murid Herpesvirus-4 gH, like that of other herpesviruses, adopts its normal virion conformation by associating with gL. However, gH switched back to a gL-independent conformation after virion endocytosis. This switch coincided with a conformation switch in gB and with capsid release. Virions lacking gL constitutively expressed the down-stream form of gH, prematurely switched gB to its down-stream form, and showed premature capsid release with poor infectivity. These data argue that gL plays a key role in regulating a gH and gB functional switch from cell binding to membrane fusion.
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Affiliation(s)
- Laurent Gillet
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Susanna Colaco
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Philip G. Stevenson
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
- * E-mail:
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16
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May JS, Smith CM, Gill MB, Stevenson PG. An essential role for the proximal but not the distal cytoplasmic tail of glycoprotein M in murid herpesvirus 4 infection. PLoS One 2008; 3:e2131. [PMID: 18461133 PMCID: PMC2329910 DOI: 10.1371/journal.pone.0002131] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2008] [Accepted: 03/31/2008] [Indexed: 01/08/2023] Open
Abstract
Murid herpesvirus-4 (MuHV-4) provides a tractable model with which to define common, conserved features of gamma-herpesvirus biology. The multi-membrane spanning glycoprotein M (gM) is one of only 4 glycoproteins that are essential for MuHV-4 lytic replication. gM binds to gN and is thought to function mainly secondary envelopment and virion egress, for which several predicted trafficking motifs in its C-terminal cytoplasmic tail could be important. We tested the contribution of the gM cytoplasmic tail to MuHV-4 lytic replication by making recombinant viruses with varying C-terminal deletions. Removing an acidic cluster and a distal YXXΦ motif altered the capsid distribution somewhat in infected cells but had little effect on virus replication, either in vitro or in vivo. In contrast, removing a proximal YXXΦ motif as well completely prevented productive replication. gM was still expressed, but unlike its longer forms showed only limited colocalization with co-transfected gN, and in the context of whole virus appeared to support gN expression less well. We conclude that some elements of the gM cytoplasmic tail are dispensible for MuHV-4 replication, but the tail as a whole is not.
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Affiliation(s)
- Janet S May
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
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17
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Gill MB, Edgar R, May JS, Stevenson PG. A gamma-herpesvirus glycoprotein complex manipulates actin to promote viral spread. PLoS One 2008; 3:e1808. [PMID: 18350146 PMCID: PMC2262946 DOI: 10.1371/journal.pone.0001808] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2008] [Accepted: 02/10/2008] [Indexed: 11/19/2022] Open
Abstract
Viruses lack self-propulsion. To move in multi-cellular hosts they must therefore manipulate infected cells. Herpesviruses provide an archetype for many aspects of host manipulation, but only for alpha-herpesviruses in is there much information about they move. Other herpesviruses are not necessarily the same. Here we show that Murine gamma-herpesvirus-68 (MHV-68) induces the outgrowth of long, branched plasma membrane fronds to create an intercellular network for virion traffic. The fronds were actin-based and RhoA-dependent. Time-lapse imaging showed that the infected cell surface became highly motile and that virions moved on the fronds. This plasma membrane remodelling was driven by the cytoplasmic tail of gp48, a MHV-68 glycoprotein previously implicated in intercellular viral spread. The MHV-68 ORF58 was also required, but its role was simply transporting gp48 to the plasma membrane, since a gp48 mutant exported without ORF58 did not require ORF58 to form membrane fronds either. Together, gp48/ORF58 were sufficient to induce fronds in transfected cells, as were the homologous BDLF2/BMRF2 of Epstein-Barr virus. Gp48/ORF58 therefore represents a conserved module by which gamma-herpesviruses rearrange cellular actin to increase intercellular contacts and thereby promote their spread.
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Affiliation(s)
- Michael B. Gill
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Rachel Edgar
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Janet S. May
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Philip G. Stevenson
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
- * To whom correspondence should be addressed. E-mail:
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18
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Xiao J, Palefsky JM, Herrera R, Berline J, Tugizov SM. The Epstein-Barr virus BMRF-2 protein facilitates virus attachment to oral epithelial cells. Virology 2007; 370:430-42. [PMID: 17945327 DOI: 10.1016/j.virol.2007.09.012] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2007] [Revised: 09/05/2007] [Accepted: 09/13/2007] [Indexed: 12/12/2022]
Abstract
We previously reported that BMRF-2, an Epstein-Barr virus (EBV) glycoprotein, binds to beta1 family integrins and is important for EBV infection of polarized oral epithelial cells. To further study the functions of BMRF-2, we constructed a recombinant EBV that lacks BMRF-2 expression by homologous recombination in B95-8 cells. We found that lack of BMRF-2 resulted in about 50% reduction of EBV attachment to oral epithelial cells, but not to B lymphocytes, suggesting that BMRF-2 is critical for EBV infection in oral epithelial cells, but not in B lymphocytes. In polarized oral epithelial cells, infection rate of the recombinant EBV virus was about 4- to 8-fold lower than the wild-type B95-8 virus. Cell adhesion assays using the BMRF-2 RGD peptide and its RGE and AAA mutants showed that the RGD motif is critical for BMRF-2 binding to integrins. These data are consistent with our previous observation that interactions between EBV BMRF-2 and integrins are critical for infection of oral epithelial cells with EBV.
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Affiliation(s)
- Jianqiao Xiao
- Department of Medicine, University of California, San Francisco, CA 94143-0654, USA
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19
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Abstract
Herpesviruses use multiple virion glycoproteins to enter cells. How these work together is not well understood: some may act separately or they may form a single complex. Murine gammaherpesvirus 68 (MHV-68) gB, gH, gL, and gp150 all participate in entry. gB and gL are involved in binding, gB and gH are conserved fusion proteins, and gp150 inhibits cell binding until glycosaminoglycans are engaged. Here we show that a gH-specific antibody coprecipitates gB and thus that gH and gB are associated in the virion membrane. A gH/gL-specific antibody also coprecipitated gB, implying a tripartite complex of gL/gH/gB, although the gH/gB association did not require gL. The association was also independent of gp150, and gp150 was not demonstrably bound to gB or gH. However, gp150 incorporation into virions was partly gL dependent, suggesting that it too contributes to a single entry complex. gp150- and gL- gp150- mutants bound better than the wild type to B cells and readily colonized B cells in vivo. Thus, gp150 and gL appear to be epithelial cell-adapted accessories of a core gB/gH entry complex. The cell binding revealed by gp150 disruption did not require gL and therefore seemed most likely to involve gB.
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Affiliation(s)
- Laurent Gillet
- Division of Virology, Department of Pathology, Tennis Court Road, Cambridge CB2 1QP, United Kingdom
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20
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Gillet L, May JS, Colaco S, Stevenson PG. The murine gammaherpesvirus-68 gp150 acts as an immunogenic decoy to limit virion neutralization. PLoS One 2007; 2:e705. [PMID: 17684552 PMCID: PMC1931612 DOI: 10.1371/journal.pone.0000705] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Accepted: 07/05/2007] [Indexed: 11/19/2022] Open
Abstract
Herpesviruses maintain long-term infectivity without marked antigenic variation. They must therefore evade neutralization by other means. Immune sera block murine gammaherpesvirus-68 (MHV-68) infection of fibroblasts, but fail to block and even enhance its infection of IgG Fc receptor-bearing cells, suggesting that the antibody response to infection is actually poor at ablating virion infectivity completely. Here we analyzed this effect further by quantitating the glycoprotein-specific antibody response of MHV-68 carrier mice. Gp150 was much the commonest glycoprotein target and played a predominant role in driving Fc receptor-dependent infection: when gp150-specific antibodies were boosted, Fc receptor-dependent infection increased; and when gp150-specific antibodies were removed, Fc receptor-dependent infection was largely lost. Neither gp150-specific monoclonal antibodies nor gp150-specific polyclonal sera gave significant virion neutralization. Gp150 therefore acts as an immunogenic decoy, distorting the MHV-68-specific antibody response to promote Fc receptor-dependent infection and so compromise virion neutralization. This immune evasion mechanism may be common to many non-essential herpesvirus glycoproteins.
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Affiliation(s)
- Laurent Gillet
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Janet S. May
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Susanna Colaco
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Philip G. Stevenson
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
- * To whom correspondence should be addressed. E-mail:
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21
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Rosa GT, Gillet L, Smith CM, de Lima BD, Stevenson PG. IgG fc receptors provide an alternative infection route for murine gamma-herpesvirus-68. PLoS One 2007; 2:e560. [PMID: 17593961 PMCID: PMC1891442 DOI: 10.1371/journal.pone.0000560] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2007] [Accepted: 05/30/2007] [Indexed: 01/22/2023] Open
Abstract
Background Herpesviruses can be neutralized in vitro but remain infectious in immune hosts. One difference between these settings is the availability of immunoglobulin Fc receptors. The question therefore arises whether a herpesvirus exposed to apparently neutralizing antibody can still infect Fc receptor+ cells. Principal Findings Immune sera blocked murine gamma-herpesvirus-68 (MHV-68) infection of fibroblasts, but failed to block and even enhanced its infection of macrophages and dendritic cells. Viral glycoprotein-specific monoclonal antibodies also enhanced infection. MHV-68 appeared to be predominantly latent in macrophages regardless of whether Fc receptors were engaged, but the infection was not abortive and new virus production soon overwhelmed infected cultures. Lytically infected macrophages down-regulated MHC class I-restricted antigen presentation, endocytosis and their response to LPS. Conclusions IgG Fc receptors limit the neutralization of gamma-herpesviruses such as MHV-68.
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MESH Headings
- Animals
- Antibodies, Monoclonal/immunology
- Antibodies, Neutralizing/immunology
- Antigen Presentation
- Cells, Cultured
- Cytomegalovirus/genetics
- DNA, Viral/genetics
- Fibroblasts/immunology
- Fibroblasts/metabolism
- Fibroblasts/pathology
- Flow Cytometry
- Fluorescent Antibody Technique
- Glycoproteins/immunology
- Green Fluorescent Proteins/metabolism
- Herpesviridae Infections/immunology
- Herpesviridae Infections/metabolism
- Herpesviridae Infections/pathology
- Immediate-Early Proteins/genetics
- Macrophages, Peritoneal/immunology
- Macrophages, Peritoneal/metabolism
- Macrophages, Peritoneal/pathology
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Neutralization Tests
- Promoter Regions, Genetic/genetics
- Receptors, Fc/immunology
- Receptors, IgG/immunology
- Rhadinovirus/immunology
- Tumor Virus Infections/immunology
- Tumor Virus Infections/metabolism
- Tumor Virus Infections/pathology
- Virion/immunology
- Virus Replication
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Affiliation(s)
- Gustavo T. Rosa
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Laurent Gillet
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Christopher M. Smith
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Brigitte D. de Lima
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Philip G. Stevenson
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, United Kingdom
- * To whom correspondence should be addressed. E-mail:
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22
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Gill MB, Gillet L, Colaco S, May JS, de Lima BD, Stevenson PG. Murine gammaherpesvirus-68 glycoprotein H-glycoprotein L complex is a major target for neutralizing monoclonal antibodies. J Gen Virol 2006; 87:1465-1475. [PMID: 16690911 DOI: 10.1099/vir.0.81760-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Herpesviruses characteristically persist in immune hosts as latent genomes, but to transmit infection they must reactivate and replicate lytically. The interaction between newly formed virions and pre-existing antibody is therefore likely to be a crucial determinant of viral fitness. Murine gammaherpesvirus-68 (MHV-68) behaves as a natural pathogen of conventional, inbred mice and consequently allows such interactions to be analysed experimentally in a relatively realistic setting. Here, monoclonal antibodies (mAbs) were derived from MHV-68-infected mice and all those recognizing infected-cell surfaces were tested for their capacity to neutralize MHV-68 virions. All of the neutralizing mAbs identified were specific for the viral glycoprotein H (gH)-gL heterodimer and required both gH and gL to reproduce their cognate epitopes. Based on antibody interference, there appeared to be two major neutralization epitopes on gH-gL. Analysis of a representative mAb indicated that it blocked infection at a post-binding step--either virion endocytosis or membrane fusion.
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Affiliation(s)
- Michael B Gill
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Laurent Gillet
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Susanna Colaco
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Janet S May
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Brigitte D de Lima
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Philip G Stevenson
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
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