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Soldan SS, Su C, Monaco MC, Yoon L, Kannan T, Zankharia U, Patel RJ, Dheekollu J, Vladimirova O, Dowling JW, Thebault S, Brown N, Clauze A, Andrada F, Feder A, Planet PJ, Kossenkov A, Schäffer DE, Ohayon J, Auslander N, Jacobson S, Lieberman PM. Multiple sclerosis patient-derived spontaneous B cells have distinct EBV and host gene expression profiles in active disease. Nat Microbiol 2024:10.1038/s41564-024-01699-6. [PMID: 38806670 DOI: 10.1038/s41564-024-01699-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 04/11/2024] [Indexed: 05/30/2024]
Abstract
Epstein-Barr virus (EBV) is an aetiologic risk factor for the development of multiple sclerosis (MS). However, the role of EBV-infected B cells in the immunopathology of MS is not well understood. Here we characterized spontaneous lymphoblastoid cell lines (SLCLs) isolated from MS patients and healthy controls (HC) ex vivo to study EBV and host gene expression in the context of an individual's endogenous EBV. SLCLs derived from MS patient B cells during active disease had higher EBV lytic gene expression than SLCLs from MS patients with stable disease or HCs. Host gene expression analysis revealed activation of pathways associated with hypercytokinemia and interferon signalling in MS SLCLs and upregulation of forkhead box protein 1 (FOXP1), which contributes to EBV lytic gene expression. We demonstrate that antiviral approaches targeting EBV replication decreased cytokine production and autologous CD4+ T cell responses in this ex vivo model. These data suggest that dysregulation of intrinsic B cell control of EBV gene expression drives a pro-inflammatory, pathogenic B cell phenotype that can be attenuated by suppressing EBV lytic gene expression.
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Affiliation(s)
| | - Chenhe Su
- The Wistar Institute, Philadelphia, PA, USA
| | - Maria Chiara Monaco
- Neuroimmunology Branch, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, USA
| | - Leena Yoon
- The Wistar Institute, Philadelphia, PA, USA
| | | | | | | | | | | | - Jack W Dowling
- The Wistar Institute, Philadelphia, PA, USA
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Simon Thebault
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | | | - Annaliese Clauze
- Neuroimmunology Clinic, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, USA
| | - Frances Andrada
- Neuroimmunology Clinic, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, USA
| | - Andries Feder
- Division of Infectious Diseases, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Paul J Planet
- Division of Infectious Diseases, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | | | | | - Joan Ohayon
- Neuroimmunology Clinic, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, USA
| | | | - Steven Jacobson
- Neuroimmunology Branch, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, USA
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2
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Soldan S, Su C, Monaco MC, Brown N, Clauze A, Andrada F, Feder A, Planet P, Kossenkov A, Schäffer D, Ohayon J, Auslander N, Jacobson S, Lieberman P. Unstable EBV latency drives inflammation in multiple sclerosis patient derived spontaneous B cells. RESEARCH SQUARE 2023:rs.3.rs-2398872. [PMID: 36778367 PMCID: PMC9915775 DOI: 10.21203/rs.3.rs-2398872/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Epidemiological studies have demonstrated that Epstein-Barr virus (EBV) is a known etiologic risk factor, and perhaps prerequisite, for the development of MS. EBV establishes life-long latent infection in a subpopulation of memory B cells. Although the role of memory B cells in the pathobiology of MS is well established, studies characterizing EBV-associated mechanisms of B cell inflammation and disease pathogenesis in EBV (+) B cells from MS patients are limited. Accordingly, we analyzed spontaneous lymphoblastoid cell lines (SLCLs) from multiple sclerosis patients and healthy controls to study host-virus interactions in B cells, in the context of an individual's endogenous EBV. We identify differences in EBV gene expression and regulation of both viral and cellular genes in SLCLs. Our data suggest that EBV latency is dysregulated in MS SLCLs with increased lytic gene expression observed in MS patient B cells, especially those generated from samples obtained during "active" disease. Moreover, we show increased inflammatory gene expression and cytokine production in MS patient SLCLs and demonstrate that tenofovir alafenamide, an antiviral that targets EBV replication, decreases EBV viral loads, EBV lytic gene expression, and EBV-mediated inflammation in both SLCLs and in a mixed lymphocyte assay. Collectively, these data suggest that dysregulation of EBV latency in MS drives a pro-inflammatory, pathogenic phenotype in memory B cells and that this response can be attenuated by suppressing EBV lytic activation. This study provides further support for the development of antiviral agents that target EBV-infection for use in MS.
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Affiliation(s)
| | | | - Maria Chiara Monaco
- National Institutes of Health - National Institute of Neurological Disorders and Stroke
| | | | | | | | | | | | | | - Daniel Schäffer
- Computational Biology Department, Carnegie Mellon University
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3
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Bencun M, Klinke O, Hotz-Wagenblatt A, Klaus S, Tsai MH, Poirey R, Delecluse HJ. Translational profiling of B cells infected with the Epstein-Barr virus reveals 5' leader ribosome recruitment through upstream open reading frames. Nucleic Acids Res 2019. [PMID: 29529302 PMCID: PMC5887285 DOI: 10.1093/nar/gky129] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The Epstein-Barr virus (EBV) genome encodes several hundred transcripts. We have used ribosome profiling to characterize viral translation in infected cells and map new translation initiation sites. We show here that EBV transcripts are translated with highly variable efficiency, owing to variable transcription and translation rates, variable ribosome recruitment to the leader region and coverage by monosomes versus polysomes. Some transcripts were hardly translated, others mainly carried monosomes, showed ribosome accumulation in leader regions and most likely represent non-coding RNAs. A similar process was visible for a subset of lytic genes including the key transactivators BZLF1 and BRLF1 in cells infected with weakly replicating EBV strains. This suggests that ribosome trapping, particularly in the leader region, represents a new checkpoint for the repression of lytic replication. We could identify 25 upstream open reading frames (uORFs) located upstream of coding transcripts that displayed 5′ leader ribosome trapping, six of which were located in the leader region shared by many latent transcripts. These uORFs repressed viral translation and are likely to play an important role in the regulation of EBV translation.
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Affiliation(s)
- Maja Bencun
- German Cancer Research Center (DKFZ), F100, Pathogenesis of Virus Associated Tumors, Im Neuenheimer Feld 242, 69120 Heidelberg, Germany.,Inserm unit U1074, DKFZ, 69120 Heidelberg, Germany
| | - Olaf Klinke
- German Cancer Research Center (DKFZ), F100, Pathogenesis of Virus Associated Tumors, Im Neuenheimer Feld 242, 69120 Heidelberg, Germany.,Inserm unit U1074, DKFZ, 69120 Heidelberg, Germany
| | - Agnes Hotz-Wagenblatt
- German Cancer Research Center (DKFZ), Core Facility Genomics & Proteomics, Im Neuenheimer Feld 580, 69120 Heidelberg, Germany
| | - Severina Klaus
- German Cancer Research Center (DKFZ), F100, Pathogenesis of Virus Associated Tumors, Im Neuenheimer Feld 242, 69120 Heidelberg, Germany.,Inserm unit U1074, DKFZ, 69120 Heidelberg, Germany
| | - Ming-Han Tsai
- German Cancer Research Center (DKFZ), F100, Pathogenesis of Virus Associated Tumors, Im Neuenheimer Feld 242, 69120 Heidelberg, Germany.,Inserm unit U1074, DKFZ, 69120 Heidelberg, Germany
| | - Remy Poirey
- German Cancer Research Center (DKFZ), F100, Pathogenesis of Virus Associated Tumors, Im Neuenheimer Feld 242, 69120 Heidelberg, Germany.,Inserm unit U1074, DKFZ, 69120 Heidelberg, Germany
| | - Henri-Jacques Delecluse
- German Cancer Research Center (DKFZ), F100, Pathogenesis of Virus Associated Tumors, Im Neuenheimer Feld 242, 69120 Heidelberg, Germany.,Inserm unit U1074, DKFZ, 69120 Heidelberg, Germany
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4
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Majerciak V, Yang W, Zheng J, Zhu J, Zheng ZM. A Genome-Wide Epstein-Barr Virus Polyadenylation Map and Its Antisense RNA to EBNA. J Virol 2019; 93:e01593-18. [PMID: 30355690 PMCID: PMC6321932 DOI: 10.1128/jvi.01593-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 10/17/2018] [Indexed: 12/14/2022] Open
Abstract
Epstein-Barr virus (EBV) is a ubiquitous human pathogen associated with Burkitt's lymphoma and nasopharyngeal carcinoma. Although the EBV genome harbors more than a hundred genes, a full transcription map with EBV polyadenylation profiles remains unknown. To elucidate the 3' ends of all EBV transcripts genome-wide, we performed the first comprehensive analysis of viral polyadenylation sites (pA sites) using our previously reported polyadenylation sequencing (PA-seq) technology. We identified that EBV utilizes a total of 62 pA sites in JSC-1, 60 in Raji, and 53 in Akata cells for the expression of EBV genes from both plus and minus DNA strands; 42 of these pA sites are commonly used in all three cell lines. The majority of identified pA sites were mapped to the intergenic regions downstream of previously annotated EBV open reading frames (ORFs) and viral promoters. pA sites lacking an association with any known EBV genes were also identified, mostly for the minus DNA strand within the EBNA locus, a major locus responsible for maintenance of viral latency and cell transformation. The expression of these novel antisense transcripts to EBNA were verified by 3' rapid amplification of cDNA ends (RACE) and Northern blot analyses in several EBV-positive (EBV+) cell lines. In contrast to EBNA RNA expressed during latency, expression of EBNA-antisense transcripts, which is restricted in latent cells, can be significantly induced by viral lytic infection, suggesting potential regulation of viral gene expression by EBNA-antisense transcription during lytic EBV infection. Our data provide the first evidence that EBV has an unrecognized mechanism that regulates EBV reactivation from latency.IMPORTANCE Epstein-Barr virus represents an important human pathogen with an etiological role in the development of several cancers. By elucidation of a genome-wide polyadenylation landscape of EBV in JSC-1, Raji, and Akata cells, we have redefined the EBV transcriptome and mapped individual polymerase II (Pol II) transcripts of viral genes to each one of the mapped pA sites at single-nucleotide resolution as well as the depth of expression. By unveiling a new class of viral lytic RNA transcripts antisense to latent EBNAs, we provide a novel mechanism of how EBV might control the expression of viral latent genes and lytic infection. Thus, this report takes another step closer to understanding EBV gene structure and expression and paves a new path for antiviral approaches.
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Affiliation(s)
- Vladimir Majerciak
- Tumor Virus RNA Biology Section, RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland, USA
| | - Wenjing Yang
- Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Jing Zheng
- Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Jun Zhu
- Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Zhi-Ming Zheng
- Tumor Virus RNA Biology Section, RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland, USA
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5
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Comprehensive profiling of EBV gene expression in nasopharyngeal carcinoma through paired-end transcriptome sequencing. Front Med 2016; 10:61-75. [DOI: 10.1007/s11684-016-0436-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 01/15/2016] [Indexed: 12/11/2022]
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6
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Initiation of Epstein-Barr virus lytic replication requires transcription and the formation of a stable RNA-DNA hybrid molecule at OriLyt. J Virol 2010; 85:2837-50. [PMID: 21191028 DOI: 10.1128/jvi.02175-10] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The genetic elements of herpesvirus origins of lytic replication have been characterized in detail; however, much remains to be elucidated concerning their functional role in replication initiation. In the case of the Epstein-Barr virus (EBV), we have found that in addition to the two well-defined critical elements required for lytic replication (the upstream and downstream essential elements, UEE and DEE), the origin of lytic replication (OriLyt) also requires the presence of a GC-rich RNA in cis. The BHLF1 transcript is similar to the essential K5 transcript identified at the Kaposi's sarcoma-associated herpesvirus OriLyt. We have found that truncation of the BHLF1 transcript or deletion of the TATA box, but not the putative ATG initiation codon, reduce OriLyt function to background levels. By using an antibody specific for RNA-DNA hybrid molecules, we found the BHLF1 RNA stably annealed to its DNA template during the early steps of lytic reactivation. Furthermore, expression of human RNase H1, which degrades RNA in RNA-DNA hybrids, drastically reduces OriLyt-dependent DNA replication as well as recruitment of the viral single-stranded DNA binding protein BALF2 to OriLyt. These studies suggest that a GC-rich OriLyt transcript is an important component of gammaherpesvirus lytic origins and is required for initial strand separation and loading of core replication proteins.
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7
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Quantitative and qualitative RNA-Seq-based evaluation of Epstein-Barr virus transcription in type I latency Burkitt's lymphoma cells. J Virol 2010; 84:13053-8. [PMID: 20943983 DOI: 10.1128/jvi.01521-10] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
RNA-seq provides a rich source of transcriptome information with high qualitative and quantitative value. Here, we provide a pipeline for Epstein-Barr virus (EBV) transcriptome analysis using RNA-seq and we apply it to two type I latency cell lines, Mutu I and Akata. This analysis revealed substantial average expression levels of many lytic genes in predominantly latent cell populations. The lytic transcripts BHLF1 and LF3 were expressed at levels greater than those for 98% of all cellular polyadenylated transcripts. Exon junction mapping accurately identified the Qp-derived EBNA1 splicing pattern, lytic gene splicing, and a complex splicing pattern within the BamHI A region.
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8
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Immune evasion in Kaposi's sarcoma-associated herpes virus associated oncogenesis. Semin Cancer Biol 2008; 18:423-36. [PMID: 18948197 DOI: 10.1016/j.semcancer.2008.09.003] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2008] [Accepted: 09/26/2008] [Indexed: 12/11/2022]
Abstract
A hallmark of herpesviruses is a lifelong persistent infection, which often leads to diseases upon immune suppression of infected host. Kaposi's sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus 8 (HHV8), is etiologically linked to the development of Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), and Multicentric Castleman's disease (MCD). In order to establish a persistent infection, KSHV dedicates a large portion of its genomic information to sabotage almost every aspect of host immune system. Thus, understanding the interplay between KSHV and the host immune system is important in not only unraveling the complexities of viral persistence and pathogenesis, but also discovering novel therapeutic targets. This review summarizes current knowledge of host immune evasion strategies of KSHV and their contributions to KSHV-associated diseases.
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9
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Xue SA, Griffin BE. Complexities associated with expression of Epstein-Barr virus (EBV) lytic origins of DNA replication. Nucleic Acids Res 2007; 35:3391-406. [PMID: 17478522 PMCID: PMC1904260 DOI: 10.1093/nar/gkm170] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
EBV has two lytic origins (oriLyt) of DNA replication lying at divergent sites on the viral genome within a duplicated sequence (DS). The latter contains potential hairpin loops, ‘hinge’ elements and the promoters for transcripts from viral genes BHLF1 and LF3. These genes themselves consist largely of 125 and 102 bp repetitive sequences, respectively, and encode basic proteins. We have examined these genomic regions in detail in attempts to understand why lytic replication—necessary for virus survival—is so inefficient, and to identify controlling elements. Our studies uncovered a diverse family of promoters (P) for BHLF1 and LF3, only one pair of which (P1) proved sensitive to chemical inducing agents. The others (P2–P3/4), abutting the replication ‘core’ origin elements in DS and extending into 5′-unique sequences, may play roles in the maintenance of viral latency. We further identified a family of overlapping small complementary-strand RNAs that transverse the replication ‘core’ origin elements in a manner suggesting a role for them as ‘antisense’ species and/or DNA replication primers. Our data are discussed in terms of alternative lytic replication models. We suggest our findings might prove useful in seeking better control over viral lytic replication and devising strategies for therapy.
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MESH Headings
- Animals
- Cell Line
- DNA Replication
- DNA, Viral/biosynthesis
- Gene Expression Regulation, Viral
- Herpesvirus 4, Human/genetics
- Herpesvirus 4, Human/metabolism
- Herpesvirus 4, Human/physiology
- Humans
- Nuclease Protection Assays
- Promoter Regions, Genetic
- RNA, Antisense/analysis
- RNA, Messenger/biosynthesis
- RNA, Messenger/chemistry
- RNA, Viral/biosynthesis
- RNA, Viral/chemistry
- Replication Origin
- Reverse Transcriptase Polymerase Chain Reaction
- Transcription Initiation Site
- Transcription, Genetic
- Viral Proteins/biosynthesis
- Viral Proteins/genetics
- Virus Replication
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Affiliation(s)
| | - Beverly E. Griffin
- *To whom correspondence should be addressed. Tel: +44-207-594-3670; Fax: +44-207-410-1037;
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10
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Xue SA, Jones MD, Lu QL, Middeldorp JM, Griffin BE. Genetic diversity: frameshift mechanisms alter coding of a gene (Epstein-Barr virus LF3 gene) that contains multiple 102-base-pair direct sequence repeats. Mol Cell Biol 2003; 23:2192-201. [PMID: 12612089 PMCID: PMC149476 DOI: 10.1128/mcb.23.6.2192-2201.2003] [Citation(s) in RCA: 18] [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
Frameshift mutations provide recognized mechanisms for changing the coding potential of an organism. Here, multiple frameshifts are identified in repetitive sequences within an Epstein-Barr virus unspliced early gene, LF3, which is associated with the viral replicative cycle and also transcriptionally expressed in many virally associated tumors. On the DNA strand encoding LF3, there are three open reading frames, only one of which contains an initiation codon. Most (>95%) of the gene consists of numerous (>20, varying with cell source) GC-rich copies of a 102-bp direct repeat (called IR 4) flanked by small unique sequences. LF3 may express a protein if its initiation and termination codons reside in the same reading frame, but this is not always the case. Frameshifting events, occurring in short runs of pyrimidines (mainly C residues) in the repeats, give rise to mutations which may provide a mechanism for escape of an LF3 function from host surveillance. Sequence studies link these frameshifts to DNA replication errors. Notably, the number of sites in LF3 at which such mutations can occur permits a very large amount of diversity in this gene. Our data also suggest a second degeneracy mechanism within the protein itself, which influences its stability and may reflect a host defense mechanism. LF3 thus provides a potentially important model for studying the quest for supremacy between a virus and its host.
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Affiliation(s)
- Shao-An Xue
- Viral Oncology Unit, Division of Medicine, Wright-Fleming Institute, Imperial College of Science, Technology and Medicine at St. Mary's, Norfolk Place, London W2 1PG, UK
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11
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Abstract
Human herpesvirus 8, also known as Kaposi sarcoma-associated herpesvirus, is etiologically associated with Kaposi sarcoma and other rare malignancies. Human herpesvirus 8 infection is common in certain areas of Africa and Italy, but occurs in only 0% to 15% of adult populations in North America and Europe. Reports of human herpesvirus 8 prevalence of 3% to over 50% among children in Central Africa, Brazil, and South Texas suggest that horizontal transmission of human herpesvirus 8 occurs among children. Primary human herpesvirus 8 infection in immunocompetent children is associated with a fever and maculopapular rash.
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Affiliation(s)
- Hal B Jenson
- Department of Pediatrics and Center for Pediatric Research, Eastern Virginia Medical School and Children's Hospital of the King's Daughters, Norfolk, 23507, USA.
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12
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Davis CL. Interferon and cytotoxic chemotherapy for the treatment of post-transplant lymphoproliferative disorder. Transpl Infect Dis 2001; 3:108-18. [PMID: 11395969 DOI: 10.1034/j.1399-3062.2001.003002108.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Interferon-alpha and cytotoxic chemotherapy may be effective treatment modalities for the post-transplant lymphoproliferative disorder. Interferon-alpha may result in a complete response in up to 40% of patients, while chemotherapy may be effective in 75% of those failing local surgical excision, a reduction in immunosuppression, and an antiviral agent. Interferon may be used early after diagnosis in patients with relatively slowly growing tumors. Chemotherapy should be selected for patients with bulky, rapidly growing malignancies. The toxicity of chemotherapy may be minimized by discontinuing maintenance immunosuppression during chemotherapy, administering GCSF, and providing antimicrobial prophylaxis. Rejection is minimized by the reintroduction of maintenance immunosuppression when the patient is no longer neutropenic.
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Affiliation(s)
- C L Davis
- Division of Nephrology, Department of Medicine, University of Washington School of Medicine, Seattle, Washington, USA.
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13
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Xue SA, Lu QL, Poulsom R, Karran L, Jones MD, Griffin BE. Expression of two related viral early genes in Epstein-Barr virus-associated tumors. J Virol 2000; 74:2793-803. [PMID: 10684296 PMCID: PMC111770 DOI: 10.1128/jvi.74.6.2793-2803.2000] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The transcription of two early "leftwardly" expressed genes carrying repetitive sequences, IR2 and IR4, has been studied for Epstein-Barr virus-associated tumors, and for established B-cell lines, using sequence-specific probes generated for this purpose. Whereas the IR4 transcript was identified in every tumor and cell line assessed (except B95-8, with a deletion that removes the gene), expression of the IR2 gene was restricted to B lymphocytes. Though the promoters for both transcripts lie within homologous regions (D(L) and D(R)) in the viral genome, the IR2 promoter appears more tightly regulated. Detailed characterization of the IR4 transcript from a nasopharyngeal carcinoma tumor, C15, identifies a sequence variant of this gene that differs from those reported for B cells; in situ hybridization methods show transcription to be restricted to a subset of cells, with the strongest signals seen adjacent to host stroma. As with B cells in culture (Y. Gao, P. R. Smith, L. Karran, Q. L. Lu, and B. E. Griffin, J. Virol. 71:84-94, 1997), chemical induction enhanced transcriptional expression of the IR4 gene in the C15 tumor, although staining for both the IR4 antigen and that of the virus lytic switch, Zta, gave negative results. In a Burkitt's lymphoma biopsy specimen, however, both proteins were found expressed, notably in the same subset of cells. The data here and elsewhere (Gao et al., J. Virol., 1997) are consistent with a block to intracellular transport of the transcript(s) and suggest nuclear roles for it in tumors, possibly in RNA processing and viral lytic replication. Both roles could be fulfilled in the absence of translation.
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MESH Headings
- Amino Acid Sequence
- Animals
- Base Sequence
- Blotting, Northern
- Burkitt Lymphoma/pathology
- Burkitt Lymphoma/virology
- Callithrix
- Cell Line
- Cloning, Molecular
- DNA Probes
- DNA, Complementary
- DNA, Viral
- Gene Expression Regulation, Viral
- Genes, Immediate-Early
- Herpesvirus 4, Human/genetics
- Humans
- Immediate-Early Proteins/genetics
- Immediate-Early Proteins/physiology
- Mice
- Mice, Nude
- Molecular Sequence Data
- Nasopharyngeal Neoplasms/pathology
- Nasopharyngeal Neoplasms/virology
- Reverse Transcriptase Polymerase Chain Reaction
- Transcription, Genetic
- Tumor Cells, Cultured
- Viral Proteins/genetics
- Viral Proteins/physiology
- Viral Regulatory and Accessory Proteins
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Affiliation(s)
- S A Xue
- Department of Infectious Diseases (Virology), Imperial College School of Medicine, London W12 ONN, United Kingdom
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14
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Gao Y, Xue SA, Griffin BE. Sensitivity of an epstein-barr virus-positive tumor line, Daudi, to alpha interferon correlates with expression of a GC-rich viral transcript. Mol Cell Biol 1999; 19:7305-13. [PMID: 10523619 PMCID: PMC84724 DOI: 10.1128/mcb.19.11.7305] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The exquisite sensitivity of the Burkitt's lymphoma (BL)-derived cell line Daudi to type I interferons has not previously been explained. Here we show that expression of an Epstein-Barr virus (EBV) transcript, designated D-HIT (Y. Gao et al., J. Virol. 71:84-94, 1997), correlates with the sensitivity of different Daudi cell isolates (or that of other EBV-carrying cells, where known) to alpha interferon (IFN-alpha). D-HIT, transcribed from a GC-rich repetitive region (IR4) of the viral genome, is highly structured, responding to RNase digestion in a manner akin to double-stranded RNA. Comparing EBV-carrying BL cell lines with differing responses to IFN-alpha, we found the protein levels of the dsRNA-activated kinase, PKR, to be similar, whereas the levels of the autophosphorylated active form of PKR varied in a manner that correlated with endogenous levels of D-HIT expression. In a classical in vitro kinase assay, addition of either poly(I)-poly(C) or an in vitro-transcribed D-HIT homolog stimulated the autophosphorylation activity of PKR from IFN-alpha-treated cells in both EBV-positive and EBV-negative B lymphocytes. By transfection experiments, these RNAs were shown to reduce cell proliferation and to sensitize otherwise relatively insensitive Raji cells to IFN-alpha. The data lead to a model wherein the D-HIT viral RNA also serves as a possible transcriptional activator of IFN-alpha or cellular genes regulated by this cytokine.
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Affiliation(s)
- Y Gao
- Department of Infectious Diseases, Imperial College School of Medicine, London W12 0NN, United Kingdom
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