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Abstract
It is more than 50 years since the Epstein-Barr virus (EBV), the first human tumour virus, was discovered. EBV has subsequently been found to be associated with a diverse range of tumours of both lymphoid and epithelial origin. Progress in the molecular analysis of EBV has revealed fundamental mechanisms of more general relevance to the oncogenic process. This Timeline article highlights key milestones in the 50-year history of EBV and discusses how this virus provides a paradigm for exploiting insights at the molecular level in the diagnosis, treatment and prevention of cancer.
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Affiliation(s)
- Lawrence S Young
- Warwick Medical School, The University of Warwick, Coventry CV4 7AL, UK
| | - Lee Fah Yap
- Department of Oral and Craniofacial Sciences and Oral Cancer Research Coordinating Centre, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia
| | - Paul G Murray
- Institute of Cancer and Genomic Medicine, University of Birmingham, Vincent Drive, Edgbaston, Birmingham B15 2TT, UK
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2
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Abstract
The double-stranded DNA genomes of herpesviruses exist in at least three alternative global chromatin states characterised by distinct nucleosome content. When encapsidated in virus particles, the viral DNA is devoid of any nucleosomes. In contrast, within latently infected nuclei herpesvirus genomes are believed to form regular nucleosomal structures resembling cellular chromatin. Finally, during productive infection nuclear viral DNA appears to adopt a state of intermediate chromatin formation with irregularly spaced nucleosomes. Nucleosome occupancy coupled with posttranslational histone modifications and other epigenetic marks may contribute significantly to the extent and timing of transcription from the viral genome and, consequently, to the outcome of infection. Recent research has provided first insights into the viral and cellular mechanisms that either maintain individual herpesvirus chromatin states or mediate transition between them. Here, we summarise and discuss both early work and new developments pointing towards common principles pertinent to the dynamic structure and epigenetic regulation of herpesvirus chromatin. Special emphasis is given to the emerging similarities in nucleosome assembly and disassembly processes on herpes simplex virus type 1 and human cytomegalovirus genomes over the course of the viral productive replication cycle and during the switch between latent and lytic infectious stages.
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Affiliation(s)
- Christina Paulus
- Institute for Medical Microbiology and Hygiene, University of Regensburg, 93053 Regensburg, Germany
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3
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Bornkamm GW, Hammerschmidt W. Molecular virology of Epstein-Barr virus. Philos Trans R Soc Lond B Biol Sci 2001; 356:437-59. [PMID: 11313004 PMCID: PMC1088437 DOI: 10.1098/rstb.2000.0781] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Epstein-Barr virus (EBV) interacts with its host in three distinct ways in a highly regulated fashion: (i) EBV infects human B lymphocytes and induces proliferation of the infected cells, (ii) it enters into a latent phase in vivo that follows the proliferative phase, and (iii) it can be reactivated giving rise to the production of infectious progeny for reinfection of cells of the same type or transmission of the virus to another individual. In healthy people, these processes take place simultaneously in different anatomical and functional compartments and are linked to each other in a highly dynamic steady-state equilibrium. The development of a genetic system has paved the way for the dissection of those processes at a molecular level that can be studied in vitro, i.e. B-cell immortalization and the lytic cycle leading to production of infectious progeny. Polymerase chain reaction analyses coupled to fluorescent-activated cell sorting has on the other hand allowed a descriptive analysis of the virus-host interaction in peripheral blood cells as well as in tonsillar B cells in vivo. This paper is aimed at compiling our present knowledge on the process of B-cell immortalization in vitro as well as in vivo latency, and attempts to integrate this knowledge into the framework of the viral life cycle in vivo.
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Affiliation(s)
- G W Bornkamm
- Institut für Klinische Molekularbiologie und Tumorgenetik, Abteilung für Genvektoren, GSF-Forschungszentrum für Umwelt und Gesundheit, Marchioninistrasse 25, D-83177 München, Germany.
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4
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Stürzl M, Hohenadl C, Zietz C, Castanos-Velez E, Wunderlich A, Ascherl G, Biberfeld P, Monini P, Browning PJ, Ensoli B. Expression of K13/v-FLIP gene of human herpesvirus 8 and apoptosis in Kaposi's sarcoma spindle cells. J Natl Cancer Inst 1999; 91:1725-33. [PMID: 10528022 DOI: 10.1093/jnci/91.20.1725] [Citation(s) in RCA: 140] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Human herpesvirus 8 (HHV8) infection is associated with all forms of Kaposi's sarcoma (KS). The HHV8 genome locus ORFK13-72-73 (ORF = open reading frame) encodes proteins that may be important in HHV8-mediated pathogenesis, i.e., the latency-associated nuclear antigen (encoded by ORF73), viral-cyc-D (v-cyc-D), a viral homologue of cellular cyclin D (encoded by ORF72), and viral-FLIP (v-FLIP), a homologue of the cellular FLICE (Fas-associated death domain-like interleukin 1 beta-converting enzyme) inhibitory protein (encoded by ORFK13; is an inhibitor of apoptosis [programmed cell death]). Through differential splicing events, this locus expresses individual RNA transcripts that encode all three proteins (tricistronic transcripts) or just two of them (v-FLIP and v-cyc-D; bicistronic transcripts). We examined expression of these transcripts in KS tissues. METHODS We collected tissues from patients with KS of different stages. By use of an optimized in situ hybridization procedure, we examined different ORFK13-72-73 locus transcripts in HHV8-infected cells in skin lesions and in one adjacent lymph node. Apoptosis in KS lesions was determined by use of an in situ assay. RESULTS AND CONCLUSIONS Our results indicate the following: 1) Transcripts from the ORFK13-72-73 locus appear to be spliced differentially in latently infected KS cells in skin lesions and in HHV8-infected cells in lymph nodes; specifically, ORFK13-ORF72 bicistronic transcripts were expressed abundantly in KS cells, whereas ORFK13-ORF72-ORF73 tricistronic transcripts were detected only in lymph node cells. 2) Sequences encoding the antiapoptotic protein v-FLIP are expressed at very low levels in early KS lesions, but expression increases dramatically in late-stage lesions. 3) The increase in expression of v-FLIP-encoding transcripts is associated with a reduction in apoptosis in KS lesions. IMPLICATIONS These data suggest that functional v-FLIP is produced in vivo and that antiapoptotic mechanisms may be involved in the rapid growth of KS lesions, where only a few cells undergoing mitosis are generally observed.
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MESH Headings
- Antigens, Viral/analysis
- Antigens, Viral/genetics
- Apoptosis
- CASP8 and FADD-Like Apoptosis Regulating Protein
- Carrier Proteins/analysis
- Carrier Proteins/genetics
- Down-Regulation
- Gene Expression
- Genes, Viral
- Herpesvirus 8, Human/genetics
- Humans
- Immunohistochemistry
- In Situ Hybridization
- In Situ Nick-End Labeling
- Intracellular Signaling Peptides and Proteins
- Lymph Nodes/metabolism
- Lymph Nodes/virology
- Neoplasm Staging
- Nuclear Proteins/analysis
- Nuclear Proteins/genetics
- Open Reading Frames
- RNA Probes
- RNA, Messenger/analysis
- RNA, Neoplasm/analysis
- RNA, Viral/analysis
- Sarcoma, Kaposi/genetics
- Sarcoma, Kaposi/pathology
- Sarcoma, Kaposi/virology
- Transcription, Genetic
- Up-Regulation
- Viral Proteins/genetics
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Affiliation(s)
- M Stürzl
- Institute of Molecular Virology, GSF-National Research Center for Environment and Health, Neuherberg, Germany.
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5
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Speirs V, Green AR, Walton DS, Kerin MJ, Fox JN, Carleton PJ, Desai SB, Atkin SL. Short-term primary culture of epithelial cells derived from human breast tumours. Br J Cancer 1998; 78:1421-9. [PMID: 9836473 PMCID: PMC2063218 DOI: 10.1038/bjc.1998.702] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
As experimental models for breast cancer, most studies rely on established human breast cancer cell lines. However, many of these lines were established over 20 years ago, many from pleural effusions rather than the primary tumour, so the validity of using them as representative models is questionable. This paper describes our experiences, over a 3-year period, in establishing short-term epithelial-cell-enriched preparations from primary breast tumours based on differential centrifugation followed by culture in selective media. Epithelial cells were successfully cultured from 55% of samples, but culture success did not appear to be correlated with tumour histology, stage, grade or node status. Epithelial cell-enriched cultures were immunopositive for broad-spectrum cytokeratin and epithelial membrane antigen (EMA). Positivity for keratin 19 confirmed that the cultures contained tumour-derived cells, which additionally showed significantly higher activity of the reductive pathway of the steroid-converting enzyme 17beta-hydroxysteroid dehydrogenase type I. That the cultures contained tumour and not normal epithelial cells was further substantiated by the complete absence of the calmodulin-like gene NB-1 in tumour-derived cultures; this is only associated with normal breast epithelia. Eighty-five per cent of cultures established from oestrogen receptor (ER)-positive tumours expressed ER in vitro; this was functional in 66% of cultures, although ER-positive phenotype was gradually lost over time. In conclusion, epithelial cells can be isolated and maintained as short-term cultures from primary breast tumours irrespective of histopathological or clinical details, providing a model system with a greater biological and clinical relevance than breast cancer cell lines.
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Affiliation(s)
- V Speirs
- Department of Medicine, University of Hull, UK
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6
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Lennette ET, Rymo L, Yadav M, Masucci G, Merk K, Timar L, Klein G. Disease-related differences in antibody patterns against EBV-encoded nuclear antigens EBNA 1, EBNA 2 and EBNA 6. Eur J Cancer 1993; 29A:1584-9. [PMID: 8217366 DOI: 10.1016/0959-8049(93)90299-u] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Antibodies to Epstein-Barr virus (EBV) nuclear antigen family (EBNA) and three of its individual members, EBNA 1, EBNA 2 (A and B) and EBNA 6, were measured by anticomplement immunofluorescence (ACIF) in sera of 75 healthy controls, 13 patients with chronic EBV infection, 38 with non-Hodgkin lymphoma (NHL), 23 with Hodgkin's disease (HD), 105 with nasopharyngeal carcinoma (NPC) and 7 patients with infectious mononucleosis (IM). Their anti-EBV lytic antigens were also measured. We observed that: (1) anti-EBNA 2A and E6 rose in parallel 4-6 weeks after IM, followed by anti-EBNA 1 at 3-6 months, (2) all seropositive individuals had anti-EBNA 1; 74% also had anti-EBNA 2A and E6, (3) anti-EBNA 1 accounted for most of the anti-EBNA reactivity in non-IM sera. Striking disease-associated differences were noted on the humoral responses to the lytic and transformation-associated antigens. Compared to the controls, anti-EBNA 1, -EBNA 2A and -EBNA 6 were simultaneously four to 10 times higher in chronic reactivations, whereas only anti-EBNA 1 was elevated (10 times) in NPC. Individual EBNA titres were normal in NHL or HD patients.
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7
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The EBNA2-related resistance towards alpha interferon (IFN-alpha) in Burkitt's lymphoma cells effects induction of IFN-induced genes but not the activation of transcription factor ISGF-3. Mol Cell Biol 1992. [PMID: 1406670 DOI: 10.1128/mcb.12.11.4930] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Transfection of a plasmid encoding the Epstein-Barr virus (EBV) nuclear antigen 2 (EBNA2) gene confers resistance to the antiproliferative effect of alpha interferon (IFN-alpha) in EBV-negative U968 cells (P. Aman and A. von Gabain, EMBO J. 9:147-152, 1990). We studied the expression of IFN-stimulated genes (ISGs) in two pairs of Burkitt's lymphoma cell lines, differing in the expression of the putative immortalizing gene of EBV, EBNA2. In EBNA2-expressing cells, the induction of four ISGs by IFN-alpha was strongly reduced or, in some cases, abolished. Chloramphenicol acetyltransferase reporter gene constructs containing different IFN-stimulated response elements were transfected into EBNA2-negative and EBNA2-positive cells. Induction of chloramphenicol acetyltransferase activity by IFN was impaired in EBNA2-positive cells. Also, a reporter gene construct driven by an IFN-gamma-sensitive promoter element was affected. However, as revealed by gel shift assays, EBNA2-positive and EBNA2-negative cells exhibited a nearly identical pattern of IFN-stimulated response element-binding proteins. Most important, activation of the factor ISGF-3, which previously has been shown to be required and sufficient for transcriptional activation of IFN-induced genes, was not inhibited in IFN-resistant cells expressing EBNA2. The mechanism of the EBNA2-related IFN resistance seems to be distinct both from the resistance mediated by hepatitis virus and adenovirus gene products and from the IFN resistance in Daudi cell variants. In these three cases, the transcriptional block of IFN-induced genes is due to inhibition of ISGF-3 activation and binding. Our data suggest that the EBNA2-related IFN resistance in Burkitt's lymphoma cells acts downstream of the activation of ISGF-3.
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8
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Kanda K, Decker T, Aman P, Wahlström M, von Gabain A, Kallin B. The EBNA2-related resistance towards alpha interferon (IFN-alpha) in Burkitt's lymphoma cells effects induction of IFN-induced genes but not the activation of transcription factor ISGF-3. Mol Cell Biol 1992; 12:4930-6. [PMID: 1406670 PMCID: PMC360425 DOI: 10.1128/mcb.12.11.4930-4936.1992] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Transfection of a plasmid encoding the Epstein-Barr virus (EBV) nuclear antigen 2 (EBNA2) gene confers resistance to the antiproliferative effect of alpha interferon (IFN-alpha) in EBV-negative U968 cells (P. Aman and A. von Gabain, EMBO J. 9:147-152, 1990). We studied the expression of IFN-stimulated genes (ISGs) in two pairs of Burkitt's lymphoma cell lines, differing in the expression of the putative immortalizing gene of EBV, EBNA2. In EBNA2-expressing cells, the induction of four ISGs by IFN-alpha was strongly reduced or, in some cases, abolished. Chloramphenicol acetyltransferase reporter gene constructs containing different IFN-stimulated response elements were transfected into EBNA2-negative and EBNA2-positive cells. Induction of chloramphenicol acetyltransferase activity by IFN was impaired in EBNA2-positive cells. Also, a reporter gene construct driven by an IFN-gamma-sensitive promoter element was affected. However, as revealed by gel shift assays, EBNA2-positive and EBNA2-negative cells exhibited a nearly identical pattern of IFN-stimulated response element-binding proteins. Most important, activation of the factor ISGF-3, which previously has been shown to be required and sufficient for transcriptional activation of IFN-induced genes, was not inhibited in IFN-resistant cells expressing EBNA2. The mechanism of the EBNA2-related IFN resistance seems to be distinct both from the resistance mediated by hepatitis virus and adenovirus gene products and from the IFN resistance in Daudi cell variants. In these three cases, the transcriptional block of IFN-induced genes is due to inhibition of ISGF-3 activation and binding. Our data suggest that the EBNA2-related IFN resistance in Burkitt's lymphoma cells acts downstream of the activation of ISGF-3.
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Affiliation(s)
- K Kanda
- Department of Bacteriology, Karolinska Institute, Stockholm, Sweden
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9
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Allan GJ, Rowe DT. Size and stability of the Epstein-Barr virus major internal repeat (IR-1) in Burkitt's lymphoma and lymphoblastoid cell lines. Virology 1989; 173:489-98. [PMID: 2556840 DOI: 10.1016/0042-6822(89)90561-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
We have used field inversion gel electrophoresis to survey EBV strains for the size of the major internal repeat, IR-1, and estimate the number of 3.1-kb repeat units present. The B95-8 strain of EBV was estimated to contain 8.6 repeats. The repeat number varies considerably among naturally occurring isolates around a mean of six repeats. Some cell lines harbored multiple viral genomes with differing numbers of repeats and our results suggest that the repeat number in IR-1 is more likely to change during lytic replication than during latency. The Jijoye strain had 6.6 repeats and the Jijoye deletion mutant clone P3HR-1 retained 5.9 repeats setting the size of the P3HR-1 deletion at 6.8 kb. Thus, the nonimmortalizing mutant has retained all of the W1 and W2 exons of the immortalizing parent and has lost only the 3' unique exons of EBNA4 and all of EBNA2.
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MESH Headings
- Antigens, Viral/biosynthesis
- Antigens, Viral/genetics
- Blotting, Southern
- Burkitt Lymphoma
- Cell Line, Transformed
- DNA, Viral/genetics
- Electrophoresis, Agar Gel
- Epstein-Barr Virus Nuclear Antigens
- Exons
- Herpesvirus 4, Human/genetics
- Herpesvirus 4, Human/immunology
- Humans
- Lymphocytes
- RNA, Messenger/genetics
- RNA, Viral/genetics
- Repetitive Sequences, Nucleic Acid
- Restriction Mapping
- Tumor Cells, Cultured
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Affiliation(s)
- G J Allan
- Ludwig Institute for Cancer Research, St. Mary's Hospital Medical School, London, England
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10
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Masucci MG, Contreras-Salazar B, Ragnar E, Falk K, Minarovits J, Ernberg I, Klein G. 5-Azacytidine up regulates the expression of Epstein-Barr virus nuclear antigen 2 (EBNA-2) through EBNA-6 and latent membrane protein in the Burkitt's lymphoma line rael. J Virol 1989; 63:3135-41. [PMID: 2470924 PMCID: PMC250871 DOI: 10.1128/jvi.63.7.3135-3141.1989] [Citation(s) in RCA: 114] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Nonproductive infection of B lymphocytes by Epstein-Barr virus (EBV) is associated with a highly restricted expression of viral genes. In growth-transformed lymphoblastoid cell lines, the products of these genes include a complex of at least six EBV nuclear antigens (EBNAs) (EBNA-1 through EBNA-6) and one membrane protein (latent membrane protein [LMP]). EBV-carrying Burkitt's lymphoma (BL) biopsies and derived cell lines that have retained a representative phenotype (group I BL lines) express only EBNA-1 (M. Rowe, D. T. Rowe, C. D. Gregory, L. S. Young, P. J. Farrell, H. Rupani, and A. B. Rickinson, EMBO J. 6:2743-2751, 1987). We have found that EBNA-2 through EBNA-6 and LMP can be up regulated by treating the group I BL line Rael with the DNA-demethylating agent 5-azacytidine (5-AzaC). The drug acted in a time- and dose-dependent manner. EBNA-2-positive cells were detected by anti-complement immunofluorescence staining just 12 h after addition of 4 microM 5-AzaC and reached a maximum number at 72 h, when up to 75% of the population was positive. EBNA-2, EBNA-3, EBNA-4, EBNA-4, EBNA-6, and LMP were demonstrated immunoblots starting at 48 h. The EBV-encoded early antigens and viral capsid antigens were also induced but at a lower level. EBNA-2 and the lytic cycle-associated antigens appeared with a different time course and in largely nonoverlapping cell subpopulations, as demonstrated by double fluorescence staining. Thus, EBNA-2 expression was not restricted to lytically infected cells, nor was EBNA-2 required for entry into the lytic cycle. The coding and regulatory sequences of EBNA-2 and LMP were found to be highly methylated in Rael cells and were, as expected, demethylated after 5-AzaC treatment. These findings suggest that DNA methylation may participate in the regulation of growth transformation-associated viral genes in BL cells.
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Affiliation(s)
- M G Masucci
- Department of Tumor Biology, Karolinska Institute, Stockholm, Sweden
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11
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Szigeti R, Kallin B, Dillner J, Henle G, Henle W, Lerner RA, Rymo L, Timar L, Klein G. Epstein-Barr virus (EBV) antigen-specific leukocyte migration inhibition in infectious mononucleosis. II. Kinetics of sensitization against five EBV-encoded nuclear proteins and the latent membrane protein. CLINICAL IMMUNOLOGY AND IMMUNOPATHOLOGY 1989; 51:396-405. [PMID: 2470542 DOI: 10.1016/0090-1229(89)90037-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The T cell-mediated immune response of infectious mononucleosis (IM) patients to five Epstein-Barr virus (EBV)-determined nuclear antigens, EBNAs, and to the membrane antigen associated with growth-transformed cells (latent membrane protein, LMP) was measured by the leukocyte migration inhibition (LMI) assay. Two different antigen sources were used: extracts from cells that only expressed EBNA-1, EBNA-2, or LMP after transfection with the corresponding EBV-DNA fragment, and synthetic peptides deduced from the corresponding genes. Patients in the acute phase of the disease failed to respond to EBNA-1, -5, -6, and LMP, but became responsive during convalescence. The majority of the patients responded to EBNA-2 and/or EBNA-3 in the acute phase (9/15 and 12/15, respectively). The response to EBNA-2 and/or EBNA-3 in the acute phase (9/15 and 12/15, respectively). The response to EBNA-3 disappeared more often in convalescence than the response to EBNA-2: 6 of 15 patients were negative to EBNA-2 and 12 of 15 to EBNA-3 during recovery. In addition to its value in the assessment of host sensitization to virus EBV antigens, these studies and the derived hypotheses also provide certain predictions about the predominant antigen expression in the EBV-infected host under normal and pathological conditions that can be subjected to direct experimental tests.
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Affiliation(s)
- R Szigeti
- Department of Tumor Biology, Karolinska Institute, Stockholm, Sweden
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12
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Thorley-Lawson DA. Immunological responses to Epstein-Barr virus infection and the pathogenesis of EBV-induced diseases. BIOCHIMICA ET BIOPHYSICA ACTA 1989; 948:263-86. [PMID: 2537659 DOI: 10.1016/0304-419x(89)90002-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- D A Thorley-Lawson
- Department of Pathology, Tufts University, School of Medicine, Boston, MA 02111
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13
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Dillner J, Wendel-Hansen V, Kjellström G, Kallin B, Rosén A. Purification and characterization of the Epstein-Barr virus nuclear antigen 2 using monoclonal antipeptide antibodies. Int J Cancer 1988; 42:721-7. [PMID: 2846447 DOI: 10.1002/ijc.2910420516] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The Epstein-Barr virus (EBV) nuclear antigen 2 (EBNA-2) is the only one of the EBNA proteins to have been implicated as an EBV-encoded transforming protein. More detailed studies of this protein have been hampered by the lack of EBNA-2-specific monoclonal antibodies (MAbs) and of purified protein. To overcome these problems, we isolated 5 hybridomas producing MAbs reactive with an 18 residue synthetic peptide corresponding to the carboxyterminus of EBNA-2. Four of the 5 MAbs were specifically reactive with EBNA-2 in its denatured form on immunoblots. The 5th antibody (115E) was reactive with the native form of EBNA-2. By using a one-step immunoaffinity purification method with 115E cross-linked to protein-A-Sepharose, we purified EBNA-2 to homogeneity, i.e., more than 1,200-fold, from Burkitt lymphoma cell extracts. A major 32-kDa associated protein and a less abundant 17-kDa protein were co-purified with EBNA-2. Immunoprecipitation with 115E from 35S-methionine-labelled cell extracts showed that the 32-kDa protein co-precipitated with EBNA-2 from EBV-positive cells, but was not detectable in immunoprecipitates of EBV-negative cells. When the immunoprecipitates or the purified proteins were immunoblotted with EBV-immune sera, only EBNA-2 was reactive, indicating that the associated proteins are of cellular origin. Immunoprecipitation of cells labelled with 32P-orthophosphate showed that EBNA-2, but not the associated proteins, is a phosphoprotein. The expression level of EBNA-2 varied between different EBV-carrying cell lines, as measured by a 2-site ELISA based on antibody 115E. In indirect immunofluorescence, the 115E MAb gave an EBNA-2-specific characteristic granular staining pattern. These characteristics of EBNA-2 resemble those of other viral transforming proteins.
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Affiliation(s)
- J Dillner
- Department of Medical Cell Genetics, Karolinska Institute, Stockholm, Sweden
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14
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Wen LT, Tanaka A, Nonoyama M. Identification of Marek's disease virus nuclear antigen in latently infected lymphoblastoid cells. J Virol 1988; 62:3764-71. [PMID: 2843674 PMCID: PMC253520 DOI: 10.1128/jvi.62.10.3764-3771.1988] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
A new Marek's disease virus (MDV) nuclear antigen (MDNA) was identified in two MDV-transformed T-lymphoblastoid cell lines, MKT-1 and MSB-1, derived from chickens bearing tumors induced by MDV. This MDNA was not detected in MSB-1 cells maintained in iododeoxyuridine, which activates the latent MDV genome. Moreover, it was not found in chicken embryo fibroblasts undergoing productive and cytolytic infection with MDV. Expression of MDNA is not related to strain pathogenicity in chickens, because chicken embryo fibroblasts productively infected with the pathogenic RBIB strain or the nonpathogenic CV-1 strain of MDV did not express this antigen. DNA-protein immunoprecipitation studies revealed that MDNA bound to two sites in the 190,00-base-pair (bp) MDV genome. One of these loci identified by MDNA obtained from MKT-1 and MSB-1 cells corresponded to a 476-bp segment within the short unique region of BamHI-A MDV DNA. A second locus located in a 280-bp segment within the short inverted repeat region of BamHI-A was also identified by MDNA from MSB-1 cells but not by MDNA obtained from MKT-1 cells. Analyses of the nucleotide sequence by DNase digestion showed that MDNA protected a 60-bp segment spanning a 22-bp palindromic sequence of the short unique region and a 103-bp sequence encompassing a 32-bp palindrome in the short inverted repeat region of BamHI-A MDV DNA.
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Affiliation(s)
- L T Wen
- Department of Virology, Showa University Research Institute for Biomedicine, St. Petersburg, Florida 33716
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15
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Pagano JS, Kenney S, Markovitz D, Kamine J. Epstein-Barr virus and interactions with human retroviruses. J Virol Methods 1988; 21:229-39. [PMID: 2846614 DOI: 10.1016/0166-0934(88)90069-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
There is accumulating evidence for interaction of Epstein-Barr virus (EBV) and human immunodeficiency virus (HIV): EBV and HIV may coinfect B-lymphocytes; the prevalence of active EBV is increased in active homosexuals; and EBV-related B-cell lymphomas occur frequently in AIDS patients. We have shown that cord-blood B-lymphocytes may become infected by HIV once preinfected and transformed by EBV. The present paper, in addition, summarizes mechanisms of transactivation of an HIV LTR construct by an EBV gene product. Also, preliminary data are presented on the activation of an EBV promoter by the human T-cell leukemia virus (HTLV-1).
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Affiliation(s)
- J S Pagano
- Department of Medicine, University of North Carolina, Chapel Hill 27599
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16
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Shimizu N, Yamaki M, Sakuma S, Ono Y, Takada K. Three Epstein-Barr virus (EBV)-determined nuclear antigens induced by the BamHI E region of EBV DNA. Int J Cancer 1988; 41:744-51. [PMID: 2835324 DOI: 10.1002/ijc.2910410518] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
In our previous study (Takada et al., 1986a), we showed that the BamHI E fragment of Epstein-Barr virus (EBV) DNA induces a nuclear antigen that is detected by human antisera against EBV-determined nuclear antigen (EBNA), when transfected into baby hamster kidney (BHK) cells. The present study shows that the sub-fragment containing the central open reading frame BERF2b of the BamHI E fragment (Baer et al., 1984) is responsible for nuclear antigen induction. In addition, 2 fragments corresponding to 2 other open reading frames of the BamHI E, BERFI and BERF4 also induce nuclear antigens upon transfection into BHK cells. These 3 antigens, designated RF2b, RFI and RF4 antigens, were serologically classified as EBNA and antigenically distinct. In immunoblotting analysis of latently EBV-infected BJ-B95-8 cells, 3 high-molecular-weight polypeptides (136, 142 and 147 kDa) were identified by anti-EBNA sera. Immunoblotting analysis of transfected BHK cells indicated that the RF2b antigen is 145 kDa in its native form and antigenically related to the 147-kDa protein of BJ-B95-8 cells. Although RFI and RF4 antigens were not detected by immunoblotting, reactivities of sera with RFI and RF4 antigens in the immunofluorescence test were correlated with those of sera with the 136- and 142-kDa polypeptides of BJ-B95-8 cells, respectively. The results suggest that 3 high-molecular-weight proteins of latently EBV-infected cells are encoded by 3 open reading frames of the BamHI E DNA fragment.
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Affiliation(s)
- N Shimizu
- Department of Microbiology, Nihon University School of Medicine, Tokyo, Japan
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17
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Kitagawa H, Iho S, Yokochi T, Hoshino T. Detection of antibodies to the Epstein-Barr virus nuclear antigens in the sera from patients with systemic lupus erythematosus. Immunol Lett 1988; 17:249-52. [PMID: 2836302 DOI: 10.1016/0165-2478(88)90037-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The sera from 65 patients with systemic lupus erythematosus (SLE) were examined by the immunoblotting method to detect antibodies to Epstein-Barr virus (EBV)-associated antigens, especially EBV nuclear antigens (EBNA), and compared with the sera from 66 healthy subjects roughly age- and sex-matched to the patients. Most sera from patients with SLE defined three major EBV-associated antigens with molecular weights (MW) of 70,000 (70K), 90K and 140K in Raji cells, which must correspond to the EBNA-1, 2, and 3, respectively. Approximately 70% of the sera from SLE patients demonstrated the antibodies to the 90K and 140K antigens, whereas the positive rates of these two antibodies were less than 10% in the sera from healthy subjects. The differences of these positive rates of the antibodies between SLE patients and healthy subjects were statistically highly significant. Antibody to EBNA-1 was conspicuously detected in the sera from both SLE patients and healthy subjects, although the difference between the two groups was still significant. The possible role of EBV infection was discussed on the basis of the pathogenesis of SLE.
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Affiliation(s)
- H Kitagawa
- Department of Immunology and Parasitology, Fukui Medical School, Japan
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18
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Affiliation(s)
- J Dillner
- Department of Tumor Biology, Karolinska Institute, Stockholm, Sweden
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19
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Joab I, Rowe DT, Bodescot M, Nicolas JC, Farrell PJ, Perricaudet M. Mapping of the gene coding for Epstein-Barr virus-determined nuclear antigen EBNA3 and its transient overexpression in a human cell line by using an adenovirus expression vector. J Virol 1987; 61:3340-4. [PMID: 3041055 PMCID: PMC255922 DOI: 10.1128/jvi.61.10.3340-3344.1987] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The open reading frame which lies within the Epstein-Barr virus (EBV) T2 cDNA isolated by Bodescot et al. (M. Bodescot, O. Brison, and M. Perricaudet, Nucleic Acids Res. 14:2611-2620, 1986) was inserted into a eucaryotic expression vector containing a strong adenovirus promoter. The T2 cDNA contains viral genomic sequences from the short BLRF3 open reading frame fused to the adjacent BERF1 long open reading frame. After transfection of human cells, the recombinant plasmid directed the expression of a 140-kilodalton protein. The expressed protein had the same molecular weight, subcellular localization, and immunological characteristics as the EBV-determined nuclear antigen EBNA3, which is made in lymphocytes latently infected with EBV. Immunoprecipitation of extracts of transfected cells labeled with [32P]phosphoric acid showed that the EBNA3 protein is phosphorylated.
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20
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Seigneurin JM, Lavoue MF, Genoulaz O, Bornkamm GW, Lenoir GM. Antibody response against the Epstein-Barr virus-coded nuclear antigen2 (EBNA2) in different groups of individuals. Int J Cancer 1987; 40:349-53. [PMID: 3040599 DOI: 10.1002/ijc.2910400311] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Specific antibody responses against the 2 major subcomponents of EBNA, EBNA1 and EBNA2 were evaluated, in order to study whether this serological study was beneficial compared to classical EBV serology. During this investigation, 491 sera, obtained from blood donors and patients with Burkitt's lymphoma (BL), nasopharyngeal carcinoma (NPC), infectious mononucleosis (IM), Hodgkin's disease, renal transplantation, rheumatoid arthritis and Human Immunodeficiency Virus (HIV) infection, were tested. While the anti-EBNA1 response followed the classical anti-EBNA/Raji response (99% of anti-EBNA/Raji-positive sera also recognize EBNA1), the anti-EBNA2 response was much less frequent and did not correlate with either anti-EBNA/Raji or anti-EA antibodies. In a control population, 8% of individuals had antiEBNA2 antibodies at titers greater than or equal to 10. The percentage was 45% in NPC and 38% in EBV-associated BL; thus, although not detected in all patients with EBV-associated tumors, anti-EBNA2 serology might be a useful marker in BL and NPC. No antibody was detected in the early course of IM, but in rheumatoid arthritis and in HIV-infected patients, the percentage of positive individuals reached 54 and 68, respectively. Seroconversion to EBNA2 was noted in a few cases, including renal transplant recipients, AIDS patients, and complicated IM. This suggests that in these situations, EBNA 2 serology might represent a useful marker related to modulation of the immune status or EBV reactivation.
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21
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Hatzubai A, Anafi M, Masucci MG, Dillner J, Lerner RA, Klein G, Sulitzeanu D. Down-regulation of the EBV-encoded membrane protein (LMP) in Burkitt lymphomas. Int J Cancer 1987; 40:358-64. [PMID: 3040601 DOI: 10.1002/ijc.2910400313] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A radioimmunoassay (RIA) has been developed and used to determine the expression of LMP-a membrane protein encoded by the LT3 region of the Epstein-Barr virus (EBV) genome-in cell lines of various origins. The RIA was highly sensitive, specific and reproducible. All EBV-negative cell lines were LMP-negative and 18 of 21 EBV-carrying cells were LMP-positive. LMP concentrations varied widely, ranging approximately from less than 4 ng up to 650 ng/mg protein. In several instances comparisons were made between lymphoblastoid (LCLs) and Burkitt lymphoma (BL) cell lines (EBV-positive or EBV-converted sublines of originally EBV-negative BL) originating from the same patient. In all such cases LMP and LMP-specific mRNA levels were higher in the LCLs. Most of the LMP was found in the cytosol fraction, yet this fraction was negative in immunoblotting tests. However, antiserum preincubated with the cytosol lost its ability to react in immunoblotting with membrane LMP, indicating that the 2 LMP forms (membrane and cytosol) are completely cross-reactive.
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22
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Welinder C, Larsson NG, Szigeti R, Ehlin-Henriksson B, Henle G, Henle W, Klein G, Ricksten A, Rymo L, Sulitzeanu D. Stable transfection of a human lymphoma line by sub-genomic fragments of Epstein-Barr virus DNA to measure humoral and cellular immunity to the corresponding proteins. Int J Cancer 1987; 40:389-95. [PMID: 3040603 DOI: 10.1002/ijc.2910400318] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
An Epstein-Barr virus (EBV)-negative human lymphoid B-cell line, DG75, was stably transfected with recombinant selection vectors that carry a subfragment of the BamHI WYH region (nucleotides 44664 to 50628), the BamHI K fragment, or a subfragment of the EcoRI D region (nucleotides 166614 to 170149) of B95-8 EBV DNA. These fragments contain the coding exons for the EBV-determined nuclear antigens EBNA2 and EBNA1, and the membrane antigen LMP, respectively. Antigen expression of the cells was detected by immunofluorescence. EBNA2 was expressed in 80-100% of the transfected cells, in contrast to EBNA1 which was expressed in only 25%, and LMP in only about 5% of the cells. Humoral antibody responses were measured by immunofluorescence and compared to cellular immunity as determined by the leukocyte migration inhibition (LMI) technique. Extracts from transfected cell lines expressing EBNA1, EBNA2 or LMP elicited an LMI response with cells from healthy EBV-seropositive individuals whereas the extract from the parental DG75 cell line did not. The results demonstrate the value of stably transfected cell lines expressing a defined EBV antigen for the monospecific analysis of host responses to the EBV-encoded antigen complex in growth-transformed cells.
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23
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Rowe M, Rowe DT, Gregory CD, Young LS, Farrell PJ, Rupani H, Rickinson AB. Differences in B cell growth phenotype reflect novel patterns of Epstein-Barr virus latent gene expression in Burkitt's lymphoma cells. EMBO J 1987; 6:2743-51. [PMID: 2824192 PMCID: PMC553698 DOI: 10.1002/j.1460-2075.1987.tb02568.x] [Citation(s) in RCA: 454] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Recently established Epstein-Barr virus (EBV)-positive Burkitt's lymphoma (BL) cell lines, carrying chromosomal translocations indicative of their malignant origin, have been monitored for their degree of in vitro progression towards a more 'lymphoblastoid' cell surface phenotype and growth pattern, and for their expression of three EBV latent gene products which are constitutively present in all virus-transformed normal lymphoblastoid cell lines (LCLs). BL cell lines which stably retained the original tumour biopsy phenotype on serial passage were all positive for the nuclear antigen EBNA 1 but did not express detectable amounts of two other 'transforming' proteins, EBNA 2 and the latent membrane protein (LMP). This novel pattern of EBV gene expression was also observed on direct analysis of BL biopsy tissue. All three viral proteins became detectable, however, in BL cell lines which had progressed towards a more LCL-like phenotype in vitro. This work establishes a link between B cell phenotype and the accompanying pattern of EBV latent gene expression, and identifies a novel type of EBV:cell interaction which may be unique to BL cells.
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Affiliation(s)
- M Rowe
- Department of Cancer Studies, University of Birmingham, U.K
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24
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Rickinson AB, Young LS, Rowe M. Influence of the Epstein-Barr virus nuclear antigen EBNA 2 on the growth phenotype of virus-transformed B cells. J Virol 1987; 61:1310-7. [PMID: 3033261 PMCID: PMC254104 DOI: 10.1128/jvi.61.5.1310-1317.1987] [Citation(s) in RCA: 238] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Epstein-Barr virus (EBV) isolates show sequence divergence in the BamHI YH region of the genome which encodes the nuclear antigen EBNA 2, a protein thought to be involved in the initiation of virus-induced B-cell transformation; type A isolates (such as B95-8 EBV) encode a 82- to 87-kilodalton EBNA 2A protein, whereas type B isolates (such as AG876 EBV) encode an antigenically distinct 75-kilodalton EBNA 2B protein. In the present work 12 type A isolates and 8 type B isolates have been compared for their ability to transform resting human B cells in vitro into permanent lymphoblastoid cell lines. Although the kinetics of initial focus formation was not markedly dependent upon the EBNA 2 type of the transforming virus, on subsequent passage type A virus-transformed cells (type A transformants) yielded cell lines much more readily than did type B transformants. Direct comparison between the two types of transformant revealed clear differences in several aspects of growth phenotype. Compared with type A transformants, cell lines established with type B virus isolates consistently displayed an unusual growth pattern with poor survival of individual cells shed from lymphoblastoid clumps, a lower growth rate and a greater sensitivity to seeding at limiting dilutions, and a significantly lower saturation density that could not be corrected by supplementation of the medium with culture supernatant containing B-cell growth factors. This is the first direct evidence that, in EBV-transformed B-cell lines, the EBNA 2 protein plays a continuing role in determining the cellular growth phenotype.
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25
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Gergely L, Czeglédy J, Váczi L, Pálóczi K, Szegedi G. Antibodies to the second Epstein-Barr virus nuclear antigen in non-Hodgkin lymphomas. Med Microbiol Immunol 1987; 176:175-9. [PMID: 3600498 DOI: 10.1007/bf00193899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Human antibodies against the first and second Epstein-Barr virus encoded nuclear antigens (EBNA-1 and EBNA-2) were analysed by modified ELISA reaction on immunoblots: 5 out of 20 EBNA-1 positive, healthy donor sera reacted with the EBNA-2. Healthy EBV seronegatives contained no antibodies against EBNA-2. The antibodies against this EBNA-2 developed several months after acute EBV infections. Four out of 8 infectious mononucleosis sera failed to react EBNA-2 in the late stage. In the group of EBV seropositive patients with non-Hodgkin lymphoma, 14 out of 18 sera contained EBNA-2 antibodies.
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26
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Wendel-Hansen V, Rosén A, Klein G. EBV-transformed lymphoblastoid cell lines down-regulate EBNA in parallel with secretory differentiation. Int J Cancer 1987; 39:404-8. [PMID: 3546163 DOI: 10.1002/ijc.2910390322] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Four monoclonal and one polyclonal lymphoblastoid cell line (LCL) were studied with regard to cytoplasmic immunoglobulin (cIg) expression, presence of the Epstein-Barr virus (EBV)-determined nuclear antigen (EBNA) and DNA synthesis. Each line was found to consist of two subpopulations, with only minimal overlap. Proliferating, EBNA-positive, cIg-negative cells formed the majority. The minority were EBNA-negative, contained abundant cIg and were largely non-proliferating. This suggests the continuous occurrence of a maturation process within each LCL. The concomitant down-regulation of EBNA raises the interesting question whether continued synthesis of the nuclear antigen is incompatible with differentiation for epigenetic reasons, or, alternatively, whether differentiation takes place when the viral genomes are suppressed or lost.
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27
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Wallace LE, Young LS, Rowe M, Rowe D, Rickinson AB. Epstein-Barr virus-specific T-cell recognition of B-cell transformants expressing different EBNA 2 antigens. Int J Cancer 1987; 39:373-9. [PMID: 3493225 DOI: 10.1002/ijc.2910390317] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Epstein-Barr (EB) virus isolates can be classified as type A or type B depending upon the identity of the virus-encoded nuclear antigen EBNA 2; the EBNA 2A and 2B proteins show limited amino-acid homology and induce largely non-cross-reactive antibody responses in humans. To examine whether EBNA 2 might also be a target for virus-specific cytotoxic T-cell responses (like "intracellular" antigens in other viral systems), normal B cells from non-immune donors of known HLA type were transformed in vitro with virus isolates either of type A (from the B95-8 and IARC-BL74 cell lines) or of type B (from the AG876 and IARC-BL16 cell lines) to provide a suitable panel of target cells. DNA hybridization with type-specific probes and immunoblotting with type-specific antisera confirmed the EBNA 2 type of the resident virus in the various in vitro transformants. These cells were then tested as targets for virus-specific cytotoxic T cells, the latter being prepared from type-A virus-infected donors by in vitro reactivation of memory cells from peripheral blood using autologous type-A virus-transformed cells as stimulators. Such effector cells lysed type-A virus-transformed and type-B virus-transformed target cells equally well, indicating that EBNA 2 (in particular that part of the protein which varies between virus types) seems not to be a dominant antigen for the induction of EB virus-specific cytotoxic responses.
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28
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Bartsch D, Brichácek B, Hirsch I. Transfection of human lymphocytes with cloned Epstein-Barr virus (EBV) DNA. Virology 1987; 157:58-66. [PMID: 3029966 DOI: 10.1016/0042-6822(87)90313-8] [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] [Indexed: 01/03/2023]
Abstract
Human primary cord-blood lymphocytes were transfected, using the DEAE-dextran technique, with a set of seven largely overlapping clones jointly covering the whole M-ABA Epstein-Barr virus (EBV) genome. Three fragments, cosmids cMB-14 and cM301-99 and plasmid pM966-20, were able to stimulate transient cellular DNA synthesis, blastic transformation, and clumps formation, as well as to prolong the life span from a maximum of 2 weeks in control cultures to up to 6 weeks. The fragments stimulating DNA synthesis also expressed this property in mutual combinations or when combined with cosmid cMSal-A or cM302-21. Their use with any other fragments in cotransfection did not result in further DNA synthesis stimulation. Cosmids cM302-23 and cMSal-B suppressed this effect. Cosmid cM301-99 but not cM302-23 induced transient EBNA-1 formation in about 1% of lymphocytes. Lymphocytes transfected with single fragments or their combinations failed to grow into immortalized cell lines. The results suggest that transient expression of viral functions at levels achievable by transfection is not sufficient for cell immortalization.
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29
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Henle W, Henle G, Andersson J, Ernberg I, Klein G, Horwitz CA, Marklund G, Rymo L, Wellinder C, Straus SE. Antibody responses to Epstein-Barr virus-determined nuclear antigen (EBNA)-1 and EBNA-2 in acute and chronic Epstein-Barr virus infection. Proc Natl Acad Sci U S A 1987; 84:570-4. [PMID: 3025881 PMCID: PMC304252 DOI: 10.1073/pnas.84.2.570] [Citation(s) in RCA: 141] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Five distinct Epstein-Barr virus (EBV)-determined nuclear antigens (EBNA-1 to EBNA-5) were recently identified. Antibody responses to these antigens could conceivably differ, and thus prove of serodiagnostic value, in EBV-associated disease processes. As a first step, murine or human cell lines transfected with appropriate EBV DNA fragments and stably expressing either EBNA-1 or EBNA-2 were used to determine the frequency and time of emergence of antibodies to these two antigens in the course of acute and chronic infectious mononucleosis (IM) and to assess their titers in so-called chronic active EBV infections. Following IM, antibodies to EBNA-2 arose first and, after reaching peak titers, declined again in time to lower persistent or even nondetectable levels. Antibodies to EBNA-1 emerged several weeks or months after anti-EBNA-2 and gradually attained the titers at which they persisted indefinitely. The ratios between the anti-EBNA-1 and anti-EBNA-2 titers therefore were generally well below 1.0 during the first 6-12 months after IM and turned to well above 1.0 during the second year. In clear cases of chronic IM, the inversion of this ratio was delayed or prevented. In the less well-defined chronic EBV infections, low ratios were observed in only some of the patients. Because many of these illnesses were not ushered in by a proven IM and often showed EBV-specific antibody profiles within the normally expected range, a causal role of the virus in these cases remains doubtful.
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Ernberg I, Kallin B, Dillner J, Falk K, Ehlin-Henriksson B, Hammarskjöld ML, Klein G. Lymphoblastoid cell lines and Burkitt-lymphoma-derived cell lines differ in the expression of a second Epstein-Barr virus encoded nuclear antigen. Int J Cancer 1986; 38:729-37. [PMID: 3021635 DOI: 10.1002/ijc.2910380517] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Twenty-seven Epstein-Barr virus (EBV)-transformed lymphoblastoid cell lines and 27 EBV-carrying Burkitt-lymphoma-derived lines were analyzed for expression of the second EBV-encoded nuclear antigen (EBNA-2) by immunoblotting and anticomplement immunofluorescence with EBNA-2-specific sera. While all lymphoblastoid cell lines expressed EBNA-2, only 10 of the 27 BL lines were EBNA-2-positive. Comparison of the EBNA-2 coding BamHI W-, Y- and H-fragments of EBV-DNA in the different cell lines by restriction enzyme analysis suggests that EBNA-2 negativity is due either to sequence diversity or to a deletion in the BamHI WYH region.
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31
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Dillner J, Kallin B, Alexander H, Ernberg I, Uno M, Ono Y, Klein G, Lerner RA. An Epstein-Barr virus (EBV)-determined nuclear antigen (EBNA5) partly encoded by the transformation-associated Bam WYH region of EBV DNA: preferential expression in lymphoblastoid cell lines. Proc Natl Acad Sci U S A 1986; 83:6641-5. [PMID: 3018741 PMCID: PMC386560 DOI: 10.1073/pnas.83.17.6641] [Citation(s) in RCA: 86] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Four peptides were synthesized on the basis of amino acid sequences deduced from a highly spliced transcript encoded by the Bam W, Y, and H fragments of the Epstein-Barr virus (EBV) genome [Bodescot, M., Chambraud, J. B., Farrell, P. J. & Perricaudet, M. (1984) EMBO J. 3, 1913-1917]. Rabbit antisera against three of the four peptides identified a nuclear polypeptide that varied between 22 and 70 kDa in molecular size. Four of 20 EBV-positive human sera contained antibodies against this polypeptide. Since this is the fifth EBV-determined nuclear antigen (EBNA) discovered in growth-transformed cells, it is designated EBNA5. The antigen was detected in virus nonproducer lines (less than 0.01% EBV early antigen expression) and is thus not dependent on the viral cycle. It was differentially expressed depending on the origin of the lines. All 10 lymphoblastoid cell lines tested expressed EBNA5, but it could not be detected in 10 of 11 EBV-carrying Burkitt lymphoma lines. Infection of tonsillar lymphocytes with the B95-8 strain of EBV induced six EBNA5-specific polypeptides that varied between 41 and 70 kDa in molecular size with regular increments of 6 kDa. This may be due to the fact that the EBNA5 coding sequence includes the Bam W internal repeat. Parallel infection of the EBV-negative Burkitt lymphoma line Ramos with the same viral substrain did not induce detectable levels of EBNA5, nor was this antigen present in permanently EBV-converted Ramos sublines. These findings imply that the expression of the viral genome varies among B cells having different phenotypes.
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32
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Wang SC, Hammarskjöld ML, Klein G. Immunoprecipitation of Epstein-Barr virus EBNA1 protein using human polyclonal serum. J Virol Methods 1986; 13:323-32. [PMID: 3018021 DOI: 10.1016/0166-0934(86)90057-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
We have developed a method that permits the use of human polyclonal serum to immunoprecipitate BamH1-K EBNA(EBNA1) from EBV transformed cell lines and from cells transfected with an expression vector containing the Bam K region of EBV. Serum from healthy seropositive donors is preabsorbed once with lysate of EBV-negative Burkitt lymphoma cells, then fractionated by gel filtration. The main IgG fraction is then used for the immunoprecipitations. Immunoprecipitated material is visualized by immunoblotting using the same serum. Two proteins with apparent molecular weights of 74 and 62 kD are specifically precipitated from extracts of B95-8 cells. Several proteins are immunoprecipitated from cells transfected with the Bam K containing vector, the apparent molecular weights of the 4 major bands are 74, 68, 62 and 57 kD. Labelling of transfected cells with [3H]glycine and [32P]orthophosphate shows that the 74 and 62 kD proteins can be labelled with both isotopes.
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Abstract
Lymphocytes were infected with the QIMR-WIL strain of Epstein-Barr virus, and the induction of Epstein-Barr virus-associated nuclear antigens was determined by using the protein immunoblot. There was a temporal increase in six antigens, with Epstein-Barr nuclear antigen 2 being detected 1 day after infection. The appearance of these antigens was shown to be independent of cellular DNA synthesis.
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34
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Sternås L, Eliasson L, Lerner R, Klein G. Quantitation of Epstein-Barr virus (EBV)-determined nuclear antigen (EBNA) by a two-site enzyme immunoassay, in parallel with EBV-DNA. J Immunol Methods 1986; 89:151-8. [PMID: 3009623 DOI: 10.1016/0022-1759(86)90352-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A two-site enzyme (TSE) immunoassay was developed for the quantitation of the Epstein-Barr virus (EBV)-determined nuclear antigen (EBNA) using a rabbit serum raised against a synthetic peptide derived from the BamHI K region of the viral genome. Comparison of 12 EBNA-positive and 3 negative cell lines proved that the test was EBV-specific. A dot-blot assay utilizing cloned and nick translated EBV-DNA BamHI M fragment confirmed the EBV-carrier status of the EBNA-positive lines. The results obtained with both the TSE immunoassay and dot-blot assay were in agreement with published values. In contrast to earlier reports, we could not demonstrate any correlation between the content of EBNA and the number of viral genome copies.
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35
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Kallin B, Dillner J, Ernberg I, Ehlin-Henriksson B, Rosén A, Henle W, Henle G, Klein G. Four virally determined nuclear antigens are expressed in Epstein-Barr virus-transformed cells. Proc Natl Acad Sci U S A 1986; 83:1499-503. [PMID: 3485288 PMCID: PMC323104 DOI: 10.1073/pnas.83.5.1499] [Citation(s) in RCA: 78] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The expression of Epstein-Barr virus (EBV)-determined antigens associated with growth-transformation of B cells was studied by immunoblotting with human sera from healthy donors. Four antigens were detected in EBV-carrying cell lines and in B lymphocytes early after infection with the transforming B95-8 substrain of virus. They were not found in uninfected cells, nor could they be demonstrated with sera lacking antibodies to EBV antigens. All four antigens were nuclear. Each of them varied in size in the different cell lines. The two antigens with the lowest molecular weight were identified as EBV-determined nuclear antigens (EBNAs) 1 and 2. The two high molecular weight antigens (140-160 kDa and 150-180 kDa, respectively) were detected with 6 of 16 EBV antibody-positive sera. These proteins appeared to be antigenically unrelated to each other and to EBNAs 1 and 2 and were designated EBNAs 3 and 4. Like EBNAs 1 and 2, they bound to double- and single-stranded DNA in vitro.
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36
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Dillner J, Kallin B, Ehlin-Henriksson B, Rymo L, Henle W, Henle G, Klein G. The Epstein-Barr virus determined nuclear antigen is composed of at least three different antigens. Int J Cancer 1986; 37:195-200. [PMID: 2417963 DOI: 10.1002/ijc.2910370205] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The EBV-determined nuclear antigen, EBNA, is the only known viral product to be regularly detected in all EBV-transformed cells. The anticomplement immunofluorescence (ACIF) staining detects an EBV-specific nuclear reaction that has recently been shown to be due to at least 2 different proteins, EBNA-1 and EBNA-2, encoded by different parts of the viral genome. We now report the existence of a third antigen of the EBNA complex, designated as EBNA-3. Serum from a patient with chronic infectious mononucleosis contained no detectable antibodies to EBNA-I and had only a low EBNA-2 antibody level. Nevertheless, it gave an EBV-specific nuclear reaction of normal intensity and stained EBNA-2-positive and EBNA-2-negative EBV-carrying lines equally well. Immunoblotting with the same serum identified a new EBV-specific nuclear protein of 143-157 kDa.
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Ernberg I, Kallin B, Dillner J. Epstein-Barr virus gene expression during primary B-lymphocyte infection, in transformed and Burkitt lymphoma-derived cell lines. Curr Top Microbiol Immunol 1986; 132:251-6. [PMID: 3024918 DOI: 10.1007/978-3-642-71562-4_38] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Hammarskjöld ML, Wang SC, Klein G. High-level expression of the Epstein-Barr virus EBNA1 protein in CV1 cells and human lymphoid cells using a SV40 late replacement vector. Gene 1986; 43:41-50. [PMID: 3019836 DOI: 10.1016/0378-1119(86)90006-5] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
To construct a recombinant plasmid designed to yield large amounts of the Epstein-Barr virus (EBV) nuclear antigen, EBNA1, the EBV BamHI-K fragment (B95-8 strain) was inserted into an expression vector composed of SV40 and pBR322 DNA. The vector replicates in both Escherichia coli and eukaryotic cells. Introduction of such a BamHI-K-containing vector into CV1 monkey cells (using DEAE-dextran, glycerol and chloroquine diphosphate) gave high yields of the correct size EBNA1 protein in 40-50% of the transfected cells. Maximal amounts of EBNA1 could be extracted from the cells at 65-72 h post transfection. Using a quantitative ELISA assay, it was estimated that transfected cells express 500-1000 times more EBNA1 than lymphoid cells, latently infected with EBV. A monoclonal antibody directed against EBNA1 immunoprecipitated two proteins of 74 and 62 kDa from transfected cells. These same two proteins were detected in immunoprecipitation and immunoblot experiments using human EBV-positive polyclonal serum, although this serum also detected several other protein products in transfected cells. In vivo labelling of transfected cells with [32P]orthophosphate showed that the 74- and 62-kDa proteins are modified by phosphorylation. The same vector construction was also used to transfect an EBV-negative human lymphoblastoid cell line (Ramos). Expression of the EBNA1 protein was obtained in up to 20% of the cells.
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Abstract
It is generally accepted that tumours arise through the accumulation of several changes affecting the control of cell growth. Recent advances in molecular biology have made it possible to define some of these changes in molecular terms and to trace the steps by which certain tumours evolve.
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