Epstein-Barr virus oncogenesis

criticll

ReviWJ in

oncology Hematology Critical

ELSEVIER

Reviews

in Oncology/Hematology

26 (1997)

117- 135

Epstein- Barr virus oncogenesis Hans Knecht ‘,*, Christoph A LINK

Laboratories

Berger ‘, A. Samer Al-Homsi Pierre Brousset b

at the Cancer

‘, Catherine

Center, University of Massachusetts Medical Center, Division 55 Luke Avenue North, Worcester, MA, USA b Laboratoire d’Anafomie Pathologique, CH U Purpan, Toulouse, France Accepted

McQuain

of Hematology/Oncology,

15 June 1997

Contents 1.

Introduction.

118

2.

Transforming 2.1. LMPl 2.1.1.

2.1.2. EBNAl 2.2.1.

2.2.

2.2.2. EBNAZ 2.3.1.

2.3.

2.3.2. 3.

* Corresponding

Future

proteins Molecular and functional characterization. 2.1.1 .l. Molecular structure 2.1.1.2. Oncogenic properties 2.1.1.3. Immunomodulating properties 2.1.1.4. NF-KB mediated transcription 2.1.1.5. TRAF-interaction 2.1.1.6. Supressor functions 2.1.1.7. Promoter regulation Clinical data Molecular and functional characterization 2.2.1.1. Structure and function. 2.2.1.2. Promoter regulation 2.2.1.3. Escape from immunosurveillance. 2.2.1.4. Oncogenic properties Clinical data Molecular and functional characterization. 2.3.1.1, Transcriptional activation 2.3.1.2. Interacting transcription factors Clinical data

directions

in translational

118 118 118 11X 120 120 120 121 122 122 122 124 124 124 125 125 125 125 126 126 126 127 121 12X

research.

Acknowledgement

12X

Reviewers

128

References

128

Biographies.

135

author.

Tel.:

+ 1 508 X563702;

1040-842X/97/$32.00 6 1997 Elsevier PII SlO40-842X(97)00016-4

Science

Ireland

Fax: Ltd.

+ 1 508 8566715. All

rights

reserved

‘,

H. Knecht

118

et al. /Critical

Reckvs

in Oncology/Hematology

1. Introduction

The Epstein-Barr virus (EBV) was originally described in cultured lymphoblasts from African Burkitt’s lymphoma in 1964 [l]. In 1967 it was realized that this rapidly growing, clinically destructive tumor was also very sensitive to chemotherapy [2]. In 1968 EBV was identified as the causative agent of infectious mononucleosis [3] usually a benign and self-limiting illness of childhood and adolescence. In 1970 EBV was detected in biopsies from anaplastic nasopharyngeal carcinoma (NW

26 (1997)

II 7-135

different numbers of terminal repeats (TR) (within a single cell all episomes have the same number of TRs, but the number of TRs differs from cell to cell), whereas in clonal EBV infection the cells are characterized by having EBV genomes with the same number of TRs [32]. A schematic presentation of EBV-clonality is given in Fig. 2.

In this review we focus on the EBV-encoded transforming latent membrane protein 1 (LMPl), the nuclear antigens 1 and 2 (EBNAl and EBNA2) and their putative role in human oncogenesis.

[41.

These original observations encompassed already the entire spectrum of EBV-associated conditions, i.e. malignant lymphoid and epithelial tumors, their susceptibility to treatment, and benign or controlled lymphoproliferations, which all 30 years later still exert the same fascination on pediatricians, clinical oncologists, virologists, molecular biologists and pathologists. The multiple facets of EBV-associated disorders, the biology of the virus itself, I he interaction of viral latent genes with basic cellular mechanisms, predispose EBV as a turntable of translational research. An overwhelming amount of new information about the mode of viral infection and molecular genetics has been accumulated over the past years (reviewed in [5- 71). In analogy. from the daily increasing knowledge about the EBV genes expressed in viral latency and their interaction with signaling pathways and defense mechanisms of the host, a molecular and functional understa.nding of EBV-associated disorders is emerging (Table 1). In vitro infection of primary B-lymphocytes occurs through binding of the envelope proteins gp 350/220 to the CD21 receptor followed by internalization of the virus [23]. Successful infection is achieved either through circularization of the viral genome in episomal localization [24], by far the most frequent form of viral latency, or by integration into the human DNA [25,26]. Fig. 1 schematically shows the steps leading to viral latency with expression of all 11 latent genes in B-lymphoblastoid cell lines (LCL). After successful infection of T-cell lines and thymocytes however, EBV appears to persist in linear non-integrated form, consistent with a different, T-cell specific form of EBV infection [27,28]. In epithelial cells the way of infection is still unknown. Possible candidates mediating viral entry are molecularly slightly different CD2 1 receptors expressed by epithelial cells and epithelial cell lines [29.30]. An alternative way of infection by internalization of viral particles coated with secretory IgA antibodies has been shown in the HT-29 epithelial cell line [31]. These IgA-virus complexes are trapped through specific binding of the IgA joining chain to a transmembrane protein expressed on epithelial cells 11311. In a polyclonal EBV infection, such as infectious mononucleosis (IM), the pool of latently infected B-cells is composrd of cells harboring viral episomes with

2. Transforming

proteins

The entire sequence of EBV, a 172 kb double-stranded DNA virus of the herpes virus family, has been published in 1984 [33]. This EBV strain, called B95-8 originated from a Massachusetts resident with infectious mononucleosis and was rescued in a marmoset cell line. The DNA sequence of the B95-8 strain is still used as a standard in EBV related research. Functional studies revealed that the following latent proteins EBNAl, EBNA2, EBNA3A, EBNA3C and LMPl are essential for transformation, i.e. immortalization of lymphoblastoid cell lines [34-401. 2.1. LMPl 2.1.1. Molecular

and functional

characterization

2.1.1.1. Molecular structure. LMPl is a integral membrane protein (Fig. 3) is composed of 386 amino acids Table I Recent reviews

in translational

Topic Burkitt’s

lymphoma

Lymphomas EBNAI Hodgkin’s disease Infection HIVand HIV+ lymphomas CD30 + lymphomas LMPI oncoprotein Latent proteins Immune regulation Viral latency T-cell infection Lymphoma Strain variation LMPI-NF-KB action

inter-

EBV-research

Focus

Year

Reference

Molecular pathogenesis T-cell recognition Oncogenic potential Gene expression Biology/treatment Clinical oncology

1992

[8]

1992 I992 1992 1993 1993

[9] [IO] [II] [I21 [13]

Immunology Carcinogenesis Transformation potential Cytotoxic T-cells Immortalizing genes RAG-machinery Hematopathology Molecular epidemi-

1993 1993 1994

[14] [15] [16]

1995 1995 1996 1996 1996

[17] [I81 [I91 [20] [21]

1997

[22]

Ol%Y Molecular

oncology

H. Knecht

et al. /Criticd

Reviews

in OncohgylHematdogy

26 (1997)

117-135

119

Kinetics of EBV infection in ~ce~s(A) and statesof viral latency (B)

A

Time:

6h Linear DNA only

II Ill/l 1 Ill/l 1 -------__-B

Latency

20-48 h

2-12 days

ONE circularization

Increaseof episomalgenomes (final number is specific cell type dependent)

I II0

1 II -----._----1I

I ooiI cm I

.------,--’

Genesexpressed

Main occurrence

I

EBERl,Z; EBNAl; (LMP2A)

Burkitt’s lymphoma CirculatingB-cells

II

EBERl,Z; EBNAl, LMPl, 2A,2B

III

EBER 1,2; EBNA 1,2,3A,3B,3C, LP, LMPl,2A,2B

Lymphoblastoidcell lines Posttransplantlymphomas AIDS-related lymphomas

Fig. 1. (A) Schematic representation of B-cell infection after Hurley and Thorley-Larson [24]. Linear DNA of about 10 virions (initial density of infection; 170 virions per cell) is observed within the nuclear membrane (dotted lines) after a few hours. One circularization event occurs around day I-2. Over the next few days the final number of viral episomes (all are copies of the initially circularized EBV genome) is achieved. (B) The three forms of viral latency after Rowe et al. [16] and their clinically most frequent identifications are shown.

and is encoded by the BNLFl

gene [41-431. In EBV

terminology B stands for Barn Hl endonuclease digest and N for the length of the DNA fragment (A being the longest, Z a very short one) and LFI for left-ward reading frame number one. The BNLFl gene is also referred to as LMPl gene. In viral latency the LMPl gene contains three exons (5’-3’: 169 474- 169 207; 168 965- 168 163). Two identically 169 128169042; spliced mRNAs of 2.8 and 3.7 kb are transcribed from the ED-L1 promoter (5’-3’: 169 540- 169 546) and from a second one, respectively, located several hundred base pairs upstream [44,45]. During lytic EBV infection LMPl is transcribed from a promoter located within the first intron (5’-3’: 169 190- 169 196) resulting in a shorter protein (lytic LMPl) which lacks the first 128 amino acids [43]. The structure of LMPl is thought to have a short cytoplasmic amino terminus of 25 amino acids, six membrane spanning domains, and a long cytoplasmic domain of about 200 amino acids at the

carboxy terminus [46]. Length variation of the carboxy terminus is frequently observed resulting from additional insertion of perfect repeats of 11 amino acids within the internal repeat region [47] or by small deletions near to the carboxy terminus [48] (Fig. 3). LMPl has a very short half life of about 2-5 h depending on the cell type analyzed [49-511. Cleavage of the protein occurs in the C-terminal domain at position Leu 242, resulting in a transmembrane fragment and a free cytoplasmic fragment containing most of the carboxy-terminal portion. The major phosphorylation sites of the protein are also within the C-terminal domain at positions Ser 313 and Thr 324 [52]. Immunohistochemical identification of LMPl is reliably performed with MoAb S12 or MoAb cocktail CSl-4, both directed against epitopes within the C-terminal part of LMPl [53,54]. A polyclonal affinity purified anti-LMPl rabbit antibody raised against the carboxy-terminus has been successfully used for Western blotting [49].

IX

H. Knecht

el al. i Critical

Recivws

in Oncology/Hematology

26 (1997)

117- 135

Clonality of EBV infection as determined by the number of Terminal Repeats(TR)

Poiyclonai (infectious mononucleosis)

Monoclonal (Hodgkin’s

Cellular pattern

Cellular pattern

1

r

Southern pattern

disease) Southern

Fig. 2. Circularized EBV genomes in episomal localization (nuclear membranes are shown as full rectangular lines) contain TRs after polyclonal EBV infection (left side). In EBV associated malignant disease all nuclei contain EBV genomes with TRs indicating that they originate from a single EBV infected cell (right side). Southern blots of DNA extracted from such when hybridized with a specific probe show only one band whereas, Southern blots of polyclonal processes reveal a ladder of to TRs of different length.

2.1.1.2. Oncogenic properties. LMPl was identified to act as an oncogene in rodent cell lines where its expression leads to contact inhibition and to anchorage independent growth [55,56]. Such LMPl-expressing transfectants, either Rat-l or BALBc/3T3 cells, are tumorigenic when inoculated into nude mice. In transgenie mice LMPl-expression in the skin is associated with hyperplasia and abnormal keratin expression [57]. In human in vitro systems LMPl-expression results in morphological transformation of epithelial RHEK- 1 cells 1581or inhibition of further differentiation of a non-tumorigenic squamous cell carcinoma cell line [59]. When expressed at high levels (driven by the strong cytomegalovirus immediate-early promoter-enhancer) LMPl is toxic for lymphoblastoid and epithelial cell lines [60]. Deletion mutant analysis rapidly identified both the amino terminus and the transmembrane domains as essential for transformation [61-631 but it was only recently that further domains essential for transformation were identified within the carboxy-terminus [64,65].

2.1.1.3. Immunomodulating properties. LMPl is also actively involved into signal transduction pathways (Table 2). LMPl expression in lymphoid cell lines of either B- or T-cell genotype induces upregulation of the cellular adhesion molecules ICAM-1, LFAl and LFA3, the transferrin receptor (CD71), activation markers CD21, CD23, and CD40, a member of the Tumor Necrosis F:actor-Receptor (TNF-R) family [61,66,67]. The LMPl regions critically involved in this upregulation are located within the carboxy terminus [67,68[ but also depend on an intact amino terminus and the first

different numbers of identical numbers of EBV positive tumors bands corresponding

two transmembrane domains because transfectants of the lytic form of LMPl (LMPl-NA128) show no upregulation of either the lymphocytic activation markers or ICAMand CD40 [61,67]. Transfectants expressing full length LMPl show upregulation of DNA synthesis and increased cellular volume [69] changes not observed after transfection of the lytic variant [61]. Upregulation of the bcl-2 oncogene has been shown in cell lines with low [70] or even lacking bcl-2 expression [71]. However, bcl-2 upregulation appears to be cell type specific and is not necessaryfor immortilization [16,72,73]. Since bcl-2 upregulation is delayed by 1 day to the induction of activation markers and adhesion molecules, it is possible that its upregulation is dependent on the previous expression of these mediators [73]. Introduction of LMPl into EBV negative Burkitt’s lymphoma cell lines (BL lines) induces surface expression of CD44, a receptor for hyaluronate [74]. Xenotransplants of such LMPl positive CD44 expressing BL lines into SCID mice are associated with tumor dissemination into lymphoid organs, whereas transplants of untransfected LMPI negative and consequently CD44 negative BL cells, remain confined to local tumor growth. Interestingly, the direct effects leading to lymphoma spread are mediated by CD44 since CD44 positive but LMPl negative transfectants show the same pattern of tumor dissemination into lymphoid organs [74]. Thus LMP-1 induced CD44 expression promotes dissemination of lymphoma.

2.1.1.4. NF-K-B mediated transcription. EBV-immortalized B-cell lines show constitutive expression of A20 zinc finger protein [5] and allow efficient HIV-replica-

H. Knecht

LMPl

et ul. ! Critid

Reviews

in Onncology/Hematology

Oncoprotein

Cell Surface 4 Plasma membrane

_._..........

. . . ...?

TRAF domain

Cytosol lmnnU.Dv ?

Fig. 3. Schematic presentation of the LMPl oncoprotein with functional domains. The short intracytoplasmic amino terminus is potentially important for interaction with cytoskeletal proteins (?). The extracellular part of the first loop contains an epitope for cytotoxic T-cells. Position 128 corresponds to the first amino acid of the LMPl molecule transcribed during active infection (lytic LMPl). The first part of the carboxy terminus immediately adjacent to the plasma membrane (amino acids 190.-232) contains a PXQXT core TRAF binding motif. A second PXQXT motif (amino acid 320-324) occurs near to the NF-K-B activation domain of the molecule. Naturally occurring deletion variants of 23. 10, 4, 1 amino acids cluster in this region. These deletion variants are often associated with amino acid substitutions in the second PXQXT motif. An insert of 6 amino acids is also shown. A domain essential for transformation is located in the last 23 amino acids of the molecule.

tion [75] consistent with the hypothesis that EBV latent genes are able to promote A20 gene expression and HIV replication. Both, A20 gene expression and HIVreplication are mediated through transcriptional activation of KB, an NF-KB responsive element present in the A20 promoter and HIV-LTR (long terminal repeat). NF-k-B is a basic transcription factor (DNA binding protein) participating in transcriptional activation of multiple growth related genes [76-781. Indeed, in cotransfection experiments LMPl functions as a transactivator of the HIV-LTR and this activation is NF-KB mediated [79]. Targeted mutation or deletion of KB within the HIV-LTR completely abolishesthe transactiTable 2 Immunomodulating

functions

of the LMPl

Induces intercellular adhesion molecules Induces DNA synthesis Induces upregulation of bcl-2 Stimulates NF-KB mediated transcription Interacts with TRAF proteins (tumor necrosis factor receptor associated Mimics signaling proteins

oncoprotein

proteins)

26 (1997)

117- 135

121

vation. The A20 zinc finger protein, which confers resistance to the toxic effects of TNF [80] has two KB elements within its promoter and NF-KB mediated transcription from the A20 gene is stimulated by LMPl [81,82]. High A20 mRNA levels are identified in EBVnegative lymphoma cell lines transfected with LMPl . In particular, cotransfection experiments with an LMPlexpression plasmid and an A20 promoter-CAT report construct result in a high expression of the CAT reporter gene, whereas point mutations within the rcB sequencecompletely abolish CAT expression [82]. Stimulation of LMPl dependent NF-KB activity appears to occur through phosphorylation and degradation of the inhibitory molecular IKBCZ,followed by translocation of the free NF-KB to the nucleus [83]. Deletional analysis of multiple domains of LMPl involved in NF-h-B activation reveals regions within the carboxy-terminus and the transmembrane domain to be important [67,84]. Four of the six transmembrane domains (one, two, five and six) and the last 32 carboxy terminal amino acids are essential for maximal NF-KB stimulation [67,84,85] (Fig. 3). The ability of LMPl to activate NF-,vB mediated transcription is cell type dependent; in the human in vitro system high NF-k-B activity is found after LMPl stimulation in the cell lines Rael, Eli, Jurkat and 293, intermediate activity in HPB-ALL and K56.2, and a low activity in the HEp2 cell line [67,84]. In 293 cells numerous LMPl deletion constructs have been assessedfor their ability to activate NF-KB mediated transcription [67,84-861. Interestingly, NF-h-B activation correlates positively with ICAMl upregulation and the formation of LMPl positive giant cells (Table 3). This experimental finding of LMPl induced giant cell formation is of interest in the pathogenesis of Hodgkin’s disease(HD), since HD-cell lines show constitutively high NF-KB activity and ICAMupregulation [87,88] and because ICAM-I expression is NF-k-B mediated [89].

2.1.1.5. TRAF-interaction.

Tumor necrosis factor receptor-associated factor (TRAF) proteins are a family of recently discovered signal transducers interacting with the cytoplasmic domains of the TNF-receptor family sharing an extensive sequence homology in their carboxy terminus which is involved in ligand binding [90]. So far, six members called TRAFl -6 have been identified [90&93]. TRAFl is induced upon EBV-infection of the BL41 cell line [94] and TRAFI, 2 and 3 interact with LMPl [94,95]. For maximal interaction of LMPl with TRAF the first 44 amino acids of the carboxy terminus, adjacent to the cell membrane are mandatory [94] (Fig. 3). In particular, the amino acid sequence PXQXT (X stands for any amino acid) has been identified as a core TRAF binding motif [95]. Interaction of TRAFl/TRAF2 heterodimers with the TRAF domain of L.MPl leads to NF-KB activation, independently of

122

H. Knecht

et al. j Critical

Renicws

in Oncology/Hematology

26 (1997)

I1 7- 135

Table 3 NF-h-B dependent giant cell formation in transfected 293 cells LMPl -construct

NF-KB activity

ICAM-

pSV neo pSV LMPl (B95-8) pSV LMPl-del 10 pSV LMPl-dcl 23 pSV LMPl CA5.5 pSV LMPl-CA199 pSV LMPI-NA43 pCMV LMPl-NA25 pCMV LMPl-NA.128

5, 3’??? 100% 110 95 30, 23” 4b 40”, 9b lib 3“

None” High, 1OO’W High High 26” 5” 20” Low 4”

induction

LMPl expressing multinuclear cells None 66% 70 68 28 nd 130 35 16

Results pooled from Rothenberger et al. [85] and Knecht et al. [86]. d Huen et al. [67]: b Mitchell and Sugden [84].

that activation mediated through the outer most 55 amino acids of the carboxy terminus. Thus, LMPl disposes of two independent ways of NF-KB activation. Further importance of the PXQXT motif is underscored by the presence of this sequence in the cytoplasmic domain of the CD30 and CD40 of man and mouse [96]. In CD30 dependent signaling, interaction of this motif with TRAF2 mediates NF-KB activation [96], and in CD40 dependent signaling interaction of TRAF3 with the TRAF binding motif of LMPl results in growth inhibition of epithelial cells [97]. Since this effect is also observed after CD40 stimulation of LMPl negative epithelial cells, LMPl appears to mimic CD40 induced growth inhibition through interaction with TRAF3. TRAF3 mediated signaling is also involved in LMPl induced expression of the epidermal growth factor receptor (EGFR) in C33A epithelial cells [98]. In this EBV-negative cell line, transient expression of CD40 leads also to upregulation of EGFR, showing again mimicking of CD40 dependent signal transduction by LMPl [98]. 2.1.1.6. Suppressorfunctions. Beside its multiple

growth promoting and transforming functions LMPl may also act as a tumor suppressor gene. In some EBV-negative BL cell lines, LMPl expression reduces either clonability and tumorigenicity [99] or c-myc expression as well as cell cycle progression into mitosis [loo]. These findings define LMPl as a multifunctional oncoprotein involved in basic mechanisms of signal transduction. 2.1.1.7. Promoter regulation. Regulation

of LMPl oncoprotein expression at the transcriptional level is cell type dependent and influenced by several positive and negative cis-acting elements localized within the LMPl regulatory regions (LTRs) extending from nucleotide + 40 to - 634 relative to the transcription initiation site [ 101~ 1041. In B-cells and epithelial cells a strong constitutive activity is localized within the proximal LTR region ( - 54/ + 40) encompassing the ED-L1

promoter [103]. Immediately adjacent ( - 54/- 144) are regulatory sequences exerting a strong negative effect. In B-LCLs these negative regulatory signals are overridden by EBNA2 mediated transactivation of a EBNA2 responsive element ( - 144/ - 214) but not in epithelial cells, where this transactivation is insignificant [ 1031. The complex EBNA2 mediated transactivation of the LMPl promoter region occurs through interaction with several transcription factors [104-1091. One of them, called CBFl or RBP-JK targets a 7 base pair core sequence located at position - 223 to - 217 of the LMPl regulatory region [106,107]. A binding site for homo-and heterodimers of the CREB-ATF family of transcription factors, shown to be critical for LMPl promoter activity, is identified at position - 37 to - 44 [105]. The transcription factor CREB induces LMPl expression through binding to the CAMP responsive element (CRE) and its inactivation is mediated through the protein phosphotases PPl and PP2A. It appears that EBNA2A, through direct contact with PPl, blocks the PPl mediated inactivation of CREB, resulting in prolonged stimulation of CRE [105]. Point mutations within this CAMP responsive element (CRE), reducing the transcription rate by 70%, have been identified in NPC [l lo] and Hodgkin’s disease [l 111. Considering the high intracellular LMPl levels in Hodgkin’s disease, low levels of transcription might be counterbalanced through prolongation of the protein half life. Indeed, experimental modification of the LMPl carboxy terminus, where mutational hot spots are identified [48], affects the protein turn over [63]. A EBNA2 independent transcriptional activation of the ED-L1 promoter region ( - 54/ + 40) is exerted from a EBNAl dependent enhancer located in oriP, more than 10 kb distant from the LMPl gene [112]. 2.1.2. Clinical data

Assuming the in vitro demonstrated oncogenic potential of LMPl to be relevant in human carcinogenesis, one would predict to identify premalignant

H. Knecht

et al. /Critical

Reniewx

in ChcologylHematology

conditions associated with LMPl oncoprotein expression. Indeed, in both lymphatic and epithelial disorders, progression from a premalignant condition to frank malignancy associated with LMPl oncoprotein expression within the cellular population concerned has been reported. First, angio-immunoblastic lymphadenopathy with dysproteinemia (AILD) is a poly-oligoclonal prelymphomatous disorder progressing to monoclonal large cell lymphoma in about 20-30(1/o of cases [113]. Lymph nodes of patients suffering from AILD contain a high copy number of EBV-genomes [114] and LMPl oncoprotein is expressed in the B-immunoblasts [l 1, 1151. Transformation into B-immunoblastic lymphoma is associated with outgrowth of a malignant clone characterized by large LMPl oncoprotein expressing tumor cells [115]. In a molecularly different entity, peripheral T-cell lymphoma of AILD type, LMPl is expressed within the T-immunoblasts of about 2/3 of cases [ 1161. Second, in a recent study of nasopharyngeal biopsy samples LMPl oncoprotein expression was identified in nine out of 19 preinvasive lesions, either dysplasia or carcinoma in situ [117]. Five of eight patients re-examined within 1 year, showed progression to nasopharyngeal carcinoma. Comprehensive reviews about EBV-associated disorders have recently been published by several groups [ 11,13,20,118]. Table 4 summarizes the most relevant disorders associated with LMPl oncoprotein expression. AIDS-related and post-transplant lymphomas are tumors of B-cells, characterized by type III latency with all latent genes expressed. However, post-transplant Hodgkin’s disease appears to be an exception still showing type II latency [152]. Proliferation of these tumors occurs in absence of a functional specific cytotoxic T-cell surveillance and therefore mimics the growth of lymphoblastoid cell lines. In post-transplant Table 4 LM PI expressing

hu-nan

disorders References

Epithelial origin Nasopharyngeal carcinoma Salivary gland carcinoma Hairy leukoplakia Lymphatic origin Hodgkin’s disease Angio-immunohlastic lymphadenopathy (AILD) Peripheral T-cell Iymphoma Anaplastic large cell lymphoma AIDS-related large cell lymphoma AIDS-related Hodgkin’s disease Post-transplant large cell lymphoma Post-transplant Hodgkin’s disease Infectious mononwlcosis

[I 19p1211

[1221 [I2331251 [126- 1301 [11,115,116,131] [1322136] [137,138] [1399143] [I4441461 [147-- 1511

u521 [139.153]

26 (1997)

117-135

123

lymphomas transfer of immunocompetent EBV-specific cytotoxic-T-cells directed against several latent gene products leads to suppression or even eradication of the lymphoma [154-1561. The situation is different in an immunocompetent individual where the tumor, either carcinoma or lymphoma, is characterized by latency type II pattern, with a restricted gene expression. In these, the targets of cytotoxic T-cell reaction are limited to EBNAI, LMPl, and LMP2 proteins [17,157-1601. Small changes in the transcription rate or molecular structure of these proteins and their processing may therefore substantially alter the balance between the virus and the host cells. In EBV-associated Hodgkin’s disease methylation of the Cp promoter results in transcriptional repression of the highly immunogenic EBNA2 and EBNA3 genes [161], leading to a much less immunogenic latency type II gene expression restricted to EBNAl, LMPl and LMP2. Methylation of the LMPl promoter results in silencing of oncoprotein expression in BL cell lines [ 1621 and may in analogy reduce LMPl transcription in the Reed-Sternberg cells (SR) of some cases of EBV-associated Hodgkin’s disease and explain the weak LMPl oncoprotein expression observed in a few cases. As shown for Hodgkin’s disease and NPC, point mutations within the CAMP responsive element of the LMPl promoter region reduce LMPl transcription by about 70% [I IO,1 111. In Hodgkin’s disease this occurred in a twice relapsing patient, indicating clinically aggressive disease associated with low LMPl promoter activity. A high number of replacement mutations and a distinct 30 base pair deletion within the carboxy terminus of the LMPl oncogene has first been identified in the CA0 LMPl gene, originating from a Chinese NPC [162]. A largely identical LMPl gene termed LMPl 1510 occurs in NPCs of Taiwanese origin [163]. Both LMPl genes are rapidly tumorigenic, compared to the B95-8 gene, when inoculated in nude or SCID mice [163,164]. LMPl oncogenes with replacement mutations and carboxy terminal 30 base pair deletions identical to the Asian variants are also present in European Hodgkin’s disease [48,165]. This carboxy terminal 30 base pair deletion variant of the LMPl oncoprotein, termed LMPl-de1 (Fig. 3) is much more frequent than initially thought. LMPI-de1 is often identified in NPC. Hodgkin’s disease, T-cell lymphomas, AIDS-associated lymphomas, post-transplant lymphomas, oral hairy leukoplakia, infectious mononucleosis, and tonsillar hyperplasia [134,135,143,146,151,166]. Recent in vitro studies suggest that the absence of the 30 base pair sequence (there is the LMPl-de1 variant) confers an enhanced oncogenic potential. Deletion of the distinct 30 base pair sequence within the B95-8 gene is associated with enhanced oncogenicity in the BALBc/3T3 cell system [167] whereas insertion of the 30 base pair sequence into LMPl 1510 abolishes the transforming

124

H. Knecht

rt ul. /Critical

Reoiews

in Oncology~Hematolog~~

26 (1997)

II 7- 13.5

activity. Cells (293) transfected with LMPl-de1 show enhanced giant cell formation compared with LMPl wild type transfectants or LMPI amino- terminal deletion variant transfectants (Fig. 4) [86]. Moreover, LMPI CA0 is non-immunogenic in a murine carcinoma model system in contrast to the wild type homologue B95-8 [168]. Deletions of 3, 12, 69 base pairs and an 18 base pair insertion, all clustering in the 30 base pair deletion region, identify this domain of the LMPl carboxy terminus as a mutational hot spot [48,134,135,166]. In particular, the 69 base pair deletion variant has been identified in Hodgkin’s disease [48], chronic lymphoproliferative syndrome [169], multiple sclerosis [ 1701, persistent polyclonal B-cell lymphocytosis [ 17 l] and AIDS-associated primary brain lymphoma [ 1721. In functional studies both the 30 and 69 base pair deletion variants fully maintain the capability to induce NF-K-B mediated transcription [85] and LCLs transformed with an EBV strain harboring an LMPl gene with the 69 base pair deletion are highly tumorigenic in SCID and nude mice [170]. So far, no prognostic difference has been found between LMPl-negative and LMPl-positive Hodgkin’s disease [ 1731 and LMPl-negative and LMPl -positive NPC [174]. However, LMPl expressing NPCs exhibit faster and more expansive tumor growth [174] and over 90% of AIDS-associated Hodgkin’s disease are LMPl positive [13,146] compared with 40% of HIV-negative cases [I 181. The association of LMPl-de1 with advanced [175] or relapsing Hodgkin’s disease, where it serves also as a marker of a particular strain [ 1761, the identification of the 69 base pair deletion variant in atypical lymphoproliferative disorders, together with experimental laboratory studies suggesting enhanced transforming potential of LMPl-de1 are at least intriguing and deserve further attention of clinicians and molecular biologists. 2.2. EBNA 1

2.2.1. Molecular

4. 293 cells transfected with LMPI deletion variants and immunostained with anti-LMPl monoclonal antibodies CSI-4. (A) Slide chamber 72 h post-transfection with plasmid LMPl-de1 (30 base pair deletion). LMPl expressing giant cell with 12 large nuclei is shown. (B) Cytospin 48 h post-transfection with plasmid LMPl-NA25 (amino terminally truncated LMPl). Most cells expressing the truncated form of LMPI are mononuclear.

and functional

characterization

2.2.1.1. Structure and function. EBNAl is a DNA binding protein, composed of 641 amino acids and encoded by the BKRFl gene (nucleotides 107 567- 110 176) of EBV [5,40]. EBNAl is the only EBV latent protein to be expressed in all three forms of viral latency [177,178]. In latency type I (Burkitt’s lymphoma, peripheral blood B-lymphocytes) and latency type II (NPC, Hodgkin’s disease) transcription of the gene is initiated TATA-less at the Qp promoter resulting in a 2.3 kb long transcript whereas in latency type III the gene is transcribed from the Wp and Cp promoter resulting in 3.4 and 3.6 kb long transcripts [179-1831. In the BL cells, expressing lytic-cycle transcripts a

H. Knecht

et al. / Criticul

Reviews

in Oncology/Hematology

fourth promoter Fp, localized 200 base pair upstream the Qp promoter, is activated defining Fp as the ‘lytic’ EBNAI promoter [179,180]. However, the protein translated is identical in all three forms of latency and is essential for lifelong viral persistence (Table 5). EBNAl is necessary for maintenance and replication of the EBV genome in mammalian cells [34,184] and these functions are mediated through specific binding of EBNAl to oriP the EBV-origin of plasmid replication which contains both the initiation and termination sites of EBV replication [185,186]. OriP (nucleotides 73339109) contains two elements termed FR (family of repeats) and DS (dyad symmetry) with binding sites for EBNAl [185,187]. Binding of EBNAl to the 30 base pair repeats of the FR region of oriP promotes transcriptional activation of several promoter constructs thus defining EBNAl as a transcriptional enhancer [187]. The consensus sequence for EBNAl binding is a 12 base pair TAGCATATGCTA palindromic nucleotide sequence [188]. The EBNAl protein itself binds with the carboxy terminal domain to the target DNA [ 189,190]. In particular, the DNA binding domain localizes to amino acids 459-487 including a 16 amino acid core receptor motif, whereas the dimerization domains (dimerization is needed for successful DNA binding) are more downstream at positions 501-532 and 5544598 [191,192]. EBNAl is also an RNA binding protein and arginine/glycine rich motifs at amino acid positions 33-56 and 330-377 are the putative RNA binding domains [ 1931. 2.2.1.2. Promoter regulution. Autoregulation of EBNAl protein expression occurs probably in latency type I where transcription from the Fp promoter is repressed through specific EBNAI-binding to a domain next to the transcription initiation site [194]. Concomitant suppression of the Wp and Cp promoter appears to be mediated through extensive DNA-methylation in the enhancer region of the Wp promoter in latency type I [195]. immunosurveillunce. Cytotoxic Tcell responses directed against EBNAl have not been detected so far and it has been hypothesized that EBNA 1 would escape immunosurveillance [ 17,196]. Recent experimental data demonstrate that failure to raise 2.2. I .3. Escape from

Table 5 EBNA 1 mediated

functions

Viral DNA replication Maintenance of episomal DNA Transactivation of gene expression Repression of gene expression (autoregulation) Escape from cytotoxic T-cell surveillance Oncogenic transformation

26 (1997)

II 7- 135

125

cytotoxic T-cell-responses against EBNAl is due to inhibition of EBNAl peptide antigen processing within the infected cell [197]. The glycine/alanine rich region of EBNAl (amino acids 93-325) functions as an inhibitory signal for antigen processing and MHC class I restricted presentation. HLA-A 11 positive fibroblasts expressing EBNAl plasmid constructs containing a highly immunogenic EBNA4 epitope (peptide 416-424) are not recognized by EBNA4 specific CTLs but the same fibroblasts when transfected with an EBNAI -EBNA4 chimeric construct lacking the glycine/alanine rich region are recognized and lysed by the same CTL clones [ 1971. 2.2.1.4. Oncogenic properties. Observations in transgenie mice and BL-cell lines suggest that EBNAl acts as a viral oncogene [10,198]. Transgenic mice were generated through micro injection of DNA fragments containing the EBNAl gene driven by the Ep immunoglobulin enhancer and polyoma virus promoter sequences [lo]. Two out of ten transgenic lines developed B-cell lymphoma. One first line showed aggressive lymphoma growth after a few months with either massively enlarged liver or generalized bulky lymphadenopathy. Transplantation of these lymphoma cells into syngeneic but not transgenic mice again resulted in rapidly growing monoclonal B-cell lymphomas as demonstrated by JH gene rearrangement. A second line developed B-cell lymphomas after prolonged latency of up to 2 years. In both mice lines EBNAl protein was expressed in the lymphomas and was even identified in lymphoid organs weeks and months prior to the onset of the tumors. These experiments, which suggest an oncogenic effect of EBNAl in the mice genome, are particularly intriguing in the context of the frequently observed genomic integration of EBV DNA in BL cell lines [25,26]. Numerous cells of the BL-line Akata, harboring an 8:14 translocation and selectively expressing EBNAl, may lose their EBV genomes after serial passage over many months [198]. Subclones originating from EBNAl negative (EBV genome negative) Akata cells, while maintaining the 8:14 translocation and light chain restriction, lose both their ability to grow in low medium (0.1% fetal calf serum) and to form anchorage-independent colonies in soft agar. These clones are also no longer tumorigenic in nude mice [198]. Thus, the malignant phenotype of the Akata cell line clearly depends upon expression of the EBNA 1 gene. 2.2.2. Clinical data

In endemic Burkitt’s lymphoma (eBL) protein is expressed in over 95% of cases breakpoints on chromosome 8 cluster 5’ to moter of the c-myc gene [199-2011. In Burkitt’s lymphoma (sBL) EBV is detected

EBNAl and the the prosporadic in only

126

H.

Knrclzt

et al. /Critical

Reviews

in One ology

about 20% of cases and the chromosomal breakpoints are dispersed over the entire c-myc gene. However. the percentage of EBV positive sBL cases is probably considerably higher because of chromosomal integration of partially deleted EBV genomes not expressing the EBNAl antigen [202]. These observations demonstrate a close relationship between EBV-infection and Burkitt’s lymphoma and suggest that there is an activated basic cellular program associated with EBV-infection, leading to breakpoint clustering and deletional insertion into the human genome. These processes may be mediated through recombination activating genes (RAG1 and RAG2) necessary for the rearrangement of Ig and T-cell receptor genes early in lymphoid differentiation [203-2051. This hypothesis is sustained by the following observations: (i) the EBV-positive BL-cell line Namalwa, phenotypically a mature B-cell line, shows RAG expression when analyzed by the sensitive PCR technique [206] and this RAG expression is induced by the EBV latent gene EBNAl [207,208]; (ii) the EBV encoded BALF-2 protein acts as a viral homologue of the RAG proteins and the TRs of the EBV genome, predilected sites for chromosomal integration, contain V(D)J-like sequences [19]; and (iii) RAG1 and RAG2 are expressed in germinal center B-cells of mice [209] and germinal center cells are abundantly present in chronically stimulated lymph nodes of African patients where BL is endemic. In chronically stimulated lymph nodes ongoing germinal center activity is also associated with somatic hypermutation of Ig-genes and Igclass switching of affinity maturating germinal center cells [210,211]. Interestingly, in Burkitt’s lymphoma clustered mutations in the c-myc transactivation domain and specific replacement mutations within the carboxy terminus of EBNAl are frequently identified [212,213]. These specific molecular changes on both c-myc gene and EBNAl in Burkitt’s lymphoma are by far not sufficient to explain the role of EBV, in particular EBNAl, in the pathogenesis of this disorder. However, it appears that EBV usurps or mimics several components of the germinal center reaction thereby accelerating production of infected cells. The latency pattern in Burkitt’s lymphoma is not exclusively restricted to EBNAl expression. A phenotypic drift with additional expression of LMPl and EBNA2 is detectable in a few cases of eBL and sBL [214,215] corresponding to phenotypic changes in BL cell lines cultured over longer periods of time [216]. However. expression of these additional latent proteins is limited to few cells and EBNAl remains the major latent protein expressed. Hopefully, antisense strategies targeting EBNAl will be a future therapeutic approach in Burkitt’s lymphoma. Indeed, antisense oligodeoxynucleotides directed against nucleotides l-1 5 of the EBNAl open reading frame significantly suppress in vitr’o proliferation of EBV-immortalized B-cells [217].

: Hemarolog}~

26 (1997)

Table 6 EBNA 2 mediated Cellular Cyclin CD21 CD23 c:fgr

I I 7- 1.35

transactivation

genes D2 (G, marker) (EBV-receptor) (IgE Fc-low affinity receptor) (proto-oncogene of the src family)

Viral genes LMPl oncoprotein LMP2A signaling Cp promoter HIV-LTR

protein

Gastric carcinoma, in particular the undifferentiated lymphoepithelioma like form is a further malignancy associated with EBV [21%220]. As in African Burkitt’s lymphoma, latent gene expression is limited to EBNAl whereas the EBNA2, 3A, 3B, 3C and LMPl genes are not expressed because of methylation of their promoter regions [221]. Clonal EBV genomes are selectively identified in the tumor cells at the primary site and in metastatic lymph nodes, but the nonmalignant epithelial cells remain EBV-negative [221]. In these cases comparative sequence analysis of the EBNAl gene appears to be promising since replacement mutations within the DNA binding domain of EBNAl are frequently identified in NPC [222]. 2.3. EBNAZ 2.3.1. Molecular and jiinctionul characterization EBNA2 is a transcription factor, is encoded by the BYRFl gene (nucleotides 48420-49966) and exists in two allelic forms [223]. EBNA2A identified from strain B95-8 consists of 483 amino acids, whereas EBNA2B, represented by the BL cell line AG 876 consists of 455 amino acids. Most of the sequence divergence is located within the mid one-third, including a 42 base pair deletion in the EBNA2B gene [223]. Both genes are essential for immortalization of EBV infected cell lines as it has been shown through complementary experiments of EBNA2 deficient strains [36,37]. However, EBNA2B shows a markedly decreased ability to transform B-lymphocytes compared with the EBNA2A gene [224]. Different from the oncoprotein LMPl the transcription factor EBNA2 undergoes significant posttranscriptional modifications [225]. 2.3.1.1. Transcriptional activation. EBNA2 is the first protein to be detected after infection of primary B-cells (as early as after 24 h) [226] underscoring its primordial function as a transcriptional activator of cellular and viral gene expression (Table 6). EBNA2 in concert with EBNA-LP (leader protein) induces expression of Cyclin D2, a marker of G, phase, and to date the earliest

H. Knecht

et ul. /Critical

Reviews

in (3ncology!liemaiolo~~~

cellular gene known to be activated upon EBV infection [227]. Thus, EBNA2 is essential for the initial stages of immortalization by EBV, i.e. the transition of a resting B lymphocyte (G, phase) into G, phase [227]. Extended mutation analysis identified the amino acid regions 95- 110, 280-337 and 425-462 as essential for transformation and transactivation [228,229]. In particular, EBNA2 upregulates expression of CD23 and CD21, the virus’ own receptor [230,231], and of the proto-oncogene c-fgr, a protein tyrosine kinase of the src: gene family [232]. It induces expression of the LMPl oncoprotein [233,234] and the signaling protein LMP2A [235,236]; thus, several downstream effects of EBNA2 may be related to LMPI expression. EBNA2 transactivates a lymphoidspecific enhancer in the Cp promoter of EBV [237] and the long terminal repeats of HIV [238]. It also counteracts the antiproliferative response to interferon-x in LCLs [239]. Interacting trunscription jhctors. All these EBNA2 dependent functions are exerted indirectly through intermediate specific DNA binding proteins. One of them CBFl (Cp binding factor 1) interacts with the Cp promoter through binding to a heptamer GTGGGAA core sequence [240]. CBFl has a 500 amino acid open reading frame, is completely identical to RBPJK (recombination signal-binding protein JK) [241] and appears to represent a basically important transcription factor, highly conserved during evolution. CBFl interacts with CD21, CD23, LMPl and LMP2A in an analogous manner through binding to the heptamer consensus sequence present in the promoter regions of these genes [242,243]. Recent results the human homologue of suggest that CBFl, Drosophilu suppressor of Hairless, functions as a transcriptional repressor, antagonized by EBNA2 [244]. On the EBNA2 protein the critical domain for interaction with CBF‘l maps between residues 310 and 336 [242]. Abolition of CBFl-mediated repression through EBNA2 follows apparently the same mechanism as used by Notch (transmembrane proteins essential in the differentiation of all three germ layers) in CBFlmediated transactivation [245]. PU.1, a transcription factor important in B-cell and red cell development, is also involved in EBNA2 mediated transactivation of the LMPl and LMP2A genes [109,246]. In the promoters of these genes PU.l binds to a consensussequence also identified in the Ig heavy and light chain enhancer elements. 2.3.1.2.

i._ ? Z.I.3 Clinicd

cl&d

EBNA2 deleted variant strains are detectable in oral hairy leukoplakia of HIV patients [247,248] and sequence polymorphism including triplet insertions

26 (I 997) I1 7 - 135

121

within the EBNA2A gene occurs in BL cell lines, Hodgkin’s disease, AILD and non-Hodgkin’s lymphoma [228,249]. Sequence polymorphism is also observed in IM and HIV patients ([250-2521, AlHomsi and Knecht, unpublished data). Triplet insertions and a distinct 51 base pair deletion (nucleotides 49 O!jO-49 140) are often detected in the EBNA2 gene of eBL and healthy carriers in New Guinea [250,253]. A further nearly identical 51 base pair deletion (nucleotides 49 119-49 169) within the EBNA2A gene of two Turkish siblings (a girl and a boy) suffering from fatal EBV-associated lymphoproliferation in the setting of ill-defined immunodeficiency has recently been reported [254]. These deletions resulting in a 17 amino acid loss localize within a region (though not essential) still involved in lymphocyte transformation and LMPl transactivation. In particular, a deletion mutant construct (amino acids 195-230) including these natural deletions has a lower transforming activity while maintaining the LMPl transactivation function [228:]. The hypothesis that EBNA2 variants, associated with imbalanced transactivating activity exerted on several target genes, may favor tumorigenesis deserves a comparative sequence analysis of larger clinical cohorts with EBV-associated malignancy in the immunocompromised host. It has been shown that EBNA2 but not LMPl is expressed in smooth-muscle tumors occurring in patients after liver and cardiac transplantation [255,256], suggesting that the transforming function of EBNA2 is fully maintained independent of LMPl transactivation. A possible explanation of this unusually restricted gene expression is cell type specificity of EBNA2 related transforming (oncogenic) functions. Mice transgenic for the EBNA2 gene develop selectively adenocarcinoma of the kidney preceded by tubular hyperplasia [257], while EBNA2 mRNA expressed in liver, spleen and intestine is not associated with tumor formation [257]. However, the long latency of 1 year until tumor development, together with the fact that EBNA2 gene expression was driven by the SV40 early enhancer,’ promoter, probably preferentially active in kidney cells [258] are also consistent with the possibility that the kidney tumors resulted from an SV40 driven, EBNA2 mediated transactivation of other. unidentified genes. In analogy to the LMPl oncogene. where clustering of deletions occurs in a region associated with NF-k-B activation, the EBNA2A 51 base pair deletion and the triplet insertions occur in a region associated with transformation and transactivation. So far most of these ‘mutational hot spots’ have been identified in malignant tumors or reactive conditions with increased germinal center activity. It is possible that the selective pressure imposed by the immune system gen-

128

H. Knecht

et al. /Critical

Reciws

in Oncol~)~~~lHematolo~~

erates EBV mutants with properties that we evaluate in vitro, but still do not really understand.

research

Comparative sequence analysis of the critical regions in all three transforming genes (LMPl, EBNAl, EBNA2) is needed in representative cohorts of infectious mononucleosis, EBV-associated tonsillar hyperplasia, and randomly selected healthy EBV carriers. These results have to be compared with data obtained from large groups of EBV-associated tumors, either HIV positive or negative. Hopefully such multicentric efforts will identify a particular variant pattern associated with increased oncogenicity. In lymph nodes from patients with Hodgkin’s disease for example, EBV positive bystander lymphocytes may harbor different LMPI genes as do the transformed Sternberg-Reed cells [259]. As performed for the LMPl deletion variants [85,8&l 111 the naturally occurring EBNA2A deletions variants need to be tested in transformation and transactivation assays. Location of these deletions near to the CBFl interactive domain of EBNA2 (amino acids 252237.5) [245,260] might confer changes in the CBFljNotch2 interaction. The recent characterization of dominant negative mutants of EBNAl capable of suppressing replication of wild type EBNAl in an experimental system [261] may offer new therapeutic approaches. Introduction of plasmids expressing dominant negative EBNAl mutants in EBV-associated tumors with high proliferating activity theoretically should shut off their proliferation. Moreover, progress in understanding of the molecular pathogenesis of EBV-associated malignancies will hopefully be relevant to the design of new immunotherapeutic or vaccine strategies [262,263].

Acknowledgements The authors would like to thank Suzanne King for her excellent secretarial assistance in assembling this manuscript.

Reviewers This paper was reviewed by Rolf A. Streuli, Spezialarzt fur Innere Krankheiten FMH, Chefarzt der Medizinischen Klinik, Regionalspital Langenthal, Switzerland, Richard F. Ambinder, John Hopkins Oncology Center. 418 North Bond Street, Baltimore, MA 2123 1. USA and Alain Sergeant, Ecole Not-male Superieure de Lyon, U412 INSERM, ENS Lyon, 46, allee d’Italie, 69364-Lyon cedex 07, France.

II 7-135

References PI

3. Future directions in translational

26 (1997)

Epstein MA, Achong BG, Barr YM. Virus particles in cultured lymphoblasts from Burkitt’s lymphoma. Lancet 1964;7022703. remissions following one and two-dose 121Burkitt D. Long-term chemotherapy for African lymphoma. Cancer 1967;20:75669. 131Henle G, Henle W, Diehl V. Relation of burkitt’s tumor-associated herpes-type virus to infectious mononucleosis. Proc Nat1 Acad Sci USA 1968;59:94&101. H, Schulte-Holthausen H, Klein G, et al. EBV [41 zur Hausen DNA in biospies of Burkitt tumours anaplastic carcinomas of the nasopharynx. Nature 1970;228:1056-8. virus and its replication. In: Fields BN, [51 Kieff E. Epstein-Barr Knipe DM, Howley PM et al., editors. Fundamental Virology. Philadelphia: Lippincott-Raven, 1996: I 109- 1163. AB, Kieff E. EpsteinBarr virus. In: Fields BN, 161Rickinson Knipe DM, Howley PM et al., editors. Fields Virology. Philadelphia: Lippincott-Raven. 1996:23972446. JW, Ernberg 1. Molecular epidemiology of Epstein [71 Grdtama Barr virus infection. Adv Cancer Res 1995;67:1977255. virus and Burkitt’s 181Magrath I, Jain V, Bhatia K. Epstein-Barr lymphoma. Semin Cancer Biol 1992;3:285595. AB, Murray RJ, Brooks J. T cell recognition of [91 Rickinson Epstein-Barr virus associated lymphomas. Cancer Surv 1992;13:53--80. IlO1 Wilson JB, Levine AJ. The oncogenic potential of Epstein Barr virus nuclear antigen 1 in transgenic mice. Curr Top Microbial Immunol 1992;182:375-84. SJ, Zhou X. The association of 1tt1 Pallesen G, Hamilton-Dutoit Epstein-Barr virus (EBV) with T cell proliferations and Hodgkin’s disease: two new developments in the EBV field. Adv Cancer Res 1993;62: 179.. 239. virus W21Straus SE, Cohen JI, Tosato G, et al. EpsteinBarr infections: Biology, pathogenesis and management. Ann Intern Med 1993; I l&45-58. H. Epstein-Barr virus in lymphomas: a u31 Joske DJL, Knecht review. Blood Rev 1993;7:215 --22. H, Stein H, Niedobitek G. Epstein-Barr virus and u41 Herbst CD30 + malignant lymphomas. Crit Rev Oncogenesis 1993;4:191l239. E, et al. Latent membrane u51 Knecht H, Brousset P, Bachmann protein 1: a key oncogene in EBV-related carcinogenesis. Acta Haematol 1993;90:167-71. SA. Huen D, Rowe M. Epstein-Barr virus trans1161Henderson forming proteins, Semin Virol 1994;5:391--9. R, Burrows SR, Moss DJ. Immune regulation in u71 Khanna virus-associated diseases. Microbial Rev Epstein-Barr 1995;59:387--405. virus immortalizing genes. Trends Mi1181Farrell PJ. Epstein-Barr cro 1995:3:10559. DH, Kelleher CA, Jones JF, et al. Epstein-Barr virus [I91 Dreyfus infection of T cells: Implications for altered T-lymphocyte activation, repertoire development and autoimmunity. Immunol Rev 1996;152:89--110. virus 1201Weiss LM, Chang KL. Association of the Epstein-Barr with hematolymphoid neoplasia. Adv Anatom Path01 1996;3:1l15. virus strains I211Jenkins PJ, Farrell PJ. Are particular Epstein-Barr linked to disease?. Cancer Biol 1996;7:209-15. 1221Berger C. Brousset P, McQuain C, Knecht H. Deletion variants within the NF-KB activation domain of the LMPl oncogene in acquired immunodeficiency syndrome-related large cell lymphomas, in prelymphomas and atypical lymphoproliferations. Leukemia Lymphoma 1997 (in press). virus gp350/220 ~231 Tanner J. Weis J, Fearon D, et al. Epstein-Barr binding to the B lymphocyte C3d receptor mediates absorption, capping. and endocytosis. Cell 1987;50:203 13.

H. Knecht

et al. /Critical

Reviews

in L)ncologylHematolo~y

[24] Hurley EA, Thorley-Lawson DA. B cell activation and the establishment of Epstein-Barr virus latency. J Exp Med 1988;168:2059 -75. [25] Lawrence JB, Villnave CA, Singer RH. Sensitive, high-resolution chromatin and chromosome mapping in situ: presence and orientation of two closely integrated copies of EBV in a lymphoma line. Cell 1988;52:51--61. [26] Hurley EA. Agger S, McNeil JA, et al. When Epstein-Barr virus persistently infects B-cell lines, it frequently integrates. J Virol 1991;65:1245-54. [27] Kelleher CA, Kaufman Paterson R, Dreyfus DH, et al. Epstein-Barr virus replicative gene transcription during de novo infection of human thymocytes: simultaneous early expression of BZLF-1 and its repressor RAZ. Virology 1995;208:685595. [28] Kaufman Paterson RL, Kelleher C, Amankonah TD, et al. Model of Epstein-Barr virus infection of human thymocytes: Expression of viral genome and impact on cellular receptor expression in the T-lymphoblastic cell line. HPB-ALL. Blood 1995;85:45664. [29] Young LS, Damon CW, Brown KW, et al. Identification of a human epithelial cell surface protein sharing an epitope with the C3diEpsteinBarr virus receptor molecule of B lymphocytes. Int J Cancer 1089:43:786694. [30] Birkenbach M, Tong X. Bradbury LE, et al. Characterization of an Epstein-Barr virus receptor on human epithelial cells. J Exp Med 1992: 176: 1405 - 14. [31] Sixbey JW. Yao QY. lmmunoglobulin A-induced shift of Epstein-Barr virus tissue tropism. Science 1992;255:1578-80. [32] Raab-Traub N. Flynn K. The structure of the termini of the Epstein-Barr virus as a marker of clonal cellular proliferation. Cell 1986;47:883 - 9. [33] Baer R. Bankier AT, Biggin MD, et al. DNA sequence and expression of the B95-8 Epstein-Barr virus genome. Nature 1984;310:207 I I. [34] Yates JL, Warren N, Sugden B. Stable replication of plasmids derived from Epstein-Barr virus in various mammalian cells. Nature 1985;3 13:812-5. [35] Lupton S, Levine AJ. Mapping genetic elements of EpsteinBarr virus that facilitate extrachromosomal persistence of Epstein-Barr virus-derived plasmids in human cells. Mol Cell Biol 1985:5:2533342. [36] Hammerschmidt W, Sugden B. Genetic analysis of immortalizing functions Iof Epstein-Barr virus in human B lymphocytes. Nature 1989:340:3937. [37] Cohen JI, Wang F. Mannick J, et al. Epstein-Barr virus nuclear protein 2 is a key determinant of lymphocyte transformation. Proc Natl Acad Sci USA 1989;86:9558-62. [38] Tomkinson B, Robertson E, Kieff E. Epstein-Barr virus nuclear proteins EBNA-3A and EBNA-3C are essential for Blymphocyte growth transformation. J Virol 1993;67:2014-25. [39] Kaye KM. Izumi KM. Kieff E. Epstein-Barr virus latent membrane protein 1 is essential for B-lymphocyte growth transformation. Proc Nat1 Acad Sci USA 1993;90:9150-4. [40] Middleton T. Gahn TA, Martin JM et al. Immortalizing genes of Epstein Barr virus. Adv Virus Res 1991;19-55. [4l] Bankier AT, Deininger PL, Satchwell SC, et al. DNA sequence analysis of the EcoRl Dhet fragment of B95-8 Epstein-Barr virus containing the terminal repeat sequences. Mol Biol Med 1983:1:425545. [42] Fennewald S, van Santen V, Kieff E. Nucleotide sequence of a mRNA transcribed in latent growth-transforming virus infection indicates that it may encode a membrane protein. J Virol 1984;51:41 I 9. [43] Hudson GS, Farrell PJ, Barrel1 BG. Two related but differentially expressed potential membrane proteins encoded by the EcoRl Dhet region of Epstein-Barr virus B95-8. J Virol 1985:53:528 35.

[44]

[45]

[46]

[47]

[48]

[49]

[50]

[51]

[52]

[53]

[54]

[55]

[56]

[57]

[58]

[59]

[60]

[61]

[62]

[63]

26 (1997)

117-135

129

Laux G, Economou A, Farrell PJ. The terminal protein gene 2 of Epstein-Barr virus is transcribed from a bidirectional latent promoter region. J Gen Virol 1989;70:307984. Gilligdn K, Sato H, Rajadurai P, et al. Novel transcription from the Epstein-Barr virus terminal Eco RI fragment DlJhet, in a nasopharyngeal carcinoma. J Virol 1990;64:4948&56. Liebowitz D, Wang D, Kieff E. Orientation and patching of the latent infection membrane protein encoded by Epstein-Barr virus. J Virol 1986;58:233-7. Hennessy K, Fennewald S, Hummel M, et al. A membrane protein encoded by Epstein-Barr virus in latent growth-transforming infection. Proc Nat1 Acad Sci USA 1984;81:7207711. Knecht H, Bachmann E, Brousset P, et al. Deletions within the LMPl oncogene of Epstein-Barr virus are clustered in Hodgkin’s disease and identical to those observed in nasopharyngeal carcinoma. Blood 1993;82:2937-42. Baichwal VR. Sugden B. Posttranslational processing of an Epstein-Barr virus encoded membrane protein expressed in cells transformed by Epstein-Barr virus, J Virol 1987;61:866675. Martin J, Sugden B. The latent membrane protein oncoprotein resembles growth factor receptors in the properties of its turnover. Cell Growth Differentiation 1991;2:5533600. Moorthy R. Thorley-Lawson DA. Processing of the EpsteinBarr virus-encoded latent membrane protein p63iLMP. J Virol 1990;64:829%37. Moorthy RK, Thorley-Lawson DA. Biochemical, genetic, and functional analyses of the phosphorylation sites on the EpsteinBarr virus-encoded oncogenic latent membrane protein LMP-I J Virol 1993;67:2637745. Mann KP. Staunton D, Thorley-Lawson DA. Epstein-Barr virus-encoded protein found in plasma membranes of transformed cells. J Virol 1985;55:710-20. Rowe M, Evans HS, Young LS, et al. Monoclonal antibodies to the latent membrane protein of Epstein-Barr virus reveal heterogeneity of the protein and inducible expression in virustransformed cells. J Gen Viral 1987;68:1575%86. Wang D, Liebowitz D, Kieff E. An EBV membrane protein expressed in immortalized lymphocytes transforms established rodent cells. Cell 1985:43:831-40. Baichwal VR, Sugden B. Transformation of Balb 3T3 cells by the BNLF-1 gene of Epstein Barr virus. Qncogene 1988;2:461 7. Wilson JB, Weinberg W, Johnson R, et al. Expression of the BNLF-1 oncogene of Epstein-Barr virus in the skin of transgenie mice induces hyerplasia and aberrant expression of Keratin 6. Cell 1990;61:1315-27. Fahraeus R, Rymo L, Rhim JS, et al. Morphological transformation of human keratinocytes expressing the LMP gene of Epstein-Barr virus. Nature 1990;345:447 -9. Dawson CW, Rickinson AB, Young LS. Epstein-Barr virus latent membrane protein inhibits human epithelial cell differentiation. Nature 1990;344:777--80. Hammerschmidt W, Sugden B, Baichwal VR. The transforming domain alone of the latent membrane protein of Epstein-Barr virus is toxic to cells when expressed at high levels. J Virol 1989;63:2469%75. Wang D, Liebowitz D, Wang F, et al. Epstein-Barr latent infection membrane protein alters the human B-lymphocyte phenotype: deletion of the amino terminus abolishes activity. J Virol 1988;62:417384. Baichwal VR, Sugden B. The multiple membraine-spanning segments of the BNLF-1 oncogene from Epstein-Barr virus are required for transformation. Oncogene I989:4:67 -74. Martin J, Sugden B. Transformation by the oncogenic latent membrane protein correlates with its rapid turnover, membrane localization, and cytoskeletal association. J Virol 1991;65:324658.

I30

H. KnecAt

et al. I Critid

RecLmx

in OncolofiyiHematol[jfi.~’

[64] Moorthy RK, Thorley-Lawson DA. All three domains of the Epstein-Barr virus-encoded latent membrane protein LMP-I are required for transformation of Rat-l fibroblasts. J Virol I993;67: 1638-46. [65] Kaye KM, Izumi KM, Mosialos G, et al. The Epstein-Barr virus LMPI cytoplasmic carboxy terminus is essential for Blymphocyte transformation; fibroblast cocultivation complements a critical function within the terminal 155 residues. J Virol 1995;69:675-83. [66] Pen& M. Lundgren E. Transient expression of the Eostein-Barr virus LMPI gene in chronic lymphocytic leukemia cells, T cells. and hematopoietic cell lines: cell-type-independent-induction of CD23, CD21, and ICAM-I. Leukemia 1993;7:104&12. [67-i Huen DS. Henderson SA. Croom-Carter D, et al. The EpsteinBarr virus latent membrane protein-l (LMPI) mediates activation of NF-h-B and cell surface phenotype via two effector regions in its carboxy-terminal cytoplasmic domain. Oncogene 1995;10:549%60. E, et al. The cytoplasmic [6X! Peng-Pilon M, Ruuth K. Lundgren C-terminal domain but not the N-terminal domain of latent membrane protein I of Epstein-Barr virus is essential for 13 cell activation. J Gen Virol 1995;76:767-77. [@I Peng M. Lundgren E. Transient expression of the Epstein.-Barr virus LMPI gene in human primary B cells induces cellular activaticn and DNA synthesis. Oncogene 1992;7: 1775 82. S, Rowe M, Gregory C, et al. Induction of bcl-2 1701 Henderson expression by Epstein-Barr virus latent membrane protein I protects infected B cells from programmed cell death. Cell lYYl~65~llO7~ 15. R. Ternes P, et al. Expression of bcl-2 in [711 Finke J Fritzen Burkitl’s lymphoma cell lines: induction by latent Epstein--Barr virus genes. Blood lY92;80:459 -69. JM. Veis D, Korsmeyer SJ. et al. Latent membrane [721 Martin protein Iof Epstein-Barr virus induces cellular phenotypes independently of expression of Bcl-2. J Virol 1993;67:5269%78:. M. Huen DS, et al. Upregulation of bcl-2 1731 Rowe M, Peng-Pilon by the EIpstein-Barr Virus Latent Membrane Protein LMPI: a B-cell specific response that is delayed relative to NF-h-B activation and to induction of cell surface markers. J Virol 1994:6X:5602 12. V, Mosier D. Induction of CD44 ex[741 Walter ii_ Schirrmacher pression b) the Epstein-Barr virus latent membrane protein LMPI is associated with lymphoma dissemination. Int J Cancer I Y95:61: 363 9. JE. Calender A, Mulder C. Epstein-Barr virus-positive [751 Monroe and -negative B-cell lines can be infected with human immunodeiiciency virus types I and 2. J Virol 1988;62:3497 500. and activation of NF-h B in [761 Baeuerle PA. Henkel T. Function the immune system. Annu Rev Immunol 1994;12:141~79. P. van Loon APGM. The complete exon[771 Heron E.. Deloukas intron structure of the l56-Kb human gene NFKBI, which encodes the ~10.5 and ~50 proteins of transcription factors NF-h B and Ir;B-;I: implications for NF-KB mediated signal transduction. Genomics 1995;30:493%505. NF-~B:lk-B family nomencla[7X1 Nabel GJ. Verma IM. Proposed ture. Genes Dev lY9?;7:2063. ML, Simurada MC. Epstein-Barr virus latent [791 Hammarskjold membra.ie protein transactivates the human immunodeficiency virus type I long terminal repeat through induction of NF-h-B activirq. J Virol 1992:66:6496&501. AW Jr.. Hu HM. Yabkowitz R, et al. The A20 zinc WI Opipari finger protem protects cells from tumor necrosis factor cytotoxicity. J Biol Chem 1992;267:12424-7. L. Kunkel S. Nabel GJ. Tumor necrosis factor x and PII Osborn mterleukin I stimulare the human immunodeficiency virus enhancer ty activation of the nuclear factor h-B. Proc Natl Acad Sci USA lYX9:Xh:2336 ~~40.

26 (1997)

II 7-1.35

Laherty CD, Hu HM, Opipari AW, et al. The Epstein-Barr virus LMPl gene product induces A20 zinc finger protein expression by activating nuclear factor r;B. J Biol Chem 1992;267:24157 -60. JA, Mathew P, Paya CV. LMP-1 activates NF-KB by F331 Herrero targeting the inhibitory molecule I&-Br. J Virol 1995:69:216874. T, Sugden B. Stimulation of NF-KB-mediated tran(841 Mitchell scription by mutant derivatives of the latent membrane protein of Epstein-Barr virus. J Virol 1995:69:2968 76. S, Bachmann E. Berger C, et al. Natural 30 bp F351 Rothenberger and 69 bp deletion variants of the LMPI oncogene do stimulate NF-KB-mediated transcription. Oncogene 1997;14:2123 6. H, McQuain C, Martin J, et al. Expression of the F61 Knecht LMPI oncoprotein in the EBV negative Hodgkin’s disease cell line L-428 is associated with Reed -Sternberg cell morphology. Oncogene 1996;13:947-53. H-J, Brach MA, Drexler HG, et al. Expression of v71 Gruss cytokine genes, cytokine receptor genes, and transcription factors in cultured Hodgkin and Reed-Sternberg cells. Cancer Res 1992;52:3353 60. HG. Recent results on the biology of Hodgkin and WI Drexler Reedy-Sternberg cells II. Continuous cell lines. Leukemia Lymphoma 1994;3:201-25. E. Stade BG, et al. l2-O-tetradeF391 van de Stolpe A, Caldenhoven canoylphorbol-I 3-acetate-and tumor necrosis factor r-medlated induction of intercellular adhesion molecule-l is inhibited by dexamethasone. J Biol Chem 1994;269:6185 92. [90] Rothe M, Wong SC, Henzel WJ, et al. .-2 novel family of putative signal transducers associated with the cytoplasmic domain of the 75 kDa tumor necrosis factor receptor. Cell lY94;78:681 -92. [91] Cao Z. Xiong J. Takeuchi M, et al. TRAF6 is a signal transducer for interleukin-I. Nature lY96;383:443-6. [92] Regnier CH. Tomasetto C, Moog-Lutz C, c‘t al. Presence of a new conserved domain in CARTI, a novel member of the tumor necrosis factor receptor-associated protein family, which is expressed in breast carcinoma. J Biol Chem 1995;270:2571521. [93] Takeuchi M, Rothe M, Goeddel DV. Distinct domains for nucelar factor+B activation and association with tumor necrosis factor signaling proteins. J Biol Chem 1996;271:19935~42. [94] Mosialos G, Birkenbach M, Yalamanchili R. et al. The Epstein-Barr virus transforming protein LMPI engages signaling proteins for the tumor necrosis factor receptor family. Cell 1995;80:389 99. [95] Devergne 0, Hatzivassiliou E, lzumi KM, et al. Association of TRAFI. TRAF2, and TRAF3 with an Epstein-Barr virus LMPI domain important for B-lymphocyte transformation: role in NF-KB activation. Mol Cell Biol lYY6:16:7098 108. [96] Ansieau S, Scheffrahn I, Mosialos G, et al. Tumor necrosis factor receptor-associated factor (TRAFI-I. TRAF-2. and TRAF-3 interact in vivo with the CD30 cytoplasmic domain; TRAF-2 mediates CD30-induced nuclear factor h-B activation. Proc Natl Acad Sci USA 1996:93: 14053~~8. [97] Eliopoulos AG, Dawson CW. Mosialos G. et al. CD40-induced growth inhibition in epithelial cells is mimicked by Epstein-Barr virus-encoded LMPI: involvement of TRAF3 as a common mediator. Oncogene 1996; 13:2243 54. [98] Miller WE, Mosialos G, Kieff E.. et al. Epstein-Barr virus LMPI induction of the epidermal growth factor receptor is mediated through a TRAF signaling pathway distinct from NF-KB activation. J Virol lY97:71-586 ~94. [99] Cuomo L. Ramquist T, Trivedi P. et al. Expression of the Epstein-Barr virus (EBV)-encoded membrane protein LMPl impairs the in vitro growth. clonability and tumorigenicity of Int J Cancer an EBV-negative Burkitt lymphoma line. lYY2:51:949 5s. [Ql

H. Knecht [IOO]

et al. : Critical

Reviells

in Oncolog~~!Hematology

Floettmann JE, Ward K, Rickinson AB, et al. Cytostatic effect of Epstein-Barr virus latent membrane protein-l analyzed using tetracycline-regulated expression in B cell lines. Virology 1996:223:29940. [lOI] Fahraeus R, Jansson A, Ricksten A, et al. Epstein-Barr virus encoded nuclear antigen 2 activates the viral latent membrane protein promoter by modulating the activity of a negative regulatory element. Proc Nat1 Acad Sci USA 1990;87:7390~4. [IO21 Ghosh D. Kieff E. <‘is-acting regulatory elements near the Epstein-Barr virus latent-infection membrane protein transcriptional start site. J Virol 1990;64:185558. [IO31 Fahraeus R. Jansson A, Sjoblom A, et al. Cell phenotype-dependent control of Epstein-Barr virus latent membrane portein I gene regulatroy sequences. Virology 1993;195:71-80. 11041 Laux G, Dugrillon F, Eckert C, et al. Identification and characterization of an Epstein-Barr virus nuclear antigen 2-responsive ci.c element in the bidirectional promoter region of latent membrane protein and terminal protein 2 genes. J Virol I Y94:68:6’)47 58. [IO51 Fahraeus R. Palmqvist L, Nerdstedt A, et al. Response to CAMP levels of the Epstein-Barr virus EBNAZ-inducible LMPl oncogene and EBNAZ inhibition of a PPI-like activity. EMBO J 1994;13:604 51. [IOh] Ling PD, Hsizh JJD, Ruf IK, et al. EBNA-2 upregulation of Epstein-Barr virus latency promoters and the cellular CD23 promoter utilizes a common targeting intermediate, CBFI. J Virol 1994;68:5375583. [IO71 Zimber-Strobl U, Strobl LJ. Meitinger C, et al. Epstein-Barr virus nuclear antigen 2 exerts its transactivation function through interaction with recombination signal binding protein RBP-Jl<. the lhomologue of Drosophilu suppressor of hairless. EMBO J 1994;13:4973 82. [IOX] Saucier C. Haiss I’, Crasser FA, et al. DNA-binding studies of the Epstein-Barr virus nuclear antigen 2 (EBNA-2): evidence for complex formation by latent membrane protein gene promoter-binding proteins in EBNA-2-positive cell lines. J Gen Virol 1994:75:3067 7’). [IO91 Johannsen E. Koh E. Mosialos G. et al. Epstein-Barr virus nuclear protein 2 transactivation of the latent membrane protein I promoter i< mediated by Jk and PU.l. J Virol lY95:69:25362. [I IO] Chen ML. Wu KC, Liu ST, et al. Characterization of 5’-upstream sequence of the latent membrane protein 1 (LMP-I) gcnc of an Epstein-Barr virus identified in nasopharyngeal carcinoma tissues. Virus Res 1995:37:75584. [I I I] Rothenberger S, Bachmann E, Knecht H. Molecular and functional analysts of the Epstein Barr virus LMPI oncogene promoter in lymphoproliferdtive diseases. Exp Hematol (in press). [I 121 Gahn TA, Sugden B. An EBNA-l-dependent enhancer acts from a distance of IO kilobase pairs to increase expression of the Epstein-B.trr virus LMP gene. J Virol 1995;69:26336. [I 131 Knecht H. Angioimmunoblastic lymphadenopathy: IO years’ experience and state of current knowledge. Semin Hematol 1989:26:20X 5. [I 141 Knecht H. Sahli R. Shaw P, et al. Detection of Epstein-Barr virus DNA by polymerase chain reaction in lymph node biopsic\ from patients with angioimmunoblastic lymphadenopathy. Br J Haematol 1990;75:610 4. [I 151 Knecht H. M,irtius F, Bachmann E, et al. A deletion mutant of the LMPl oncogcne of Epstein-Barr virus is associated with transformation of angioimmunoblastic lymphadenopathy into B-immunoblartic lymphoma. Leukemia 1995;9:458865. [l 161 Anagnostopo.ilos I. Hummel M, Finn T, et al. Heterogenous Epstein-Barr virus infection patterns in peripheral T-cell Iymphoma of angio-immunoblastic lymphadenopathy type. Blood 19’)3;8l): I X04 12.

26 (1997)

117-135

131

[I 171 Pathmanathan R, Prdsad U, Sadler R, et al. Clonal proliferations of cells infected with Epstein-Barr virus in preinvasive lesions related to nasopharyngeal carcinoma. N Engl J Med 1995;333:693-8. [I 181 Glaser SL, Lin RJ, Stewart SL, et al. Epstein-Barr virus-associated Hodgkin’s diesease: Epidemiologic characteristics in international data. Int J Cancer 1997;70:375582. [119] Fahraeus R, Fu HL, Ernberg I, et al. Expression of EpsteinBarr virus-encoded proteins in nasopharyngeal carcinoma. Int J Cancer 1988;42:329938. [I201 Brousset P, Butet V, Chittal S, et al. Comparison of In situ hybridization using different nonisotopic probes for detection of Epstein-Barr virus in nasopharyngeal carcinoma and immunohistochemical correlation with anti-latent membrane protein antibody. Lab Invest 1992;67:457 -64. [121! Chang YS, Su IJ, Chung PJ, et al. Detection of an EpsteinBarr-virus variant in T-cell-lymphoma tissues identical to the distinct strain observed in nasopharyngeal carcinoma in the Taiwanese population. Int J Cancer 1995:62:673 7. [122/ Raab-Traub N, Rajadurai I, Flynn K, et al. Epstein-Barr virus infection in carcinoma of the salivary gland. J Virol 1991:65:7032 6. [1231 Gill&an K, Rajadurai P, Resnick L, et al. Epstein-Barr virus small nuclear RNAs are not expressed in permissively infected cells in AIDS-associated leukoplakia. Proc Nat1 Acad Sci USA 1990;87:87904. [124.] Sandvej K, Krenacs L. Hamilton-Dutoit SJ, et al. Epstein-Barr virus latent and replicative gene expression in oral hairy leukoplakia. Histopathology 1992;20:387’95. [125.] Palefsky JM, Berline J, Penaranda ME, et al. Sequence variation of latent membrane protein-l of Epstein-Barr virus strains associated with hairy leukoplakia. J Infect Dis 1996;173:7104. 1261 Pallesen G, Hamilton-Dutoit SJ, Rowe M et al.. Expression of Epstein Barr virus latent gene products in tumour cells of Hodgkin’s disease. Lancet 199l;i:320-322. 1271 Herbst H, Dallenbach F, Hummel M, et al. Epstein-Barr virus latent membrane portein expression in Hodgkin and ReedSternberg cells. Proc Nat1 Acad Sci USA 1991;88:4766670. 1281 Joske DJL. Emery-Goodman A, Odermatt BF, et al. EpsteinBarr virus burden in Hodgkin’s disease is related to latent membrane protein gene expression but not to active viral replication. Blood 1992;80:2610 3. [I291 Brousset P. Knecht H, Rubin B, et al. Demonstration of Epstein-Barr virus replication in Reed-Sternberg cells of Hodgkin’s disease. Blood 1993;82:872 ~~6. [130] Deacon EM, Pallesen G. Niedobitek G, et al. Epstein-Barr virus and Hodgkin’s disease: transcriptional analysis of virus latency in malignant cells. J Exp Med 1993:177:339949. [I311 Weiss LM, Jaffe ES. Liu XF, et al. Detection and localization of Epstein-Barr viral genomes in angioimmunoblastic lymphadenopathy and angioimmunoblastic lymphadenopathylike lymphoma. Blood 1992;79: 1789 -95. [132] Chen CL, Sadler RH, Walling DM, et al. Epstein-Barr virus (EBV) gene expression in EBV-positive peripheral T-cell lymphomas. J Virol 1993;67:6303-8. [I331 Korbjuhn P, Anagnostopoulos I, Hummel M, et al. Frequent latent Epstein-Barr virus infection of neoplastic T cells and bystander B cells in human immonodeficiency virus-negative European peripheral pleomorphic T-cell lymphomas. Blood 1993;82:217 23. [I341 Sandvej K, Peh SC, Andresen BY, et al. Identification 01 potential hot spots in the carboxy-terminal part of the EpsteinBarr virus (EBV) BNLF-1 gene in both malignant and benign EBV-associated diseases: High frequency of a 30.bp deletion in Malaysian and Danish peripheral T-cell lymphomas. Blood 1994:84:4053360.

132

H. Knrcht

[I351

Knecht H, Bachmann E, Brousset P, et al. Mutational hot spots within the carboxy terminal region of the LMPI oncogene of Epstein-Barr virus are frequent in lymphoproliferative disorders. Qncogene 1995;10:52338. Wen S, Mizugaki Y. Shinozaki F, et al. Epstein-Barr virus (EBV) infection in salivary gland tumors: lytic EBV infection in nonmalignant epithelial cells surrounded by EBV-positive Tlymphoma cells. Virology 1997;227:48447. Herbst H. Dallenbach F, Hummel M, et al. Epstein-Barr virus DNA and latent gene products in Ki-I (CD30)-postive anaplastic large cell lymphomas. Blood 1991;78:266673. Kamel QW. Van de Rijn M, Weiss LM, et al. Reversible lymphomas associated with Epstein-Barr virus occurring during Methotrexate therapy for rheumatoid arthritis and dermatomyositis. N Engl J Med 1993;328:1317721. Pallesen G, Hamilton-Dutoit SJ, Rowe M, et al. Expression 01 Epstein-Rarr virus replicative proteins in AIDS-related nonHodgkin’s lymphoma cells. J Pathol 1993;165:289999. Carbone A, Tirelli U. Gloghini A, et al. Human immunodeticiency virus-associated systemic lymphomas may be subdivded into two main groups according to Epstein-Barr viral latent gene expression. J Clin Oncol 1993;11:1674481. Thomas JA. Cotter F. Hanby AM, et al. Epstein-Barr virus-related oral T-cell lymphoma associated with human immunodeficiency virus immunosuppression. Blood 1993;81:3350&6. Camilleri-Broet S, Davi F. Feuillard J, et al. High expression of latent membrane protein I of Epstein-Barr virus and BCL-2 oncoprotein in acquired immunodenciency syndrome-related primary brain lymphomas. Blood 1995;86:43225. Kingma DW, Weiss WB, Jaffe ES. et al. Epstein-Barr virus latent mzmbrane protein-l oncogene deletions: correlations with malignancy in Epstein-Barr virus-associated lymphoproliferdtive disorders and malignant lymphomas. Blood 1996;88:242 51. 4udouin J, Diebold J, Pallesen G. Frequent expression of Epstein-Barr virus latent membrane protein-l in tumour cells of Hodgkin’s disease m HIV-positive patients. J Path01 1992;167:381 4. Santon A, Manzanal Al, Campo E, et al. Deletions in the Epstein-Barr virus latent membrane protein-l oncogene in Hodgkin’s disease. J Clin Pathol: Mol Path01 1995;48:M18&7. Bellas C. Santon A. Manzanal A, et al. Pathological, immunological. and molecular features of Hodgkin’s disease associated with HIV infection. Am J Surg Path01 1996;20:1520&4. Young L, Alfieri C. Hennessy K, et al. Expression of EpsteinBarr I irui transformation-associated genes in tissues of patients wjith EBV tymphoproliferdtive disease. N Engl J Med 1989:331:10X0~~5. Thomas JA. Hotchin NA. Allday MJ, et al. Immunohistogogy of Epstein-Barr virus-associated antigens in B cell disorders from immunocompromised individuals. Transplantation 1990:49:943 53. Gratama JW. Ztttter MM, Minarovits J. et al. Expression of Epstein-Barr virus-encoded growth-transformation-associated proreins in lymphoproliferations of bone-marrow transplant recipients. Int J Cancer 1991:47:188892. Cen H. Williams PA. McWilliams HP. et al. Evidence of restricted Epstein-Barr virus latent gene expression and antiEBNA antibody response in solid organ transplant recipients with posttransplant lymphoproliferdtive disorders. Blood 1993:81:1393 403. Smir BN, Hauke RJ, Bierman PJ, et al. Molecular epidemiology of deletions and mutations of the latent membrane protein I oncogene of the Epstein-Barr virus in posttransplant lymphoproliferative disorders. Lab Invest 1996;75:575-88. Garnier JL. Lebranchu Y, Dantal J, et al. Hodgkin’s disease after tral..splantatio~l. Transplantation 1996:61:71 6.

[I361

[I371

[I381

[I391

[I401

[I411

[I421

[I431

[I441

[I451

[I461

[147]

[I481

[I491

[I501

[I 511

[I521

et al.

Criticul

Reciews

in Onc,olo~~,‘Hemntolofi!,

16 (1997)

II 7-115

[I531 Anagnostopoulos I, Hummel M, Kreschel C, et al. Morphology, immunophenotype. and distribution of latently and/or productively Epstein-Barr virus-infected cells in acute infectious mononucleosis: implications for the interindividual infection route of Epstein-Barr virus. Blood 1995;85:74450. [I541 Papadopouios EB. Ladanyi M. Emanuel D. et al. Infusion of donor leukocytes to treat Epstein-Barr virus associated lymphoproliferative disorders after allogeneic bone marrow transplantation N Engl J Med 1994;331:679980. [I551 Rooney CM, Smith CA, Ng CY. et al. Use of gene-modified virus-specific T lymphocytes to control Epstein-Barr-virus related lymphoproliferdtion. Lancet 1995;345:9 13. [I561 Heslop HE. Ng CY. Li C. et al. Long-term restoration of immunity against Epstein-Barr virus infection by adoptive transfer of gene-modified virus-specific T lymphocytes. Nature Med 1996;2:551~ 5. [I571 Thorley-Lawson DA, Israelsohn ES. Generation of specific cytotoxic T cells with a fragment of the Epstein-Barr virus-encoded P63:latent membrane protein. Proc Nat1 Acad Sci USA 1987:88:53848. [158] Khanna R, Burrows SR. Kurilla MC. et al. Localization of Epstein-Barr virus cytotoxic T cell epitoes using recombinant vaccinia: implications for vaccme development. J Exp Med 1992;176:169976. [159] Murray RJ, Kurilla MC, Brooks MJ, et al. Identification of target antigens for the human cytotoxic 7‘ cell response to Epstein-Barr virus (EBV): implications for the immune control of EBV-positive malignancies. J Exp Med 1992;176:157 -68. [I601 Lee SP. Thomas WA, Murray RJ. et al. HLA A2.1-restricted cytotoxic T cells recognizing a range of Epstein-Barr virus isolates through a defined epitope in latent membrane protein LMP2. J Virol 1993;67:74288743. [I611 Robertson KD, Manns A, Swinnen LJ, et al. CpG methylation of the major Epstein-Barr virus latency promoter in Burkitt’s lymphoma and Hodgkin’s disease. Blood 1996;88:3129936. [I621 Hu LF, Zabarovsky ER, Chen F, et al. Isolation and sequencing of the Epstein-Barr virus BNLF-I gent (LMPI) from a Chinese nasopharyngeal carcinoma. J Gen Virol 1991:72:2399409. [163] Chen ML, Tsai CN, Liang CL, et al. Cloning and characterization of the latent membrane protein (LMP) of a specific Epstein-Barr virus variant derived from the nasopharyngeal carcinoma in the Taiwanese population. Oncogene 1992;7:213 I-40. [I641 Hu LF. Chen F, Zheng X, et al. Clonability and tumorigenicity of human epithelial cells expressing the EBV encoded membrane protein LMPI. Oncogene 1993:8: 1575 83. [I651 Knecht H. Bachmann E, Joske DJL. et al. Molecular anaylsis of the LMP (latent membrane protein) oncopene in Hodgkin’s disease. Leukemia 1993;7:580-5. [I661 Berger C, McQuain C, Sullivan JL, et al. The latent membrane protein 1 deletion variant with enhanced oncogenic activity prevails in acute infectious mononucleosis and EBV-associated tonsillar hyperplasia. Blood 1996:88:202a. [I671 Li SN. Chang YS. Liu ST. Effect of a IO-amino acid deletion on the oncogenic activity of latent membrane protein 1 of Epstein-Barr virus, Oncogene 1996:12:2 129 35. [168] Trivedi P, Masucci MC, Winberg G. et al. The Epstein-Barrvirus-encoded membrane protein LMP but not the nuclear antigen EBNA-I induces rejection of transfected murine mammary carcinoma cells, Int J Cancer 1991:48:7944800. [I691 Klein C, Rothenberger S. Niemeyer C, et al. EBV-associated lymphoproliferative syndrome with a distinct 69 base-pair deletion in the LMP-I oncogene. Br J Haematol 1995;91:938-40. [I701 Sandvej K, Munch M. Hamilton-Dutoit S. Mutations in the Epstein-Barr virus latent membrane protein-l (BNLF-I) gene in spontaneous lymphoblastoid cell lines: effect on in vitro

H. Knecht

et al. /Critical

Reviews

in Oncology/Hematology

transformation associated parameters and tumorigenicity in SCID and nude mice. J Clin Pathol: Mol Pathol 1996;49:M290&7. [I711 Larcher C. McQuain C, Berger C, et al. Epstein-Barr virus associated persistent polyclonal B-cell lymphocytosis with a distinct 69 ba:se pair deletion in the LMP-I oncogene. Ann Hematol 1997;74:238. [ 1721 Knecht H, Raphael M. McQuain C, et al. Deletion variants within the NF-h-B activation domain of the LMPI oncogene prevail in AIDS-related large cell lymphomas and HIV-negative atypical lymphoproliferdtion. Blood 1996;87:876-81. [I731 Vestlev PM, Pallesen G, Sandvej K, et al. Prognosis of Hodgkin’s disease is not influenced by Epstein-Barr virus latent membrane protein. Int J Cancer 1992;50:670&1. [I741 Hu LF, Chen F. Zhen QF, et al. Differences in the growth pattern and clinical course of EBV-LMPI expressing and nonexpressing nasopharyngeal carcinomas. Eur J Can 1995:3 I A:658 60. [I751 Vasef MA. Kamel OW. Chen YY, et al. Detection of EpsteinBarr virus in multiple sites involved by Hodgkin’s disease. Am J Pathol 1995;147:140&15. [ 1761 Brousset P. Srhlaifer D, Meggetto F, et al. Persistance of the same viral strain in early and late relapses of Epstein-Barr virus associated Hodgkin’s disease. Blood 1994;84:2447751, [I771 Kerr BM, Lear AL, Rowe M, et al. Three transcriptionally distinct forms of Epstein-Barr virus latency in somatic cell hybrids: cell phenotype dependence on virus promoter usage. Virology 1992..187: 189. 201. [I781 Rowe M, Lear AL, Croom-Carter D, et al. Three pathways of Epstein-Barr virus gene activation from EBNAI-positive latency in B lymphocytes. J Virol 1992;66:122-31. [I791 Nonkwelo C. Skinner J, Bell A, Rickinson A, Sample J. Transcription start sites downstream of the Epstein-Barr virus (EBV) Fp promoter in early-passage Burkitt lymphoma cells define a fourth promoter for expression of the EBV EBNAI protein. J Viral 1996;70:623 7. [I801 Schaefer BC, Strominger JL, Speck SH. Redefining the EpsteinBarr virus-encoded nuclear antigen EBNA-I gene promoter and transcription initiation site in group I Burkitt lymphoma cell lines. Proc Natl Acad Sci USA 1995;92:10565-9. [1X1] Hitt MM, Allday MJ. Hara T, et al. EBV gene expression in an NPC-related tumour. EMBO J 1989;8:2639951. [I821 Brooks L, Yao QY, Rickinson AB, et al. Epstein-Barr virus latent gene transcription in nasopharyngeal carcinoma cells: coexpression of EBNA I, LMPl and LMP2 transcripts. J Virol 1992:66:2689-97. [I831 Tierney RJ. Steven N, Young LS, et al. Epstein-Barr virus latency in blood mononuclear cells: Analysis of viral gene transcription during primary infection and in the carrier state. J Virol 1994:68:737485. [I841 Yates J, Warren N. Reisman D, Sugden B. A cis-acting element from the Epstein-Barr viral genome that permits stable replication of recombinant plasmids in latently infected cells. Proc Natl Acad SCI USA 1984;81:3806610. [I851 Rawlins DR. Milman G, Hayward SD, et al. Sequence-specific DNA binding of the Epstein-Barr virus nuclear antigen (EBNA-I) to clustered sites in the plasmid maintenance region. Cell 1985;42:859 -68. [186] Gahn TA, Schildkraut CL. The Epstein-Barr virus origin of plasmid replication, oriP, contains both the initiation and termination sites of DNA replication. Cell 1989;58:527-35. [I871 Reisman D, Sugden B. Tram activation of an Epstein-Barr viral transcriptional enhancer by the Epstein-Barr viral nuclear antigen I. Mol Cell Biol 1986;6:3838846. [188] Ambinder RF, Shah WA, Rawlins DR, et al. Definition of the sequence requirements for binding of the EBNAl protein to its palindromic target sites in Epstein-Barr virus DNA. J Virol

[I891

[I901

[I911

[I921

[I931

[I941

[I951

[I961

[I971

[I981

[I991

[200]

[2Ol]

[202]

[203]

[204] [205]

[206]

[207]

[208]

26 (1997)

I 17-135

133

1990;64:2369979. Shah WA, Ambinder RF, Hayward GS. et al. Binding of EBNA-I to DNA creates a protease-resistant domain that encompasses the DNA recognition and dimerization functions. J Virol 1992;66:3355562. Ambinder RF, Mullen MA, Chang YN, et al. Functional domains of Epstein-Barr virus nuclear antigen EBNAI J Virol 1991;65:1466678. Chen MR, Middeldorp JM, Hayward SD. Separation of the complex DNA binding domain of EBNA-1 into DNA recognition and dimerization subdomains of novel structure. J Virol 1993;67:4875-85. Chen MR, Zong J. Hayward SD. Delineation of a 16 amino acid sequence that forms a core DNA recognition motif in the Epstein-Barr virus EBNA-I protein. Virology 1994:205:486-95, Snudden DK, Hearing J, Smith PR, et al. EBNA-I, the major nuclear antigen of Epstein-Barr virus, resembles ‘RGG’ RNA binding proteins. EMBO J 1994;13:4840--7. Sample J, Henson EBD, Sample C. The Epstein-Barr virus nuclear protein I promoter active in type I latency is autoregulated. J Virol 1992;66:4654461. Jansson A, Masucci M, Rymo L. Methylation of discrete sites within the enhancer region regulates the activity of the EpsteinBarr virus BamHI promoter in Burkitt lymphoma lines. J Virol 1992;66:6229. Masucci MG. Ernberg 1. Epstein-Barr virus: adaptation to a life within the immune system. Trends Microbial 1994:2:125-m 30. Levitskaya J, Coram M, Levitsky V, et al. Inhibition of antigen processing by the internal repeat region of the Epstein-Barr virus nuclear antigen-l. Nature 1995;375:685-8. Shimizu N, Tanabe-Tochikura A, Kuroiwa Y, et al. Isolation of Epstein-Barr Virus (EBV)-negative cell clones from the EBVpositive Burkitt’s lymphoma (BL) line akata: malignant phenotypes of BL cells are dependent on EBV. J Virol 1994;68:6069-73. Lenoir GM, Bornkamm GW. Burkitt’s lymphoma, a human cancer model for the study of the multistep development of cancer: proposal of a new scenario. In: Klein G. editor. Advances in Viral Oncology 1987;7:173 -206. Shiramizu B, Barriga F, Neequaye J. et al. Patterns of chromosomal breakpoint locations in Burkitt’s lymphoma: relevance to geography and Epstein-Barr virus association. Blood 1991;77:151626. Miller G. Epstein-Barr virus: biology, pathogenesis and medical aspects. In: Fields BN, Knipe DM, editors. New York: Raven Press, 1990:1921~1958. Razzouk BI, Srinivas S, Sample CE, et al. Epstein Barr virus DNA recombination and loss in sporadic Burkitt’s lymphoma. J Infect Dis 1996;173:529935. Yancopoulos GD. Blackwell TK, Suh H. et al. Introduced T cell receptor variable region gene segments recombine in pre-B cells: evidence that B and T cells use a common recombinase. Cell 1986;44:25 I -9. Schatz DG, Oettinger MA, Baltimore D. The V(D)J recombination activating gene, RAG-l. Cell 1989;59: 1035 -48. Oettinger MA, Schatz DG, Gorka C, et al. RAG-l and RAG2. adjacent genes that synergistically activate V(D)J recombination. Science 1990;248:1517-23. Knecht H, Joske DJL, Emery-Goodman A, et al. Expression of human recombinase activating genes (RAG-l and RAG-2) in Hodgkin’s disease. Blood 1992;80:2867772. Kuhn-Hallek I, Sage DR, Stein L, et al. Expression of recombinationm activating genes (RAG-l and RAG-2) in Epstein-Barr virus-bearing B cells. Blood 1995;85: 1289- 99. Srinivas S, Sixbey JW. Epstein-Barr virus induction of recombinase-activating genes RAGI and RAG2. J Virol 1995:69:81558.

134

H. Knrcht

et ul. / Critical

Reoiews

in Onc~~log~~He~ato~og~~

in lymphocytes: ~2091 Han S. Zheng B, Schatz DC, et al. Neoteny Rag1 and Rag2 expression in germinal center B cells, Science 1996;274:2094&7. Liu YJ. Joshua DE, Williams CT, et al. Mechanism of antigendriven selection in germinal centres. Nature 1989;342:92931. Liu YJ, de Boutellier 0, Guret C, et al. Within germinal centers, isotype switching of immunoglobulin genes occurs after the onset of somatic mutation. Immunity 1996;4:24ll50. [212] Bhatia K, Huppi K, Spangler G, et al. Point mutations in the c-myc transactivation domain are common in Burkitt’s lymphoma and mouse plasmacytomas. Nature Genetics 1993;5:50 61. Bhatia K, Raj A, Gutierrez MI, et al. Variation in the sequence v31 of Epstein-Barr virus nuclear antigen 1 in normal peripheral blood lymphocytes and in Burkitt’s lymphoma. Oncogene 1996:13:177 81. [214] Niedobitek G. Agathanggelou A, Rowe M, et al. Heterogeneous expression Epstein-Barr virus latent proteins in endemic burkitt’s lymphoma. Blood 1995;86:659-65. [215] Carbone A. Gloghini A. Expression of Epstein-Barr virus-encoded latent membrane protein I in nonendemic burkitt’s lymphomas. Blood 1996:87: 1202-3. [216] Rowe M, Rowe DT, Gregory CD, et al. Differences in B cell growth phenotype reflect novel patterns of Epstein-Barr virus latent gene expression in Burkitt’s lymphoma cells, EMBO J 1987;6:2;‘43 -5 1. [217] Roth G, Curie1 T. Lacy J. Epstein-Barr viral nuclear antigen I antisense oligodeoxynucleotide inhibits proliferation of EpsteinBarr virus-immortalized B cells. Blood 1994;84:582-7. [218] Shibata D. Weiss LM. Epstein-Barr virus-associated gastric adenocarcinoma. Am J Pathol 1992;140:769974. [219] Selves J, Bibeau F, Brousset P, et al. Epstein-Barr virus latent and replicative gene expression in gastric carcinoma. Histopathol0g.y 1996;28:1217. [220] Oda K, l‘amaru J. Takenouchi T, et al. Association of EpsreinBarr virus with gastric carcinoma with lymphoid stroma. Am J Path01 1!)93;143:1063 71. [22l] lmai S, Koizumi S, Sugiura M, et al. Gastric carcinoma: monoclonal epithelial malignant cells expressing Epstein-Barr virus latent infection protein. Proc Nat1 Acad Sci IJSA 1994;91:9131~~5. [222] Snudden DK, Smith PR, Lai D, et al. Alterations in the structure of the EBV nuclear antigen, EBNAI, in epithelial cell turnours. Oncogene 1995;10:1545552. [223] Dambaugh T, Hennessy K, Chamnankit L, et al. U2 region of Epstein-Barr virus DNA may encode Epstein-Barr nuclear antigen 2. Proc Nat1 Acad Sci USA 1984;81:763226. [224] Rickinson AB. Young LS. Rowe M. Influence of the EpsleinBarr virus nuclear antigen EBNA2 on the growth phenotype of virus-transformed B cells. J Virol 1987;61:1310~7. [225] Petti L, Sample c‘. Kieff E. Subnuclear localization and phosphorylation of Epstein-Barr virus latent infection nuclear proteins. Virology 1990; 176:563374. C, Howe JG, Speck SH, et al. Influences of Burkitt’s [326] Rooney lymphoma and primary B cells on latent gene expression by the nonimmortalizing P3J-HR-I strain of Epstein-Barr virus. J Virol 1989:63:1531 ~-9. [227] Sinclair AJ, Palmer0 I, Peters G, Farrell PJ. EBNA-2 and EBNA-LP cooperate to cause GO and Cl transition during immortalization of resting human B lymphocytes by EpsteinBarr virus. EMBO J 1994;13:332lI8. [228] Cohen JI, Wang F, Kieff E. Epstein-Barr virus nuclear protein 2 mutations define essential domains for transformation and transactivation. J Viral 1991;65:2545554. [229] ‘Tong X. Yalamanchili R, Harada S, et al. The EBNA-2 arginine-glycine domain is critical but not essential for Blymphocyte growth transformation; the rest of region 3 lacks essential interactive domains. J Virol 1994;68:6188897.

26 (1997)

117-135

C, Sample C. et al. Epstein-Barr virus latent ~2301 Wang F, Gregory membrane protein (LMPl) and nuclear proteins 2 and 3C are effecters of phenotypic changes in B lymphocytes: EBNA-2 and LMPI cooperatively induce CD23. J Virol 1990;64:230918. A, Billaud M. et al. Stable transfection of [23u Cordier M, Calendar Epstein-Barr virus (EBV) nuclear antigen 2 in lymphoma cells containing the EBV P3HRI genome induces expression of B-cell activation molecules CD21 and CD23. J Virol 1990;64:1002-13. JC. The level of c-f,& RNA is increased by EBNA-2, [2321 Knutson an Epstein-Barr virus gene required for B-cell immortalization. J Virol 1990;64:2530&6. Abbot SD, Rowe M, Cadwallader K. et al. Epstein-Barr virus WI nuclear antigen 2 induces expression of the virus-encoded latent membrane protein. J Virol 1990;64:2126 -34. virus WI Wang F, Tsang SF, Kurilla MC. et al. Epstein-Barr nuclear antigen 2 transactivates latent membrane protein LMPl J Virol 1990;64:3407I h. [235] Zimber-Strobl U, Suentzenich KO, Laux G, et al. Epstein-Barr virus nucelar antigen 2 activates transcription of the terminal protein gene. J Virol 1991;65:415 -23. U, Kremmer E. Crasser F. et al. The EpsteinP361 Zimber-Strobl Barr virus nuclear antigen 2 interacts with an EBNA2 responsive c+s-element of the terminal protein I gene promoter. EMBO J 1993;12:167~75. a WI Sung NS, Kenney S, Gutsch D, et al. EBNA-2 transactivates lymphoid-specific enhancer in the BamHI C promoter of Epstein-Barr virus. J Virol 1991:65:2164-9. [238] Scala G, Quint0 I, Ruocco MR, et al. Epstein-Barr virus nuclear antigen 2 transactivates the long terminal repeat of human immunodeficiency virus type I. J Virol 1993;67:285361. [239] Aman P, von Gabain A. An Epstein-Barr virus immortalization associated gene segment interferes specifically with the IFN-induced anti-proliferative response in human B-lymphoid cell lines. EMBO J 1990;9: 147-52. DR, Hayward SD. The Epstein-Barr virus v401 Ling PD, Rawlins immortalizing protein EBNA-2 is targeted to DNA by a cellular enhancer-binding protein. Proc Nat1 Acad Sci USA 1993;90:9237 ~-4 I. SD. et al. Mediation of Epstein~2411 Henkel T. Ling PD. Hayward Barr virus EBNA2 transactivation by recombination signalbinding protein Jx. Science 1994;265:92 5. SR, Johannsen E, Tong X. et al. The Epstein-Barr v421 Grossman virus nucelar antigen 2 transactivator is directed to response elements by the Jx recombination signal binding protein. Proc Nat] Acad Sci USA 1994:91:7568&72. Waltzer L. Logeat F, Brou C, et al. The human Jx recombinaP'V tion signal sequence binding protein (RBP-Jk-) targets the Epstein-Barr virus EBNAZ protein to its DNA responsive elements. EMBO J 1994;13:5633%8. Waltzer L, Bourillot PY. Sergeant A. et al. RBP-Jk- repression P‘K activity is mediated by a co-repressor and antagonized by the Epstein-Barr virus transcription factor EBNAZ. Nucleic Acid Res 1995;23:4939945. [245] Hsieh JJD, Henkel T, Salmon P, et al. Truncated mammalian notch I activates CDF I /RBPJK-repressed genes by a mechanism resembling that of Epstein-Barr virus EBN.42. Mol Cell Biol 1996;16:952 9. [246] Laux G, Adam B, Strobl LJ, et al. The Spi-1;PU.l and Spi-B ets family transcription factors and the recombination signal binding protein RBP-JK interact with an Epstein-Barr virus nuclear antigen 2 responsive c,tr-element. EMBO J 1994;13:5624-32. [247] Sixbey JW, Shirley P. Sloas M, et al. A transformation-incompetent, nuclear antigen 2-deleted Epstein-Barr virus associated with replicative infection. J Inf Dis 1991:16?:1008&15.

H. Knecht

et ul. / Critical

Reviews

in OncologylHemalology

[248] Walling DM, Perkins AG, Webster-Cyriaque J, et al. The Epstein-Barr virus EBNA-2 gene in oral hairy leukoplakia: strain variation. genetic recombination, and transcriptional expression. J Virol 1994;68:7918-26. [249] Schuster V, Ott G, Seidenspinner S, et al. Common EpsteinBarr virus (EBV) type-l variant strains in both malignant and benign EBV-associated disorders. Blood 1996;87:1579-85. [250] Aitken C, Sengupta SK, Aedes C, et al. Heterogeneity within the Epstein-Barr virus nuclear antigen 2 gene in different strains of Epstein-Barr virus. J Gen Virol 1994;75:955 100. [251] GratdIIId JW, Oosterveer MAP, Weimar W, et al. Detection of multiple ‘ebnotypes’ in individual Epstein-Barr virus carriers following lymphocyte transformation by virus derived from peripheral blood and oropharynx. J Gen Virol 1994;75:8594. RJ. Croom-Carter D, et al. Isolation of [25’] Yao QY, Tierney intertypic recombinants of Epstein-Barr virus from T-cell-immunocompromised individuals, J Virol 1996;70:4895-903. JM, Khanna R, Sculley TB, et al. Identification of a [253] Burrows naturally occurring recombinant Epstein-Barr virus isolate from new guinea that encodes both Type 1 and Type 2 nuclear antigen sequences. J Virol 1996;70:4829--33. [254] Schuster V, Seidenspinner S, Kreth HW. Detection of nuclear antigen 2 (EBNA2)-variant Epstein-Barr virus strain in two siblings with fatal lymphoproliferative disease. J Med Viral 1996:48:114~20. J, Nalesnik M, et al. The association of [255] Lee ES, Locker Epstein-Barr virus with smooth-muscle tumors occurring after organ transplantation. N Engl J Med 1995;332:19-25. DW. Shad A. Tsokos M, et al. Epstein-Barr virus ]2561 Kingma (EBV)-associaled smooth-muscle tumor arising in a post-transplant patient treated successfully for two PT-EBV-associated large-cell lymphomas. Am J Surg Pathol 1996;20:151 l-9. [257] Tornell J, Farzad S. Espander-Jansson A, et al. Expression of Epstein-Barr nuclear antigen 2 in kidney tubule cells induces tumors in transgenic mice. Oncogene 1996;12:1521-8. [258] Fanning E, Knippers R. Structure and function of simian virus 40 large tumor antigen. Annu Rev Biochem 1992:61:55585. [259] Meggetto F, Brousset P. Selves J, et al. ReeddSternberg cells and ‘bystander‘ lymphocytes in lymph nodes affected by Hodgkin’s disease are infected with different strains of Epstein-

26 (1997)

117- 135

135

Barr virus. J Virol 1997;71:254779. Hsieh JJD, Nofziger DE, Weinmaster G, et al. Epstein-Barr virus immortalization: notch2 interacts with CBFI and blocks differentiation. J Viral 1997;71:1938-45. [26l] Kirchmaier AL, Sugden B. Dominant-negative inhibitors of EBNA-I of Epstein-Barr virus. J Virol 1997;71:1766 --75. [262] Sing AP, Ambinder RF, Hong DJ, Jensen M. Batten W, Petersdorf E, Greenberg PD. Isolation of Epstein-Barr virus (EBV)-specific cytotoxic T lymphocytes that lyse Reed-Sternberg cells: implications for immune-mediated therapy of EBV + Hodgkin’s disease. Blood 1997;89:1978-86. [263] Moss DJ, Schmidt C, Elliott S, Suhrbier A. Burrows S, Khanna R. Strategies involved in developing an effective vaccine for EBV-associated diseases. Adv Can Res 1996;69:2 13 45. [260]

Biographies Hans Knecht, M.D., a graduate of Zurich Medical School, received his education with Karl Lennert (Hematopathology) and Maxime Seligmann (Clinical Hematology). He currently is an Attending Physician at University of Massachusetts Medical Center, Worcester, and Director of the Cancer Molecular Genetics Laboratory at the Cancer Center. Christq~h Berger, M.D., a graduate from Zurich Medical School, is a pediatrician working as a post-doctoral fellow. A. Sumer Al-Homsl, a graduate from Damaskus Medical School is a hemato-oncologist working as a postdoctoral fellow. Cathy McQuain, B.A., a graduate of Anna Maria College, Worcester, is a Research Associate. Pierre Brousset, M.D., Ph.D., a graduate from Toulouse University, received his education with Georges Delsol, and currently is an Attending Physician with the Department of Pathology, CHU Purpan, Toulouse.