EBV-associated Hodgkin's Disease Research Articles

EBV-Specific Cytotoxic T Lymphocytes by LMP2a- and EBNA3a-Specific T Cell Receptor Gene Transfer for Adoptive Therapy in EBV-Associated Hodgkin's Disease and Post-Transplant Lymphoma.

Adoptive transfer of polyclonal EBV-specific T cell lines has been used as prophylaxis and therapy in patients with EBV-associated malignancies. However, this strategy is time-consuming and demands difficult generation of lymphoblastoid cell lines (LCLs) and corresponding T cells for each individual patient. We applied an alternative strategy to confer T cell immunity against EBV-antigens by isolating EBV antigen-specific T cell receptors (TCRs) for transduction of primary human T cells for adoptive therapy. Previously, we have demonstrated the feasibility of using peptide-pulsed dendritic cells (DC) for generating high-affinity EBV antigen-specific T cell lines and T cell clones. Based on this strategy, T cell clones directed against LMP2a and EBNA3a were generated and functionally analyzed. Monospecificity was demonstrated by homogeneous double staining with CD8 and appropriate tetramers. High avidity of T cell clones (< 0.01 μM) was shown by peptide titration in an ELISPOT assay for IFN-γ secretion. In addition, the cytokine secretion profiles of some of the T cell clones were tested by cytokine bead array assay. High secretion levels of IFN-γ, IL-2 as well as TNF-α after stimulation with the EBNA3a- or LMP2a-peptide were shown for the corresponding T cell clones. Potent TCRs from one LMP2a-specific, HLA-A2-restricted and one EBNA3a-specific, HLA-B8-restricted T cell clone were isolated and cloned into the retroviral vector MP71. Transduction efficiency of TCR-deficient T cell lines was > 40% (TCR-LMP2a) and > 30% (TCR-EBNA3a) as measured by tetramer staining. Both TCR-LMP2a- and TCR-EBNA3a-redirected T cell lines were functional as indicated by NFAT-mediated luciferase expression upon TCR-MHC-peptide ligation. Primary human T cells were successfully transduced with TCR-LMP2a (∼ 12% tetramer-positive) and TCR-EBNA3a (∼ 3% tetramer-positive). Importantly, both TCRs conferred similar cytolytic activity against EBV-transformed B cell lines. Our data support the development of TCR-transduced T cells for adoptive transfer in EBV-associated malignancies, including Hodgkin′ s disease and nasopharyngeal carcinoma in which only subdominant EBV antigens are expressed. The feasibility and the therapeutic potential of TCR-transduced T cells for adoptive transfer have already been shown in a clinical phase I trial in patients with metastatic melanoma. We believe that redirecting human PBLs is a rapid and efficient tool toward adoptive transfer in EBV-associated malignancies.

EBV-associated recurrent Hodgkin's disease after renal transplantation

SummaryHodgkin's disease is recognized as part of the spectrum of post-transplantation lymphoproliferative disorders (PTLD), although it is still an uncommon de novo malignancy in this population. Epstein–Barr virus (EBV) has been linked to both post-transplant non-Hodgkin's lymphomas and Hodgkin's disease. We report a case of recurrent Hodgkin's disease in a patient who received a renal transplant in childhood and later developed EBV-associated Hodgkin's disease with remission after chemotherapy until subsequent relapse 9 years later that was successfully treated. To our knowledge, this is the first report of recurrent Hodgkin's disease in a transplant recipient. We briefly discuss the pathogenesis of and risk factors for EBV-related PTLD, utility of EBV load surveillance, and the options for treatment of PTLD including immunosuppression reduction, antiviral therapy, anti-CD20 monoclonal antibodies, cytotoxic T cells, and the possible roles of interferon-α and rapamycin.

The clinical use of LMP2-specific cytotoxic T lymphocytes for the treatment of relapsed EBV +ve Hodgkin disease (HD) and non-Hodgkin lymphoma (NHL)

EBV-associated HD and NHL show type II latency expressing subdominant EBV antigens such as LMP2, which may serve as targets for immunotherapy. Previously, we used polyclonal EBV-specific CTL in patients with relapsed EBV +ve HD and saw 2 CRs and 1 PR in 11 patients. We now hypothesize that CTL specifically targeting LMP2 might have greater efficacy. LMP2-CTL were generated using dendritic cells and lymphoblastoid cell lines which had been genetically modified to overexpress LMP2 by transduction with an Ad5f35LMP2 vector.

The Use of Autologous LMP2-Specific Cytotoxic T Lymphocytes (CTL) for the Treatment of Relapsed EBV-Positive Hodgkin Disease and Non-Hodgkin Lymphoma.

EBV-associated Hodgkin's Disease (HD) and some non-Hodgkins lymphoma (NHL) show type II latency expressing the subdominant EBV antigens EBNA1, LMP1 and LMP2, which may serve as targets for immunotherapy approaches. In previous studies, we used polyclonal EBV-specific CTL in patients with relapsed EBV +ve HD and saw 2 complete and 1 partial response in 11 patients. Analyses of EBV-CTL lines showed that small populations of T cells reactive against the tumor-associated antigen LMP2 were present in the majority of the infused lines, with some expansion in the peripheral blood following infusion. We therefore hypothesized that CTL specifically targeting LMP2 might have greater efficacy in these patients. LMP2-CTL were generated from 14 patients using Dendritic Cells for initial stimulations then Lymphoblastoid Cell Lines (LCL) both of which had been genetically modified to overexpress LMP2 by transduction with an Ad5f35LMP2 vector. Polyclonal LMP2-CTL lines recognized 1–7 (median 2) LMP2 epitopes, as determined using pentamers and overlapping LMP2 peptide pools in ELISPOT assays. A mean of 22.8% (5–42.1%) of CD8+ T cells bound HLA-restricted LMP2 pentamers, compared to a mean of 0.11% (0.01–0.24%) of LMP2-pentamer positive CD8+ T cells found in CTL generated with genetically unmodified LCL from the same patients. So far, 11 patients have been treated on this dose escalation study - 6 patients have been treated on dose level (DL)1 (2 doses of CTL at 2x107/m2/dose given 2 wks apart in the outpatient clinic), 4 patients on DL2 (2x107/m2 and 1x108/m2) and 1 patient on DL3 (1x108/m2 and 2x108/m2). No immediate toxicity was observed. After CTL infusion, an increase in the frequency of EBV +/- LMP2-specific T cells could be detected in the blood in 8/10 evaluated patients (range 2–17.6 fold). Five of 6 patients who received LMP2-CTL as adjuvant therapy post stem cell transplant or chemotherapy remain in remission up to 22mths post LMP2-CTL. 1 patient presented with progressive disease 8 wks post CTL therapy. Five patients had detectable disease at the time of CTL therapy of whom 1 had progressive disease 8 wks post CTL and 4 had clinical responses (1 very good partial response and 3 clinical or radiologic complete responses). One of these 3 patients was evaluated 7 wks after receiving CTLs, which were predominantly CD4+ve (91.6%). Biopsies showed minimal residual NHL cells with increased CD4+ve T cells compared to pre-CTL biopsy specimens. Imaging studies performed 1 wk later were negative for NHL. This patient received 2 extra doses of CTL (given 8 wks apart) and re-evaluations showed CR on PET and CT scans. Two other patients had stable disease 8 wks post LMP2-CTL. Both patients received 2 further doses of LMP2-CTL. One patient is without evidence of disease 12 months post CTL. The other patient had a complete radiological response. This patient had a supraclavicular lymph node resection, which showed selective accumulation of LMP2-tetramer +ve T cells (0.3% compared to 0.01% in the peripheral blood) with few residual tumor cells. Immunotherapy with autologous LMP2-CTL is therefore well tolerated in patients with relapsed EBV+ve HD/NHL and infused LMP2-CTL cells can accumulate at tumor sites and induce clinical responses.

Coexpression of major histocompatibility complex class I and LMP1 in Epstein‐Barr virus‐positive Hodgkin's Lymphoma in a pediatric age group

The Epstein-Barr virus (EBV)-encoded latent membrane proteins (LMP1 and LMP2) are consistently expressed by malignant Hodgkin Reed-Sternberg (HRS) cells of EBV-associated Hodgkin's disease (HD). The EBV LMP1 has been implicated in tumorogenesis. Cytotoxic T lymphocyte (CTL) responses to both of these proteins have been shown in the blood of EBV-seropositive individuals, and in HD, the apparent failure of the CTL response to eliminate HRS cells expressing LMP1 in vivo has given rise to the suggestion that HD may be characterized by the presence of defects in antigen CTL-presentation or in CTL dysfunction. This study examined 28 cases seen at the Regional Children's Hospital Arturo Grullón in Santiago, the Dominican Republic, by immunohistochemistry. High level of expression of major histocompatibility complex (MHC) class I molecules in HRS cells of EBV-associated HD was recorded. These results suggest that deregulation of MHC class I molecules does not account for the apparent ability of EBV to infect HRS cells and to evade CTL protection. Therefore, the result from our work and similar studies will help to determine whether, or which, immunotherapy should be used in positive and negative cases of HD related to EBV.

795. The Use of Autologous LMP2-Specific Cytotoxic T Lymphocytes for the Treatment of Relapsed EBV +ve Hodgkin Disease and Non-Hodgkin Lymphoma

EBV-associated Hodgkin's Disease (HD) and some non-Hodgkins lymphoma (NHL) show type II latency expressing the subdominant EBV antigens EBNA1, LMP1 and LMP2, which may serve as targets for immunotherapy approaches. In previous studies, we used polyclonal EBV-specific CTL in patients with relapsed EBV +ve HD and saw 2 complete and 1 partial response in 11 patients. Analyses of EBV-CTL lines showed that small populations of T cells reactive against the tumor-associated antigen LMP2 were present in the majority of the infused lines, with some expansion in the peripheral blood following infusion. We therefore hypothesized that CTL specifically targeting LMP2 might have greater efficacy in these patients. LMP2-CTL were generated from 10 patients using Dendritic Cells and Lymphoblastoid Cell Lines (LCL) that had been genetically modified to overexpress LMP2 by transduction with an Ad5f35LMP2 vector. Polyclonal LMP2-CTL lines recognized 2-6 (median 4) LMP2 epitopes, as determined using overlapping LMP2 peptide pools in ELISPOT assays. A mean of 22.8% (5-42.1%) of CD8+ T cells bound HLA-restricted LMP2 tetramers, compared to a mean of 0.11% (0.01-0.24%) of LMP2-tetramer positive CD8+ T cells found in CTL generated with genetically unmodified LCL from the same patients. So far, 10 patients have been treated on this dose escalation study. No toxicity has been seen |[ndash]| 6 patients have been treated on dose level 1 (2 doses of CTL at 2x10e7/m2/dose given 2 weeks apart in the outpatient clinic) and 4 patients on dose level 2 (1 dose of 2|[times]|10e7/m2 and second dose of 1|[times]|10e8/m2). No immediate toxicity was observed. In patients with identified LMP2-epitopes, measurement of IFN|[gamma]| secretion by CD8+ T cells after stimulation with appropriate LMP2-peptides in ELISPOT assays showed a 4-25-fold increase in spot forming cells after infusions. In contrast, frequencies of CMV and superantigen-specific T cells did not increase. Four of five patients who received LMP2-CTL as adjuvant therapy post stem cell transplant or chemotherapy remain in remission up to 12 months post LMP2-CTL. One patient presented with progressive disease 8 weeks post CTL therapy. Five patients had detectable disease at the time of CTL therapy. 1 patient had a very good partial response and for 2 patients it is too early to assess. The two remaining patients had stable disease 8 weeks post LMP2-CTL and were eligible to receive further doses. Both patients received 2 further doses of LMP2-CTL. One patient continues with stable disease 6 months post CTL therapy and the other patient had a complete radiological response. This patient had a supraclavicular lymph node resection, which showed selective accumulation of LMP2-tetramer positive cells (0.3% compared to 0.01% in the peripheral blood) with few residual tumor cells. Immunotherapy with autologous LMP2-CTL is therefore well tolerated in patients with relapsed EBV+ve HD/NHL and infused LMP2-CTL cells can localize to the tumor and induce a clinical response.

LMP2-Cytotoxic T Lymphocyte Therapy for Relapsed EBV Positive Lymphoma.

EBV-associated Hodgkin's Disease (HD) and non-Hodgkins Lymphoma (NHL) show type II latency. They express the subdominant EBV antigens EBNA1, LMP1 and LMP2, which may serve as targets for immunotherapy approaches. In our previous studies, we used polyclonal EBV-specific CTL (EBV-CTL) in patients with relapsed EBV +ve HD and saw 2 complete and 1 partial response in 11 patients. Tetramer and functional analyses of EBV-CTL lines showed that small populations of T cells reactive against the tumor-associated antigen LMP2 were present in the majority of the infused lines, with some expansion in the peripheral blood following infusion. We therefore hypothesized that CTL specifically targeting type II viral latency antigens might have greater efficacy in these patients. LMP2-CTL could be generated from normal donors using dendritic cells (DC) genetically modified with a recombinant adenovirus encoding LMP2a (Ad5LMP2a) to direct the CTL response to LMP2. However, this approach required the generation of large numbers of DC to expand LMP2-CTL and was not practical in these heavily pretreated patients. We therefore modified the LMP2-CTL generation protocol to use DC for the initial stimulation, followed by stimulation with LCL that had been genetically modified to overexpress LMP2a by transduction with an Ad5f35LMP2a vector. This approach allowed us to specifically expand LMP2-CTL from patients to the numbers required for clinical use. We have generated LMP2 specific CTL lines in 10 patients with EBV+ve HD or NHL. LMP2 peptide tetramers were used for analysis of the polyclonal LMP2-CTL lines where HLA-restricted tetramers were available, and the lines recognized 2–6 (median 4) LMP2 epitopes, as determined by ELISPOT assay. A mean of 22.8% (5–42.1%) of CD8+ T cells bound these LMP2 tetramers, compared to a mean of 0.11% (0.01–0.24%) of LMP2-tetramer positive CD8+ T cells found in CTL generated with genetically unmodified LCL from the same patients. So far, 6 patients have been treated, initially receiving 2 doses of 2x107 CTL/m2 two weeks apart. All patients were off other therapies for at least 1 month prior to receiving CTL. No immediate toxicity was observed. In patients with identified LMP2-epitopes, measurement of IFNγ secretion by CD8+ T cells after stimulation with appropriate LMP2-peptides in ELISPOT assays showed a 4–25-fold increase in spot forming cells after infusions. In contrast, the frequency of CMV and superantigen-specific T cells did not increase. Four patients without radiological evidence of disease who received CTL as adjuvant therapy post stem cell transplant or chemotherapy remain well up to 9 months post CTL. Two patients with measurable disease at the time of CTL infusion had stable disease 8 weeks post CTL. They received 2 further doses of LMP2-CTL at 2x107/m2/dose. Re-evaluation was performed 8 weeks after the additional CTL infusions and one patient continues with stable disease. In the second patient, radiological review now revealed no evidence of disease, and a supraclavicular lymph node resection showed selective accumulation of LMP2-tetramer positive cells (0.3% compared to 0.01% in the peripheral blood) with scanty residual tumor cells. Immunotherapy with autologous LMP2-CTL is therefore well tolerated in patients with relapsed EBV+ve HD/NHL and infused LMP2-CTL cells can localize to the tumor and induce a clinical response.

Epstein Barr Virus (EBV)-Specific Cytotoxic T Lymphocytes (CTL) Expressing an Anti-CD30 Chimeric T Cell Receptor (CTCR) for the Treatment of Hodgkin's Disease (HD).

HD may be a suitable target for immunotherapy, and in patients with EBV-associated HD, adoptive transfer of EBV-CTL has produced disease responses. An alternative target is the CD30 molecule, which is present on the malignant cells of almost all patients with HD. CD30 is a member of the TNF superfamily and monoclonal antibodies directed to this antigen are currently under investigation in patients with relapsed HD. An alternative way to target CD30 is by the construction of T cells expressing cTcR specific for the antigen. T lymphocytes engineered to express this cTcR can specifically kill CD30+ HD cell lines {Cancer Res , 1998; 58:1116}. However, these chimeric molecules connect the antigen-recognition properties of CD30 antibodies with the endodomain of CD3ζ, which is insufficient to fully activate resting T cells to proliferate and release cytokines. As a consequence chimeric T cells that express these endodomains divide infrequently, lose activity and have performed poorly in-vivo. Full T cell activation requires receptor engagement to be accompanied by a sequence of co-stimulatory stimuli. We have shown that EBV-CTL can fulfill this need, since the co-stimulatory signals delivered by EBV-infected B cells after native receptor engagement ensure full functionality when the CTL subsequently bind to tumor cells through their cTcR. We first evaluated whether EBV-CTL can be redirected to kill CD30+ HD cell lines and whether they retain their specificity and antigen repertoire. EBV-CTLs were prepared from 8 EBV+ healthy donors using weekly stimulation with irradiated autologous EBV-transformed lymphoblastoid cell lines (LCL) in the presence of IL-2 (50U/mL). CTL were transduced after the 3rd stimulation and further expanded with 3–4 weekly LCL/IL-2 stimulations. The expansion rate of the transduced CTL was similar to that of control EBV-CTL. Transduced CTL retained killing of their autologous LCL targets through their native receptor (64.4±16% at 20:1 E:T ratio), and became able to lyse CD30+ malignant lymphoma targets through their cTcR (e.g. HDLM-2=45.4±16% and Karpas-299=42.5±17%). Killing of CD30+ tumor cells was significantly inhibited by preincubation with an anti-CD30 blocking antibody (16.5±12%). Of potential concern, however, is that CD30 is expressed by activated normal T lymphocytes: expression was undetectable on resting T cells, but increased to 3–32% on day 4–7 after stimulation with LCL. Fortunately, expression dwindles to 3–6% by two weeks as an EBV-specific line emerges, suggesting that CD30 is expressed only in the early phases of T cell activation. As anticipated from these data, therefore, expression of a CD30 cTcR did not impair the antigenic repertoire of the EBV-CTL, which retained the same pattern of immunodominant MHC class I epitopes (detected by tetramer) as control cells. We also performed co-culture experiments to evaluate whether infusion of CTL-CD30 cTcR could cross-compromise the primary reactivation of other virus-specific CTL. Autologous EBV-CTLs engineered to express the CD30-cTcR were added to cultures of PBMC stimulated to reactivate cytomegalovirus- or adenovirus-specific CTL. In 4/4 donors, the percentage of CMV pp65+ T cells did not change, while generation of adenovirus-specific T cells (Hexon-tetramer+) was significantly reduced in only 1/3 donor. These data support the feasibility of using EBV-CTL bearing a cTcR for CD30 to treat both EBV+ and EBV− HD.

Therapeutic LMP1 polyepitope vaccine for EBV-associated Hodgkin disease and nasopharyngeal carcinoma

AbstractDevelopment of an epitope-based vaccination strategy designed to enhance Epstein-Barr virus (EBV)–specific CD8+cytotoxic T lymphocytes (CTLs) is increasingly being considered as a preferred approach for the treatment of EBV-associated relapsed Hodgkin disease (HD) and nasopharyngeal carcinoma (NPC). EBV-encoded latent membrane proteins, LMP1 and LMP2, are the only target antigens available for therapeutic augmentation of CTL responses in patients with HD and NPC. Here, we describe preclinical studies using a recombinant poxvirus vaccine that encodes a polyepitope protein comprising 6 HLA A2–restricted epitopes derived from LMP1. Human cells infected with this recombinant polyepitope construct were efficiently recognized by LMP1-specific CTL lines from HLA A2 healthy individuals. Furthermore, immunization of HLA A2/Kbmice with this polyepitope vaccine consistently generated strong LMP1-specific CTL responses to 5 of the 6 epitopes, which were readily detected by both ex vivo and in vitro assays. More important, this polyepitope vaccine successfully reversed the outgrowth of LMP1-expressing tumors in HLA A2/Kbmice. These studies provide an important platform for the development of an LMP-based polyepitope vaccine as an immunotherapeutic tool for the treatment of EBV-associated HD and NPC.

CD99 expression is positively regulated by Sp1 and is negatively regulated by Epstein-Barr virus latent membrane protein 1 through nuclear factor-κB

Epstein-Barr virus (EBV)-encoded latent membrane protein-1 (LMP1) is highly expressed in Hodgkin and Reed-Sternberg (H-RS) cells from patients with EBV-associated Hodgkin disease. It was previously demonstrated that CD99 can be negatively regulated by LMP1 at the transcriptional level, and the decreased expression of CD99 in a B lymphocyte cell line generates H-RS-like cells. In this study, detailed dissection of the CD99 promoter region was performed to search regulatory factor(s) involved in the expression of the gene. Using various mutant constructs containing deletions in the promoter region, it was revealed that the maximal promoter activity was retained on 5'-deletion to the position -137 from the transcriptional initiation site. Despite the presence of multiple putative Sp1-binding sites in the promoter region, the site located at -95 contributes heavily as a positive cis-acting element to its basal promoter activity. However, on examination of the involvement of the positive-acting Sp1-binding site of the promoter for the repressive activity of LMP1, it appeared to be dispensable. Instead, the repressive effect was mapped to the nuclear factor (NF)-kappaB activation domains in the cytoplasmic carboxyl terminus of LMP1 despite the absence of the NF-kappaB consensus sequences in the CD99 promoter region. Furthermore, the decreased CD99 promoter activity by LMP1 was markedly restored when NF-kappaB activity was inhibited. Taken together, these data suggest that Sp1 activates, whereas LMP1 represses, transcription from the CD99 promoter through the NF-kappaB signaling pathway, and they might aid in the understanding of the molecular mechanisms of viral pathogenesis in EBV-positive Hodgkin disease. (Blood. 2001;97:3596-3604)

Expression of human tumor-associated antigen RCAS1 in Reed-Sternberg cells in association with Epstein-Barr virus infection: a potential mechanism of immune evasion.

RCAS1 (receptor-binding cancer antigen expressed on SiSo cells) is present in neoplastic cells, induces apoptosis of natural killer (NK)/T cells and plays a role in immune evasion. Fas ligand (FasL) is considered to have similar roles. The Epstein-Barr virus (EBV)-encoded latent membrane protein is expressed by malignant Hodgkin and Reed-Sternberg (H&RS) cells of EBV-associated Hodgkin's disease (HD) and considered to be a target of cytotoxic T lymphocytes (CTLs). However, CTL response is inadequate in HD. To determine whether RCAS1 and FasL are expressed in EBV-associated HD and participate in immune evasion, tissues of 20 EBV(-) and 15 EBV(+) HD cases were immunohistochemically stained for RCAS1, FasL and HLA classes I and II, whose deficiencies could explain CTL escape. Lymphocytes surrounding H&RS cells tended to be CD4(+) cells and rarely CD8(+), TIA-1(+) (cytotoxic marker) or NK cells. HLA class I and/or II were expressed in all EBV(+) HD cases, and RCAS1-expressing H&RS cells were found in 14/15 (93%) EBV(+) HD cases but only 8/20 (40%) EBV(-) HD cases (p < 0.05). FasL was detected in 9/15 (60%) and 7/20 (35%) EBV(+) and EBV(-) HD cases, respectively. ssDNA-positive (apoptotic) lymphocytes, surrounding H&RS cells, were rarely seen but were present in RCAS1(+) cases (20/22 cases, 91%) rather than negative cases (0/13 cases, 0%) (p < 0.005). Our findings suggest that EBV(+) H&RS cells might evade the host immune response by expressing RCAS1 rather than FasL.

Viral latent membrane protein 1 (LMP-1)–induced CD99 down-regulation in B cells leads to the generation of cells with Hodgkin's and Reed-Sternberg phenotype

AbstractRecently we reported that the down-regulation of CD99 (Mic2) is a primary requirement for the generation of Hodgkin's and Reed-Sternberg (H-RS) cells seen in Hodgkin's disease. In this study, we provide evidence that the down-regulation of CD99 is induced by high expression of Epstein-Barr virus (EBV) latent membrane protein 1 (LMP-1), which is highly expressed in H-RS cells of EBV-associated Hodgkin's disease. To investigate the effect of LMP-1 on the expression of CD99 in vitro, we established a stable cell line by transfecting an SV40-early promoter driven-LMP-1 expression construct into a neoplastic lymphoblastoid B cell line, IM9, in which the level of endogenous LMP-1 expression is almost negligible. In this cell line, the overexpression of LMP-1 led to the down-regulation of CD99 and the acquisition of morphological and functional characteristics of H-RS cells indistinguishable from those in lymph nodes of Hodgkin's disease patients and in CD99-deficient B cells. In addition, induced LMP-1 expression in an EBV-negative B cell clone, BJAB, directly caused the down-regulation of surface CD99 expression. Northern and Western analysis data, showing that overexpression of LMP-1 negatively influenced the expression of CD99, were supported by experiments in which a CD99 promoter-driven luciferase promoter reporter construct transfected into 293T cells was down-regulated when LMP-1 was coexpressed. Therefore, our data strongly suggest that the EBV LMP-1 protein plays a pivotal role in the down-regulation of CD99 via transcriptional regulation, which leads to the generation of the H-RS cells. (Blood. 2000;95:294-300)

Viral latent membrane protein 1 (LMP-1)–induced CD99 down-regulation in B cells leads to the generation of cells with Hodgkin's and Reed-Sternberg phenotype

Recently we reported that the down-regulation of CD99 (Mic2) is a primary requirement for the generation of Hodgkin's and Reed-Sternberg (H-RS) cells seen in Hodgkin's disease. In this study, we provide evidence that the down-regulation of CD99 is induced by high expression of Epstein-Barr virus (EBV) latent membrane protein 1 (LMP-1), which is highly expressed in H-RS cells of EBV-associated Hodgkin's disease. To investigate the effect of LMP-1 on the expression of CD99 in vitro, we established a stable cell line by transfecting an SV40-early promoter driven-LMP-1 expression construct into a neoplastic lymphoblastoid B cell line, IM9, in which the level of endogenous LMP-1 expression is almost negligible. In this cell line, the overexpression of LMP-1 led to the down-regulation of CD99 and the acquisition of morphological and functional characteristics of H-RS cells indistinguishable from those in lymph nodes of Hodgkin's disease patients and in CD99-deficient B cells. In addition, induced LMP-1 expression in an EBV-negative B cell clone, BJAB, directly caused the down-regulation of surface CD99 expression. Northern and Western analysis data, showing that overexpression of LMP-1 negatively influenced the expression of CD99, were supported by experiments in which a CD99 promoter-driven luciferase promoter reporter construct transfected into 293T cells was down-regulated when LMP-1 was coexpressed. Therefore, our data strongly suggest that the EBV LMP-1 protein plays a pivotal role in the down-regulation of CD99 via transcriptional regulation, which leads to the generation of the H-RS cells. (Blood. 2000;95:294-300)

Latent membrane protein 1 associated signaling pathways are important in tumor cells of Epstein-Barr virus negative Hodgkin's disease.

The latent membrane protein 1 (LMP1) oncogene of Epstein-Barr virus (EBV) is selectively expressed in the Reed-Sternberg (RS) cells of EBV-associated Hodgkin's disease (HD). However, no differences in clinical presentation and course are found between EBV positive and EBV negative forms of HD suggesting a common pathogenetic mechanism. We have studied the LMP1 associated signaling pathways and their dominant negative inhibition in the myelomonocytic HD-MyZ and the B-lymphoid L-428 HD cell lines. In both EBV negative cell lines expression of LMP1 is associated with the formation of multinuclear RS cells. Dominant negative inhibition of NF-kappa B mediated signaling at the step of I kappa B-alpha phosphorylation results in increased cell death with only a few typical RS cells resistant to overexpression of the dominant negative inhibitor I kappa B-alpha-N delta 54. However, dominant negative inhibition of NF-kappa B mediated signaling at the early step of TRAF2 interaction results in the formation of multinuclear cells in both cell lines and, in addition, in clusters of small mononuclear cells in the HD-MyZ cell line. In HD-MyZ cells overexpression of the powerful JBD-inhibitor of the JNK signal transduction pathway is restricted to small cells and never observed in RS cells. These small cells undergo apoptosis as shown by the TUNEL technique. Apoptosis of small cells is still observed after co-transfection of JBD and LMP1 but in addition a few apoptotic HD-MyZ cells with large fused nuclear masses are identified suggesting that specific inhibition of JNK leads also to apoptosis of LMP1 induced RS cells. Thus, activation of the JNK signaling pathway is also important in the formation of Reed-Sternberg cells. Our findings are consistent with a model where all three LMP1 associated functions, i.e. NF-kappa B mediated transcription, TRAF2 dependent signaling, and c-Jun activation act as a common pathogenetic denominator of both EBV negative and EBV positive HD.

Epstein-Barr Virus (EBV) Nuclear Antigen (EBNA)-4 Mutation in EBV-Associated Malignancies in Three Different Populations

Different ethnic groups with a high human leukocyte antigen (HLA)-A11 prevalence have been shown to experience a high rate of Epstein-Barr virus (EBV) infection, EBV-associated malignancies, and Epstein-Barr nuclear antigen (EBNA)-4 mutations. The epitopes 399-408 and 416-424 of EBNA-4 are major antigenic epitopes that elicit an HLA-A11 cytotoxic T lymphocyte (CTL) response to EBV infection. Mutations selectively involving one or more nucleotide residues in these epitopes affect the antigenicity of EBNA-4, because the mutant EBV strains are not recognized by the HLA-A11-restricted CTLs. To investigate these mutations in common EBV-associated malignancies occurring in different populations, we studied the mutation rate of epitopes 399-408 and 416-424 of EBNA-4 in 25 cases of EBV-associated Hodgkin's disease (HD), nine cases of AIDS-related non-Hodgkin's lymphoma, and 37 cases of EBV-associated gastric carcinoma (GC) from the United States, Brazil, and Japan. We found one or more mutations in these two epitopes in 50% (6/12) of United States HD, 15% (2/13) of Brazilian HD, 50% (6/12) United States GC and 28% (7/25) Japanese GC, and 22% (2/9) of United States AIDS-lymphoma. Similar mutations were found in 30% (3/10) of United States reactive, 0% (0/6) of Brazilian reactive, and 25% (2/8) Japanese reactive tissues. The most frequent amino acid substitutions were virtually identical to those seen in previously reported isolates from EBV-associated nasopharyngeal carcinomas and Burkitt's lymphomas occurring in high prevalence HLA-A11 regions. However, only 2/28 (7%) mutations occurred in HLA-A11-positive patients. Our studies suggest that: 1) EBNA-4 mutations are a common phenomenon in EBV-associated HD, GC, and AIDS-lymphoma; 2) the mutation rate does not vary in these geographic areas and ethnic groups; 3) EBNA-4 mutations in EBV-associated United States and Brazilian HD, United States and Japanese GC, and United States AIDS lymphomas are not related to patients' HLA-A11 status.

Analysis of Major Histocompatibility Complex Class I, TAP Expression, and LMP2 Epitope Sequence in Epstein-Barr Virus–Positive Hodgkin's Disease

The Epstein-Barr virus (EBV)-encoded latent membrane proteins, LMP1 and LMP2, are consistently expressed by the malignant Hodgkin/Reed-Sternberg (HRS) cells of EBV-associated Hodgkin's disease (HD). Cytotoxic T lymphocyte (CTL) responses to both of these proteins have been shown in the blood of EBV-seropositive individuals, yet in HD the apparent failure of the CTL response to eliminate HRS cells expressing LMP1 and LMP2 in vivo has given rise to the suggestion that HD may be characterized by the presence of defects in antigen processing/presentation or in CTL function. This study has used immunohistochemistry to show high-level expression of major histocompatibility complex (MHC) class I molecules by the HRS cells of EBV-associated HD and either low level or absence of expression of MHC class I molecules on HRS cells of EBV-negative tumors. In addition, HRS cells expressed high levels of transporter-associated proteins (TAP-1, -2), irrespective of the presence of latent EBV infection. These results suggest that global downregulation of MHC class I molecules does not account for the apparent ability of EBV-infected HRS cells to evade CTL responses, but may be important in the understanding of EBV-negative disease.We have also sequenced an epitope in LMP2A (CLGGLLTMV) that is restricted through HLA A2.1, a relatively common allele in Caucasian populations, and showed that this epitope is wild type in a small group of EBV-associated HLA A2.1-positive HD tumors. This result may be relevant to proposed immunotherapeutic approaches for EBV-positive HD patients that target CTL epitopes.

Analysis of Major Histocompatibility Complex Class I, TAP Expression, and LMP2 Epitope Sequence in Epstein-Barr Virus–Positive Hodgkin's Disease

The Epstein-Barr virus (EBV)-encoded latent membrane proteins, LMP1 and LMP2, are consistently expressed by the malignant Hodgkin/Reed-Sternberg (HRS) cells of EBV-associated Hodgkin's disease (HD). Cytotoxic T lymphocyte (CTL) responses to both of these proteins have been shown in the blood of EBV-seropositive individuals, yet in HD the apparent failure of the CTL response to eliminate HRS cells expressing LMP1 and LMP2 in vivo has given rise to the suggestion that HD may be characterized by the presence of defects in antigen processing/presentation or in CTL function. This study has used immunohistochemistry to show high-level expression of major histocompatibility complex (MHC) class I molecules by the HRS cells of EBV-associated HD and either low level or absence of expression of MHC class I molecules on HRS cells of EBV-negative tumors. In addition, HRS cells expressed high levels of transporter-associated proteins (TAP-1, -2), irrespective of the presence of latent EBV infection. These results suggest that global downregulation of MHC class I molecules does not account for the apparent ability of EBV-infected HRS cells to evade CTL responses, but may be important in the understanding of EBV-negative disease.We have also sequenced an epitope in LMP2A (CLGGLLTMV) that is restricted through HLA A2.1, a relatively common allele in Caucasian populations, and showed that this epitope is wild type in a small group of EBV-associated HLA A2.1-positive HD tumors. This result may be relevant to proposed immunotherapeutic approaches for EBV-positive HD patients that target CTL epitopes.

Determination of HLA-A*02 antigen status in Hodgkin's disease and analysis of an HLA-A*02-restricted epitope of the Epstein-Barr virus LMP-2 protein.

There is good evidence for an association between Epstein-Barr virus (EBV) and Hodgkin's disease (HD). In approximately one-third of cases, the EBV genome is detectable in Reed-Sternberg (RS) cells and there is expression of the viral nuclear antigen EBNA-1 and the latent membrane protein LMP-1. Expression of LMP-2 has been demonstrated at the mRNA level, and it is presumed that the protein is expressed alongside LMP-1. The LMP-2 protein is known to contain an epitope presented to cytotoxic T-cells which is restricted through the HLA class I antigen A*0201 in healthy seropositive individuals. Since most HLA-A*02-positive Caucasians are HLA-A*0201-positive, it was hypothesized that HLA-A*02-positive individuals would be under-represented among Caucasians with EBV-associated HD. HLA-A*02 status was determined, using flow cytometry and/or the polymerase chain reaction, for 276 individuals including 176 cases of HD. There was no significant difference between the frequency of HLA-A*02 positivity in HD cases and controls, and between EBV-associated and non-associated cases of HD. The A*02 alleles of 14 cases of EBV-associated HD were further subtyped using nested PCR; all except one case were found to be A*0201-positive. We therefore investigated whether there was any evidence for mutation of the epitope representing amino acids 426-434 of LMP-2a which is restricted through HLA-A*0201. In 10/11 cases the nucleotide sequence encoding this epitope was identical to the published sequence; in the remaining case there was a mutation which would not be expected to alter the conformation of the epitope. Overall, our data suggest that other mechanisms of immune escape must be operative in EBV-associated HD.

Modulation of interleukin-6 expression in Hodgkin and Reed-Sternberg cells by Epstein-Barr virus.

Variable proportions of Hodgkin's disease (HD) cases are associated with the Epstein-Barr virus (EBV), but the role of EBV in HD is not entirely clear. Hodgkin and Reed-Sternberg (HRS) cells of EBV-associated HD are characterized by expression of the EBV gene product LMP1. In other cellular environments, LMP1 has been shown to induce interleukin (IL)-6. In this study, 105 HD cases were tested for differences in IL-6 expression among LMP1-positive and -negative cases. Isotopic in situ hybridization and correlation with the presence of EBV gene products revealed significantly higher proportions of cases with IL-6-expressing tumour cells in LMP1-positive (31 of 37, 84 per cent) as compared with LMP1-negative HD cases (35 of 68, 51 per cent). Thus, although not exclusive to EBV-positive HRS cells, IL-6 expression appears to be upregulated in EBV-associated HD. IL-6 receptor (CD126) expression was tested by in situ hybridization and found in a broad spectrum of cell types, regularly including HRS cells. Superinduction of IL-6 expression may be among the mechanisms by which EBV confers a growth advantage on virus-infected HRS cells and by which the virus may contribute to the morphological and clinical peculiarities of HD.

Reed-Sternberg cells and "bystander" lymphocytes in lymph nodes affected by Hodgkin's disease are infected with different strains of Epstein-Barr virus.

In most cases of Epstein-Barr virus (EBV)-associated Hodgkin's disease (HD), EBV-positive Reed-Sternberg (RS) cells and rare EBV-positive reservoir lymphocytes coexist in lymph nodes. Here we show that, in two cases of EBV-associated HD, strains infecting RS cells and reservoir lymphocytes of the same patient have different BNLF-1 genes. This suggests that RS cells and reservoir lymphocytes of the same patient are infected by different EBV strains.