Control Of Epstein-Barr Virus Infection Research Articles

HLA Allele E*01:01 Is Associated with a Reduced Risk of EBV-Related Classical Hodgkin Lymphoma Independently of HLA-A*01/*02.

BackgroundAn inefficient immune response against Epstein-Barr virus (EBV) infection is related to the pathogenesis of a subgroup of classical Hodgkin lymphomas (cHL). Some EBV immune-evasion mechanisms target HLA presentation, including the non-classical HLA-E molecule. HLA-E can be recognized by T cells via the TCR, and it also regulates natural killer (NK) cell signaling through the inhibitory CD94/NKG2A receptor. Some evidences indicate that EBV-infected B-cells promote the proliferation of NK subsets bearing CD94/NKG2A, suggesting a relevant function of these cells in EBV control. Variations in CD94/NKG2A-HLA-E interactions could affect NK cell-mediated immunity and, consequently, play a role in EBV-driven transformation and lymphomagenesis. The two most common HLA-E alleles, E*01:01 and E*01:03, differ by a single amino acid change that modifies the molecule function. We hypothesized that the functional differences in these variants might participate in the pathogenicity of EBV.AimWe studied two series of cHL patients, both with EBV-positive and-negative cases, and a cohort of unrelated controls, to assess the impact of HLA-E variants on EBV-related cHL susceptibility.ResultsWe found that the genotypes with at least one copy of E*01:01 (i.e., E*01:01 homozygous and heterozygous) were underrepresented among cHL patients from both series compared to controls (72.6% and 71.6% vs 83%, p = 0.001). After stratification by EBV status, we found low rates of E*01:01-carriers mainly among EBV-positive cases (67.6%). These reduced frequencies are seen independently of other factors such as age, gender, HLA-A*01 and HLA-A*02, HLA alleles positively and negatively associated with the disease (adjusted OR = 0.4, p = 0.001). Furthermore, alleles from both HLA loci exert a cumulative effect on EBV-associated cHL susceptibility.ConclusionsThese results indicate that E*01:01 is a novel protective genetic factor in EBV-associated cHL and support a role for HLA-E recognition on the control of EBV infection and lymphomagenesis.

Abstract 4568: Inhibition of autophagy in EBV-positive Burkitt's lymphoma cells enhances EBV lytic genes expression and replication

Abstract Autophagy, an important degradation system involved in maintaining cellular homeostasis, serves also to eliminate pathogens and process their fragments for presentation to the immune system. Several viruses have been shown to interact with the host autophagic machinery to suppress or make use of this cellular catabolic pathway to enhance their survival and replication. Epstein Barr virus (EBV) is a γ-herpes virus associated with a number of malignancies of epithelial and lymphoid origin in which establishes a predominantly latent infection. EBV lytic cycle characterized by the sequential expression of immediate early (IE), early and late antigens results in the production of infectious particles which allow the virus to spread. In this study we analyzed the relationship between EBV and autophagy after inducing the virus productive cycle in Burkitt's lymphoma (BL) cells. By monitoring autophagy markers and EBV lytic genes expression, we demonstrate that autophagy is enhanced in the early phases of EBV lytic activation but decreases thereafter concomitantly with increased levels of EBV lytic proteins. In a cell line defective for late antigens expression, we found an inverse correlation between EBV early antigens expression and autophagosomes formation indicating that early after activation, the virus is able to suppress autophagy. We report that inhibition of autophagy by Bafilomycin A1 or shRNA knockdown of beclin1 gene, enhance EBV lytic genes expression as well as intracellular viral DNA and viral progeny yield. Taken together, these findings indicate that viral replication induces an autophagic response which can inhibit the further expression of EBV early lytic products. Moreover, our findings open the possibility to utilize pharmacological modulators of autophagy to control EBV infection and treat EBV-related lymphomas. Citation Format: Alessandra De Leo, Francesca Colavita, Fabiola Ciccosanti, Gian Maria Fimia, Paul Lieberman, Elena Mattia. Inhibition of autophagy in EBV-positive Burkitt's lymphoma cells enhances EBV lytic genes expression and replication. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4568. doi:10.1158/1538-7445.AM2015-4568

Role of the 2B4 Receptor in CD8+ T-Cell-Dependent Immune Control of Epstein-Barr Virus Infection in Mice With Reconstituted Human Immune System Components.

Patients with X-linked lymphoproliferative (XLP) disease due to deficiency in the adaptor molecule signaling lymphocytic activation molecule-associated protein (SAP) are highly susceptible to one specific viral pathogen, the Epstein-Barr virus (EBV). This susceptibility might result from impaired CD8(+) T-cell and natural killer cell responses to EBV infection in these patients. We demonstrate that antibody blocking of the SAP-dependent 2B4 receptor is sufficient to induce XLP-like aggravation of EBV disease in mice with reconstituted human immune system components. CD8(+) T cells require 2B4 for EBV-specific immune control, because 2B4 blockade after CD8(+) T-cell depletion did not further aggravate symptoms of EBV infection.

Primary Immunodeficiencies Associated with EBV Disease.

Epstein-Barr virus (EBV) infects nearly all humans and usually is asymptomatic, or in the case of adolescents and young adults, it can result in infectious mononucleosis. EBV-infected B cells are controlled primarily by NK cells, iNKT cells,CD4 T cells, and CD8 T cells. While mutations in proteins important for B cell function can affect EBV infection of these cells, these mutations do not result in severe EBV infection. Some genetic disorders affecting T and NK cell function result in failure to control EBV infection, but do not result in increased susceptibility to other virus infections. These include mutations in SH2D1A, BIRC4, ITK, CD27, MAGT1, CORO1A, and LRBA. Since EBV is the only virus that induces proliferation of B cells, the study of these diseases has helped to identify proteins critical for interactions of T and/or NK cells with B cells. Mutations in three genes associated with hemophagocytic lymphohistocytosis, PRF1, STXBP2, and UNC13D, can also predispose to severe chronic active EBV disease. Severe EBV infection can be associated with immunodeficiencies that also predispose to other viral infections and in some cases other bacterial and fungal infections. These include diseases due to mutations in PIK3CD,PIK3R1, CTPS1, STK4, GATA2, MCM4, FCGR3A, CARD11, ATM, and WAS. In addition, patients with severe combined immunodeficiency, which can be due to mutations in a number of different genes, are at high risk for various infections as well as EBV B cell lymphomas. Identification of proteins important for control of EBV may help to identify new targets for immunosuppressive therapies.

EBV- DNA Viral Load in Peripheral Blood Mononuclear Cells of Patients with Chronic Lymphocytic Leukemia Is Associated with Unfavorable Prognosis

Background: Epstein-Barr virus (EBV) is a ubiquitous γ-herpesvirus that infects more than 90% of the world population. Following primary infection in the oropharynx, EBV remains latently present in B cells. Asymptomatic EBV reactivations periodically occur in oral mucosa-associated lymphoid tissues in healthy carriers. B cells infected by EBV are suspected to be involved in the etiology of various human lymphoma. Previously, EBV reactivation has been diagnosed by serologic IgG, IgM, IgA profiles that suggested virus replication. However, serologic responses, in immunocompromised subjects, like patients with chronic lymphocytic leukemia (CLL), do not necessarily indicate ongoing replicative activity. CLL is the most frequent form of leukemia in adults in western countries. Despite by definition chronic character, CLL is characterized by marked heterogeneity. Potential involvement of EBV in the pathogenesis of CLL is still to be explain. Latent EBV infection in healthy carriers is controlled by a cell-mediated immune response that is impaired in CLL patients and might result in poor control of EBV infection. Since EBV may activate B cells, stimulate their proliferation and inhibit their apoptosis, we hypothesize that it could contribute to unfavorable clinical course of CLL and may be one of reason of its heterogeneity.Objective: The aim of this study was to determine whether EBV-DNA load in the peripheral blood mononuclear cells (PBMCs) of CLL patients may influence heterogeneity in clinical course of the disease. We analyzed the association between EBV-DNA load in PBMC and stage of the disease, adverse prognostic factors (including CD38 and ZAP-70 expression and cytogenetic abnormalities) and clinical outcome.Material and methods: Peripheral blood samples were obtained from 115 untreated CLL patients and 20 healthy individuals. Real-time PCR was used to quantitate EBV-DNA copy number in PBMCs (viral load). As the sensitivity of the system amounts to 10 copies per µl, all the samples with the EBV-DNA copy number below this detection threshold were considered EBV-negative. The immunophenotype of peripheral blood lymphocytes was analyzed by flow cytometer.Results: Detectable EBV-DNA load in PBMCs was found in 62 out of 115 CLL patients (53.91%). The median EBV-DNA copy number in these group was 184 per 1 µg DNA (range: 12.79-8957.69). The EBV-DNA copy number per 1 µg DNA was significantly higher in patients who required the treatment (p<0.0001) than in untreated ones, in patients with lymphocyte count doubling time <12 months than in than patients with lymphocyte count doubling time >12 months (p<0.0001), in patients with hepatomegaly (p=0.023) and, splenomegaly (p=0.005) than in patients without organomegaly. It was also significantly higher in patients with CD38 (p<0.0001) and ZAP-70 expression (p=0.008) comparing to the patients CD38- and ZAP-70-, respectively, as well as in the patients with del (11q22.3) as comparing to the patients without this cytogenetic abnormality. Furthermore, the EBV-DNA copy number per 1 µg DNA showed significant positive correlation with the concentrations of LDH (r=0.531, p=0.00001) and beta-2-microglobulin (r=0.425, p=0.00057). The presence of more than 12.79 copies of EBV DNA in 1 µg DNA isolated from PBMCs was associated with reduced time to first treatment (p=0.00001), and lymphocyte count doubling-free survival (p<0.000001).Conclusions: We proved for the first time, that higher of EBV-DNA copy number in PBMCs of patients with CLL is associated with adverse prognostic factors as well as more progressive clinical course of the disease expressed by reduced time to first treatment. These results suggest that higher of EBV-DNA copy number in peripheral blood mononuclear cells blood predicts poor clinical outcome of CLL. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Epstein-Barr virus and multiple sclerosis: potential opportunities for immunotherapy.

Multiple sclerosis (MS) is a common chronic inflammatory demyelinating disease of the central nervous system (CNS) causing progressive disability. Many observations implicate Epstein–Barr virus (EBV) in the pathogenesis of MS, namely universal EBV seropositivity, high anti-EBV antibody levels, alterations in EBV-specific CD8+ T-cell immunity, increased spontaneous EBV-induced transformation of peripheral blood B cells, increased shedding of EBV from saliva and accumulation of EBV-infected B cells and plasma cells in the brain. Several mechanisms have been postulated to explain the role of EBV in the development of MS including cross-reactivity between EBV and CNS antigens, bystander damage to the CNS by EBV-specific CD8+ T cells, activation of innate immunity by EBV-encoded small RNA molecules in the CNS, expression of αB-crystallin in EBV-infected B cells leading to a CD4+ T-cell response against oligodendrocyte-derived αB-crystallin and EBV infection of autoreactive B cells, which produce pathogenic autoantibodies and provide costimulatory survival signals to autoreactive T cells in the CNS. The rapidly accumulating evidence for a pathogenic role of EBV in MS provides ground for optimism that it might be possible to prevent and cure MS by effectively controlling EBV infection through vaccination, antiviral drugs or treatment with EBV-specific cytotoxic CD8+ T cells. Adoptive immunotherapy with in vitro-expanded autologous EBV-specific CD8+ T cells directed against viral latent proteins was recently used to treat a patient with secondary progressive MS. Following the therapy, there was clinical improvement, decreased disease activity on magnetic resonance imaging and reduced intrathecal immunoglobulin production.

160: Unveiling a novel immunomodulatory role for interferon-β therapy in multiple sclerosis: The selective reduction of pathogenic memory B cells

Objective B cells are emerging as central players in Multiple sclerosis (MS) pathogenesis, thus we sought to evaluate whether IFN-β therapy may regulate B cell responses in Relapsing Remitting MS (RRMS) patients. Methods Apoptotic phenotype of naive and memory B cells was analyzed longitudinally in MS patients before and after therapy either by staining with Annexin-V and 7-actinomycin D or by evaluating intracellular Caspase 3 activation and Fas Receptor (Fas) expression. In vitro experiments were also conducted treating with an anti-Fas mAb PBMCs isolated from MS patients. Results Our results showed that IFN-β specifically targets the B cell compartment by reducing memory B cell frequency. Enhanced expression of Fas, Annexin-V and active Caspase 3 was found in memory B cells upon IFN-β therapy, suggesting a specific induction of apoptosis in this population also confirmed by in vitro experiments with anti-Fas mAb. Taking into account that memory B cells represent the major Epstein barr-virus (EBV) reservoir and that EBV represents one of the candidate for MS etiopathogenesis, the ability of IFN-β therapy to reduce the enhanced expression of the EBV latent LMP2A transcript found in MS patients as compared to healthy subjects, indicates that this treatment may also exert some antiviral effects in MS patients. Conclusions All our findings suggest that the specific reduction of memory B cells is a novel effect induced by IFN-β therapy, similarly to what found for the anti-CD20 mAb Rituximab. Thus, IFN-β therapy may play a dual role by exerting both immunomodulatory and anti-viral activities, modulating pathogenic B cell responses and controlling EBV infection in MS patients via the depletion of EBV-harboring cells. This work was supported by FISM Grant ( #2009/R/7 to EMC).

Adoptive transfer of EBV specific CD8+ T cell clones can transiently control EBV infection in humanized mice.

Epstein Barr virus (EBV) infection expands CD8+ T cells specific for lytic antigens to high frequencies during symptomatic primary infection, and maintains these at significant numbers during persistence. Despite this, the protective function of these lytic EBV antigen-specific cytotoxic CD8+ T cells remains unclear. Here we demonstrate that lytic EBV replication does not significantly contribute to virus-induced B cell proliferation in vitro and in vivo in a mouse model with reconstituted human immune system components (huNSG mice). However, we report a trend to reduction of EBV-induced lymphoproliferation outside of lymphoid organs upon diminished lytic replication. Moreover, we could demonstrate that CD8+ T cells against the lytic EBV antigen BMLF1 can eliminate lytically replicating EBV-transformed B cells from lymphoblastoid cell lines (LCLs) and in vivo, thereby transiently controlling high viremia after adoptive transfer into EBV infected huNSG mice. These findings suggest a protective function for lytic EBV antigen-specific CD8+ T cells against EBV infection and against virus-associated tumors in extra-lymphoid organs. These specificities should be explored for EBV-specific vaccine development.

SLAM-associated protein modulates CD8 T cell responses primed by antigen-presenting B cells (IRM4P.503)

Abstract Mutations in the SH2D1A gene, that encodes SLAM-associated protein (SAP), cause X-linked lymphoproliferative disease (XLP), a rare congenital immunodeficiency defined by exquisite sensitivity to Epstein-Barr virus (EBV). The inability of boys with XLP to control EBV infection results in fulminant, often fatal, infectious mononucleosis, massive expansions of EBV-infected B cells and malignant B cell lymphomas. However, the precise mechanism of how SAP loss contributes to susceptibility to EBV remains unclear. Given the unique B cell tropism of EBV and the purported role of SAP in regulating lymphocyte/lymphocyte interactions, we hypothesized that SAP expression within CD8 T cells is critical for T cells to mount responses towards antigen-expressing B cells. Wild type and Sh2d1a-/- CD8 T cells responded strongly when stimulated in vitro with cognate antigen-coated whole splenocytes. However, Sh2d1a-/- CD8 T cells exhibited greatly diminished proliferation and effector functions relative to wild type CD8 T cells when cultured with antigen-coated B cells in vitro or challenged with antigen-expressing B cell lymphoma in vivo. These results demonstrate that SAP is required for the priming of CD8 T cells when B cells act as the primary APC. Together, our findings suggest that the susceptibility of XLP patients to EBV infection may at least in part be a consequence of an inability of their naïve CD8 T cells to differentiate into effectors upon encountering virally-infected B cells.

Aggressive Mature Natural Killer Cell Neoplasms: From EBV-Infection to Disease Etiopathogeny

Mature Natural Killer (NK) cell neoplasms are rare tumors with higher prevalence in Asia, Central and South America, which are related to Epstein Barr Virus (EBV) infection. Nature killer /T cell lymphoma, nasal type, presents as a localized or generalized destructive tumor, affecting the nose, the upper aero digestive tract or any organ or tissue, whereas aggressive NK-cell leukemia manifests as a systemic disease that preferentially affects the bone marrow, the spleen and the liver, and rapidly evolve to multiorgan failure resulting in death. Both NK-cell neoplasms arise as a consequence of the inability of the immune system to control EBV infection and of the transforming potential of multiple EBV gene products. Chronic active EBV infection and EBV-related lymphoproliferative disorders of NK-cells are predisposing conditions. The tumor NK-cells do express an EBV infection type II latency pattern, specific EBV-encoded latent membrane proteins and early region EBV RNAs being detected on lymphoma cells. The EBV encoded proteins and non-coding EBV RNAs and micro-RNAs expressed on the infected cells are involved in immune deregulation and play a crucial role in cell transformation and oncogenesis. This review addresses the mechanisms used by EBV to infect the cells and to evade the immune-surveillance as well as to induce cell survival and transformation, and characterizes the spectrum of the clinical manifestations associated with chronic EBV-infection and related T-and NK-lymphoproliferative disorders. Improving the knowledge in this subject will help to develop new therapeutic approaches for chronic EBV-infection and even prevention strategies for the aggressive NK-cell malignancies.

X-linked lymphoproliferative syndromes and related autosomal recessive disorders

X-linked lymphoproliferative (XLP) syndromes and related autosomal disorders are severe primary immune deficiencies triggered by infection with Epstein-Barr virus (EBV), the causative agent of infectious mononucleosis. Recent findings reviewed herein provided key new insights into the genetic and immunological basis of these diseases. They also improved our comprehension of the immunological mechanisms controlling EBV infection. Mutations of an X-linked gene, SH2D1A, which encodes the signaling lymphocytic activation molecule (SLAM)-associated protein (SAP), are responsible for most cases of XLP disorders. More recently, other genetic causes for XLP syndromes and autosomal recessive variants of this disease were elucidated. Mutations in genes such as XIAP, ITK, and CD27 were identified. The clinical manifestations and immunological defects seen in these patients were characterized. The similarities and differences in immunological defects and clinical manifestations between XLP syndromes and related autosomal recessive disorders enabled important new insights into the pathogenesis of these diseases. They also helped our comprehension of the mechanisms implicated in the control of EBV infection. They suggested that CD8+ T cells, natural killer (NK) cells, and NKT cells are critically involved.

Immunogenicity of a Multiepitope Plasmid DNA Encoding T and B Lymphocyte Epitopes from Latent Membrane Protein 2 (LMP2) of Epstein-Barr Virus as a Vaccine in Mice

Epstein-Barr virus (EBV) is a human oncogenic herpesvirus associating with several malignant diseases. Latent membrane protein 2 (LMP2) of EBV is considered to be an ideal candidate for immunotherapy or prophylactic EBV vaccine. We designed a LMP2 multiepitope containing T and B-cell epitope-rich peptides and constructed a recombinant plasmid containing mammalian codonoptimization EBV LMP2 multiepitope (pcDNA3.1+/EBV-LMP2 multiepitope). After pcDNA3.1+/EBV-LMP2 multiepitope was transfected into COS-7 cells, significant expression of the multiepitope in COS-7 cells was confirmed by RT-PCR and immunofluorescence assay. Western blot analysis indicated that serum from immunized mice could be discerned by the EBV-LMP2 protein and the EBV-LMP2 multiepitope specifically. The plasmid DNA of EBV-LMP2 multiepitope induced high levels anti-EBV membrane protein and anti-EBV LMP2 multiepitope IgG in mice. T lymphocytes from spleen of immunized mice showed a strong CTL activity. The present study suggested that plasmid DNA encoding EBV LMP2 multiepitope capable of stimulating enough cellular and humoral immunity could have potential for preventing or controlling EBV infection and EBV associated disease in mice.

Increased CD8+ T cell response to Epstein-Barr virus lytic antigens in the active phase of multiple sclerosis.

It has long been known that multiple sclerosis (MS) is associated with an increased Epstein-Barr virus (EBV) seroprevalence and high immune reactivity to EBV and that infectious mononucleosis increases MS risk. This evidence led to postulate that EBV infection plays a role in MS etiopathogenesis, although the mechanisms are debated. This study was designed to assess the prevalence and magnitude of CD8+ T-cell responses to EBV latent (EBNA-3A, LMP-2A) and lytic (BZLF-1, BMLF-1) antigens in relapsing-remitting MS patients (n = 113) and healthy donors (HD) (n = 43) and to investigate whether the EBV-specific CD8+ T cell response correlates with disease activity, as defined by clinical evaluation and gadolinium-enhanced magnetic resonance imaging. Using HLA class I pentamers, lytic antigen-specific CD8+ T cell responses were detected in fewer untreated inactive MS patients than in active MS patients and HD while the frequency of CD8+ T cells specific for EBV lytic and latent antigens was higher in active and inactive MS patients, respectively. In contrast, the CD8+ T cell response to cytomegalovirus did not differ between HD and MS patients, irrespective of the disease phase. Marked differences in the prevalence of EBV-specific CD8+ T cell responses were observed in patients treated with interferon-β and natalizumab, two licensed drugs for relapsing-remitting MS. Longitudinal studies revealed expansion of CD8+ T cells specific for EBV lytic antigens during active disease in untreated MS patients but not in relapse-free, natalizumab-treated patients. Analysis of post-mortem MS brain samples showed expression of the EBV lytic protein BZLF-1 and interactions between cytotoxic CD8+ T cells and EBV lytically infected plasma cells in inflammatory white matter lesions and meninges. We therefore propose that inability to control EBV infection during inactive MS could set the stage for intracerebral viral reactivation and disease relapse.

EBNA3B-deficient EBV promotes B cell lymphomagenesis in humanized mice and is found in human tumors.

Epstein-Barr virus (EBV) persistently infects more than 90% of the human population and is etiologically linked to several B cell malignancies, including Burkitt lymphoma (BL), Hodgkin lymphoma (HL), and diffuse large B cell lymphoma (DLBCL). Despite its growth transforming properties, most immune-competent individuals control EBV infection throughout their lives. EBV encodes various oncogenes, and of the 6 latency-associated EBV-encoded nuclear antigens, only EBNA3B is completely dispensable for B cell transformation in vitro. Here, we report that infection with EBV lacking EBNA3B leads to aggressive, immune-evading monomorphic DLBCL-like tumors in NOD/SCID/γc-/- mice with reconstituted human immune system components. Infection with EBNA3B-knockout EBV (EBNA3BKO) induced expansion of EBV-specific T cells that failed to infiltrate the tumors. EBNA3BKO-infected B cells expanded more rapidly and secreted less T cell-chemoattractant CXCL10, reducing T cell recruitment in vitro and T cell-mediated killing in vivo. B cell lines from 2 EBV-positive human lymphomas encoding truncated EBNA3B exhibited gene expression profiles and phenotypic characteristics similar to those of tumor-derived lines from the humanized mice, including reduced CXCL10 secretion. Screening EBV-positive DLBCL, HL, and BL human samples identified additional EBNA3B mutations. Thus, EBNA3B is a virus-encoded tumor suppressor whose inactivation promotes immune evasion and virus-driven lymphomagenesis.

CD8+ T-Cell Deficiency, Epstein-Barr Virus Infection, Vitamin D Deficiency, and Steps to Autoimmunity: A Unifying Hypothesis

CD8+ T-cell deficiency is a feature of many chronic autoimmune diseases, including multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus, Sjögren's syndrome, systemic sclerosis, dermatomyositis, primary biliary cirrhosis, primary sclerosing cholangitis, ulcerative colitis, Crohn's disease, psoriasis, vitiligo, bullous pemphigoid, alopecia areata, idiopathic dilated cardiomyopathy, type 1 diabetes mellitus, Graves' disease, Hashimoto's thyroiditis, myasthenia gravis, IgA nephropathy, membranous nephropathy, and pernicious anaemia. It also occurs in healthy blood relatives of patients with autoimmune diseases, suggesting it is genetically determined. Here it is proposed that this CD8+ T-cell deficiency underlies the development of chronic autoimmune diseases by impairing CD8+ T-cell control of Epstein-Barr virus (EBV) infection, with the result that EBV-infected autoreactive B cells accumulate in the target organ where they produce pathogenic autoantibodies and provide costimulatory survival signals to autoreactive T cells which would otherwise die in the target organ by activation-induced apoptosis. Autoimmunity is postulated to evolve in the following steps: (1) CD8+ T-cell deficiency, (2) primary EBV infection, (3) decreased CD8+ T-cell control of EBV, (4) increased EBV load and increased anti-EBV antibodies, (5) EBV infection in the target organ, (6) clonal expansion of EBV-infected autoreactive B cells in the target organ, (7) infiltration of autoreactive T cells into the target organ, and (8) development of ectopic lymphoid follicles in the target organ. It is also proposed that deprivation of sunlight and vitamin D at higher latitudes facilitates the development of autoimmune diseases by aggravating the CD8+ T-cell deficiency and thereby further impairing control of EBV. The hypothesis makes predictions which can be tested, including the prevention and successful treatment of chronic autoimmune diseases by controlling EBV infection.

Inhibition of Transfer Infection of Epstein-Barr Virus to Epithelial Cells by Integrin β6 siRNA

Epstein-Barr virus (EBV) establishes a latent infection in greater than 90% of the worlds adult population and associates with various tumors. EBV primarily infects epithelial cells and B cell in vivo. Mechanism of EBV infection in B cells is known to involve binding of EBV glycoprotein gp350 to CD21 on B cell surface. Epithelial cells are infected with EBV even though most of epithelial cells do not express CD21. Recently, integrin αvβ5, αvβ6 and αvβ8 on epithelial cells were reported to facilitate EBV infection by interacting with gHgL complex. We examined the expression profile of integrins known to be expressed on epithelial cells. Integrin αvβ5 and αvβ6, but not αvβ8 were detected in a gastric epithelial cell line, AGS. We then tested whether siRNAs specific to β6 can inhibit EBV infection of epithelial cells. One among the four tested siRNAs significantly reduced β6 expression and suppressed transfer infection of EBV to AGS cells. Our data suggest that siRNAs to integrins might be useful to control EBV infection to epithelial cells.

Epstein-Barr virus and multiple sclerosis: interaction with HLA

Epstein-Barr virus (EBV) infection, history of infectious mononucleosis (IM) and HLA-A and DRB1 have all been proposed as risk factors for multiple sclerosis (MS). Our aim was to analyse possible interactions between antibodies against Epstein-Barr virus nuclear antigen 1 (EBNA1) or EBNA1 fragments, presence of DRB1*15 and absence of A*02. The study population includes newly diagnosed cases and matched controls. Interaction on the additive scale was calculated using attributable proportion due to interaction (AP), which is the proportion of the incidence among individuals exposed to two interacting factors that is attributable to the interaction per se. IM showed association with MS, odds ratio (OR)=1.89 (1.45-2.48% confidence interval (CI)), as did raised EBNA1 IgG OR=1.74 (1.38-2.18 95%CI). All EBNA1 fragment IgGs were associated with MS risk. However, EBNA1 fragment 385-420 IgG levels were more strongly associated to MS than total EBNA1 IgG, OR=3.60 (2.75-4.72 95%CI), and also interacted with both DRB1*15 and absence of A*02, AP 0.60 (0.45-0.76 95%CI) and AP 0.39 (0.18-0.61 95%CI), respectively. The observed interaction between HLA class I and II genotype and reactivity to EBV-related epitopes suggest that the mechanism through which HLA genes influence the risk of MS may, at least in part, involve the immune control of EBV infection.

The role of virus-specific CD4+ T cells in the control of Epstein-Barr virus infection

Epstein-Barr virus (EBV) establishes lifelong persistent infections in humans and has been implicated in the pathogenesis of several human malignancies. Protective immunity against EBV is mediated by T cells, as indicated by an increased incidence of EBV-associated malignancies in immunocompromised patients, and by the successful treatment of EBV-associated post-transplant lymphoproliferative disease (PTLD) in transplant recipients by the infusion of polyclonal EBV-specific T cell lines. To implement this treatment modality as a conventional therapeutic option, and to extend this protocol to other EBV-associated diseases, generic and more direct approaches for the generation of EBV-specific T cell lines enriched in disease-relevant specificities need to be developed. To this aim, we studied the poorly defined EBV-specific CD4+ T cell response during acute and chronic infection.

The Essential Role of Epstein-Barr Virus in the Pathogenesis of Multiple Sclerosis

There is increasing evidence that infection with the Epstein-Barr virus (EBV) plays a role in the development of multiple sclerosis (MS), a chronic inflammatory demyelinating disease of the CNS. This article provides a four-tier hypothesis proposing (1) EBV infection is essential for the development of MS; (2) EBV causes MS in genetically susceptible individuals by infecting autoreactive B cells, which seed the CNS where they produce pathogenic autoantibodies and provide costimulatory survival signals to autoreactive T cells that would otherwise die in the CNS by apoptosis; (3) the susceptibility to develop MS after EBV infection is dependent on a genetically determined quantitative deficiency of the cytotoxic CD8+ T cells that normally keep EBV infection under tight control; and (4) sunlight and vitamin D protect against MS by increasing the number of CD8+ T cells available to control EBV infection. The hypothesis makes predictions that can be tested, including the prevention and successful treatment of MS by controlling EBV infection.

The Effect of Antiretroviral Combination Treatment on Epstein-Barr Virus (EBV) Genome Load in HIV-Infected Patients

We evaluated the effect of combination anti-retroviral treatment (cART) on the host control of EBV infection in moderately immunosuppressed HIV-1 patients. Twenty HIV-1 infected individuals were followed for five years with repeated measurements of EBV DNA load in peripheral blood lymphocytes in relation to HIV-RNA titers and CD4+ cell counts. Individuals with optimal response, i.e. durable non-detectable HIV-RNA, showed a decline of EBV load to the level of healthy controls. Individuals with non-optimal HIV-1 control did not restore their EBV control. Long-lasting suppression of HIV-replication after early initiation of cART is a prerequisite for re-establishing the immune control of EBV.