scholarly journals CD8 T Cell Recognition of Endogenously Expressed Epstein-Barr Virus Nuclear Antigen 1

2004 ◽  
Vol 199 (10) ◽  
pp. 1409-1420 ◽  
Author(s):  
Steven P. Lee ◽  
Jill M. Brooks ◽  
Hatim Al-Jarrah ◽  
Wendy A. Thomas ◽  
Tracey A. Haigh ◽  
...  

The Epstein-Barr virus (EBV) nuclear antigen (EBNA)1 contains a glycine-alanine repeat (GAr) domain that appears to protect the antigen from proteasomal breakdown and, as measured in cytotoxicity assays, from major histocompatibility complex (MHC) class I–restricted presentation to CD8+ T cells. This led to the concept of EBNA1 as an immunologically silent protein that although unique in being expressed in all EBV malignancies, could not be exploited as a CD8 target. Here, using CD8+ T cell clones to native EBNA1 epitopes upstream and downstream of the GAr domain and assaying recognition by interferon γ release, we show that the EBNA1 naturally expressed in EBV-transformed lymphoblastoid cell lines (LCLs) is in fact presented to CD8+ T cells via a proteasome/peptide transporter–dependent pathway. Furthermore, LCL recognition by such CD8+ T cells, although slightly lower than seen with paired lines expressing a GAr-deleted EBNA1 protein, leads to strong and specific inhibition of LCL outgrowth in vitro. Endogenously expressed EBNA1 is therefore accessible to the MHC class I pathway despite GAr-mediated stabilization of the mature protein. We infer that EBNA1-specific CD8+ T cells do play a role in control of EBV infection in vivo and might be exploitable in the control of EBV+ malignancies.

2001 ◽  
Vol 193 (3) ◽  
pp. 405-412 ◽  
Author(s):  
Marion Subklewe ◽  
Casper Paludan ◽  
Ming L. Tsang ◽  
Karsten Mahnke ◽  
Ralph M. Steinman ◽  
...  

Dendritic cells (DCs) are not targets for infection by the transforming Epstein-Barr virus (EBV). To test if the adjuvant role of DCs could be harnessed against EBV latency genes by cross-presentation, DCs were allowed to process either autologous or human histocompatibility leukocyte antigen (HLA)-mismatched, transformed, B lymphocyte cell lines (LCLs) that had been subject to apoptotic or necrotic cell death. After phagocytosis of small numbers of either type of dead LCL, which lacked direct immune-stimulatory capacity, DCs could expand CD8+ T cells capable of killing LCLs that were HLA matched to the DCs. Necrotic EBV-transformed, major histocompatibility complex (MHC) class I–negative LCLs, when presented by DCs, also could elicit responses to MHC class II–negative, EBV-transformed targets that were MHC class I matched to the DCs, confirming efficient cross-presentation of LCL antigens via MHC class I on the DC. Part of this EBV-specific CD8+ T cell response, in both lytic and interferon γ secretion assays, was specific for the EBV nuclear antigen (EBNA)3A and latent membrane protein (LMP)2 latency antigens that are known to be expressed at low levels in transformed cells. The induced CD8+ T cells recognized targets at low doses, 1–10 nM, of peptide. Therefore, the capacity of DCs to cross-present antigens from dead cells extends to the expansion of high affinity T cells specific for viral latency antigens involved in cell transformation.


2004 ◽  
Vol 199 (4) ◽  
pp. 459-470 ◽  
Author(s):  
Kui Shin Voo ◽  
Tihui Fu ◽  
Helen Y. Wang ◽  
Judy Tellam ◽  
Helen E. Heslop ◽  
...  

The Epstein-Barr virus (EBV)-encoded nuclear antigen 1 (EBNA1) is expressed in all EBV-associated tumors, making it an important target for immunotherapy. However, evidence for major histocompatibility complex (MHC) class I–restricted EBNA1 peptides endogenously presented by EBV-transformed B and tumor cells remains elusive. Here we describe for the first time the identification of an endogenously processed human histocompatibility leukocyte antigen (HLA)-B8–restricted EBNA1 peptide that is recognized by CD8+ T cells. T cell recognition could be inhibited by the treatment of target cells with proteasome inhibitors that block the MHC class I antigen processing pathway, but not by an inhibitor (chloroquine) of MHC class II antigen processing. We also demonstrate that new protein synthesis is required for the generation of the HLA-B8 epitope for T cell recognition, suggesting that defective ribosomal products (DRiPs) are the major source of T cell epitopes. Experiments with protease inhibitors indicate that some serine proteases may participate in the degradation of EBNA1 DRiPs before they are further processed by proteasomes. These findings not only provide the first evidence of the presentation of an MHC class I–restricted EBNA1 epitope to CD8+ T cells, but also offer new insight into the molecular mechanisms involved in the processing and presentation of EBNA1.


Blood ◽  
1998 ◽  
Vol 91 (10) ◽  
pp. 3875-3883 ◽  
Author(s):  
Rachel A. Nazaruk ◽  
Rosemary Rochford ◽  
Monte V. Hobbs ◽  
Martin J. Cannon

Abstract Epstein-Barr virus (EBV)-specific CD8+ cytotoxic T cells are thought to be critical for the control of EBV, which persists in healthy individuals as a latent infection of B cells. However, recent observations have indicated that CD8+ T-cell responses are not uniformly cytotoxic and that CD8+ T cells may be subdivided into type 1 and type 2 subsets that parallel the classically described Th1 and Th2 subsets of CD4+ T cells. Using two-color flow cytometric analysis of intracellular cytokine expression at the single-cell level, we have identified two distinct but overlapping subsets of EBV-specific CD8+ T cells, the first of which expressed high levels of interferon γ (IFNγ), but little or no interleukin-4 (IL-4), whereas the second subset was IFNγ+/IL-4+ double-positive. A significant proportion of EBV-specific CD8+ T cells also expressed IL-13. Subsequent analysis of a panel of 27 EBV-specific CD8+ T-cell clones showed inverse relationships between EBV-specific cytotoxicity and secretion of IL-4, IL-10, and IFNγ, respectively. IL-10 was not secreted by the 11 most strongly cytotoxic clones, suggesting that IL-10 secretion may provide a functional definition of an EBV-specific type 2 CD8+ T-cell subset with reduced EBV-specific cytotoxicity. Finally, we have demonstrated that EBV-specific CD8+ T cells that express type 2 cytokines possess the ability to activate resting B cells. EBV-specific CD8+ T cells thus have the potential to reactivate latent EBV infection in vivo and may contribute to the development of EBV-associated lymphoproliferative disorders and lymphoma.


2021 ◽  
Vol 12 ◽  
Author(s):  
Caterina Veroni ◽  
Francesca Aloisi

The cause and the pathogenic mechanisms leading to multiple sclerosis (MS), a chronic inflammatory disease of the central nervous system (CNS), are still under scrutiny. During the last decade, awareness has increased that multiple genetic and environmental factors act in concert to modulate MS risk. Likewise, the landscape of cells of the adaptive immune system that are believed to play a role in MS immunopathogenesis has expanded by including not only CD4 T helper cells but also cytotoxic CD8 T cells and B cells. Once the key cellular players are identified, the main challenge is to define precisely how they act and interact to induce neuroinflammation and the neurodegenerative cascade in MS. CD8 T cells have been implicated in MS pathogenesis since the 80’s when it was shown that CD8 T cells predominate in MS brain lesions. Interest in the role of CD8 T cells in MS was revived in 2000 and the years thereafter by studies showing that CNS-recruited CD8 T cells are clonally expanded and have a memory effector phenotype indicating in situ antigen-driven reactivation. The association of certain MHC class I alleles with MS genetic risk implicates CD8 T cells in disease pathogenesis. Moreover, experimental studies have highlighted the detrimental effects of CD8 T cell activation on neural cells. While the antigens responsible for T cell recruitment and activation in the CNS remain elusive, the high efficacy of B-cell depleting drugs in MS and a growing number of studies implicate B cells and Epstein-Barr virus (EBV), a B-lymphotropic herpesvirus that is strongly associated with MS, in the activation of pathogenic T cells. This article reviews the results of human studies that have contributed to elucidate the role of CD8 T cells in MS immunopathogenesis, and discusses them in light of current understanding of autoreactivity, B-cell and EBV involvement in MS, and mechanism of action of different MS treatments. Based on the available evidences, an immunopathological model of MS is proposed that entails a persistent EBV infection of CNS-infiltrating B cells as the target of a dysregulated cytotoxic CD8 T cell response causing CNS tissue damage.


Blood ◽  
1998 ◽  
Vol 91 (10) ◽  
pp. 3875-3883 ◽  
Author(s):  
Rachel A. Nazaruk ◽  
Rosemary Rochford ◽  
Monte V. Hobbs ◽  
Martin J. Cannon

Epstein-Barr virus (EBV)-specific CD8+ cytotoxic T cells are thought to be critical for the control of EBV, which persists in healthy individuals as a latent infection of B cells. However, recent observations have indicated that CD8+ T-cell responses are not uniformly cytotoxic and that CD8+ T cells may be subdivided into type 1 and type 2 subsets that parallel the classically described Th1 and Th2 subsets of CD4+ T cells. Using two-color flow cytometric analysis of intracellular cytokine expression at the single-cell level, we have identified two distinct but overlapping subsets of EBV-specific CD8+ T cells, the first of which expressed high levels of interferon γ (IFNγ), but little or no interleukin-4 (IL-4), whereas the second subset was IFNγ+/IL-4+ double-positive. A significant proportion of EBV-specific CD8+ T cells also expressed IL-13. Subsequent analysis of a panel of 27 EBV-specific CD8+ T-cell clones showed inverse relationships between EBV-specific cytotoxicity and secretion of IL-4, IL-10, and IFNγ, respectively. IL-10 was not secreted by the 11 most strongly cytotoxic clones, suggesting that IL-10 secretion may provide a functional definition of an EBV-specific type 2 CD8+ T-cell subset with reduced EBV-specific cytotoxicity. Finally, we have demonstrated that EBV-specific CD8+ T cells that express type 2 cytokines possess the ability to activate resting B cells. EBV-specific CD8+ T cells thus have the potential to reactivate latent EBV infection in vivo and may contribute to the development of EBV-associated lymphoproliferative disorders and lymphoma.


Blood ◽  
2000 ◽  
Vol 96 (8) ◽  
pp. 2814-2821 ◽  
Author(s):  
Natalie A. Marshall ◽  
John Greg Howe ◽  
Richard Formica ◽  
Diane Krause ◽  
John E. Wagner ◽  
...  

Epstein-Barr virus (EBV)–specific CD8 T lymphocytes are present at remarkably high frequencies in healthy EBV+individuals and provide protection from EBV-associated lymphoproliferative diseases. Allogeneic peripheral blood stem cell transplantation (allo-PBSCT) is a commonly used therapy in which T-cell surveillance for EBV is temporarily disrupted. Herein, human leukocyte antigen (HLA) class I tetramers were used to investigate the reestablishment of the EBV-specific CD8 T-cell repertoire in patients following allo-PBSCT. CD8+ T cells specific for lytic and latent cycle–derived EBV peptides rapidly repopulate the periphery of matched sibling allo-PBSCT patients. The relative frequencies of T cells specific for different EBV peptides in transplantation recipients closely reflect those of their respective donors. Investigation of patients at monthly intervals following unmanipulated allo-PBSCT demonstrated that the frequency of EBV-specific T cells correlates with the number of EBV genome copies in the peripheral blood and that expansion of EBV-specific T-cell populations occurs even in the setting of immunosuppressive therapy. In contrast, patients undergoing T-cell–depleted or unrelated cord blood transplantation have undetectable EBV-specific T cells, even in the presence of Epstein-Barr viremia. The protective shield provided by EBV-specific CD8 T cells is rapidly established following unmanipulated matched sibling allo-PBSCT and demonstrates that HLA class I tetramers complexed with viral peptides can provide direct and rapid assessment of pathogen-specific immunity in this and other vulnerable patient populations.


2004 ◽  
Vol 199 (10) ◽  
pp. 1421-1431 ◽  
Author(s):  
Judy Tellam ◽  
Geoff Connolly ◽  
Katherine J. Green ◽  
John J. Miles ◽  
Denis J. Moss ◽  
...  

Epstein-Barr virus (EBV)–encoded nuclear antigen (EBNA)1 is thought to escape cytotoxic T lymphocyte (CTL) recognition through either self-inhibition of synthesis or by blockade of proteasomal degradation by the glycine-alanine repeat (GAr) domain. Here we show that EBNA1 has a remarkably varied cell type–dependent stability. However, these different degradation rates do not correspond to the level of major histocompatibility complex class I–restricted presentation of EBNA1 epitopes. In spite of the highly stable expression of EBNA1 in B cells, CTL epitopes derived from this protein are efficiently processed and presented to CD8+ T cells. Furthermore, we show that EBV-infected B cells can readily activate EBNA1-specific memory T cell responses from healthy virus carriers. Functional assays revealed that processing of these EBNA1 epitopes is proteasome and transporter associated with antigen processing dependent. We also show that the endogenous presentation of these epitopes is dependent on the newly synthesized protein rather than the long-lived stable EBNA1. Based on these observations, we propose that defective ribosomal products, not the full-length antigen, are the primary source of endogenously processed CD8+ T cell epitopes from EBNA1.


2007 ◽  
Vol 204 (9) ◽  
pp. 2023-2030 ◽  
Author(s):  
Ian Galea ◽  
Martine Bernardes-Silva ◽  
Penny A. Forse ◽  
Nico van Rooijen ◽  
Roland S. Liblau ◽  
...  

CD8 T cells are nature's foremost defense in encephalitis and brain tumors. Antigen-specific CD8 T cells need to enter the brain to exert their beneficial effects. On the other hand, traffic of CD8 T cells specific for neural antigen may trigger autoimmune diseases like multiple sclerosis. T cell traffic into the central nervous system is thought to occur when activated T cells cross the blood-brain barrier (BBB) regardless of their antigen specificity, but studies have focused on CD4 T cells. Here, we show that selective traffic of antigen-specific CD8 T cells into the brain occurs in vivo and is dependent on luminal expression of major histocompatibility complex (MHC) class I by cerebral endothelium. After intracerebral antigen injection, using a minimally invasive technique, transgenic CD8 T cells only infiltrated the brain when and where their cognate antigen was present. This was independent of antigen presentation by perivascular macrophages. Marked reduction of antigen-specific CD8 T cell infiltration was observed after intravenous injection of blocking anti–MHC class I antibody. These results expose a hitherto unappreciated route by which CD8 T cells home onto their cognate antigen behind the BBB: luminal MHC class I antigen presentation by cerebral endothelium to circulating CD8 T cells. This has implications for a variety of diseases in which antigen-specific CD8 T cell traffic into the brain is a beneficial or deleterious feature.


Blood ◽  
1999 ◽  
Vol 94 (9) ◽  
pp. 3094-3100 ◽  
Author(s):  
Kiyotaka Kuzushima ◽  
Yo Hoshino ◽  
Ken Fujii ◽  
Naoaki Yokoyama ◽  
Masatoshi Fujita ◽  
...  

Abstract We have developed an efficient and rapid method for detection of Epstein-Barr virus (EBV)-specific CD8+ T-cell frequencies both in freshly isolated peripheral blood mononuclear cells (PBMCs) and in vitro established cytotoxic T lymphocyte (CTL) lines. Responder cells are thereby stimulated with an autologous lymphoblastoid cell line for 5 hours and intracellular accumulation of interferon γ (IFNγ) is detected by multiparameter flow cytometric analysis. EBV-specific CD8+ T-cell frequencies ranged between 0.63% and 1.29% in PBMCs of 5 healthy long-term EBV carriers. Using EBV-specific T-cell lines, it was shown that flow cytometric analysis is more sensitive than limiting dilution analysis for CTL precursors and enzyme-linked immunospot assay detecting IFNγ-producing T cells. The class I restriction of IFNγ production was confirmed using an anti-class I monoclonal antibody (MoAb). Information on other cytokine production of EBV-specific CTLs could be obtained using combinations of anti-cytokine MoAbs. The sensitive and rapid nature of the flow cytometric assay for EBV-specific CD8+ T-cell frequency has significant advantages for evaluation of EBV-specific CD8+ T-cell responses in PBMCs of patients with EBV-related diseases.


Sign in / Sign up

Export Citation Format

Share Document