scholarly journals Evidence for the Presentation of Major Histocompatibility Complex Class I–restricted Epstein-Barr Virus Nuclear Antigen 1 Peptides to CD8+ T Lymphocytes

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.

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.


2006 ◽  
Vol 81 (3) ◽  
pp. 1390-1400 ◽  
Author(s):  
Andre Ortlieb Guerreiro-Cacais ◽  
Mehmet Uzunel ◽  
Jelena Levitskaya ◽  
Victor Levitsky

ABSTRACT The mechanisms of major histocompatibility complex (MHC) class I downregulation during Epstein-Barr virus (EBV) replication are not well characterized. Here we show that in several cell lines infected with a recombinant EBV strain encoding green fluorescent protein (GFP), the virus lytic cycle coincides with GFP expression, which thus can be used as a marker of virus replication. EBV replication resulted in downregulation of MHC class II and all classical MHC class I alleles independently of viral DNA synthesis or late gene expression. Although assembled MHC class I complexes, the total pool of heavy chains, and β2-microglobulin (β2m) were significantly downregulated, free class I heavy chains were stabilized at the surface of cells replicating EBV. Calnexin expression was increased in GFP+ cells, and calnexin and calreticulin accumulated at the cell surface that could contribute to the stabilization of class I heavy chains. Decreased expression levels of another chaperone, ERp57, and TAP2, a transporter associated with antigen processing and presentation, correlated with delayed kinetics of MHC class I maturation. Levels of both class I heavy chain and β2m mRNA were reduced, and metabolic labeling experiments demonstrated a very low rate of class I heavy chain synthesis in lytically infected cells. MHC class I and MHC class II downregulation was mimicked by pharmacological inhibition of protein synthesis in latently infected cells. Our data suggest that although several mechanisms may contribute to MHC class I downregulation in the course of EBV replication, inhibition of MHC class I synthesis plays the primary role in the process.


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.


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.


Blood ◽  
1998 ◽  
Vol 92 (7) ◽  
pp. 2477-2483 ◽  
Author(s):  
Paul G. Murray ◽  
Christothea M. Constandinou ◽  
John Crocker ◽  
Lawrence S. Young ◽  
Richard F. Ambinder

Abstract 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.


Blood ◽  
1996 ◽  
Vol 87 (9) ◽  
pp. 3844-3851 ◽  
Author(s):  
JJ Oudejans ◽  
NM Jiwa ◽  
JA Kummer ◽  
A Horstman ◽  
W Vos ◽  
...  

To get insight into the failure of the immune system to eradicate Epstein-Barr virus (EBV) harboring Hodgkin and Reed-Sternberg cells (H- RS cells), expressing the latent membrane protein 1 (LMP1), we analyzed major histocompatibility complex (MHC) class I expression on H-RS cells in relation to the presence of activated cytotoxic cells, i.e., granzyme-B-expressing lymphocytes. H-RS cells in EBV+ cases of Hodgkin's disease (HD) were found to express significantly higher levels of MCH class I heavy- and light-chain molecules compared with EBV- HD cases. When low levels of MHc class I expression were found (mainly in EBV- cases), these were not associated with low levels of the transporter protein associated with antigen presentation 1 (TAP-1). The relatively high levels of MHC class I expression in H-RS cells in EBV+ HD cases were accompanied by significantly higher numbers of activated cytotoxic T lymphocytes (CTLs) as shown by the presence of increased numbers of CD8 and granzyme B+ lymphocytes. However, these cells were only sporadically detected in the close vicinity of the H-RS cells. These data suggest that mechanisms other than downregulation of MHC class I or TAP-1 expression on H-RS cells are involved in the failure of the immune system to eradicate EBV harboring H-RS cells. Probably, the function of activated CTLs is locally inhibited by the H- RS cells or by reactive cells in the vicinity of the H-RS cells.


2003 ◽  
Vol 77 (7) ◽  
pp. 4298-4305 ◽  
Author(s):  
Kong-Wee Ong ◽  
A. Douglas Wilson ◽  
Timothy R. Hirst ◽  
Andrew J. Morgan

ABSTRACT Epstein-Barr virus (EBV) is associated with a number of important human cancers, including nasopharyngeal carcinoma, gastric carcinoma, and Hodgkin's lymphoma. These tumors express a viral nuclear antigen, EBV nuclear antigen 1 (EBNA1), which cannot be presented to T cells in a major histocompatibility complex class I context, and the viral latent membrane proteins (LMPs). Although the LMPs are expressed in these tumors, no effective immune response is made. We report here that exposure to the cholera-like enterotoxin B subunit (EtxB) in EBV-infected lymphoblastoid cell lines (LCLs) enhances their susceptibility to killing by LMP-specific CD8+ cytotoxic T lymphocytes (CTLs) in a HLA class I-restricted manner. CTL killing of LCLs is dramatically increased through both transporter-associated protein-dependent and -independent epitopes after EtxB treatment. The use of mutant B subunits revealed that the enhanced susceptibility of LCLs to CTL killing is dependent on the B subunit's interaction with GM1 but not its signaling properties. These important findings could underpin the development of novel approaches to treating EBV-associated malignancies and may offer a general approach to increasing the presentation of other tumor and viral antigens.


Blood ◽  
1998 ◽  
Vol 92 (7) ◽  
pp. 2477-2483 ◽  
Author(s):  
Paul G. Murray ◽  
Christothea M. Constandinou ◽  
John Crocker ◽  
Lawrence S. Young ◽  
Richard F. Ambinder

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.


2007 ◽  
Vol 204 (8) ◽  
pp. 1863-1873 ◽  
Author(s):  
Andrew D. Hislop ◽  
Maaike E. Ressing ◽  
Daphne van Leeuwen ◽  
Victoria A. Pudney ◽  
Daniëlle Horst ◽  
...  

γ1-Herpesviruses such as Epstein-Barr virus (EBV) have a unique ability to amplify virus loads in vivo through latent growth-transforming infection. Whether they, like α- and β-herpesviruses, have been driven to actively evade immune detection of replicative (lytic) infection remains a moot point. We were prompted to readdress this question by recent work (Pudney, V.A., A.M. Leese, A.B. Rickinson, and A.D. Hislop. 2005. J. Exp. Med. 201:349–360; Ressing, M.E., S.E. Keating, D. van Leeuwen, D. Koppers-Lalic, I.Y. Pappworth, E.J.H.J. Wiertz, and M. Rowe. 2005. J. Immunol. 174:6829–6838) showing that, as EBV-infected cells move through the lytic cycle, their susceptibility to EBV-specific CD8+ T cell recognition falls dramatically, concomitant with a reductions in transporter associated with antigen processing (TAP) function and surface human histocompatibility leukocyte antigen (HLA) class I expression. Screening of genes that are unique to EBV and closely related γ1-herpesviruses of Old World primates identified an early EBV lytic cycle gene, BNLF2a, which efficiently blocks antigen-specific CD8+ T cell recognition through HLA-A–, HLA-B–, and HLA-C–restricting alleles when expressed in target cells in vitro. The small (60–amino acid) BNLF2a protein mediated its effects through interacting with the TAP complex and inhibiting both its peptide- and ATP-binding functions. Furthermore, this targeting of the major histocompatibility complex class I pathway appears to be conserved among the BNLF2a homologues of Old World primate γ1-herpesviruses. Thus, even the acquisition of latent cycle genes endowing unique growth-transforming ability has not liberated these agents from evolutionary pressure to evade CD8+ T cell control over virus replicative foci.


Sign in / Sign up

Export Citation Format

Share Document