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Dowell AC, Haigh TA, Ryan GB, Turner JE, Long HM, Taylor GS. Cytotoxic CD4+ T-cells specific for EBV capsid antigen BORF1 are maintained in long-term latently infected healthy donors. PLoS Pathog 2021; 17:e1010137. [PMID: 34882759 PMCID: PMC8691624 DOI: 10.1371/journal.ppat.1010137] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 12/21/2021] [Accepted: 11/22/2021] [Indexed: 12/15/2022] Open
Abstract
Epstein Barr Virus (EBV) infects more than 95% of the population whereupon it establishes a latent infection of B-cells that persists for life under immune control. Primary EBV infection can cause infectious mononucleosis (IM) and long-term viral carriage is associated with several malignancies and certain autoimmune diseases. Current efforts developing EBV prophylactic vaccination have focussed on neutralising antibodies. An alternative strategy, that could enhance the efficacy of such vaccines or be used alone, is to generate T-cell responses capable of recognising and eliminating newly EBV-infected cells before the virus initiates its growth transformation program. T-cell responses against the EBV structural proteins, brought into the newly infected cell by the incoming virion, are prime candidates for such responses. Here we show the structural EBV capsid proteins BcLF1, BDLF1 and BORF1 are frequent targets of T-cell responses in EBV infected people, identify new CD8+ and CD4+ T-cell epitopes and map their HLA restricting alleles. Using T-cell clones we demonstrate that CD4+ but not CD8+ T-cell clones specific for the capsid proteins can recognise newly EBV-infected B-cells and control B-cell outgrowth via cytotoxicity. Using MHC-II tetramers we show a CD4+ T-cell response to an epitope within the BORF1 capsid protein epitope is present during acute EBV infection and in long-term viral carriage. In common with other EBV-specific CD4+ T-cell responses the BORF1-specific CD4+ T-cells in IM patients expressed perforin and granzyme-B. Unexpectedly, perforin and granzyme-B expression was sustained over time even when the donor had entered the long-term infected state. These data further our understanding of EBV structural proteins as targets of T-cell responses and how CD4+ T-cell responses to EBV change from acute disease into convalescence. They also identify new targets for prophylactic EBV vaccine development. Epstein-Barr virus is a widespread herpesvirus carried by most individuals. Whilst infection is usually asymptomatic, development of a prophylactic vaccine against EBV is desirable because of the virus’s association with infectious mononucleosis in primary infection and several cancers and autoimmune diseases during long-term virus carriage. Identifying T-cell responses that can recognise newly infected B-cells at very early stages of infection may provide novel targets for T-cell vaccination. Here we characterise T-cell responses against three virus proteins, BcLF1, BDLF1 and BORF1 that, as structural proteins of the virus particle, are delivered into the cell by the infecting virus. We find that all three proteins are recognised by T-cells from infected individuals. Moreover, isolated structural antigen-specific CD4+ T-cells rapidly recognise newly infected B-cells and prevent their outgrowth in vitro. As reported for CD4+ T-cells against other EBV proteins, structural antigen-specific CD4+ T-cells induced by primary EBV infection have cytotoxic function. However, we also demonstrate that, unusually, this cytotoxic function is retained in memory T-cells present in long-term infected individuals. Structural antigens may therefore represent useful targets for prophylactic EBV vaccine development to induce CD4+ T-cells able to rapidly eliminate virus-infected cells.
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Affiliation(s)
- Alexander C. Dowell
- Institute of Immunology and Immunotherapy, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Tracey A. Haigh
- Institute of Immunology and Immunotherapy, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Gordon B. Ryan
- Institute of Immunology and Immunotherapy, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - James E. Turner
- Department for Health, University of Bath, Claverton Down, Bath, United Kingdom
| | - Heather M. Long
- Institute of Immunology and Immunotherapy, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Graham S. Taylor
- Institute of Immunology and Immunotherapy, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- * E-mail:
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Rock KL, Farfán-Arribas DJ, Colbert JD, Goldberg AL. Re-examining class-I presentation and the DRiP hypothesis. Trends Immunol 2014; 35:144-52. [PMID: 24566257 DOI: 10.1016/j.it.2014.01.002] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 01/16/2014] [Accepted: 01/21/2014] [Indexed: 01/03/2023]
Abstract
MHC class I molecules present peptides derived from intracellular proteins, enabling immune surveillance by CD8(+) T cells and the elimination of virus-infected and cancerous cells. It has been argued that the dominant source of MHC class I-presented peptides is through proteasomal degradation of newly synthesized defective proteins, termed defective ribosomal products (DRiPs). Here, we critically examine the DRiP hypothesis and discuss recent studies indicating that antigenic peptides are generated from the entire proteome and not just from failures in protein synthesis or folding.
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Affiliation(s)
- Kenneth L Rock
- Department of Pathology, University of Massachusetts Medical School, Worcester, Massachusetts, USA.
| | - Diego J Farfán-Arribas
- Department of Pathology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Jeff D Colbert
- Department of Pathology, University of Massachusetts Medical School, Worcester, Massachusetts, USA.
| | - Alfred L Goldberg
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
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3
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Colbert JD, Farfán-Arribas DJ, Rock KL. Substrate-induced protein stabilization reveals a predominant contribution from mature proteins to peptides presented on MHC class I. THE JOURNAL OF IMMUNOLOGY 2013; 191:5410-9. [PMID: 24174619 DOI: 10.4049/jimmunol.1300078] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The origin of the MHC class I-presented peptides are thought to be primarily from newly synthesized but defective proteins, termed defective ribosomal products. Most of the data supporting this concept come from studies in which inhibitors of protein synthesis were found to rapidly block Ag presentation even when cells contained a pool of mature proteins. However, these data only indirectly address the origin of presented peptides, and in most studies, the contribution of mature functional proteins to the class I peptide pool has not been directly quantified. In this report, we address the efficiency and contribution of mature proteins using a tetracycline-inducible system to express Ags that are conditionally stabilized upon ligand binding. This system circumvents the use of general inhibitors of protein synthesis to control Ag expression. Moreover, by controlling Ag stabilization, we could investigate whether the degradation of mature Ags contributed to Ag presentation at early and/or late time points. We show that mature proteins are the major contributor of peptides presented on class I for two distinct antigenic constructs. Furthermore, our data show that the protein synthesis inhibitors used previously to test the contribution of defective proteins actually block Ag presentation in ways that are independent from blocking Ag synthesis. These data suggest that for the constructs we have analyzed, mature functional proteins, rather than defective ribosomal products, are the predominant source of MHC class I-presented peptides.
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Affiliation(s)
- Jeff D Colbert
- Department of Pathology, University of Massachusetts Medical School, Worcester, MA 01605
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Zuo J, Rowe M. Herpesviruses placating the unwilling host: manipulation of the MHC class II antigen presentation pathway. Viruses 2012; 4:1335-53. [PMID: 23012630 PMCID: PMC3446767 DOI: 10.3390/v4081335] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 08/14/2012] [Accepted: 08/15/2012] [Indexed: 12/18/2022] Open
Abstract
Lifelong persistent infection by herpesviruses depends on the balance between host immune responses and viral immune evasion. CD4 T cells responding to antigens presented on major histocompatibility complex class II (MHC-II) molecules are known to play an important role in controlling herpesvirus infections. Here we review, with emphasis on human herpesvirus infections, the strategies evolved to evade CD4 T cell immunity. These viruses target multiple points on the MHC class II antigen presentation pathway. The mechanisms include: suppression of CIITA to inhibit the synthesis of MHC class II molecules, diversion or degradation of HLA-DR molecules during membrane transport, and direct targeting of the invariant chain chaperone of HLA-DR.
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Affiliation(s)
- Jianmin Zuo
- Cancer Research UK Birmingham Cancer Centre, University of Birmingham, Birmingham B15 2TT, UK.
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Long HM, Leese AM, Chagoury OL, Connerty SR, Quarcoopome J, Quinn LL, Shannon-Lowe C, Rickinson AB. Cytotoxic CD4+ T cell responses to EBV contrast with CD8 responses in breadth of lytic cycle antigen choice and in lytic cycle recognition. THE JOURNAL OF IMMUNOLOGY 2011; 187:92-101. [PMID: 21622860 DOI: 10.4049/jimmunol.1100590] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
EBV, a B lymphotropic herpesvirus, encodes two immediate early (IE)-, >30 early (E)-, and >30 late (L)-phase proteins during its replication (lytic) cycle. Despite this, lytic Ag-induced CD8 responses are strongly skewed toward IE and a few E proteins only, all expressed before HLA I presentation is blocked in lytically infected cells. For comparison, we examined CD4(+) T cell responses to eight IE, E, or L proteins, screening 14 virus-immune donors to overlapping peptide pools in IFN-γ ELISPOT assays, and established CD4(+) T cell clones against 12 defined epitopes for target-recognition assays. We found that the lytic Ag-specific CD4(+) T cell response differs radically from its CD8 counterpart in that it is widely distributed across IE, E, and L Ag targets, often with multiple reactivities detectable per donor and with IE, E, or L epitope responses being numerically dominant, and that all CD4(+) T cell clones, whether IE, E, or L epitope-specific, show strong recognition of EBV-transformed B cell lines, despite the lines containing only a small fraction of lytically infected cells. Efficient recognition occurs because lytic Ags are released into the culture and are acquired and processed by neighboring latently infected cells. These findings suggested that lytic Ag-specific CD4 responses are driven by a different route of Ag display than drives CD8 responses and that such CD4 effectors could be therapeutically useful against EBV-driven lymphoproliferative disease lesions, which contain similarly small fractions of EBV-transformed cells entering the lytic cycle.
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Affiliation(s)
- Heather M Long
- School of Cancer Sciences and Medical Research Council Centre for Immune Regulation, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, United Kingdom
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Mautner J, Bornkamm GW. The role of virus-specific CD4+ T cells in the control of Epstein-Barr virus infection. Eur J Cell Biol 2011; 91:31-5. [PMID: 21458882 DOI: 10.1016/j.ejcb.2011.01.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2010] [Accepted: 01/22/2011] [Indexed: 11/15/2022] Open
Abstract
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.
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Affiliation(s)
- Josef Mautner
- Clinical Cooperation Group, Pediatric Tumor Immunology, Helmholtz-Zentrum München, Marchioninistrasse 25, Munich, Germany.
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7
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The T-Cell Immune Response against Kaposi's Sarcoma-Associated Herpesvirus. Adv Virol 2011; 2010:340356. [PMID: 22331985 PMCID: PMC3275983 DOI: 10.1155/2010/340356] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Accepted: 12/20/2010] [Indexed: 12/13/2022] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) is the aetiological agent of Kaposi's sarcoma (KS), the most frequently arising malignancy in individuals with untreated HIV/AIDS. There are several lines of evidence to indicate that Kaposi's sarcoma oncogenesis is associated with loss of T-cell-mediated control of KSHV-infected cells. KSHV can establish life-long asymptomatic infection in immune-competent individuals. However, when T-cell immune control declines, for example, through AIDS or treatment with immunosuppressive drugs, both the prevalence of KSHV infection and the incidence of KS in KSHV carriers dramatically increase. Moreover, a dramatic and spontaneous improvement in KS is frequently seen when immunity is restored, for example, through antiretroviral therapy or the cessation of iatrogenic drugs. In this paper we describe the current state of knowledge on the T-cell immune responses against KSHV.
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Iijima N, Linehan MM, Zamora M, Butkus D, Dunn R, Kehry MR, Laufer TM, Iwasaki A. Dendritic cells and B cells maximize mucosal Th1 memory response to herpes simplex virus. ACTA ACUST UNITED AC 2008; 205:3041-52. [PMID: 19047439 PMCID: PMC2605233 DOI: 10.1084/jem.20082039] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Although the importance of cytotoxic T lymphocytes and neutralizing antibodies for antiviral defense is well known, the antiviral mechanism of Th1 remains unclear. We show that Th1 cells mediate noncytolytic antiviral protection independent of direct lysis through local secretion of IFN-gamma after herpes simplex virus (HSV) 2 infection. IFN-gamma acted on stromal cells, but not on hematopoietic cells, to prevent further viral replication and spread throughout the vaginal mucosa. Importantly, unlike other known Th1 defense mechanisms, this effector function did not require recognition of virally infected cells via MHC class II. Instead, recall Th1 response was elicited by MHC class II(+) antigen-presenting cells at the site of infection. Dendritic cells (DCs) were not required and only partially sufficient to induce a recall response from memory Th1 cells. Importantly, DCs and B cells together contributed to restimulating memory CD4 T cells to secrete IFN-gamma. In the absence of both DCs and B cells, immunized mice rapidly succumbed to HSV-2 infection and death. Thus, these results revealed a distinct mechanism by which memory Th1 cells mediate noncytolytic IFN-gamma-dependent antiviral protection after recognition of processed viral antigens by local DCs and B cells.
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Affiliation(s)
- Norifumi Iijima
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
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Delecluse HJ, Feederle R, Behrends U, Mautner J. Contribution of viral recombinants to the study of the immune response against the Epstein-Barr virus. Semin Cancer Biol 2008; 18:409-15. [DOI: 10.1016/j.semcancer.2008.09.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2008] [Accepted: 09/23/2008] [Indexed: 12/26/2022]
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10
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Adhikary D, Behrends U, Boerschmann H, Pfünder A, Burdach S, Moosmann A, Witter K, Bornkamm GW, Mautner J. Immunodominance of lytic cycle antigens in Epstein-Barr virus-specific CD4+ T cell preparations for therapy. PLoS One 2007; 2:e583. [PMID: 17611619 PMCID: PMC1894652 DOI: 10.1371/journal.pone.0000583] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2007] [Accepted: 06/03/2007] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Epstein-Barr virus (EBV) is associated with a number of human malignancies. EBV-positive post-transplant lymphoproliferative disease in solid organ and hematopoietic stem cell transplant recipients has been successfully treated by the adoptive transfer of polyclonal EBV-specific T cell lines containing CD4+ and CD8+ T cell components. Although patients receiving T cell preparations with a higher CD4+ T cell proportion show better clinical responses, the specificity of the infused CD4+ component has remained completely unknown. METHODOLOGY/PRINCIPAL FINDINGS We generated LCL-stimulated T cell lines from 21 donors according to clinical protocols, and analyzed the antigen specificity of the CD4+ component in EBV-specific T cell preparations using a genetically engineered EBV mutant that is unable to enter the lytic cycle, and recombinantly expressed and purified EBV proteins. Surprisingly, CD4+ T cell lines from acutely and persistently EBV-infected donors consistently responded against EBV lytic cycle antigens and autoantigens, but barely against latent cycle antigens of EBV hitherto considered principal immunotherapeutic targets. Lytic cycle antigens were predominantly derived from structural proteins of the virus presented on MHC II via receptor-mediated uptake of released viral particles, but also included abundant infected cell proteins whose presentation involved intercellular protein transfer. Importantly, presentation of virion antigens was severely impaired by acyclovir treatment of stimulator cells, as currently performed in most clinical protocols. CONCLUSIONS/SIGNIFICANCE These results indicate that structural antigens of EBV are the immunodominant targets of CD4+ T cells in LCL-stimulated T cell preparations. These findings add to our understanding of the immune response against this human tumor-virus and have important implications for the improvement of immunotherapeutic strategies against EBV.
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Affiliation(s)
- Dinesh Adhikary
- Clinical Cooperation Group, Institute for Clinical and Molecular Biology, GSF-National Research Center for Environment and Health, Munich, Germany; Children's Hospital, Hematology-Oncology, University of Technology, Munich, Germany
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Hislop AD, Taylor GS, Sauce D, Rickinson AB. Cellular responses to viral infection in humans: lessons from Epstein-Barr virus. Annu Rev Immunol 2007; 25:587-617. [PMID: 17378764 DOI: 10.1146/annurev.immunol.25.022106.141553] [Citation(s) in RCA: 550] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Epstein-Barr virus (EBV) provides a useful model to study cellular immunity to a genetically stable, persistent human virus. Different sets of proteins expressed during EBV's lytic and cell transforming infections induce qualitatively different cellular immune responses. The factors governing immunodominance hierarchies and the biological effectiveness of these different responses are now being revealed. Analysis of infectious mononucleosis (IM), a clinical syndrome that can arise during primary EBV infection, has allowed the evolution of the responses to be tracked over time, giving an understanding of the immune response kinetics and of those determinants affecting selection into memory. Furthermore, following IM, expression of the receptor for the homeostatic cytokine IL-15 on NK and T cells is lost within these individuals. This experiment of nature provides a system to advance understanding of immunological homeostasis in humans, illustrating how data obtained from the study of EBV have wider significance to the immunological community.
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Affiliation(s)
- Andrew D Hislop
- CRUK Institute for Cancer Studies and MRC Centre for Immune Regulation, University of Birmingham, Birmingham, UK B15 2TT
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12
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Heemskerk B, van Vreeswijk T, Veltrop-Duits LA, Sombroek CC, Franken K, Verhoosel RM, Hiemstra PS, van Leeuwen D, Ressing ME, Toes REM, van Tol MJD, Schilham MW. Adenovirus-specific CD4+ T cell clones recognizing endogenous antigen inhibit viral replication in vitro through cognate interaction. THE JOURNAL OF IMMUNOLOGY 2007; 177:8851-9. [PMID: 17142788 DOI: 10.4049/jimmunol.177.12.8851] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Human adenovirus (HAdV) infection is a frequent and potentially severe complication following allogeneic stem cell transplantation in children. Because treatment with antiviral drugs is often ineffective, adoptive transfer of donor-derived HAdV-specific T cells able to control viral replication of HAdV of multiple serotypes may be an option for therapy. In healthy donors, predominantly HAdV-specific T cells expressing CD4 are detected. In this study, a preclinical in vitro model was used to measure the antiviral effect of HAdV-specific CD4+ T cells. CD4+ HAdV-specific T cell clones restricted by HLA class II molecules were generated and most of these clones recognized conserved peptides derived from the hexon protein. These cross-reactive T cell clones were able to control viral replication of multiple serotypes of HAdV in EBV-transformed B cells (B-LCL), melanoma cells (MJS) and primary bronchial epithelial cells through cognate interaction. The HAdV-specific CD4+ T cell clones were able to specifically lyse infected target cells using a perforin-dependent mechanism. Antigenic peptides were also presented to the CD4+ T cell clones when derived from endogenously produced hexon protein. Together, these results show that cross-reactive HAdV-specific CD4+ T cells can control replication of HAdV in vitro and provide a rationale for the use of HAdV-specific T cells in adoptive immunotherapy protocols for control of life-threatening HAdV-infections in immunocompromised patients.
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Affiliation(s)
- Bianca Heemskerk
- Department of Pediatrics, Leiden University Medical Center, 2300 RC Leiden, The Netherlands
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Taylor GS, Long HM, Haigh TA, Larsen M, Brooks J, Rickinson AB. A Role for Intercellular Antigen Transfer in the Recognition of EBV-Transformed B Cell Lines by EBV Nuclear Antigen-Specific CD4+T Cells. THE JOURNAL OF IMMUNOLOGY 2006; 177:3746-56. [PMID: 16951335 DOI: 10.4049/jimmunol.177.6.3746] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The CD4+ T cell response to EBV may have an important role in controlling virus-driven B lymphoproliferation because CD4+ T cell clones to a subset of EBV nuclear Ag (EBNA) epitopes can directly recognize virus-transformed lymphoblastoid cell lines (LCLs) in vitro and inhibit their growth. In this study, we used a panel of EBNA1, 2, 3A, and 3C-specific CD4+ T cell clones to study the route whereby endogenously expressed EBNAs access the HLA class II-presentation pathway. Two sets of results spoke against a direct route of intracellular access. First, none of the clones recognized cognate Ag overexpressed in cells from vaccinia vectors but did recognize Ag fused to an endo/lysosomal targeting sequence. Second, focusing on clones with the strongest LCL recognition that were specific for EBNA2- and EBNA3C-derived epitopes LCL recognition was unaffected by inhibiting autophagy, a postulated route for intracellular Ag delivery into the HLA class II pathway in LCL cells. Subsequently, using these same epitope-specific clones, we found that Ag-negative cells with the appropriate HLA-restricting allele could be efficiently sensitized to CD4+ T cell recognition by cocultivation with Ag-positive donor lines or by exposure to donor line-conditioned culture medium. Sensitization was mediated by a high m.w. antigenic species and required active Ag processing by recipient cells. We infer that intercellular Ag transfer plays a major role in the presentation of EBNA-derived CD4 epitopes by latently infected target cells.
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Affiliation(s)
- Graham S Taylor
- Cancer Research U.K. Institute for Cancer Studies, University of Birmingham, Birmingham, United Kingdom
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Abstract
CD4+ T cells are classically thought to orchestrate adaptive immune responses. But recent studies demonstrate that they can also kill infected cells directly. A new paper shows that highly efficient processing of Epstein Barr virus (EBV) glycoproteins for presentation on MHC class II makes virus-transformed B cells susceptible to lysis by CD4+ T cells. Thus, antiviral vaccines should aim to stimulate both helper and cytolytic CD4+ T cells.
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Affiliation(s)
- Kevin N Heller
- Laboratory of Viral Immunobiology and Christopher H. Browne Center for Immunology and Immune Diseases, The Rockefeller University, New York, NY 10021, USA
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Adhikary D, Behrends U, Moosmann A, Witter K, Bornkamm GW, Mautner J. Control of Epstein-Barr virus infection in vitro by T helper cells specific for virion glycoproteins. ACTA ACUST UNITED AC 2006; 203:995-1006. [PMID: 16549597 PMCID: PMC2118290 DOI: 10.1084/jem.20051287] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Epstein-Barr virus (EBV) establishes lifelong persistent infections in humans by latently infecting B cells, with occasional cycles of reactivation, virus production, and reinfection. Protective immunity against EBV is mediated by T cells, but the role of EBV-specific T helper (Th) cells is still poorly defined. Here, we study the Th response to the EBV lytic cycle proteins BLLF1 (gp350/220), BALF4 (gp110), and BZLF1 and show that glycoprotein-specific Th cells recognize EBV-positive cells directly; surprisingly, a much higher percentage of target cells than those expressing lytic cycle proteins were recognized. Antigen is efficiently transferred to bystander B cells by receptor-mediated uptake of released virions, resulting in recognition of target cells incubated with <1 virion/cell. T cell recognition does not require productive infection and occurs early after virus entry before latency is established. Glycoprotein-specific Th cells are cytolytic and inhibit proliferation of lymphoblastoid cell lines (LCL) and the outgrowth of LCL after infection of primary B cells with EBV. These results establish a novel role for glycoprotein-specific Th cells in the control of EBV infection and identify virion proteins as important immune targets. These findings have implications for the treatment of diseases associated with EBV and potentially other coated viruses infecting MHC class II–positive cells.
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Affiliation(s)
- Dinesh Adhikary
- Clinical Cooperation Group, Institute for Clinical and Molecular Biology, GSF-National Research Center for Environment and Health, Technical University Munich, 80804 Munich, Germany
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