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Huang W, Bai L, Tang H. Epstein-Barr virus infection: the micro and macro worlds. Virol J 2023; 20:220. [PMID: 37784180 PMCID: PMC10546641 DOI: 10.1186/s12985-023-02187-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 09/19/2023] [Indexed: 10/04/2023] Open
Abstract
Epstein‒Barr virus (EBV) is a DNA virus that belongs to the human B lymphotropic herpesvirus family and is highly prevalent in the human population. Once infected, a host can experience latent infection because EBV evades the immune system, leading to hosts harboring the virus for their lifetime. EBV is associated with many diseases and causes significant challenges to human health. This review first offers a description of the natural history of EBV infection, clarifies the interaction between EBV and the immune system, and finally focuses on several major types of diseases caused by EBV infection.
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Affiliation(s)
- Wei Huang
- Center of Infectious Diseases, West China Hospital of Sichuan University, Chengdu, 610041, China
- Division of Infectious Diseases, State Key Laboratory of Biotherapy and Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Lang Bai
- Center of Infectious Diseases, West China Hospital of Sichuan University, Chengdu, 610041, China.
- Division of Infectious Diseases, State Key Laboratory of Biotherapy and Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, 610041, China.
| | - Hong Tang
- Center of Infectious Diseases, West China Hospital of Sichuan University, Chengdu, 610041, China.
- Division of Infectious Diseases, State Key Laboratory of Biotherapy and Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, 610041, China.
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2
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Jaeger HK, Davis DA, Nair A, Shrestha P, Stream A, Yaparla A, Yarchoan R. Mechanism and therapeutic implications of pomalidomide-induced immune surface marker upregulation in EBV-positive lymphomas. Sci Rep 2023; 13:11596. [PMID: 37463943 DOI: 10.1038/s41598-023-38156-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 07/04/2023] [Indexed: 07/20/2023] Open
Abstract
Epstein-Barr virus (EBV) downregulates immune surface markers to avoid immune recognition. Pomalidomide (Pom) was previously shown to increase immune surface marker expression in EBV-infected tumor cells. We explored the mechanism by which Pom leads to these effects in EBV-infected cells. Pom increased B7-2/CD86 mRNA, protein, and surface expression in EBV-infected cells but this was virtually eliminated in EBV-infected cells made resistant to Pom-induced cytostatic effects. This indicates that Pom initiates the upregulation of these markers by interacting with its target, cereblon. Interestingly, Pom increased the proinflammatory cytokines IP-10 and MIP-1∝/β in EBV infected cells, supporting a possible role for the phosphoinositide 3-kinase (PI3K)/AKT pathway in Pom's effects. Idelalisib, an inhibitor of the delta subunit of PI3 Kinase, blocked AKT-Ser phosphorylation and Pom-induced B7-2 surface expression. PU.1 is a downstream target for AKT that is expressed in EBV-infected cells. Pom treatment led to an increase in PU.1 binding to the B7-2 promoter based on ChIP analysis. Thus, our data indicates Pom acts through cereblon leading to degradation of Ikaros and activation of the PI3K/AKT/PU.1 pathway resulting in upregulation of B7-2 mRNA and protein expression. The increased immune recognition in addition to the increases in proinflammatory cytokines upon Pom treatment suggests Pom may be useful in the treatment of EBV-positive lymphomas.
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Affiliation(s)
- Hannah K Jaeger
- HIV and AIDS Malignancy Branch, Center for Cancer Research, National Cancer Institute, Building 10, Rm. 6N106, MSC 1868, 10 Center Drive, Bethesda, MD, 20892-1868, USA
| | - David A Davis
- HIV and AIDS Malignancy Branch, Center for Cancer Research, National Cancer Institute, Building 10, Rm. 6N106, MSC 1868, 10 Center Drive, Bethesda, MD, 20892-1868, USA
| | - Ashwin Nair
- HIV and AIDS Malignancy Branch, Center for Cancer Research, National Cancer Institute, Building 10, Rm. 6N106, MSC 1868, 10 Center Drive, Bethesda, MD, 20892-1868, USA
| | - Prabha Shrestha
- HIV and AIDS Malignancy Branch, Center for Cancer Research, National Cancer Institute, Building 10, Rm. 6N106, MSC 1868, 10 Center Drive, Bethesda, MD, 20892-1868, USA
| | - Alexandra Stream
- HIV and AIDS Malignancy Branch, Center for Cancer Research, National Cancer Institute, Building 10, Rm. 6N106, MSC 1868, 10 Center Drive, Bethesda, MD, 20892-1868, USA
| | - Amulya Yaparla
- HIV and AIDS Malignancy Branch, Center for Cancer Research, National Cancer Institute, Building 10, Rm. 6N106, MSC 1868, 10 Center Drive, Bethesda, MD, 20892-1868, USA
| | - Robert Yarchoan
- HIV and AIDS Malignancy Branch, Center for Cancer Research, National Cancer Institute, Building 10, Rm. 6N106, MSC 1868, 10 Center Drive, Bethesda, MD, 20892-1868, USA.
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3
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Murata T. Tegument proteins of Epstein-Barr virus: Diverse functions, complex networks, and oncogenesis. Tumour Virus Res 2023; 15:200260. [PMID: 37169175 DOI: 10.1016/j.tvr.2023.200260] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Revised: 05/02/2023] [Accepted: 05/04/2023] [Indexed: 05/13/2023] Open
Abstract
The tegument is the structure between the envelope and nucleocapsid of herpesvirus particles. Viral (and cellular) proteins accumulate to create the layers of the tegument. Some Epstein-Barr virus (EBV) tegument proteins are conserved widely in Herpesviridae, but others are shared only by members of the gamma-herpesvirus subfamily. As the interface to envelope and nucleocapsid, the tegument functions in virion morphogenesis and budding of the nucleocapsid during progeny production. When a virus particle enters a cell, enzymes such as kinase and deubiquitinase, and transcriptional activators are released from the virion to promote virus infection. Moreover, some EBV tegument proteins are involved in oncogenesis. Here, we summarize the roles of EBV tegument proteins, in comparison to those of other herpesviruses.
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Affiliation(s)
- Takayuki Murata
- Department of Virology, Fujita Health University School of Medicine, Toyoake, Japan.
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4
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The lytic phase of Epstein-Barr virus plays an important role in tumorigenesis. Virus Genes 2023; 59:1-12. [PMID: 36242711 DOI: 10.1007/s11262-022-01940-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 10/02/2022] [Indexed: 01/13/2023]
Abstract
Epstein-Barr virus (EBV) is a recognized oncogenic virus that is related to the occurrence of lymphoma, nasopharyngeal carcinoma (NPC), and approximately 10% of gastric cancer (GC). EBV is a herpesvirus, and like other herpesviruses, EBV has a biphasic infection mode made up of latent and lytic infections. It has been established that latent infection promotes tumorigenesis in previous research, but in recent years, there has been new evidence that suggests that the lytic infection mode could also promote tumorigenesis. In this review, we mainly discuss the contribution of the EBV lytic phase to tumorigenesis, and graphically illustrate their relationship in detail. In addition, we described the relationship between the lytic cycle of EBV and autophagy. Finally, we also preliminarily explored the influence of the tumorigenesis effect of the EBV lytic phase on the future treatment of EBV-associated tumors.
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5
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Functional Implications of Epstein-Barr Virus Lytic Genes in Carcinogenesis. Cancers (Basel) 2022; 14:cancers14235780. [PMID: 36497262 PMCID: PMC9740547 DOI: 10.3390/cancers14235780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/19/2022] [Accepted: 11/21/2022] [Indexed: 11/27/2022] Open
Abstract
Epstein-Barr virus (EBV) is associated with a diverse range of tumors of both lymphoid and epithelial origin. Similar to other herpesviruses, EBV displays a bipartite life cycle consisting of latent and lytic phases. Current dogma indicates that the latent genes are key drivers in the pathogenesis of EBV-associated cancers, while the lytic genes are primarily responsible for viral transmission. In recent years, evidence has emerged to show that the EBV lytic phase also plays an important role in EBV tumorigenesis, and the expression of EBV lytic genes is frequently detected in tumor tissues and cell lines. The advent of next generation sequencing has allowed the comprehensive profiling of EBV gene expression, and this has revealed the consistent expression of several lytic genes across various types of EBV-associated cancers. In this review, we provide an overview of the functional implications of EBV lytic gene expression to the oncogenic process and discuss possible avenues for future investigations.
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6
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Viral immune evasins impact antigen presentation by allele-specific trapping of MHC I at the peptide-loading complex. Sci Rep 2022; 12:1516. [PMID: 35087068 PMCID: PMC8795405 DOI: 10.1038/s41598-022-05000-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 12/30/2021] [Indexed: 11/30/2022] Open
Abstract
Major histocompatibility complex class I (MHC I) molecules present antigenic peptides to cytotoxic T cells to eliminate infected or cancerous cells. The transporter associated with antigen processing (TAP) shuttles proteasomally generated peptides into the ER for MHC I loading. As central part of the peptide-loading complex (PLC), TAP is targeted by viral factors, which inhibit peptide supply and thereby impact MHC I-mediated immune responses. However, it is still poorly understood how antigen presentation via different MHC I allotypes is affected by TAP inhibition. Here, we show that conditional expression of herpes simplex viral ICP47 suppresses surface presentation of HLA-A and HLA-C, but not of HLA-B, while the human cytomegaloviral US6 reduces surface levels of all MHC I allotypes. This marked difference in HLA-B antigen presentation is echoed by an enrichment of HLA-B allomorphs at US6-arrested PLC in comparison to ICP47-PLC. Although both viral factors prevent TAP-mediated peptide supply, our data imply that MHC I allomorphs favor different conformationally arrested states of the PLC, leading to differential downregulation of MHC I surface presentation. These findings will help understand MHC I biology in general and will even advance the targeted treatment of infections depending on patients’ allotypes.
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7
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EBNA2 driven enhancer switching at the CIITA-DEXI locus suppresses HLA class II gene expression during EBV infection of B-lymphocytes. PLoS Pathog 2021; 17:e1009834. [PMID: 34352044 PMCID: PMC8370649 DOI: 10.1371/journal.ppat.1009834] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 08/17/2021] [Accepted: 07/23/2021] [Indexed: 11/18/2022] Open
Abstract
Viruses suppress immune recognition through diverse mechanisms. Epstein-Barr Virus (EBV) establishes latent infection in memory B-lymphocytes and B-cell malignancies where it impacts B-cell immune function. We show here that EBV primary infection of naïve B-cells results in a robust down-regulation of HLA genes. We found that the viral encoded transcriptional regulatory factor EBNA2 bound to multiple regulatory regions in the HLA locus. Conditional expression of EBNA2 correlated with the down regulation of HLA class II transcription. EBNA2 down-regulation of HLA transcription was found to be dependent on CIITA, the major transcriptional activator of HLA class II gene transcription. We identified a major EBNA2 binding site downstream of the CIITA gene and upstream of DEXI, a dexamethasone inducible gene that is oriented head-to-head with CIITA gene transcripts. CRISPR/Cas9 deletion of the EBNA2 site upstream of DEXI attenuated CIITA transcriptional repression. EBNA2 caused an increase in DEXI transcription and a graded change in histone modifications with activation mark H3K27ac near the DEXI locus, and a loss of activation marks at the CIITA locus. A prominent CTCF binding site between CIITA and DEXI enhancers was mutated and further diminished the effects of EBNA2 on CIITA. Analysis of HiC data indicate that DEXI and CIITA enhancers are situated in different chromosome topological associated domains (TADs). These findings suggest that EBNA2 down regulates HLA-II genes through the down regulation of CIITA, and that this down regulation is an indirect consequence of EBNA2 enhancer formation at a neighboring TAD. We propose that enhancer competition between these neighboring chromosome domains represents a novel mechanism for gene regulation demonstrated by EBNA2.
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8
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Bruce JP, To KF, Lui VWY, Chung GTY, Chan YY, Tsang CM, Yip KY, Ma BBY, Woo JKS, Hui EP, Mak MKF, Lee SD, Chow C, Velapasamy S, Or YYY, Siu PK, El Ghamrasni S, Prokopec S, Wu M, Kwan JSH, Liu Y, Chan JYK, van Hasselt CA, Young LS, Dawson CW, Paterson IC, Yap LF, Tsao SW, Liu FF, Chan ATC, Pugh TJ, Lo KW. Whole-genome profiling of nasopharyngeal carcinoma reveals viral-host co-operation in inflammatory NF-κB activation and immune escape. Nat Commun 2021; 12:4193. [PMID: 34234122 PMCID: PMC8263564 DOI: 10.1038/s41467-021-24348-6] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 05/19/2021] [Indexed: 02/07/2023] Open
Abstract
Interplay between EBV infection and acquired genetic alterations during nasopharyngeal carcinoma (NPC) development remains vague. Here we report a comprehensive genomic analysis of 70 NPCs, combining whole-genome sequencing (WGS) of microdissected tumor cells with EBV oncogene expression to reveal multiple aspects of cellular-viral co-operation in tumorigenesis. Genomic aberrations along with EBV-encoded LMP1 expression underpin constitutive NF-κB activation in 90% of NPCs. A similar spectrum of somatic aberrations and viral gene expression undermine innate immunity in 79% of cases and adaptive immunity in 47% of cases; mechanisms by which NPC may evade immune surveillance despite its pro-inflammatory phenotype. Additionally, genomic changes impairing TGFBR2 promote oncogenesis and stabilize EBV infection in tumor cells. Fine-mapping of CDKN2A/CDKN2B deletion breakpoints reveals homozygous MTAP deletions in 32-34% of NPCs that confer marked sensitivity to MAT2A inhibition. Our work concludes that NPC is a homogeneously NF-κB-driven and immune-protected, yet potentially druggable, cancer.
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Affiliation(s)
- Jeff P Bruce
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Ka-Fai To
- Department of Anatomical and cellular Pathology, The Chinese University of Hong Kong, Hong Kong SAR, China.,State Key Laboratory of Translational Oncology, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Vivian W Y Lui
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Grace T Y Chung
- Department of Anatomical and cellular Pathology, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Yuk-Yu Chan
- Department of Anatomical and cellular Pathology, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Chi Man Tsang
- Department of Anatomical and cellular Pathology, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Kevin Y Yip
- Department of Computer Science and Engineering, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Brigette B Y Ma
- State Key Laboratory of Translational Oncology, The Chinese University of Hong Kong, Hong Kong SAR, China.,Sir Y.K. Pao Centre for Cancer, The Chinese University of Hong Kong, Hong Kong SAR, China.,Department of Clinical Oncology, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - John K S Woo
- Department of Otorhinolaryngology, Head and Neck Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Edwin P Hui
- State Key Laboratory of Translational Oncology, The Chinese University of Hong Kong, Hong Kong SAR, China.,Sir Y.K. Pao Centre for Cancer, The Chinese University of Hong Kong, Hong Kong SAR, China.,Department of Clinical Oncology, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Michael K F Mak
- Department of Anatomical and cellular Pathology, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Sau-Dan Lee
- Department of Computer Science and Engineering, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Chit Chow
- Department of Anatomical and cellular Pathology, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Sharmila Velapasamy
- Department of Anatomical and cellular Pathology, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Yvonne Y Y Or
- Department of Anatomical and cellular Pathology, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Pui Kei Siu
- Department of Anatomical and cellular Pathology, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Samah El Ghamrasni
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Stephenie Prokopec
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Man Wu
- Department of Anatomical and cellular Pathology, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Johnny S H Kwan
- Department of Anatomical and cellular Pathology, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Yuchen Liu
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Jason Y K Chan
- Department of Otorhinolaryngology, Head and Neck Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - C Andrew van Hasselt
- Department of Otorhinolaryngology, Head and Neck Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong SAR, China
| | | | | | - Ian C Paterson
- Department of Oral & Craniofacial Sciences and Oral Cancer Research and Coordinating Centre, University of Malaya, Kuala Lumpur, Malaysia
| | - Lee-Fah Yap
- Department of Oral & Craniofacial Sciences and Oral Cancer Research and Coordinating Centre, University of Malaya, Kuala Lumpur, Malaysia
| | - Sai-Wah Tsao
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Fei-Fei Liu
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada.,Department of Radiation Oncology, University of Toronto, Toronto, ON, Canada
| | - Anthony T C Chan
- Department of Computer Science and Engineering, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Trevor J Pugh
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada. .,Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada. .,Ontario Institute for Cancer Research, Toronto, ON, Canada.
| | - Kwok-Wai Lo
- Department of Anatomical and cellular Pathology, The Chinese University of Hong Kong, Hong Kong SAR, China. .,State Key Laboratory of Translational Oncology, The Chinese University of Hong Kong, Hong Kong SAR, China.
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9
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Pathogenic Role of Epstein-Barr Virus in Lung Cancers. Viruses 2021; 13:v13050877. [PMID: 34064727 PMCID: PMC8151745 DOI: 10.3390/v13050877] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 04/27/2021] [Accepted: 05/07/2021] [Indexed: 01/02/2023] Open
Abstract
Human oncogenic viruses account for at least 12% of total cancer cases worldwide. Epstein–Barr virus (EBV) is the first identified human oncogenic virus and it alone causes ~200,000 cancer cases and ~1.8% of total cancer-related death annually. Over the past 40 years, increasing lines of evidence have supported a causal link between EBV infection and a subgroup of lung cancers (LCs). In this article, we review the current understanding of the EBV-LC association and the etiological role of EBV in lung carcinogenesis. We also discuss the clinical impact of the knowledge gained from previous research, challenges, and future directions in this field. Given the high clinical relevance of EBV-LC association, there is an urgent need for further investigation on this topic.
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10
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Trowitzsch S, Tampé R. Multifunctional Chaperone and Quality Control Complexes in Adaptive Immunity. Annu Rev Biophys 2020; 49:135-161. [PMID: 32004089 DOI: 10.1146/annurev-biophys-121219-081643] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The fundamental process of adaptive immunity relies on the differentiation of self from nonself. Nucleated cells are continuously monitored by effector cells of the immune system, which police the peptide status presented via cell surface molecules. Recent integrative structural approaches have provided insights toward our understanding of how sophisticated cellular machineries shape such hierarchical immune surveillance. Biophysical and structural achievements were invaluable for defining the interconnection of many key factors during antigen processing and presentation, and helped to solve several conundrums that persisted for many years. In this review, we illuminate the numerous quality control machineries involved in different steps during the maturation of major histocompatibility complex class I (MHC I) proteins, from their synthesis in the endoplasmic reticulum to folding and trafficking via the secretory pathway, optimization of antigenic cargo, final release to the cell surface, and engagement with their cognate receptors on cytotoxic T lymphocytes.
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Affiliation(s)
- Simon Trowitzsch
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany; ,
| | - Robert Tampé
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany; ,
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11
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Dearborn AD, Marcotrigiano J. Hepatitis C Virus Structure: Defined by What It Is Not. Cold Spring Harb Perspect Med 2020; 10:cshperspect.a036822. [PMID: 31501263 DOI: 10.1101/cshperspect.a036822] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Hepatitis C virus (HCV) represents an important and growing public health problem, chronically infecting an estimated 70 million people worldwide. This blood-borne pathogen is generating a new wave of infections in the United States, associated with increasing intravenous drug use over the last decade. In most cases, HCV establishes a chronic infection, sometimes causing cirrhosis, end-stage liver disease, and hepatocellular carcinoma. Although a curative therapy exists, it is extremely expensive and provides no barrier to reinfection; therefore, a vaccine is urgently needed. The virion is asymmetric and heterogeneous with the buoyancy and protein content similar to low-density lipoparticles. Core protein is unstructured, and of the two envelope glycoproteins, E1 and E2, the function of E1 remains enigmatic. E2 is responsible for specifically binding host receptors CD81 and scavenger receptor class B type I (SR-BI). This review will focus on structural progress on HCV virion, core protein, envelope glycoproteins, and specific host receptors.
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Affiliation(s)
- Altaira D Dearborn
- The Protein Expression Laboratory, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.,Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Joseph Marcotrigiano
- The Protein Expression Laboratory, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
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12
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Morgens DW, Chan C, Kane AJ, Weir NR, Li A, Dubreuil MM, Tsui CK, Hess GT, Lavertu A, Han K, Polyakov N, Zhou J, Handy EL, Alabi P, Dombroski A, Yao D, Altman RB, Sello JK, Denic V, Bassik MC. Retro-2 protects cells from ricin toxicity by inhibiting ASNA1-mediated ER targeting and insertion of tail-anchored proteins. eLife 2019; 8:48434. [PMID: 31674906 PMCID: PMC6858068 DOI: 10.7554/elife.48434] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 10/28/2019] [Indexed: 12/11/2022] Open
Abstract
The small molecule Retro-2 prevents ricin toxicity through a poorly-defined mechanism of action (MOA), which involves halting retrograde vesicle transport to the endoplasmic reticulum (ER). CRISPRi genetic interaction analysis revealed Retro-2 activity resembles disruption of the transmembrane domain recognition complex (TRC) pathway, which mediates post-translational ER-targeting and insertion of tail-anchored (TA) proteins, including SNAREs required for retrograde transport. Cell-based and in vitro assays show that Retro-2 blocks delivery of newly-synthesized TA-proteins to the ER-targeting factor ASNA1 (TRC40). An ASNA1 point mutant identified using CRISPR-mediated mutagenesis abolishes both the cytoprotective effect of Retro-2 against ricin and its inhibitory effect on ASNA1-mediated ER-targeting. Together, our work explains how Retro-2 prevents retrograde trafficking of toxins by inhibiting TA-protein targeting, describes a general CRISPR strategy for predicting the MOA of small molecules, and paves the way for drugging the TRC pathway to treat broad classes of viruses known to be inhibited by Retro-2.
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Affiliation(s)
- David W Morgens
- Department of Genetics, Stanford University, Stanford, United States
| | - Charlene Chan
- Department of Molecular and Cellular Biology, Northwest Labs, Harvard University, Cambridge, United States
| | - Andrew J Kane
- Department of Molecular and Cellular Biology, Northwest Labs, Harvard University, Cambridge, United States
| | - Nicholas R Weir
- Department of Molecular and Cellular Biology, Northwest Labs, Harvard University, Cambridge, United States
| | - Amy Li
- Department of Genetics, Stanford University, Stanford, United States
| | | | - C Kimberly Tsui
- Department of Genetics, Stanford University, Stanford, United States
| | - Gaelen T Hess
- Department of Genetics, Stanford University, Stanford, United States
| | - Adam Lavertu
- Biomedical Informatics Training Program, Stanford University, Stanford, United States
| | - Kyuho Han
- Department of Genetics, Stanford University, Stanford, United States
| | - Nicole Polyakov
- Department of Molecular and Cellular Biology, Northwest Labs, Harvard University, Cambridge, United States
| | - Jing Zhou
- Department of Molecular and Cellular Biology, Northwest Labs, Harvard University, Cambridge, United States
| | - Emma L Handy
- Department of Chemistry, Brown University, Providence, United States
| | - Philip Alabi
- Department of Chemistry, Brown University, Providence, United States
| | - Amanda Dombroski
- Department of Chemistry, Brown University, Providence, United States
| | - David Yao
- Department of Genetics, Stanford University, Stanford, United States
| | - Russ B Altman
- Department of Genetics, Stanford University, Stanford, United States.,Bioengineering, Stanford University, Stanford, United States
| | - Jason K Sello
- Department of Chemistry, Brown University, Providence, United States
| | - Vladimir Denic
- Department of Molecular and Cellular Biology, Northwest Labs, Harvard University, Cambridge, United States
| | - Michael C Bassik
- Department of Genetics, Stanford University, Stanford, United States.,Program in Cancer Biology, Stanford University, Stanford, United States.,Stanford University Chemistry, Engineering, and Medicine for Human Health (ChEM-H), Stanford, United States
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13
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Praest P, Liaci AM, Förster F, Wiertz EJ. New insights into the structure of the MHC class I peptide-loading complex and mechanisms of TAP inhibition by viral immune evasion proteins. Mol Immunol 2019; 113:103-114. [DOI: 10.1016/j.molimm.2018.03.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 03/16/2018] [Accepted: 03/22/2018] [Indexed: 01/08/2023]
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14
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Detection of Epstein-Barr Virus Infection in Non-Small Cell Lung Cancer. Cancers (Basel) 2019; 11:cancers11060759. [PMID: 31159203 PMCID: PMC6627930 DOI: 10.3390/cancers11060759] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 05/27/2019] [Accepted: 05/28/2019] [Indexed: 12/12/2022] Open
Abstract
Previous investigations proposed a link between the Epstein-Barr virus (EBV) and lung cancer (LC), but the results are highly controversial largely due to the insufficient sample size and the inherent limitation of the traditional viral screening methods such as PCR. Unlike PCR, current next-generation sequencing (NGS) utilizes an unbiased method for the global assessment of all exogenous agents within a cancer sample with high sensitivity and specificity. In our current study, we aim to resolve this long-standing controversy by utilizing our unbiased NGS-based informatics approaches in conjunction with traditional molecular methods to investigate the role of EBV in a total of 1127 LC. In situ hybridization analysis of 110 LC and 10 normal lung samples detected EBV transcripts in 3 LC samples. Comprehensive virome analyses of RNA sequencing (RNA-seq) data sets from 1017 LC and 110 paired adjacent normal lung specimens revealed EBV transcripts in three lung squamous cell carcinoma and one lung adenocarcinoma samples. In the sample with the highest EBV coverage, transcripts from the BamHI A region accounted for the majority of EBV reads. Expression of EBNA-1, LMP-1 and LMP-2 was observed. A number of viral circular RNA candidates were also detected. Thus, we for the first time revealed a type II latency-like viral transcriptome in the setting of LC in vivo. The high-level expression of viral BamHI A transcripts in LC suggests a functional role of these transcripts, likely as long non-coding RNA. Analyses of cellular gene expression and stained tissue sections indicated an increased immune cell infiltration in the sample expressing high levels of EBV transcripts compared to samples expressing low EBV transcripts. Increased level of immune checkpoint blockade factors was also detected in the sample with higher levels of EBV transcripts, indicating an induced immune tolerance. Lastly, inhibition of immune pathways and activation of oncogenic pathways were detected in the sample with high EBV transcripts compared to the EBV-low LC indicating the direct regulation of cancer pathways by EBV. Taken together, our data support the notion that EBV likely plays a pathological role in a subset of LC.
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Zhao MH, Sun L, Li P, Liu L, Luo B, Wang XF. Sequence analysis of Epstein–Barr virus (EBV) BNLF2a gene in malignant hematopathy of Northern China. Future Virol 2019. [DOI: 10.2217/fvl-2018-0129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
BNLF2a is an early Epstein–Barr virus gene whose protein plays an immune escaping role by inhibiting the transporter associated with antigen processing. To explore the association between BNLF2a gene variations and EBV tumorigenesis, the BNLF2a gene of 259 EBV-positive samples (171 lymphohematopoietic disease samples and 88 throat washings from healthy donors) from northern China were sequenced. On the basis of phylogenetic tree and mutation characteristics of BNLF2a, all specimens were divided into two major genotypes: BNLF2a-A and BNLF2a-B. BNLF2a-A type, similar to the prototype B95-8, was the major subtype in all subpopulations. Healthy donors carried less BNLF2a-A and more BNLF2a-B than donors with lymphohematopoietic disease. The conservation of the BNLF2a gene may be crucial to its function.
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Affiliation(s)
- Meng-He Zhao
- Department of Pathogenic Biology, Qingdao University Medical College, 38 Dengzhou Road, Qingdao, 266021, PR China
| | - Lingling Sun
- Department of Pathology, Affiliated Hospital of Qingdao University Medical College, 59 Haier Road, Qingdao, 266003, PR China
| | - Ping Li
- Department of Blood Transfusion, Affiliated Hospital of Qingdao University Medical College, 16 Jiangsu Road, Qingdao, 266003, PR China
| | - Lei Liu
- Department of Laboratory, Qingdao commercial staff hospital, 6 Haipo Road, Qingdao, 266011, Shandong Province, China
| | - Bing Luo
- Department of Pathogenic Biology, Qingdao University Medical College, 38 Dengzhou Road, Qingdao, 266021, PR China
| | - Xiao-Feng Wang
- Department of Pathogenic Biology, Qingdao University Medical College, 38 Dengzhou Road, Qingdao, 266021, PR China
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16
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Forrest C, Hislop AD, Rickinson AB, Zuo J. Proteome-wide analysis of CD8+ T cell responses to EBV reveals differences between primary and persistent infection. PLoS Pathog 2018; 14:e1007110. [PMID: 30248160 PMCID: PMC6171963 DOI: 10.1371/journal.ppat.1007110] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 10/04/2018] [Accepted: 08/27/2018] [Indexed: 02/07/2023] Open
Abstract
Human herpesviruses are antigenically rich agents that induce strong CD8+T cell responses in primary infection yet persist for life, continually challenging T cell memory through recurrent lytic replication and potentially influencing the spectrum of antigen-specific responses. Here we describe the first lytic proteome-wide analysis of CD8+ T cell responses to a gamma1-herpesvirus, Epstein-Barr virus (EBV), and the first such proteome-wide analysis of primary versus memory CD8+ T cell responses to any human herpesvirus. Primary effector preparations were generated directly from activated CD8+ T cells in the blood of infectious mononucleosis (IM) patients by in vitro mitogenic expansion. For memory preparations, EBV-specific cells in the blood of long-term virus carriers were first re-stimulated in vitro by autologous dendritic cells loaded with a lysate of lytically-infected cells, then expanded as for IM cells. Preparations from 7 donors of each type were screened against each of 70 EBV lytic cycle proteins in combination with the donor's individual HLA class I alleles. Multiple reactivities against immediate early (IE), early (E) and late (L) lytic cycle proteins, including many hitherto unrecognised targets, were detected in both contexts. Interestingly however, the two donor cohorts showed a different balance between IE, E and L reactivities. Primary responses targeted IE and a small group of E proteins preferentially, seemingly in line with their better presentation on the infected cell surface before later-expressed viral evasins take full hold. By contrast, target choice equilibrates in virus carriage with responses to key IE and E antigens still present but with responses to a select subset of L proteins now often prominent. We infer that, for EBV at least, long-term virus carriage with its low level virus replication and lytic antigen release is associated with a re-shaping of the virus-specific response.
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Affiliation(s)
- Calum Forrest
- Institute for Immunology and Immunotherapy, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Andrew D. Hislop
- Institute for Immunology and Immunotherapy, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Alan B. Rickinson
- Institute for Immunology and Immunotherapy, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Jianmin Zuo
- Institute for Immunology and Immunotherapy, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
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17
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The Immune Response to Epstein Barr Virus and Implications for Posttransplant Lymphoproliferative Disorder. Transplantation 2017; 101:2009-2016. [PMID: 28376031 DOI: 10.1097/tp.0000000000001767] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Posttransplant lymphoproliferative disorder (PTLD) is a serious complication in organ transplant recipients and is most often associated with the Epstein Barr virus (EBV). EBV is a common gammaherpes virus with tropism for B lymphocytes and infection in immunocompetent individuals is typically asymptomatic and benign. However, infection in immunocompromised or immunosuppressed individuals can result in malignant B cell lymphoproliferations, such as PTLD. EBV+ PTLD can arise after primary EBV infection, or because of reactivation of a prior infection, and represents a leading malignancy in the transplant population. The incidence of EBV+ PTLD is variable depending on the organ transplanted and whether the recipient has preexisting immunity to EBV but can be as high as 20%. It is generally accepted that impaired immune function due to immunosuppression is a primary cause of EBV+ PTLD. In this overview, we review the EBV life cycle and discuss our current understanding of the immune response to EBV in healthy, immunocompetent individuals, in transplant recipients, and in PTLD patients. We review the strategies that EBV uses to subvert and evade host immunity and discuss the implications for the development of EBV+ PTLD.
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18
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Conserved targeting information in mammalian and fungal peroxisomal tail-anchored proteins. Sci Rep 2015; 5:17420. [PMID: 26627908 PMCID: PMC4667187 DOI: 10.1038/srep17420] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 10/22/2015] [Indexed: 11/22/2022] Open
Abstract
The targeting signals and mechanisms of soluble peroxisomal proteins are well understood, whereas less is known about the signals and targeting routes of peroxisomal membrane proteins (PMP). Pex15 and PEX26, tail-anchored proteins in yeast and mammals, respectively, exert a similar cellular function in the recruitment of AAA peroxins at the peroxisomal membrane. But despite their common role, Pex15 and PEX26 are neither homologs nor they are known to follow similar targeting principles. Here we show that Pex15 targets to peroxisomes in mammalian cells, and PEX26 reaches peroxisomes when expressed in yeast cells. In both proteins C-terminal targeting information is sufficient for correct sorting to the peroxisomal membrane. In yeast, PEX26 follows the pathway that also ensures correct targeting of Pex15: PEX26 enters the endoplasmic reticulum (ER) in a GET-dependent and Pex19-independent manner. Like in yeast, PEX26 enters the ER in mammalian cells, however, independently of GET/TRC40. These data show that conserved targeting information is employed in yeast and higher eukaryotes during the biogenesis of peroxisomal tail-anchored proteins.
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Latent Expression of the Epstein-Barr Virus (EBV)-Encoded Major Histocompatibility Complex Class I TAP Inhibitor, BNLF2a, in EBV-Positive Gastric Carcinomas. J Virol 2015; 89:10110-4. [PMID: 26178981 DOI: 10.1128/jvi.01110-15] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 07/07/2015] [Indexed: 12/14/2022] Open
Abstract
The Epstein-Barr virus (EBV) BNLF2a gene product provides immune evasion properties to infected cells through inhibition of transporter associated with antigen processing (TAP)-mediated transport of antigen peptides. Although BNLF2a is considered to be a lytic gene, we demonstrate that it is expressed in nearly half of the EBV-associated gastric carcinomas analyzed. Further, we show that BNLF2a expression is dissociated from lytic gene expression. BNLF2a is therefore expressed in this latency setting, potentially helping protect the infected tumor cells from immunosurveillance.
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20
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Liu S, Wang X, Shu J, Zhao Z, Sun Z, Luo B. Sequence analysis of EBV immune evasion gene BNLF2a in EBV associated tumors and healthy individuals from nasopharyngeal carcinoma endemic and non-endemic regions of China. J Med Virol 2015; 87:1946-52. [PMID: 25959517 DOI: 10.1002/jmv.24254] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/04/2015] [Indexed: 11/07/2022]
Abstract
BNLF2a is an Epstein-Barr virus (EBV) immune evasion gene. Its protein is located in the endoplasmic reticulum (ER) membrane, and can inhibit the antigen transporting function of TAP, thereby perturbing the immune response to EBV in lytic and prelatent phase. In order to explore whether the polymorphism of BNLF2a gene has a role in different types of EBV associated tumors, we conducted complete sequencing of the gene BNLF2a in 408 cases of EBV positive tumors (76 lymphomas, 45 gastric carcinomas, and 85 nasopharyngeal carcinomas in northern China and 27 lymphomas, 30 gastric carcinomas, and 57 nasopharyngeal carcinomas in southern China) and throat washings from healthy individuals (39 in northern China and 49 in southern China). Two main variant types of BNLF2a were identified. Type BNLF2a-A, which was similar to B95-8, was dominant in all sub-populations (66.7-100%) in this study. Type BNLF2a-B was characterized by the mutations at position 8 and 40. The variation patterns of BNLF2a were significantly different between samples from northern and southern China (P < 0.05), and between the tumors and healthy donor samples from the northern China (P < 0.0167). Type BNLF2a-B was more frequent in healthy donors of northern China (33.3%), and the proportion of this type was higher in the northern than in the southern NPCs. These data demonstrate that the BNLF2a gene is highly conserved, and its polymorphism is geographically restricted. Type BNLF2a-B is more prevalent in northern China and may be less tumor transformative.
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Affiliation(s)
- Song Liu
- Department of Medical Microbiology, Qingdao University Medical College, Qingdao, China
| | - Xiaofeng Wang
- Department of Medical Microbiology, Qingdao University Medical College, Qingdao, China
| | - Jun Shu
- Department of Medical Microbiology, Qingdao University Medical College, Qingdao, China
| | - Zhenzhen Zhao
- Department of Medical Microbiology, Qingdao University Medical College, Qingdao, China
| | - Zhifu Sun
- Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota
| | - Bing Luo
- Department of Medical Microbiology, Qingdao University Medical College, Qingdao, China
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21
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Verweij MC, Horst D, Griffin BD, Luteijn RD, Davison AJ, Ressing ME, Wiertz EJHJ. Viral inhibition of the transporter associated with antigen processing (TAP): a striking example of functional convergent evolution. PLoS Pathog 2015; 11:e1004743. [PMID: 25880312 PMCID: PMC4399834 DOI: 10.1371/journal.ppat.1004743] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Herpesviruses are large DNA viruses that are highly abundant within their host populations. Even in the presence of a healthy immune system, these viruses manage to cause lifelong infections. This persistence is partially mediated by the virus entering latency, a phase of infection characterized by limited viral protein expression. Moreover, herpesviruses have devoted a significant part of their coding capacity to immune evasion strategies. It is believed that the close coexistence of herpesviruses and their hosts has resulted in the evolution of viral proteins that specifically attack multiple arms of the host immune system. Cytotoxic T lymphocytes (CTLs) play an important role in antiviral immunity. CTLs recognize their target through viral peptides presented in the context of MHC molecules at the cell surface. Every herpesvirus studied to date encodes multiple immune evasion molecules that effectively interfere with specific steps of the MHC class I antigen presentation pathway. The transporter associated with antigen processing (TAP) plays a key role in the loading of viral peptides onto MHC class I molecules. This is reflected by the numerous ways herpesviruses have developed to block TAP function. In this review, we describe the characteristics and mechanisms of action of all known virus-encoded TAP inhibitors. Orthologs of these proteins encoded by related viruses are identified, and the conservation of TAP inhibition is discussed. A phylogenetic analysis of members of the family Herpesviridae is included to study the origin of these molecules. In addition, we discuss the characteristics of the first TAP inhibitor identified outside the herpesvirus family, namely, in cowpox virus. The strategies of TAP inhibition employed by viruses are very distinct and are likely to have been acquired independently during evolution. These findings and the recent discovery of a non-herpesvirus TAP inhibitor represent a striking example of functional convergent evolution.
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Affiliation(s)
- Marieke C. Verweij
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Daniëlle Horst
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Bryan D. Griffin
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Rutger D. Luteijn
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Andrew J. Davison
- MRC—University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Maaike E. Ressing
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Emmanuel J. H. J. Wiertz
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
- * E-mail:
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22
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van de Weijer ML, Luteijn RD, Wiertz EJHJ. Viral immune evasion: Lessons in MHC class I antigen presentation. Semin Immunol 2015; 27:125-37. [PMID: 25887630 DOI: 10.1016/j.smim.2015.03.010] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 03/13/2015] [Indexed: 12/19/2022]
Abstract
The MHC class I antigen presentation pathway enables cells infected with intracellular pathogens to signal the presence of the invader to the immune system. Cytotoxic T lymphocytes are able to eliminate the infected cells through recognition of pathogen-derived peptides presented by MHC class I molecules at the cell surface. In the course of evolution, many viruses have acquired inhibitors that target essential stages of the MHC class I antigen presentation pathway. Studies on these immune evasion proteins reveal fascinating strategies used by viruses to elude the immune system. Viral immunoevasins also constitute great research tools that facilitate functional studies on the MHC class I antigen presentation pathway, allowing the investigation of less well understood routes, such as TAP-independent antigen presentation and cross-presentation of exogenous proteins. Viral immunoevasins have also helped to unravel more general cellular processes. For instance, basic principles of ER-associated protein degradation via the ubiquitin-proteasome pathway have been resolved using virus-induced degradation of MHC class I as a model. This review highlights how viral immunoevasins have increased our understanding of MHC class I-restricted antigen presentation.
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Affiliation(s)
| | - Rutger D Luteijn
- Medical Microbiology, University Medical Center Utrecht, 3584CX Utrecht, The Netherlands
| | - Emmanuel J H J Wiertz
- Medical Microbiology, University Medical Center Utrecht, 3584CX Utrecht, The Netherlands.
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23
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Antigen Translocation Machineries in Adaptive Immunity and Viral Immune Evasion. J Mol Biol 2015; 427:1102-18. [DOI: 10.1016/j.jmb.2014.09.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 09/04/2014] [Accepted: 09/05/2014] [Indexed: 11/23/2022]
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24
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Ressing ME, van Gent M, Gram AM, Hooykaas MJG, Piersma SJ, Wiertz EJHJ. Immune Evasion by Epstein-Barr Virus. Curr Top Microbiol Immunol 2015; 391:355-81. [PMID: 26428381 DOI: 10.1007/978-3-319-22834-1_12] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Epstein-Bar virus (EBV) is widespread within the human population with over 90% of adults being infected. In response to primary EBV infection, the host mounts an antiviral immune response comprising both innate and adaptive effector functions. Although the immune system can control EBV infection to a large extent, the virus is not cleared. Instead, EBV establishes a latent infection in B lymphocytes characterized by limited viral gene expression. For the production of new viral progeny, EBV reactivates from these latently infected cells. During the productive phase of infection, a repertoire of over 80 EBV gene products is expressed, presenting a vast number of viral antigens to the primed immune system. In particular the EBV-specific CD4+ and CD8+ memory T lymphocytes can respond within hours, potentially destroying the virus-producing cells before viral replication is completed and viral particles have been released. Preceding the adaptive immune response, potent innate immune mechanisms provide a first line of defense during primary and recurrent infections. In spite of this broad range of antiviral immune effector mechanisms, EBV persists for life and continues to replicate. Studies performed over the past decades have revealed a wide array of viral gene products interfering with both innate and adaptive immunity. These include EBV-encoded proteins as well as small noncoding RNAs with immune-evasive properties. The current review presents an overview of the evasion strategies that are employed by EBV to facilitate immune escape during latency and productive infection. These evasion mechanisms may also compromise the elimination of EBV-transformed cells, and thus contribute to malignancies associated with EBV infection.
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Affiliation(s)
- Maaike E Ressing
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
- Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - Michiel van Gent
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Anna M Gram
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
- Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - Marjolein J G Hooykaas
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Sytse J Piersma
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Emmanuel J H J Wiertz
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands.
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25
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Lin J, Eggensperger S, Hank S, Wycisk AI, Wieneke R, Mayerhofer PU, Tampé R. A negative feedback modulator of antigen processing evolved from a frameshift in the cowpox virus genome. PLoS Pathog 2014; 10:e1004554. [PMID: 25503639 PMCID: PMC4263761 DOI: 10.1371/journal.ppat.1004554] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 11/04/2014] [Indexed: 12/31/2022] Open
Abstract
Coevolution of viruses and their hosts represents a dynamic molecular battle between the immune system and viral factors that mediate immune evasion. After the abandonment of smallpox vaccination, cowpox virus infections are an emerging zoonotic health threat, especially for immunocompromised patients. Here we delineate the mechanistic basis of how cowpox viral CPXV012 interferes with MHC class I antigen processing. This type II membrane protein inhibits the coreTAP complex at the step after peptide binding and peptide-induced conformational change, in blocking ATP binding and hydrolysis. Distinct from other immune evasion mechanisms, TAP inhibition is mediated by a short ER-lumenal fragment of CPXV012, which results from a frameshift in the cowpox virus genome. Tethered to the ER membrane, this fragment mimics a high ER-lumenal peptide concentration, thus provoking a trans-inhibition of antigen translocation as supply for MHC I loading. These findings illuminate the evolution of viral immune modulators and the basis of a fine-balanced regulation of antigen processing. Virus-infected or malignant transformed cells are eliminated by cytotoxic T lymphocytes, which recognize antigenic peptide epitopes in complex with major histocompatibility complex class I (MHC I) molecules at the cell surface. The majority of such peptides are derived from proteasomal degradation in the cytosol and are then translocated into the ER lumen in an energy-consuming reaction via the transporter associated with antigen processing (TAP), which delivers the peptides onto MHC I molecules as final acceptors. Viruses have evolved sophisticated strategies to escape this immune surveillance. Here we show that the cowpox viral protein CPXV012 inhibits the ER peptide translocation machinery by allosterically blocking ATP binding and hydrolysis by TAP. The short ER resident active domain of the viral protein evolved from a reading frame shift in the cowpox virus genome and exploits the ER-lumenal negative feedback peptide sensor of TAP. This CPXV012-induced conformational arrest of TAP is signaled by a unique communication across the ER membrane to the cytosolic motor domains of the peptide pump. Furthermore, this study provides the rare opportunity to decipher on a molecular level how nature plays hide and seek with a pathogen and its host.
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Affiliation(s)
- Jiacheng Lin
- Institute of Biochemistry, Biocenter, Goethe-University Frankfurt, Frankfurt, Germany
| | - Sabine Eggensperger
- Institute of Biochemistry, Biocenter, Goethe-University Frankfurt, Frankfurt, Germany
| | - Susanne Hank
- Institute of Biochemistry, Biocenter, Goethe-University Frankfurt, Frankfurt, Germany
| | - Agnes I. Wycisk
- Institute of Biochemistry, Biocenter, Goethe-University Frankfurt, Frankfurt, Germany
| | - Ralph Wieneke
- Institute of Biochemistry, Biocenter, Goethe-University Frankfurt, Frankfurt, Germany
| | - Peter U. Mayerhofer
- Institute of Biochemistry, Biocenter, Goethe-University Frankfurt, Frankfurt, Germany
- * E-mail: (PUM); (RT)
| | - Robert Tampé
- Institute of Biochemistry, Biocenter, Goethe-University Frankfurt, Frankfurt, Germany
- Cluster of Excellence – Macromolecular Complexes, Goethe-University Frankfurt, Frankfurt, Germany
- * E-mail: (PUM); (RT)
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26
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Quinn LL, Zuo J, Abbott RJM, Shannon-Lowe C, Tierney RJ, Hislop AD, Rowe M. Cooperation between Epstein-Barr virus immune evasion proteins spreads protection from CD8+ T cell recognition across all three phases of the lytic cycle. PLoS Pathog 2014; 10:e1004322. [PMID: 25144360 PMCID: PMC4140850 DOI: 10.1371/journal.ppat.1004322] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 07/08/2014] [Indexed: 12/20/2022] Open
Abstract
CD8+ T cell responses to Epstein-Barr virus (EBV) lytic cycle expressed antigens display a hierarchy of immunodominance, in which responses to epitopes of immediate-early (IE) and some early (E) antigens are more frequently observed than responses to epitopes of late (L) expressed antigens. It has been proposed that this hierarchy, which correlates with the phase-specific efficiency of antigen presentation, may be due to the influence of viral immune-evasion genes. At least three EBV-encoded genes, BNLF2a, BGLF5 and BILF1, have the potential to inhibit processing and presentation of CD8+ T cell epitopes. Here we examined the relative contribution of these genes to modulation of CD8+ T cell recognition of EBV lytic antigens expressed at different phases of the replication cycle in EBV-transformed B-cells (LCLs) which spontaneously reactivate lytic cycle. Selective shRNA-mediated knockdown of BNLF2a expression led to more efficient recognition of immediate-early (IE)- and early (E)-derived epitopes by CD8+ T cells, while knock down of BILF1 increased recognition of epitopes from E and late (L)-expressed antigens. Contrary to what might have been predicted from previous ectopic expression studies in EBV-negative model cell lines, the shRNA-mediated inhibition of BGLF5 expression in LCLs showed only modest, if any, increase in recognition of epitopes expressed in any phase of lytic cycle. These data indicate that whilst BNLF2a interferes with antigen presentation with diminishing efficiency as lytic cycle progresses (IE>E>>L), interference by BILF1 increases with progression through lytic cycle (IE
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Affiliation(s)
- Laura L. Quinn
- School of Cancer Sciences and Centre for Human Virology, University of Birmingham College of Medical and Dental Sciences, Edgbaston, Birmingham, United Kingdom
| | - Jianmin Zuo
- School of Cancer Sciences and Centre for Human Virology, University of Birmingham College of Medical and Dental Sciences, Edgbaston, Birmingham, United Kingdom
| | - Rachel J. M. Abbott
- School of Cancer Sciences and Centre for Human Virology, University of Birmingham College of Medical and Dental Sciences, Edgbaston, Birmingham, United Kingdom
| | - Claire Shannon-Lowe
- School of Cancer Sciences and Centre for Human Virology, University of Birmingham College of Medical and Dental Sciences, Edgbaston, Birmingham, United Kingdom
| | - Rosemary J. Tierney
- School of Cancer Sciences and Centre for Human Virology, University of Birmingham College of Medical and Dental Sciences, Edgbaston, Birmingham, United Kingdom
| | - Andrew D. Hislop
- School of Cancer Sciences and Centre for Human Virology, University of Birmingham College of Medical and Dental Sciences, Edgbaston, Birmingham, United Kingdom
| | - Martin Rowe
- School of Cancer Sciences and Centre for Human Virology, University of Birmingham College of Medical and Dental Sciences, Edgbaston, Birmingham, United Kingdom
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27
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Luteijn RD, Hoelen H, Kruse E, van Leeuwen WF, Grootens J, Horst D, Koorengevel M, Drijfhout JW, Kremmer E, Früh K, Neefjes JJ, Killian A, Lebbink RJ, Ressing ME, Wiertz EJHJ. Cowpox virus protein CPXV012 eludes CTLs by blocking ATP binding to TAP. THE JOURNAL OF IMMUNOLOGY 2014; 193:1578-89. [PMID: 25024387 DOI: 10.4049/jimmunol.1400964] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
CD8(+) CTLs detect virus-infected cells through recognition of virus-derived peptides presented at the cell surface by MHC class I molecules. The cowpox virus protein CPXV012 deprives the endoplasmic reticulum (ER) lumen of peptides for loading onto newly synthesized MHC class I molecules by inhibiting the transporter associated with Ag processing (TAP). This evasion strategy allows the virus to avoid detection by the immune system. In this article, we show that CPXV012, a 9-kDa type II transmembrane protein, prevents peptide transport by inhibiting ATP binding to TAP. We identified a segment within the ER-luminal domain of CPXV012 that imposes the block in peptide transport by TAP. Biophysical studies show that this domain has a strong affinity for phospholipids that are also abundant in the ER membrane. We discuss these findings in an evolutionary context and show that a frameshift deletion in the CPXV012 gene in an ancestral cowpox virus created the current form of CPXV012 that is capable of inhibiting TAP. In conclusion, our findings indicate that the ER-luminal domain of CPXV012 inserts into the ER membrane, where it interacts with TAP. CPXV012 presumably induces a conformational arrest that precludes ATP binding to TAP and, thus, activity of TAP, thereby preventing the presentation of viral peptides to CTLs.
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Affiliation(s)
- Rutger D Luteijn
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Hanneke Hoelen
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Elisabeth Kruse
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Wouter F van Leeuwen
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Jennine Grootens
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Daniëlle Horst
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Martijn Koorengevel
- Department of Membrane Biochemistry and Biophysics, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Jan W Drijfhout
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, 2333 ZA Leiden, the Netherlands
| | - Elisabeth Kremmer
- Helmholtz Center Munich, German Research Center for Environmental Health, Institute of Molecular Immunology, 81377 Munich, Germany
| | - Klaus Früh
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, Beaverton, OR 97006; and
| | - Jacques J Neefjes
- Department of Cell Biology, The Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands
| | - Antoinette Killian
- Department of Membrane Biochemistry and Biophysics, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Robert Jan Lebbink
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Maaike E Ressing
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Emmanuel J H J Wiertz
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands;
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28
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Hu Z, Usherwood EJ. Immune escape of γ-herpesviruses from adaptive immunity. Rev Med Virol 2014; 24:365-78. [PMID: 24733560 DOI: 10.1002/rmv.1791] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 03/06/2014] [Accepted: 03/07/2014] [Indexed: 01/23/2023]
Abstract
Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV) are two γ-herpesviruses identified in humans and are strongly associated with the development of malignancies. Murine γ-herpesvirus (MHV-68) is a naturally occurring rodent pathogen, representing a unique experimental model for dissecting γ-herpesvirus infection and the immune response. These γ-herpesviruses actively antagonize the innate and adaptive antiviral responses, thereby efficiently establishing latent or persistent infections and even promoting development of malignancies. In this review, we summarize immune evasion strategies of γ-herpesviruses. These include suppression of MHC-I-restricted and MHC-II-restricted antigen presentation, impairment of dendritic cell functions, downregulation of costimulatory molecules, activation of virus-specific regulatory T cells, and induction of inhibitory cytokines. There is a focus on how both γ-herpesvirus-derived and host-derived immunomodulators interfere with adaptive antiviral immunity. Understanding immune-evasive mechanisms is essential for developing future immunotherapies against EBV-driven and KSHV-driven tumors.
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Affiliation(s)
- Zhuting Hu
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Lebanon, NH, USA
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29
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Feng P, Moses A, Früh K. Evasion of adaptive and innate immune response mechanisms by γ-herpesviruses. Curr Opin Virol 2013; 3:285-95. [PMID: 23735334 DOI: 10.1016/j.coviro.2013.05.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 05/01/2013] [Accepted: 05/14/2013] [Indexed: 01/05/2023]
Abstract
γ-Herpesviral immune evasion mechanisms are optimized to support the acute, lytic and the longterm, latent phase of infection. During acute infection, specific immune modulatory proteins limit, but also exploit, the antiviral activities of cell intrinsic innate immune responses as well as those of innate and adaptive immune cells. During latent infection, a restricted gene expression program limits immune targeting and cis-acting mechanisms to reduce the antigen presentation as well as antigenicity of latency-associated proteins. Here, we will review recent progress in our understanding of γ-herpesviral immune evasion strategies.
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Affiliation(s)
- Pinghui Feng
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
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30
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Spencer CT, Dragovic SM, Conant SB, Gray JJ, Zheng M, Samir P, Niu X, Moutaftsi M, Van Kaer L, Sette A, Link AJ, Joyce S. Sculpting MHC class II-restricted self and non-self peptidome by the class I Ag-processing machinery and its impact on Th-cell responses. Eur J Immunol 2013; 43:1162-72. [PMID: 23386199 DOI: 10.1002/eji.201243087] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Revised: 01/02/2013] [Accepted: 01/30/2013] [Indexed: 01/14/2023]
Abstract
It is generally assumed that the MHC class I antigen (Ag)-processing (CAP) machinery - which supplies peptides for presentation by class I molecules - plays no role in class II-restricted presentation of cytoplasmic Ags. In striking contrast to this assumption, we previously reported that proteasome inhibition, TAP deficiency or ERAAP deficiency led to dramatically altered T helper (Th)-cell responses to allograft (HY) and microbial (Listeria monocytogenes) Ags. Herein, we tested whether altered Ag processing and presentation, altered CD4(+) T-cell repertoire, or both underlay the above finding. We found that TAP deficiency and ERAAP deficiency dramatically altered the quality of class II-associated self peptides suggesting that the CAP machinery impacts class II-restricted Ag processing and presentation. Consistent with altered self peptidomes, the CD4(+) T-cell receptor repertoire of mice deficient in the CAP machinery substantially differed from that of WT animals resulting in altered CD4(+) T-cell Ag recognition patterns. These data suggest that TAP and ERAAP sculpt the class II-restricted peptidome, impacting the CD4(+) T-cell repertoire, and ultimately altering Th-cell responses. Together with our previous findings, these data suggest multiple CAP machinery components sequester or degrade MHC class II-restricted epitopes that would otherwise be capable of eliciting functional Th-cell responses.
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Affiliation(s)
- Charles T Spencer
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA.
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31
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Evaluation of viral interference with MHC class I-restricted antigen processing and presentation using a flow cytometry-based approach. Methods Mol Biol 2013. [PMID: 23329483 DOI: 10.1007/978-1-62703-218-6_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
The peptide content of MHC class I molecules present at the cell surface is monitored by surveilling CD8(+) cytotoxic T cells. In case of a viral infection, a proportion of the MHC class I molecules will carry peptides derived from viral proteins. This allows the CD8(+) T cells to recognize and eliminate virus-infected cells. This highly sensitive detection system of the host is counteracted by viruses, which have acquired functions to downregulate cell surface expression of MHC class I molecules. In this chapter, we describe a flow cytometry-based method to identify viral gene product(s) responsible for evasion from MHC class I-restricted antigen presentation. To this end, cells are transiently transfected using polyethylenimine (PEI) as a transfection reagent, followed by cell surface staining with MHC class I-specific monoclonal antibodies. Once viral proteins responsible for MHC class I downregulation have been identified, their mechanism of action can be characterized. Identification and characterization of virus-encoded MHC class I inhibitors augments our understanding of virus-host interactions and often provides new insights into antigen processing and presentation pathways, including related cellular processes such as protein trafficking and degradation.
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32
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Human herpesviridae methods of natural killer cell evasion. Adv Virol 2012; 2012:359869. [PMID: 22829821 PMCID: PMC3399383 DOI: 10.1155/2012/359869] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2012] [Accepted: 04/24/2012] [Indexed: 11/17/2022] Open
Abstract
Human herpesviruses cause diseases of considerable morbidity and mortality, ranging from encephalitis to hematologic malignancies. As evidence emerges about the role of innate immunity and natural killer (NK) cells in the control of herpesvirus infection, evidence of viral methods of innate immune evasion grows as well. These methods include interference with the ligands on infected cell surfaces that bind NK cell activating or inhibitory receptors. This paper summarizes the most extensively studied NK cell receptor/ligand pairs and then describes the methods of NK cell evasion used by all eight herpesviruses through these receptors and ligands. Although great strides have been made in elucidating their mechanisms, there is still a disparity between viruses in the amount of knowledge regarding innate immune evasion. Further research of herpesvirus innate immune evasion can provide insight for circumventing viral mechanisms in future therapies.
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33
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Epstein-Barr virus isolates retain their capacity to evade T cell immunity through BNLF2a despite extensive sequence variation. J Virol 2011; 86:572-7. [PMID: 22013037 DOI: 10.1128/jvi.05151-11] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The Epstein-Barr virus (EBV)-encoded immune evasion protein BNLF2a inhibits the transporter associated with antigen processing (TAP), thereby downregulating HLA class I expression at the cell surface. As a consequence, recognition of EBV-infected cells by cytotoxic T cells is impaired. Here, we show that sequence polymorphism of the BNLF2a protein is observed with natural EBV isolates, with evidence for positive selection. Despite these mutations, the BNLF2a variants efficiently reduce cell surface HLA class I levels. This conservation of BNLF2a function during evolution of EBV implies an important role for the viral TAP inhibitor in preventing T cell recognition during viral infection.
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34
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Wycisk AI, Lin J, Loch S, Hobohm K, Funke J, Wieneke R, Koch J, Skach WR, Mayerhofer PU, Tampé R. Epstein-Barr viral BNLF2a protein hijacks the tail-anchored protein insertion machinery to block antigen processing by the transport complex TAP. J Biol Chem 2011; 286:41402-41412. [PMID: 21984826 DOI: 10.1074/jbc.m111.237784] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Virus-infected cells are eliminated by cytotoxic T lymphocytes, which recognize viral epitopes displayed on major histocompatibility complex class I molecules at the cell surface. Herpesviruses have evolved sophisticated strategies to escape this immune surveillance. During the lytic phase of EBV infection, the viral factor BNLF2a interferes with antigen processing by preventing peptide loading of major histocompatibility complex class I molecules. Here we reveal details of the inhibition mechanism of this EBV protein. We demonstrate that BNLF2a acts as a tail-anchored protein, exploiting the mammalian Asna-1/WRB (Get3/Get1) machinery for posttranslational insertion into the endoplasmic reticulum membrane, where it subsequently blocks antigen translocation by the transporter associated with antigen processing (TAP). BNLF2a binds directly to the core TAP complex arresting the ATP-binding cassette transporter in a transport-incompetent conformation. The inhibition mechanism of EBV BNLF2a is distinct and mutually exclusive of other viral TAP inhibitors.
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Affiliation(s)
- Agnes I Wycisk
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue Str. 9, 60438 Frankfurt, Germany
| | - Jiacheng Lin
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue Str. 9, 60438 Frankfurt, Germany
| | - Sandra Loch
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue Str. 9, 60438 Frankfurt, Germany
| | - Kathleen Hobohm
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue Str. 9, 60438 Frankfurt, Germany
| | - Jessica Funke
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue Str. 9, 60438 Frankfurt, Germany
| | - Ralph Wieneke
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue Str. 9, 60438 Frankfurt, Germany
| | - Joachim Koch
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue Str. 9, 60438 Frankfurt, Germany
| | - William R Skach
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239
| | - Peter U Mayerhofer
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue Str. 9, 60438 Frankfurt, Germany
| | - Robert Tampé
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue Str. 9, 60438 Frankfurt, Germany.
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