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Brüggemann Y, Klöhn M, Wedemeyer H, Steinmann E. Hepatitis E virus: from innate sensing to adaptive immune responses. Nat Rev Gastroenterol Hepatol 2024; 21:710-725. [PMID: 39039260 DOI: 10.1038/s41575-024-00950-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/29/2024] [Indexed: 07/24/2024]
Abstract
Hepatitis E virus (HEV) infections are a major cause of acute viral hepatitis in humans worldwide. In immunocompetent individuals, the majority of HEV infections remain asymptomatic and lead to spontaneous clearance of the virus, and only a minority of individuals with infection (5-16%) experience symptoms of acute viral hepatitis. However, HEV infections can cause up to 30% mortality in pregnant women, become chronic in immunocompromised patients and cause extrahepatic manifestations. A growing body of evidence suggests that the host immune response to infection with different HEV genotypes is a critical determinant of distinct HEV infection outcomes. In this Review, we summarize key components of the innate and adaptive immune responses to HEV, including the underlying immunological mechanisms of HEV associated with acute and chronic liver failure and interactions between T cell and B cell responses. In addition, we discuss the current status of vaccines against HEV and raise outstanding questions regarding the immune responses induced by HEV and treatment of the disease, highlighting areas for future investigation.
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Affiliation(s)
- Yannick Brüggemann
- Department of Molecular and Medical Virology, Ruhr University Bochum, Bochum, Germany
| | - Mara Klöhn
- Department of Molecular and Medical Virology, Ruhr University Bochum, Bochum, Germany
| | - Heiner Wedemeyer
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany
- German Center for Infection Research (DZIF), Partner Sites Hannover-Braunschweig, Hannover, Germany
- Cluster of Excellence RESIST (EXC 2155), Hannover Medical School, Hannover, Germany
| | - Eike Steinmann
- Department of Molecular and Medical Virology, Ruhr University Bochum, Bochum, Germany.
- German Center for Infection Research (DZIF), External Partner Site, Bochum, Germany.
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Csernalabics B, Marinescu MS, Maurer L, Kelsch L, Werner J, Baumann K, Zoldan K, Panning M, Reuken P, Bruns T, Bengsch B, Neumann-Haefelin C, Hofmann M, Thimme R, Dao Thi VL, Boettler T. Efficient formation and maintenance of humoral and CD4 T-cell immunity targeting the viral capsid in acute-resolving hepatitis E infection. J Hepatol 2024; 80:564-575. [PMID: 38154741 DOI: 10.1016/j.jhep.2023.12.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 12/06/2023] [Accepted: 12/11/2023] [Indexed: 12/30/2023]
Abstract
BACKGROUND & AIMS CD4 T cells shape the neutralizing antibody (nAb) response and facilitate viral clearance in various infections. Knowledge of their phenotype, specificity and dynamics in hepatitis E virus (HEV) infection is limited. HEV is enterically transmitted as a naked virus (nHEV) but acquires a host-derived quasi-envelope (eHEV) when budding from cells. While nHEV is composed of the open reading frame (ORF)-2-derived capsid, eHEV particles also contain ORF3-derived proteins. We aimed to longitudinally characterize the HEV-specific CD4 T cells targeting ORF1, 2 and 3 and antibodies against nHEV or eHEV in immunocompetent individuals with acute and resolved HEV infection. METHODS HEV-specific CD4 T cells were analyzed by intracellular cytokine staining after stimulation with in silico-predicted ORF1- and ORF2-derived epitopes and overlapping peptides spanning the ORF3 region. Ex vivo multiparametric characterization of capsid-specific CD4 T cells was performed using customized MHC class II tetramers. Total and neutralizing antibodies targeting nHEV or eHEV particles were determined. RESULTS HEV-specific CD4 T-cell frequencies and antibody titers are highest in individuals with acute infection and decline in a time-dependent process with an antigen hierarchy. HEV-specific CD4 T cells strongly target the ORF2-derived capsid and ORF3-specific CD4 T cells are hardly detectable. NAbs targeting nHEV are found in high titers while eHEV particles are less efficiently neutralized. Capsid-specific CD4 T cells undergo memory formation and stepwise contraction, accompanied by dynamic phenotypical and transcriptional changes over time. CONCLUSION The viral capsid is the main target of HEV-specific CD4 T cells and antibodies in acute-resolving infection, correlating with efficient neutralization of nHEV. Capsid-specific immunity rapidly emerges followed by a stepwise contraction several years after infection. IMPACT AND IMPLICATIONS The interplay of CD4 T cells and neutralizing antibody responses is critical in the host defense against viral infections, yet little is known about their characteristics in hepatitis E virus (HEV) infection. We conducted a longitudinal study of immunocompetent individuals with acute and resolved HEV infection to understand the characteristics of HEV-specific CD4 T cells and neutralizing antibodies targeting different viral proteins and particles. We found that HEV-specific CD4 T cells mainly target capsid-derived epitopes. This correlates with efficient neutralization of naked virions while quasi-enveloped particles are less susceptible to neutralization. As individuals with pre-existing liver disease and immunocompromised individuals are at risk for fulminant or chronic courses of HEV infection, these individuals might benefit from the development of vaccination strategies which require a detailed knowledge of the composition and longevity of HEV-specific CD4 T-cell and antibody immunity.
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Affiliation(s)
- Benedikt Csernalabics
- Department of Medicine II, Medical Center - University of Freiburg, Germany; Faculty of Medicine, University of Freiburg, Germany
| | - Mircea Stefan Marinescu
- Department of Medicine II, Medical Center - University of Freiburg, Germany; Faculty of Medicine, University of Freiburg, Germany
| | - Lars Maurer
- Schaller Research Group, Department of Infectious Diseases and Virology, Heidelberg University Hospital, Germany
| | - Lara Kelsch
- Department of Medicine II, Medical Center - University of Freiburg, Germany; Faculty of Medicine, University of Freiburg, Germany
| | - Jill Werner
- Department of Medicine II, Medical Center - University of Freiburg, Germany; Faculty of Medicine, University of Freiburg, Germany
| | - Katharina Baumann
- Department of Medicine II, Medical Center - University of Freiburg, Germany; Faculty of Medicine, University of Freiburg, Germany
| | - Katharina Zoldan
- Department of Medicine II, Medical Center - University of Freiburg, Germany; Faculty of Medicine, University of Freiburg, Germany
| | - Marcus Panning
- Institute of Virology, University Hospital Freiburg, Germany
| | - Philipp Reuken
- Department of Internal Medicine IV, University Hospital Jena, Germany
| | - Tony Bruns
- Department of Internal Medicine IV, University Hospital Jena, Germany; Department of Internal Medicine III, University Hospital RWTH Aachen, Germany
| | - Bertram Bengsch
- Department of Medicine II, Medical Center - University of Freiburg, Germany; Faculty of Medicine, University of Freiburg, Germany; Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Christoph Neumann-Haefelin
- Department of Medicine II, Medical Center - University of Freiburg, Germany; Faculty of Medicine, University of Freiburg, Germany
| | - Maike Hofmann
- Department of Medicine II, Medical Center - University of Freiburg, Germany; Faculty of Medicine, University of Freiburg, Germany
| | - Robert Thimme
- Department of Medicine II, Medical Center - University of Freiburg, Germany; Faculty of Medicine, University of Freiburg, Germany
| | - Viet Loan Dao Thi
- Schaller Research Group, Department of Infectious Diseases and Virology, Heidelberg University Hospital, Germany; German Centre for Infection Research (DZIF), Partner Site Heidelberg, Heidelberg, Germany
| | - Tobias Boettler
- Department of Medicine II, Medical Center - University of Freiburg, Germany; Faculty of Medicine, University of Freiburg, Germany.
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Lang-Meli J, Neumann-Haefelin C, Thimme R. Targeting virus-specific CD8+ T cells for treatment of chronic viral hepatitis: from bench to bedside. Expert Opin Biol Ther 2024; 24:77-89. [PMID: 38290716 DOI: 10.1080/14712598.2024.2313112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 01/29/2024] [Indexed: 02/01/2024]
Abstract
INTRODUCTION More than 350 million people worldwide live with chronic viral hepatitis and are thus at risk for severe complications like liver cirrhosis and hepatocellular carcinoma (HCC). To meet the goals of the World Health Organization (WHO) global hepatitis strategy, there is an urgent need for new immunotherapeutic approaches. These are particularly required for chronic hepatitis B virus infection and - B/D coinfection. AREAS COVERED This review summarizes data on mechanisms of CD8+ T cells failure in chronic hepatitis B, D, C and E virus infection. The relative contribution of the different concepts (viral escape, CD8+ T cell exhaustion, defective priming) will be discussed. On this basis, examples for future therapeutic approaches targeting virus-specific CD8+ T cells for the individual hepatitis viruses will be discussed. EXPERT OPINION Immunotherapeutic approaches targeting virus-specific CD8+ T cells have the potential to change clinical practice, especially in chronic hepatitis B virus infection. Further clinical development, however, requires a more detailed understanding of T cell immunology in chronic viral hepatitis. Some important conceptual questions remain to be addressed, e.g. regarding heterogeneity of exhausted virus-specific CD8+ T cells.
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Affiliation(s)
- Julia Lang-Meli
- Department of Medicine II, Medical Center - University of Freiburg and Faculty of Medicine, University Hospital Freiburg, Freiburg, Germany
- IMM-PACT Programm, Faculty of Medicine, University Hospital Freiburg, Freiburg, Germany
| | - Christoph Neumann-Haefelin
- Department of Medicine II, Medical Center - University of Freiburg and Faculty of Medicine, University Hospital Freiburg, Freiburg, Germany
| | - Robert Thimme
- Department of Medicine II, Medical Center - University of Freiburg and Faculty of Medicine, University Hospital Freiburg, Freiburg, Germany
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Al-Eitan L, Alnemri M, Alkhawaldeh M, Mihyar A. Rodent-borne viruses in the region of Middle East. Rev Med Virol 2023:e2440. [PMID: 36924105 DOI: 10.1002/rmv.2440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 02/22/2023] [Accepted: 03/02/2023] [Indexed: 03/18/2023]
Abstract
Rodents are one of the most abundant mammal species in the world. They form more than two-fifth of all mammal species and there are approximately 4600 existing rodent species. Rodents are capable of transmitting deadly diseases, especially those that are caused by viruses. Viruses and their consequences have plagued the world for the last two centuries, three pandemics occurred during the last century only. The Middle East is situated at the crossroads of Africa and Asia, along with the Mediterranean Sea and the Indian Ocean, its geographic importance is gained through the diversity of topographies, biosphere, as well as climate aspects that make the region vulnerable to host emerging diseases. Refugee crises also play a major role in expected epidemic outbreaks in the region. Public health has always been the most important priority, and our aim in this review is to raise awareness among public health organisations across the Middle East about the dangers of rodent borne diseases that have been reported or are suspected to be found in the region.
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Affiliation(s)
- Laith Al-Eitan
- Department of Biotechnology and Genetic Engineering, Jordan University of Science and Technology, Irbid, Jordan
| | - Malek Alnemri
- Department of Biotechnology and Genetic Engineering, Jordan University of Science and Technology, Irbid, Jordan
| | - Mishael Alkhawaldeh
- Department of Biotechnology and Genetic Engineering, Jordan University of Science and Technology, Irbid, Jordan
| | - Ahmad Mihyar
- Department of Biotechnology and Genetic Engineering, Jordan University of Science and Technology, Irbid, Jordan
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Zhou YH, Zhao H. Immunobiology and Host Response to HEV. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1417:93-118. [PMID: 37223861 DOI: 10.1007/978-981-99-1304-6_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Hepatitis E virus (HEV) usually causes acute self-limiting hepatitis but sometimes leads to chronic infection in immunocompromised persons. HEV is not directly cytopathic. Immunologically mediated events after HEV infection are believed to play important roles in the pathogenesis and clearance of infection. The anti-HEV antibody responses have been largely clarified since the determination of major antigenic determinant of HEV, which is located in the C-terminal portion of ORF2. This major antigenic determinant also forms the conformational neutralization epitopes. Robust anti-HEV immunoglobulin M (IgM) and IgG responses usually develop 3-4 weeks after infection in experimentally infected nonhuman primates. In humans, potent specific IgM and IgG responses occur in the very early phase of the disease and are critical in eliminating the virus, in concert with the innate and adaptive T-cell immune responses. Testing anti-HEV IgM is valuable in the diagnosis of acute hepatitis E. The long-term persistence and protection of anti-HEV IgG provide the basis for estimating the prevalence of HEV infection and for the development of a hepatitis E vaccine. Although human HEV has four genotypes, all the viral strains are considered to belong to a single serotype. It is becoming increasingly clear that the innate and adaptive T-cell immune responses play critical roles in the clearance of the virus. Potent and multispecific CD4+ and CD8+ T cell responses to the ORF2 protein occur in patients with acute hepatitis E, and weaker HEV-specific CD4+ and CD8+ T cell responses appear to be associated with chronic hepatitis E in immunocompromised individuals.
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Affiliation(s)
- Yi-Hua Zhou
- Departments of Experimental Medicine and Infectious Diseases, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Hong Zhao
- Department of Infectious Diseases, Second Hospital of Nanjing, Southeast University School of Medicine, Nanjing, China
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Ma Z, de Man RA, Kamar N, Pan Q. Chronic hepatitis E: Advancing research and patient care. J Hepatol 2022; 77:1109-1123. [PMID: 35605741 DOI: 10.1016/j.jhep.2022.05.006] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 05/08/2022] [Accepted: 05/10/2022] [Indexed: 12/15/2022]
Abstract
The hepatitis E virus (HEV) was initially thought to exclusively cause acute hepatitis. However, the first diagnosis of chronic hepatitis E in transplant recipients in 2008 profoundly changed our understanding of this pathogen. We have now begun to understand that specific HEV genotypes can cause chronic infection in certain immunocompromised populations. Over the past decade, dedicated clinical and experimental research has substantiated knowledge on the epidemiology, transmission routes, pathophysiological mechanisms, diagnosis, clinical features and treatment of chronic HEV infection. Nevertheless, many gaps and major challenges remain, particularly regarding the translation of knowledge into disease prevention and improvement of clinical outcomes. This article aims to highlight the latest developments in the understanding and management of chronic hepatitis E. More importantly, we attempt to identify major knowledge gaps and discuss strategies for further advancing both research and patient care.
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Affiliation(s)
- Zhongren Ma
- Biomedical Research Center, Northwest Minzu University, Lanzhou, China
| | - Robert A de Man
- Department of Gastroenterology and Hepatology, Erasmus MC-University Medical Center, Rotterdam, the Netherlands
| | - Nassim Kamar
- Department of Nephrology, Dialysis and Organ Transplantation, CHU Rangueil, INSERM UMR 1291, Toulouse Institute for Infectious and Inflammatory Disease (Infinity), University Paul Sabatier, Toulouse, France
| | - Qiuwei Pan
- Department of Gastroenterology and Hepatology, Erasmus MC-University Medical Center, Rotterdam, the Netherlands.
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Kemming J, Gundlach S, Panning M, Huzly D, Huang J, Lütgehetmann M, Pischke S, Schulze Zur Wiesch J, Emmerich F, Llewellyn-Lacey S, Price DA, Tanriver Y, Warnatz K, Boettler T, Thimme R, Hofmann M, Fischer N, Neumann-Haefelin C. Mechanisms of CD8+ T-cell failure in chronic hepatitis E virus infection. J Hepatol 2022; 77:978-990. [PMID: 35636577 DOI: 10.1016/j.jhep.2022.05.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 05/11/2022] [Accepted: 05/16/2022] [Indexed: 01/19/2023]
Abstract
BACKGROUND & AIMS In immunosuppressed patients, persistent HEV infection is common and may lead to cirrhosis and liver failure. HEV clearance depends on an effective virus-specific CD8+ T-cell response; however, the knowledge gap around HEV-specific CD8+ T-cell epitopes has hindered analysis of the mechanisms of T-cell failure in persistent infection. METHODS We comprehensively studied HEV-specific CD8+ T-cell responses in 46 patients with self-limiting (n = 34) or chronic HEV infection (n = 12), by epitope-specific expansion, functional testing, ex vivo peptide HLA class I tetramer multi-parametric staining, and viral sequence analysis. RESULTS We identified 25 HEV-specific CD8+ T-cell epitopes restricted by 9 different HLA class I alleles. In self-limiting HEV infection, HEV-specific CD8+ T cells were vigorous, contracted after resolution of infection, and formed functional memory responses. In contrast, in chronic infection, the HEV-specific CD8+ T-cell response was diminished, declined over time, and displayed phenotypic features of exhaustion. However, improved proliferation of HEV-specific CD8+ T cells, increased interferon-γ production and evolution of a memory-like phenotype were observed upon reduction of immunosuppression and/or ribavirin treatment and were associated with viral clearance. In 1 patient, mutational viral escape in a targeted CD8+ T-cell epitope contributed to CD8+ T-cell failure. CONCLUSION Chronic HEV infection is associated with HEV-specific CD8+ T-cell exhaustion, indicating that T-cell exhaustion driven by persisting antigen recognition also occurs in severely immunosuppressed hosts. Functional reinvigoration of virus-specific T cells is at least partially possible when antigen is cleared. In a minority of patients, viral escape also contributes to HEV-specific CD8+ T-cell failure and thus needs to be considered in personalized immunotherapeutic approaches. LAY SUMMARY Hepatitis E virus (HEV) infection is usually cleared spontaneously (without treatment) in patients with fully functioning immune systems. In immunosuppressed patients, chronic HEV infection is common and can progress rapidly to cirrhosis and liver failure. Herein, we identified the presence of HEV-specific CD8+ T cells (a specific type of immune cell that can target HEV) in immunosuppressed patients, but we show that these cells do not function properly. This dysfunction appears to play a role in the development of chronic HEV infection in vulnerable patients.
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Affiliation(s)
- Janine Kemming
- Department of Medicine II (Gastroenterology, Hepatology, Endocrinology and Infectious Diseases), Freiburg University Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany; Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Swantje Gundlach
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany; German Center for Infection Research (DZIF), Hamburg-Lübeck-Borstel-Riems, Germany
| | - Marcus Panning
- Institute of Virology, Freiburg University Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Daniela Huzly
- Institute of Virology, Freiburg University Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Jiabin Huang
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany; German Center for Infection Research (DZIF), Hamburg-Lübeck-Borstel-Riems, Germany
| | - Marc Lütgehetmann
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany; German Center for Infection Research (DZIF), Hamburg-Lübeck-Borstel-Riems, Germany
| | - Sven Pischke
- German Center for Infection Research (DZIF), Hamburg-Lübeck-Borstel-Riems, Germany; Institute of Virology, Freiburg University Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Julian Schulze Zur Wiesch
- German Center for Infection Research (DZIF), Hamburg-Lübeck-Borstel-Riems, Germany; Department of Medicine, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | - Florian Emmerich
- Institute for Transfusion Medicine and Gene Therapy, Freiburg University Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Sian Llewellyn-Lacey
- Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff, United Kingdom
| | - David A Price
- Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff, United Kingdom; Systems Immunity Research Institute, Cardiff University School of Medicine, Cardiff, United Kingdom
| | - Yakup Tanriver
- Department of Medicine IV (Nephrology and Primary Care), Freiburg University Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Klaus Warnatz
- Department of Rheumatology and Clinical Immunology, Freiburg University Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Tobias Boettler
- Department of Medicine II (Gastroenterology, Hepatology, Endocrinology and Infectious Diseases), Freiburg University Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Robert Thimme
- Department of Medicine II (Gastroenterology, Hepatology, Endocrinology and Infectious Diseases), Freiburg University Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Maike Hofmann
- Department of Medicine II (Gastroenterology, Hepatology, Endocrinology and Infectious Diseases), Freiburg University Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Nicole Fischer
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany; German Center for Infection Research (DZIF), Hamburg-Lübeck-Borstel-Riems, Germany
| | - Christoph Neumann-Haefelin
- Department of Medicine II (Gastroenterology, Hepatology, Endocrinology and Infectious Diseases), Freiburg University Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
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Bremer W, Blasczyk H, Yin X, Duron ES, Grakoui A, Feng Z, Walker C. Resolution of hepatitis E virus infection in CD8+ T cell-depleted rhesus macaques. J Hepatol 2021; 75:557-564. [PMID: 33961939 PMCID: PMC8603813 DOI: 10.1016/j.jhep.2021.04.036] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 04/15/2021] [Accepted: 04/16/2021] [Indexed: 01/14/2023]
Abstract
BACKGROUND & AIMS HEV is a significant cause of acute hepatitis globally. Some genotypes establish persistent infection when immunity is impaired. Adaptive immune mechanisms that mediate resolution of infection have not been identified. Herein, the requirement for CD8+ T cells to control HEV infection was assessed in rhesus macaques, a model of acute and persistent HEV infection in humans. METHODS Rhesus macaques were untreated or treated with depleting anti-CD8α monoclonal antibodies before challenge with an HEV genotype (gt)3 isolate derived from a chronically infected human patient. HEV replication, alanine aminotransferase, anti-capsid antibody and HEV-specific CD4+ and CD8+ T cell responses were assessed after infection. RESULTS HEV control in untreated macaques coincided with the onset of a neutralizing IgG response against the ORF2 capsid and liver infiltration of functional HEV-specific CD4+ and CD8+ T cells. Virus control was delayed by 1 week in CD8+ T cell-depleted macaques. Infection resolved with onset of a neutralizing IgG antibody response and a much more robust expansion of CD4+ T cells with antiviral effector function. CONCLUSIONS Liver infiltration of functional CD8+ T cells coincident with HEV clearance in untreated rhesus macaques, and a 1-week delay in HEV clearance in CD8+ T cell-depleted rhesus macaques, support a role for this subset in timely control of virus replication. Resolution of infection in the absence of CD8+ T cells nonetheless indicates that neutralizing antibodies and/or CD4+ T cells may act autonomously to inhibit HEV replication. HEV susceptibility to multiple adaptive effector mechanisms may explain why persistence occurs only with generalized immune suppression. The findings also suggest that neutralizing antibodies and/or CD4+ T cells should be considered as a component of immunotherapy for chronic infection. LAY SUMMARY The hepatitis E virus (HEV) is a major cause of liver disease globally. Some genetic types (genotypes) of HEV persist in the body if immunity is impaired. Our objective was to identify immune responses that promote clearance of HEV. Findings indicate that HEV may be susceptible to multiple arms of the immune response that can act independently to terminate infection. They also provide a pathway to assess immune therapies for chronic HEV infection.
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Affiliation(s)
- William Bremer
- Center for Vaccines and Immunity, The Research Institute at Nationwide Children’s, 700 Children’s Drive, Columbus, OH, USA
| | - Heather Blasczyk
- Center for Vaccines and Immunity, The Research Institute at Nationwide Children’s, 700 Children’s Drive, Columbus, OH, USA
| | - Xin Yin
- Center for Vaccines and Immunity, The Research Institute at Nationwide Children’s, 700 Children’s Drive, Columbus, OH, USA
| | - Eduardo Salinas Duron
- Division of Microbiology and Immunology, Emory Vaccine Center and Emory University School of Medicine, Atlanta, GA, USA
| | - Arash Grakoui
- Division of Microbiology and Immunology, Emory Vaccine Center and Emory University School of Medicine, Atlanta, GA, USA
| | - Zongdi Feng
- Center for Vaccines and Immunity, The Research Institute at Nationwide Children’s, 700 Children’s Drive, Columbus, OH, USA.,Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Christopher Walker
- Center for Vaccines and Immunity, The Research Institute at Nationwide Children's, 700 Children's Drive, Columbus, OH, USA; Division of Microbiology and Immunology, Emory Vaccine Center and Emory University School of Medicine, Atlanta, GA, USA.
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El Costa H, Gouilly J, Abravanel F, Bahraoui E, Peron JM, Kamar N, Jabrane-Ferrat N, Izopet J. Effector memory CD8 T cell response elicits Hepatitis E Virus genotype 3 pathogenesis in the elderly. PLoS Pathog 2021; 17:e1009367. [PMID: 33617602 PMCID: PMC7932504 DOI: 10.1371/journal.ppat.1009367] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 03/04/2021] [Accepted: 02/09/2021] [Indexed: 12/17/2022] Open
Abstract
Genotype 3 Hepatitis E virus (HEV-3) is an emerging threat for aging population. More than one third of older infected patients develops clinical symptoms with severe liver damage, while others remain asymptomatic. The origin of this discrepancy is still elusive although HEV-3 pathogenesis appears to be immune-mediated. Therefore, we investigated the role of CD8 T cells in the outcome of the infection in immunocompetent elderly subjects. We enrolled twenty two HEV-3-infected patients displaying similar viral determinants and fifteen healthy donors. Among the infected group, sixteen patients experienced clinical symptoms related to liver disease while six remained asymptomatic. Here we report that symptomatic infection is characterized by an expansion of highly activated effector memory CD8 T (EM) cells, regardless of antigen specificity. This robust activation is associated with key features of early T cell exhaustion including a loss in polyfunctional type-1 cytokine production and partial commitment to type-2 cells. In addition, we show that bystander activation of EM cells seems to be dependent on the inflammatory cytokines IL-15 and IL-18, and is supported by an upregulation of the activating receptor NKG2D and an exuberant expression of T-Bet and T-Bet-regulated genes including granzyme B and CXCR3. We also show that the inflammatory chemokines CXCL9-10 are increased in symptomatic patients thereby fostering the recruitment of highly cytotoxic EM cells into the liver in a CXCR3-dependent manner. Finally, we find that the EM-biased immune response returns to homeostasis following viral clearance and disease resolution, further linking the EM cells response to viral burden. Conversely, asymptomatic patients are endowed with low-to-moderate EM cell response. In summary, our findings define immune correlates that contribute to HEV-3 pathogenesis and emphasize the central role of EM cells in governing the outcome of the infection. The outcome of Genotype 3 Hepatitis E virus (HEV-3) infection differs among the elderly. Some patients develop severe forms of Hepatitis E while others remain asymptomatic. Nonetheless, parameters which can lead to severe versus silent infection are largely unknown. Therefore, we investigated immunological features of CD8 T cells in infected patients (aged ≥55) with similar viral determinants but distinct clinical outcomes. We show that drastic phenotypic changes were specifically observed within the effector memory (EM) compartment. Compared to asymptomatic patients, symptomatic ones display a strong activation of both HEV-3-specific and -nonspecific EM CD8 T cells associated with qualitative and quantitative alterations in cytokine production. In addition, EM cells are endowed with high cytotoxic capacity and have the ability to rapidly migrate to the liver. Finally, we report that the inflammatory response to HEV-3 infection shape EM cell activation and function in symptomatic elderly patients. In summary, our results present the first report demonstrating that the nature and the magnitude of EM CD8 T cell response play an important role in the outcome of HEV-3 infection in the elderly.
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Affiliation(s)
- Hicham El Costa
- Infinity—Université Toulouse, CNRS, Inserm, Toulouse, France
- Laboratoire de Virologie, Centre National de référence HEV, Institut Fédératif de Biologie, CHU Toulouse, Toulouse, France
- * E-mail:
| | - Jordi Gouilly
- Infinity—Université Toulouse, CNRS, Inserm, Toulouse, France
| | - Florence Abravanel
- Infinity—Université Toulouse, CNRS, Inserm, Toulouse, France
- Laboratoire de Virologie, Centre National de référence HEV, Institut Fédératif de Biologie, CHU Toulouse, Toulouse, France
| | | | - Jean-Marie Peron
- Département de Gastroentérologie, CHU Toulouse, Toulouse, France
| | - Nassim Kamar
- Infinity—Université Toulouse, CNRS, Inserm, Toulouse, France
| | | | - Jacques Izopet
- Infinity—Université Toulouse, CNRS, Inserm, Toulouse, France
- Laboratoire de Virologie, Centre National de référence HEV, Institut Fédératif de Biologie, CHU Toulouse, Toulouse, France
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10
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Joshi SS, Davis RP, Ma MM, Tam E, Cooper CL, Ramji A, Kelly EM, Jayakumar S, Swain MG, Jenne CN, Coffin CS. Reduced immune responses to hepatitis B primary vaccination in obese individuals with nonalcoholic fatty liver disease (NAFLD). NPJ Vaccines 2021; 6:9. [PMID: 33431890 PMCID: PMC7801497 DOI: 10.1038/s41541-020-00266-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 12/02/2020] [Indexed: 02/06/2023] Open
Abstract
Obesity and cirrhosis are associated with poor hepatitis B virus (HBV) vaccine responses, but vaccine efficacy has not been assessed in nonalcoholic fatty liver disease (NAFLD). Sixty-eight HBV-naïve adults with NAFLD were enrolled through the Canadian HBV network and completed three-dose HBV or HBV/HAV vaccine (Engerix-B®, or Twinrix®, GlaxoSmithKline). Anti-HBs titers were measured at 1-3 months post third dose. In 31/68 subjects enrolled at the coordinating-site, T-cell proliferation and follicular T-helper cells (pTFH) were assessed using PBMC. Immune response was also studied in NAFLD mice. NAFLD patients were stratified as low-risk-obesity, BMI < 35 (N = 40) vs. medium-high-risk obesity, BMI > 35 (N = 28). Anti-HBs titers were lower in medium/high-risk obesity, 385 IU/L ± 79 vs. low-risk obesity class, 642 IU/L ± 68.2, p = 0.02. High-risk obesity cases, N = 14 showed lower vaccine-specific-CD3+ CD4+ T-cell response compared to low-risk obesity patients, N = 17, p = 0.02. Low vaccine responders showed dysfunctional pTFH. NAFLD mice showed lower anti-HBs levels and T-cell response vs. controls. In conclusion, we report here that obese individuals with NAFLD exhibit decreased HBV vaccine-specific immune responses.
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Affiliation(s)
- Shivali S Joshi
- Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Rachelle P Davis
- Department of Microbiology, Immunology & Infectious Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Mang M Ma
- University of Alberta, Edmonton, AB, Canada
| | - Edward Tam
- Pacific Gastroenterology Associates, Vancouver, BC, Canada
| | | | - Alnoor Ramji
- Division of Gastroenterology, University of British Columbia, Vancouver, BC, Canada
| | - Erin M Kelly
- Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - Saumya Jayakumar
- Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- University of British Columbia, Vancouver, BC, Canada
| | - Mark G Swain
- Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Craig N Jenne
- Department of Microbiology, Immunology & Infectious Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Carla S Coffin
- Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.
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11
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Lhomme S, Marion O, Abravanel F, Izopet J, Kamar N. Clinical Manifestations, Pathogenesis and Treatment of Hepatitis E Virus Infections. J Clin Med 2020; 9:E331. [PMID: 31991629 PMCID: PMC7073673 DOI: 10.3390/jcm9020331] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 01/14/2020] [Accepted: 01/22/2020] [Indexed: 02/07/2023] Open
Abstract
Hepatitis E virus (HEV) is the most common cause of acute viral hepatitis throughout the world. Most infections are acute but they can become chronic in immunocompromised patients, such as solid organ transplant patients, patients with hematologic malignancy undergoing chemotherapy and those with a human immunodeficiency virus (HIV) infection. Extra-hepatic manifestations, especially neurological and renal diseases, have also been described. To date, four main genotypes of HEV (HEV1-4) were described. HEV1 and HEV2 only infect humans, while HEV3 and HEV4 can infect both humans and animals, like pigs, wild boar, deer and rabbits. The real epidemiology of HEV has been underestimated because most infections are asymptomatic. This review focuses on the recent advances in our understanding of the pathophysiology of acute HEV infections, including severe hepatitis in patients with pre-existing liver disease and pregnant women. It also examines the mechanisms leading to chronic infection in immunocompromised patients and extra-hepatic manifestations. Acute infections are usually self-limiting and do not require antiviral treatment. Conversely, a chronic HEV infection can be cleared by decreasing the dose of immunosuppressive drugs or by treating with ribavirin for 3 months. Nevertheless, new drugs are needed for those cases in which ribavirin treatment fails.
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Affiliation(s)
- Sébastien Lhomme
- Virology Laboratory, National Reference Center for Hepatitis E Virus, Toulouse Purpan University Hospital, 31300 Toulouse, France; (F.A.); (J.I.)
- INSERM UMR1043, Center for Pathophysiology of Toulouse Purpan, 31300 Toulouse, France;
- Université Toulouse III Paul Sabatier, 31330 Toulouse, France
| | - Olivier Marion
- INSERM UMR1043, Center for Pathophysiology of Toulouse Purpan, 31300 Toulouse, France;
- Université Toulouse III Paul Sabatier, 31330 Toulouse, France
- Department of Nephrology and Organs Transplantation, Toulouse Rangueil University Hospital, 31400 Toulouse, France
| | - Florence Abravanel
- Virology Laboratory, National Reference Center for Hepatitis E Virus, Toulouse Purpan University Hospital, 31300 Toulouse, France; (F.A.); (J.I.)
- INSERM UMR1043, Center for Pathophysiology of Toulouse Purpan, 31300 Toulouse, France;
- Université Toulouse III Paul Sabatier, 31330 Toulouse, France
| | - Jacques Izopet
- Virology Laboratory, National Reference Center for Hepatitis E Virus, Toulouse Purpan University Hospital, 31300 Toulouse, France; (F.A.); (J.I.)
- INSERM UMR1043, Center for Pathophysiology of Toulouse Purpan, 31300 Toulouse, France;
- Université Toulouse III Paul Sabatier, 31330 Toulouse, France
| | - Nassim Kamar
- INSERM UMR1043, Center for Pathophysiology of Toulouse Purpan, 31300 Toulouse, France;
- Université Toulouse III Paul Sabatier, 31330 Toulouse, France
- Department of Nephrology and Organs Transplantation, Toulouse Rangueil University Hospital, 31400 Toulouse, France
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12
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Neumann-Haefelin C. Paving the way for T cell-based immunotherapies in chronic hepatitis E. J Hepatol 2019; 71:648-650. [PMID: 31447222 DOI: 10.1016/j.jhep.2019.07.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Revised: 07/16/2019] [Accepted: 07/21/2019] [Indexed: 12/18/2022]
Affiliation(s)
- Christoph Neumann-Haefelin
- Department of Medicine II, University Hospital Freiburg, Medical Faculty, University of Freiburg, Germany.
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13
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Soon CF, Behrendt P, Todt D, Manns MP, Wedemeyer H, Sällberg Chen M, Cornberg M. Defining virus-specific CD8+ TCR repertoires for therapeutic regeneration of T cells against chronic hepatitis E. J Hepatol 2019; 71:673-684. [PMID: 31203151 DOI: 10.1016/j.jhep.2019.06.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 05/24/2019] [Accepted: 06/05/2019] [Indexed: 12/24/2022]
Abstract
BACKGROUND & AIMS Immunosuppressed patients with chronic hepatitis E virus infection (cHEV), who are ineligible or have failed current treatment with off-label ribavirin, are a potential target population for T cell-based therapy. T cell responses are important for viral control. Herein, we aimed to identify human leukocyte antigen (HLA)-A2 restricted HEV-specific CD8+ T cell epitopes and T cell receptors (TCR) targeting these epitopes, as the basis for a redirected TCR treatment approach for patients with cHEV. METHODS HEV genotype 3 overlapping peptide pools were used to screen HEV-specific CD8+ T cell immune responses in HLA-A2+ patients with acute HEV infection and healthy donors, by intracellular cytokine staining. CD8+ T cells targeting the identified epitopes were sorted for sequencing of the TCR repertoires by next generation sequencing. Messenger RNA encoding these TCRs were introduced into lymphocytes of healthy donors and patients with cHEV through TCR redirection. TCR-engineered lymphocytes were evaluated for Dextramer®-binding capacity, target sensitivity and cytotoxicity against peptide-loaded T2 cells. RESULTS HEV-specific responses were observed across open reading frame (ORF)1 and ORF2 of the HEV genome in patients with acute resolving HEV infection. HLA-A2-restricted HEV-specific CD8+ T cell epitopes targeting the HEV RNA helicase and RNA-dependent RNA polymerase were selected for functional studies. Introduction of HEV-specific TCRs into lymphocytes of immunocompetent donors and patients with chronic hepatitis E enabled the lymphocytes to bind HEV Dextramers, secrete multiple cytokines and exert cytotoxicity in a target-specific manner. CONCLUSION We identified TCRs that target HEV-specific CD8+ T cell epitopes, and characterized their immune properties, which may have clinical potential in future T cell-based therapy. LAY SUMMARY Patients who are immunosuppressed are vulnerable to developing chronic liver disease following infection with hepatitis E virus (HEV). To-date, there is no approved therapy for chronic hepatitis E. Interferon-α and ribavirin are off-label treatment options, but their applications are limited by side effects. Thus, immunotherapy, more specifically T cell-based therapy, may be an alternative approach. We designed T cell receptor-engineered T cells that effectively conferred immune cells, taken from patients with chronic hepatitis E, with the ability to recognize virus-specific epitopes and mediate killing of target cells in vitro.
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Affiliation(s)
- Chai Fen Soon
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany
| | - Patrick Behrendt
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany; German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Germany; Institute for Experimental Virology, TWINCORE Centre for Experimental and Clinical Infection Research, Germany
| | - Daniel Todt
- Department for Molecular and Medical Virology, Ruhr-Universität Bochum, Bochum, Germany
| | - Michael Peter Manns
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany
| | - Heiner Wedemeyer
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany; German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Germany; Department of Gastroenterology and Hepatology, University Clinic Essen, Essen, Germany
| | - Margaret Sällberg Chen
- Department of Dental Medicine and Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden; Shanghai Tenth People's Hospital, Tongji University, Shanghai, China
| | - Markus Cornberg
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany; German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Germany; Centre for Individualised Infection Medicine (CIIM), Hannover, Germany; Helmholtz Centre for Infection Research (HZI), Braunschweig, Germany.
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14
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Walker CM. Adaptive Immune Responses in Hepatitis A Virus and Hepatitis E Virus Infections. Cold Spring Harb Perspect Med 2019; 9:cshperspect.a033472. [PMID: 29844218 DOI: 10.1101/cshperspect.a033472] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Both hepatitis A virus (HAV) and hepatitis E virus (HEV) cause self-limited infections in humans that are preventable by vaccination. Progress in characterizing adaptive immune responses against these enteric hepatitis viruses, and how they contribute to resolution of infection or liver injury, has therefore remained largely frozen for the past two decades. How HAV and HEV infections are so effectively controlled by B- and T-cell immunity, and why they do not have the same propensity to persist as HBV and HCV infections, cannot yet be adequately explained. The objective of this review is to summarize our understanding of the relationship between patterns of virus replication, adaptive immune responses, and acute liver injury in HAV and HEV infections. Gaps in knowledge, and recent studies that challenge long-held concepts of how antibodies and T cells contribute to control and pathogenesis of HAV and HEV infections, are highlighted.
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Affiliation(s)
- Christopher M Walker
- Center for Vaccines and Immunity, The Research Institute at Nationwide Children's, Columbus, Ohio 43004
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15
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Rogers E, Todd SM, Pierson FW, Kenney SP, Heffron CL, Yugo DM, Matzinger SR, Mircoff E, Ngo I, Kirby C, Jones M, Siegel P, Jobst P, Hall K, Etches RJ, Meng XJ, LeRoith T. CD8 + lymphocytes but not B lymphocytes are required for protection against chronic hepatitis E virus infection in chickens. J Med Virol 2019; 91:1960-1969. [PMID: 31317546 DOI: 10.1002/jmv.25548] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 07/09/2019] [Indexed: 12/12/2022]
Abstract
Hepatitis E is an important global disease, causing outbreaks of acute hepatitis in many developing countries and sporadic cases in industrialized countries. Hepatitis E virus (HEV) infection typically causes self-limiting acute hepatitis but can also progress to chronic disease in immunocompromised individuals. The immune response necessary for the prevention of chronic infection is T cell-dependent; however, the arm of cellular immunity responsible for this protection is not currently known. To investigate the contribution of humoral immunity in control of HEV infection and prevention of chronicity, we experimentally infected 20 wild-type (WT) and 18 immunoglobulin knockout (JH-KO) chickens with a chicken strain of HEV (avian HEV). Four weeks postinfection (wpi) with avian HEV, JH-KO chickens were unable to elicit anti-HEV antibody but had statistically significantly lower liver lesion scores than the WT chickens. At 16 wpi, viral RNA in fecal material and liver, and severe liver lesions were undetectable in both groups. To determine the role of cytotoxic lymphocytes in the prevention of chronicity, we infected 20 WT and 20 cyclosporine and CD8+ antibody-treated chickens with the same strain of avian HEV. The CD8 + lymphocyte-depleted, HEV-infected chickens had higher incidences of prolonged fecal viral shedding and statistically significantly higher liver lesion scores than the untreated, HEV-infected birds at 16 wpi. The results indicate that CD8 + lymphocytes are required for viral clearance and reduction of liver lesions in HEV infection while antibodies are not necessary for viral clearance but may contribute to the development of liver lesions in acute HEV infection.
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Affiliation(s)
- Eda Rogers
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
| | - Stephanie Michelle Todd
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
| | - Frank William Pierson
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
| | - Scott P Kenney
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
| | - Connie Lynn Heffron
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
| | - Danielle M Yugo
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
| | - Shannon R Matzinger
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
| | - Elena Mircoff
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
| | - Irene Ngo
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
| | - Charles Kirby
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
| | - Michaela Jones
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
| | - Paul Siegel
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
| | - Peter Jobst
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
| | - Karen Hall
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
| | | | - Xiang-Jin Meng
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
| | - Tanya LeRoith
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
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16
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Harrison L, DiCaprio E. Hepatitis E Virus: An Emerging Foodborne Pathogen. FRONTIERS IN SUSTAINABLE FOOD SYSTEMS 2018. [DOI: 10.3389/fsufs.2018.00014] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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