201
|
Ait-goughoulte M, Lucifora J, Zoulim F, Durantel D. Innate antiviral immune responses to hepatitis B virus. Viruses 2010; 2:1394-1410. [PMID: 21994686 PMCID: PMC3185716 DOI: 10.3390/v2071394] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2010] [Revised: 06/22/2010] [Accepted: 07/01/2010] [Indexed: 02/06/2023] Open
Abstract
Hepatitis B virus (HBV) is a major cause of acute and chronic hepatitis in humans. As HBV itself is currently viewed as a non-cytopathic virus, the liver pathology associated with hepatitis B is mainly thought to be due to immune responses directed against HBV antigens. The outcome of HBV infection is the result of complex interactions between replicating HBV and the immune system. While the role of the adaptive immune response in the resolution of HBV infection is well understood, the contribution of innate immune mechanisms remains to be clearly defined. The innate immune system represents the first line of defense against viral infection, but its role has been difficult to analyze in humans due to late diagnosis of HBV infection. In this review, we discuss recent advances in the field of innate immunity to HBV infection.
Collapse
Affiliation(s)
- Malika Ait-goughoulte
- INSERM, U871, Molecular Physiopathology and New Treatment of Viral Hepatitis, 151 Cours Albert Thomas, 69003 Lyon, France; E-Mails: (M.A.-g.); (J.L.); (F.Z.)
- Université de Lyon, UCBL, and IFR62 Lyon Est, 69008 Lyon, France
| | - Julie Lucifora
- INSERM, U871, Molecular Physiopathology and New Treatment of Viral Hepatitis, 151 Cours Albert Thomas, 69003 Lyon, France; E-Mails: (M.A.-g.); (J.L.); (F.Z.)
- Université de Lyon, UCBL, and IFR62 Lyon Est, 69008 Lyon, France
| | - Fabien Zoulim
- INSERM, U871, Molecular Physiopathology and New Treatment of Viral Hepatitis, 151 Cours Albert Thomas, 69003 Lyon, France; E-Mails: (M.A.-g.); (J.L.); (F.Z.)
- Université de Lyon, UCBL, and IFR62 Lyon Est, 69008 Lyon, France
- Hospices Civils de Lyon (HCL), Hôtel Dieu Hospital, 69002 Lyon, France
| | - David Durantel
- INSERM, U871, Molecular Physiopathology and New Treatment of Viral Hepatitis, 151 Cours Albert Thomas, 69003 Lyon, France; E-Mails: (M.A.-g.); (J.L.); (F.Z.)
- Université de Lyon, UCBL, and IFR62 Lyon Est, 69008 Lyon, France
- Hospices Civils de Lyon (HCL), Hôtel Dieu Hospital, 69002 Lyon, France
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +33-472-681-970; Fax: +33-472-681-971
| |
Collapse
|
202
|
Arababadi MK, Pourfathollah AA, Jafarzadeh A, Hassanshahi G, Mohit M, Hajghani M, Shamsizadeh A. Peripheral Blood CD8+T Cells CCR5 Expression and Its Δ32 Mutation in Iranian Patients with Occult Hepatitis B Infections. Lab Med 2010. [DOI: 10.1309/lmvukwrox0ebqr01] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
|
203
|
Ectopic B7-H4-Ig expression attenuates concanavalin A-induced hepatic injury. Clin Immunol 2010; 136:30-41. [PMID: 20346734 DOI: 10.1016/j.clim.2010.02.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2009] [Revised: 12/28/2009] [Accepted: 02/28/2010] [Indexed: 01/21/2023]
Abstract
Previous studies demonstrate that both membrane B7-H4 and B7-H4-Ig fusion protein could inhibit T-cell responses. In the present study, we explored the potential effect of B7-H4-Ig on liver injury in a hepatitis mouse model induced by concanavalin A (ConA). A B7-H4-Ig construct was introduced into animals by the hydrodynamic gene delivery approach. It was found that ectopic expression of B7-H4-Ig could inhibit ConA-induced elevation of serum levels of ALT and AST, suppress liver necrosis and even mortality of mice. Furthermore, we observed that pretreatment of B7-H4-Ig dramatically decreased serum levels and the expression of mRNA for IL-2, IFN-gamma and IL-4, but increased IL-10 in ConA-treated mice. Our results suggest that B7-H4-Ig may protect animals from liver injury induced by ConA, which could be associated with reduced serum levels for IL-2, IFN-gamma and IL-4 as well as enhanced IL-10 production.
Collapse
|
204
|
Scott-Algara D, Mancini-Bourgine M, Fontaine H, Pol S, Michel ML. Changes to the natural killer cell repertoire after therapeutic hepatitis B DNA vaccination. PLoS One 2010; 5:e8761. [PMID: 20090916 PMCID: PMC2807462 DOI: 10.1371/journal.pone.0008761] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Accepted: 12/21/2009] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Improvements to the outcome of adaptive immune responses could be achieved by inducing specific natural killer (NK) cell subsets which can cooperate with dendritic cells to select efficient T cell responses. We previously reported the induction or reactivation of T cell responses in chronic hepatitis B patients vaccinated with a DNA encoding hepatitis B envelope proteins during a phase I clinical trial. METHODOLOGY/PRINCIPAL FINDINGS In this study, we examined changes in the peripheral NK cell populations occurring during this vaccine trial using flow cytometry analysis. Despite a constant number of NK cells in the periphery, a significant increase in the CD56(bright) population was observed after each vaccination and during the follow up. Among the 13 different NK cell markers studied by flow cytometry analysis, the expression of CD244 and NKG2D increased significantly in the CD56(bright) NK population. The ex vivo CD107a expression by CD56(bright) NK cells progressively increased in the vaccinated patients to reach levels that were significantly higher compared to chronically HBV-infected controls. Furthermore, modifications to the percentage of the CD56(bright) NK cell population were correlated with HBV-specific T cell responses detected by the ELISPOT assay. CONCLUSIONS/SIGNIFICANCE These changes in the CD56(bright) population may suggest a NK helper effect on T cell adaptive responses. Activation of the innate and adaptive arms of the immune system by DNA immunization may be of particular importance to the efficacy of therapeutic interventions in a context of chronic infections. TRIAL REGISTRATION ClinicalTrials.gov NCT00988767.
Collapse
Affiliation(s)
- Daniel Scott-Algara
- Unité de Régulation des Infections Rétrovirales, Institut Pasteur, Paris, France
| | - Maryline Mancini-Bourgine
- Laboratoire de pathogenèse des virus de l'hépatite B, Institut Pasteur, Paris, France
- Institut National de la Santé et de la Recherche Médicale U845, Paris, France
| | - Hélène Fontaine
- AP-HP, Service d'hépatologie, Hôpital Cochin, Université René Descartes Paris V, INSERM U 567, Paris, France
| | - Stanislas Pol
- AP-HP, Service d'hépatologie, Hôpital Cochin, Université René Descartes Paris V, INSERM U 567, Paris, France
| | - Marie-Louise Michel
- Laboratoire de pathogenèse des virus de l'hépatite B, Institut Pasteur, Paris, France
- Institut National de la Santé et de la Recherche Médicale U845, Paris, France
- AP-HP, Service d'hépatologie, Hôpital Cochin, Paris, France
- * E-mail:
| |
Collapse
|
205
|
Lucifora J, Durantel D, Testoni B, Hantz O, Levrero M, Zoulim F. Control of hepatitis B virus replication by innate response of HepaRG cells. Hepatology 2010; 51:63-72. [PMID: 19877170 DOI: 10.1002/hep.23230] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
UNLABELLED Hepatitis B virus (HBV) is currently viewed as a stealth virus that does not elicit innate immunity in vivo. This assumption has not yet been challenged in vitro because of the lack of a relevant cell culture system. The HepaRG cell line, which is physiologically closer to differentiated hepatocytes and permissive to HBV infection, has opened new perspectives in this respect.HBV baculoviruses were used to initiate an HBV replication in both HepG2 and HepaRG cells. To monitor HBV replication, the synthesis of encapsidated DNA, and secretion of hepatitis B surface antigen (HBsAg), was respectively analyzed by southern blot and enzyme-linked immunosorbent assay. The induction of a type I interferon (IFN) response was monitored by targeted quantitative reverse transcription polymerase chain reaction (qRT-PCR), low-density arrays, and functional assays. The invalidation of type I IFN response was obtained by either antibody neutralization or RNA interference. We demonstrate that HBV elicits a strong and specific innate antiviral response that results in a noncytopathic clearance of HBV DNA in HepaRG cells. Challenge experiment showed that transduction with Bac-HBV-WT, but not with control baculoviruses, leads to this antiviral response in HepaRG cells, whereas no antiviral response is observed in HepG2 cells. Cellular gene expression analyses showed that IFN-beta and other IFN-stimulated genes were up-regulated in HepG2 and HepaRG cells, but not in cells transduced by control baculoviruses. Interestingly, a rescue of viral replication was observed when IFN-beta action was neutralized by antibodies or RNA interference of type I IFN receptor. CONCLUSION Our data suggest that a strong HBV replication is able to elicit a type I IFN response in HepaRG-transduced cells.
Collapse
Affiliation(s)
- Julie Lucifora
- INSERM (Institut National de la Santé et de la Recherche Médicale), U871, Lyon, France
| | | | | | | | | | | |
Collapse
|
206
|
Durantel D, Zoulim F. Innate response to hepatitis B virus infection: observations challenging the concept of a stealth virus. Hepatology 2009; 50:1692-5. [PMID: 19937686 DOI: 10.1002/hep.23361] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
|
207
|
Hösel M, Quasdorff M, Wiegmann K, Webb D, Zedler U, Broxtermann M, Tedjokusumo R, Esser K, Arzberger S, Kirschning CJ, Langenkamp A, Falk C, Büning H, Rose-John S, Protzer U. Not interferon, but interleukin-6 controls early gene expression in hepatitis B virus infection. Hepatology 2009; 50:1773-82. [PMID: 19937696 DOI: 10.1002/hep.23226] [Citation(s) in RCA: 270] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
UNLABELLED With about 350 million virus carriers, hepatitis B virus (HBV) infection remains a major health problem. HBV is a noncytopathic virus causing persistent infection, but it is still unknown whether host recognition of HBV may activate an innate immune response. We describe that upon infection of primary human liver cells, HBV is recognized by nonparenchymal cells of the liver, mainly by liver macrophages (Kupffer cells), although they are not infected. Within 3 hours, this recognition leads to the activation of nuclear factor kappa B (NF-kappaB) and subsequently to the release of interleukin-6 (IL-6) and other proinflammatory cytokines (IL-8, TNF-alpha, IL-1beta), but does not induce an interferon response. The activation of proinflammatory cytokines, however, is transient, and even inhibits responsiveness toward a subsequent challenge. IL-6 released by Kupffer cells after activation of NF-kappaB controls HBV gene expression and replication in hepatocytes at the level of transcription shortly after infection. Upon binding to its receptor complex, IL-6 activates the mitogen-activated protein kinases exogenous signal-regulated kinase 1/2, and c-jun N-terminal kinase, which inhibit expression of hepatocyte nuclear factor (HNF) 1alpha and HNF 4alpha, two transcription factors essential for HBV gene expression and replication. CONCLUSION Our results demonstrate recognition of HBV patterns by nonparenchymal liver cells, which results in IL-6-mediated control of HBV infection at the transcriptional level. Thus, IL-6 ensures early control of the virus, limiting activation of the adaptive immune response and preventing death of the HBV-infected hepatocyte. This pattern recognition may be essential for a virus, which infects a new host with only a few virions. Our data also indicate that therapeutic neutralization of IL-6 for treatment of certain diseases may represent a risk if the patient is HBV-infected.
Collapse
Affiliation(s)
- Marianna Hösel
- Center for Molecular Medicine Cologne (ZMMK), University Hospital Cologne, Köln, Germany
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
208
|
Gao B, Radaeva S, Park O. Liver natural killer and natural killer T cells: immunobiology and emerging roles in liver diseases. J Leukoc Biol 2009; 86:513-28. [PMID: 19542050 DOI: 10.1189/jlb.0309135] [Citation(s) in RCA: 270] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Hepatic lymphocytes are enriched in NK and NKT cells that play important roles in antiviral and antitumor defenses and in the pathogenesis of chronic liver disease. In this review, we discuss the differential distribution of NK and NKT cells in mouse, rat, and human livers, the ultrastructural similarities and differences between liver NK and NKT cells, and the regulation of liver NK and NKT cells in a variety of murine liver injury models. We also summarize recent findings about the role of NK and NKT cells in liver injury, fibrosis, and repair. In general, NK and NKT cells accelerate liver injury by producing proinflammatory cytokines and killing hepatocytes. NK cells inhibit liver fibrosis via killing early-activated and senescent-activated stellate cells and producing IFN-gamma. In regulating liver fibrosis, NKT cells appear to be less important than NK cells as a result of hepatic NKT cell tolerance. NK cells inhibit liver regeneration by producing IFN-gamma and killing hepatocytes; however, the role of NK cells on the proliferation of liver progenitor cells and the role of NKT cells in liver regeneration have been controversial. The emerging roles of NK/NKT cells in chronic human liver disease will also be discussed.Understanding the role of NK and NKT cells in the pathogenesis of chronic liver disease may help us design better therapies to treat patients with this disease.
Collapse
Affiliation(s)
- Bin Gao
- Section on Liver Biology, Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland 20892, USA.
| | | | | |
Collapse
|
209
|
Wang FS, Zhang Z. Host immunity influences disease progression and antiviral efficacy in humans infected with hepatitis B virus. Expert Rev Gastroenterol Hepatol 2009; 3:499-512. [PMID: 19817672 DOI: 10.1586/egh.09.50] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Hepatitis B virus (HBV) infection can lead to several severe liver diseases, including hepatitis, cirrhosis and hepatocellular carcinoma, although the underlying mechanisms responsible for the clinical outcome have not been well characterized. In this review, we retrospectively examine the history of immunological responses to HBV infection and summarize the current understanding of innate and adaptive immunity in the context of HBV-associated liver disease. Recent data indicate that the interaction between HBV and the host immune response not only substantially drives disease progression, but also significantly influences antiviral efficacy in HBV-infected individuals. Advances in the field have provided insight into the immunopathology of HBV infection. Based on the characteristics of host immune responses in patients with HBV infection, a 'climbing slope hypothesis' is proposed to suggest that therapeutic strategies aimed at modulating the immune activity of the host may represent a complementary approach to antiviral drug treatment for the management of chronically HBV-infected patients.
Collapse
Affiliation(s)
- Fu-Sheng Wang
- Research Center for Biological Therapy, Beijing 302 Hospital, Beijing 100039, China.
| | | |
Collapse
|
210
|
Dunn C, Peppa D, Khanna P, Nebbia G, Jones M, Brendish N, Lascar RM, Brown D, Gilson RJ, Tedder RJ, Dusheiko GM, Jacobs M, Klenerman P, Maini MK. Temporal analysis of early immune responses in patients with acute hepatitis B virus infection. Gastroenterology 2009; 137:1289-300. [PMID: 19591831 DOI: 10.1053/j.gastro.2009.06.054] [Citation(s) in RCA: 263] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Revised: 05/20/2009] [Accepted: 06/18/2009] [Indexed: 02/06/2023]
Abstract
BACKGROUND & AIMS Hepatitis B virus (HBV) causes more than 1 million deaths annually from immune-mediated liver damage. The long incubation period has been difficult to study; by the time most patients present, massive viremia and the majority of viral clearance have already occurred. The aim of this study was to investigate the contribution of innate and adaptive immune mechanisms in early acute HBV through access to an unusual cohort of patients sampled in the preclinical phase and followed up to resolution of their infection. METHODS Twenty-one patients with acute HBV were studied, 8 of them from before the peak of viremia. Circulating innate cytokines were quantitated by enzyme-linked immunosorbent assay and natural killer (NK) and T-cell effector function by flow cytometry. Results were correlated with temporal changes in viral load, serology, and liver inflammation and compared with healthy controls. RESULTS Type I interferon (IFN) remained barely detectable throughout, with concentrations no higher than those found in healthy controls. Similarly, interleukin-15 and IFN-lambda1 were not induced during peak viremia. NK cell activation and capacity for IFN-gamma production were reduced at peak viremia. Early functional HBV-specific CD4 and CD8 T-cell responses were attenuated as viral load increased and recovered again as infection resolved. The transient inhibition of NK and T-cell responses coincided with a surge in the immunosuppressive cytokine interleukin-10 accompanying HBV viremia. CONCLUSIONS The early stages of acute HBV are characterized by induction of interleukin-10 rather than type I IFN, accompanied by a temporary attenuation of NK and T-cell responses.
Collapse
Affiliation(s)
- Claire Dunn
- Division of Infection and Immunity, University College London, London, England
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
211
|
Bertoletti A, Tan AT, Gehring AJ. HBV-Specific Adaptive Immunity. Viruses 2009; 1:91-103. [PMID: 21994540 PMCID: PMC3185487 DOI: 10.3390/v1020091] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2009] [Revised: 07/08/2009] [Accepted: 07/16/2009] [Indexed: 02/08/2023] Open
Abstract
The successful control of HBV infection requires an efficient expansion of distinct elements of the adaptive immune system (B cells, helper and cytotoxic T cells) that, due to the hepatotropic nature of HBV, need to operate in the liver parenchyma. In this respect, we will discuss broad features of HBV immunity in patients with resolved or chronic HBV infection and analyze how the liver environment can directly modulate HBV-immunity.
Collapse
Affiliation(s)
- Antonio Bertoletti
- Laboratory of Hepatic Viral Diseases, Singapore Institute for Clinical Sciences, Agency of Science Technology and Research (A*Star), 30 Medical Drive, 117609, Singapore; E-Mails: ;
- Singapore Immunology Network, Agency of Science Technology and Research (A*Star), Singapore
- Program Emerging Viral Diseases Unit, Duke-NUS Graduate Medical School, Singapore
- Author to whom correspondence should be addressed; E-mail: ; Tel.: +65 64070091; Fax: +65 67766837
| | - Anthony T. Tan
- Laboratory of Hepatic Viral Diseases, Singapore Institute for Clinical Sciences, Agency of Science Technology and Research (A*Star), 30 Medical Drive, 117609, Singapore; E-Mails: ;
| | - Adam J. Gehring
- Laboratory of Hepatic Viral Diseases, Singapore Institute for Clinical Sciences, Agency of Science Technology and Research (A*Star), 30 Medical Drive, 117609, Singapore; E-Mails: ;
| |
Collapse
|
212
|
Lee BO, Tucker A, Frelin L, Sallberg M, Jones J, Peters C, Hughes J, Whitacre D, Darsow B, Peterson DL, Milich DR. Interaction of the hepatitis B core antigen and the innate immune system. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2009; 182:6670-81. [PMID: 19454661 PMCID: PMC2685464 DOI: 10.4049/jimmunol.0803683] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Previous studies demonstrated that the primary APCs for the hepatitis B core Ag (HBcAg) were B cells and not dendritic cells (DC). We now report that splenic B1a and B1b cells more efficiently present soluble HBcAg to naive CD4(+) T cells than splenic B2 cells. This was demonstrated by direct HBcAg-biotin-binding studies and by HBcAg-specific T cell activation in vitro in cultures of naive HBcAg-specific T cells and resting B cell subpopulations. The inability of DC to function as APCs for exogenous HBcAg relates to lack of uptake of HBcAg, not to processing or presentation, because HBcAg/anti-HBc immune complexes can be efficiently presented by DC. Furthermore, HBcAg-specific CD4(+) and CD8(+) T cell priming with DNA encoding HBcAg does not require B cell APCs. TLR activation, another innate immune response, was also examined. Full-length (HBcAg(183)), truncated (HBcAg(149)), and the nonparticulate HBeAg were screened for TLR stimulation via NF-kappaB activation in HEK293 cells expressing human TLRs. None of the HBc/HBeAgs activated human TLRs. Therefore, the HBc/HBeAg proteins are not ligands for human TLRs. However, the ssRNA contained within HBcAg(183) does function as a TLR-7 ligand, as demonstrated at the T and B cell levels in TLR-7 knockout mice. Bacterial, yeast, and mammalian ssRNA encapsidated within HBcAg(183) all function as TLR-7 ligands. These studies indicate that innate immune mechanisms bridge to and enhance the adaptive immune response to HBcAg and have important implications for the use of hepadnavirus core proteins as vaccine carrier platforms.
Collapse
Affiliation(s)
- Byung O Lee
- Vaccine Research Institute of San Diego, San Diego, CA 92109, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
213
|
Immunopathogenesis of hepatitis B persistent infection: implications for immunotherapeutic strategies. Clin J Gastroenterol 2009; 2:71-79. [PMID: 26192169 DOI: 10.1007/s12328-009-0074-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Accepted: 03/09/2009] [Indexed: 12/26/2022]
Abstract
It has been shown that cellular immunity, especially by cytotoxic T lymphocytes (CTLs), NK cells and NK-T cells, plays a central role in the control of virus infection. In addition, CD4+ T cells facilitate both CTL and B-cell responses. Hyporesponsiveness of HBV-specific T cells in peripheral blood has been shown in patients with chronic HBV infection. Interferon and nucleos(t)ide analogs, such as lamivudine, adefovir, entecavir and tenofovir, are the currently available treatments. Unfortunately, the efficacy of nucleos(t)ide analogs is limited by viral reactivation by the emergence of escaped mutants in cases of prolonged treatment. Therefore, immunotherapy is one of the significant options to eradicate or control HBV replication without drugs. The aim of immunotherapies is to decrease the levels of viral replication and to eradicate infected hepatocytes. For this reason, new strategies for immunotherapies by vaccination target not only the induction or stimulation of CD4+ and CD8+ T cell responses, but also the induction of proinflammatory cytokines capable of controlling viral replication. We will review the immunopathogenesis of persistent HBV infection, especially focusing on the mechanisms of immune suppression. Then we will review the immunotherapy for HBV persistent infection.
Collapse
|