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Barnaba V. Hepatitis C virus infection: a "liaison a trois" amongst the virus, the host, and chronic low-level inflammation for human survival. J Hepatol 2010; 53:752-61. [PMID: 20673595 DOI: 10.1016/j.jhep.2010.06.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2010] [Revised: 05/20/2010] [Accepted: 06/09/2010] [Indexed: 01/26/2023]
Abstract
This review covers the various aspects of the immune system that allows the relationship between the hepatitis-C virus, the host and chronic low-level inflammation, to be highly flexible and able to defend the host from persistent infections. This ambiguity mainly stems from the property of the immune system that can be both protective and harmful. Immunity cannot be fully protective without producing a certain degree of damage (acute hepatitis resulting in resolving HCV infection). In addition, the balance between protection and tissue damage is critical for the development of chronic HCV infection. The establishment of a state of chronic low-level inflammation is instrumental to limit liver immunopathology, to limit viral spread, and ultimately to ensure a long-lasting survival of the host. It is dictated by a fine equilibrium maintained by multiple immunologic mechanisms, including: sensory perception of innate immunity, virus-specific T and B cell functions, control of immune responses, and finally the balance between immunity and immunopathology that has principally evolved to favor the survival of the species.
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Affiliation(s)
- Vincenzo Barnaba
- Departimento of Medicina Interna, Sapienza Università di Roma, Fondazione Andrea Cesalpino, Fondazione Cenci Bolognetti, Italy.
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Hall CHT, Kassel R, Tacke RS, Hahn YS. HCV+ hepatocytes induce human regulatory CD4+ T cells through the production of TGF-beta. PLoS One 2010; 5:e12154. [PMID: 20730048 PMCID: PMC2921368 DOI: 10.1371/journal.pone.0012154] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Accepted: 07/21/2010] [Indexed: 02/07/2023] Open
Abstract
Background Hepatitis C Virus (HCV) is remarkably efficient at establishing persistent infection and is associated with the development of chronic liver disease. Impaired T cell responses facilitate and maintain persistent HCV infection. Importantly, CD4+ regulatory T cells (Tregs) act by dampening antiviral T cell responses in HCV infection. The mechanism for induction and/or expansion of Tregs in HCV is unknown. Methodology/Principal Findings HCV-expressing hepatocytes were used to determine if hepatocytes are able to induce Tregs. The infected liver environment was modeled by establishing the co-culture of the human hepatoma cell line, Huh7.5, containing the full-length genome of HCV genotype 1a (Huh7.5-FL) with activated CD4+ T cells. The production of IFN-γ was diminished following co-culture with Huh7.5-FL as compared to controls. Notably, CD4+ T cells in contact with Huh7.5-FL expressed an increased level of the Treg markers, CD25, Foxp3, CTLA-4 and LAP, and were able to suppress the proliferation of effector T cells. Importantly, HCV+ hepatocytes upregulated the production of TGF-β and blockade of TGF-β abrogated Treg phenotype and function. Conclusions/Significance These results demonstrate that HCV infected hepatocytes are capable of directly inducing Tregs development and may contribute to impaired host T cell responses.
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Affiliation(s)
- Caroline H. T. Hall
- Department of Microbiology, Beirne B. Carter Center for Immunology Research, University of Virginia, Charlottesville, Virginia, United States of America
| | - Rachel Kassel
- Department of Microbiology, Beirne B. Carter Center for Immunology Research, University of Virginia, Charlottesville, Virginia, United States of America
| | - Robert S. Tacke
- Department of Microbiology, Beirne B. Carter Center for Immunology Research, University of Virginia, Charlottesville, Virginia, United States of America
| | - Young S. Hahn
- Department of Microbiology, Beirne B. Carter Center for Immunology Research, University of Virginia, Charlottesville, Virginia, United States of America
- Department of Pathology, University of Virginia, Charlottesville, Virginia, United States of America
- * E-mail:
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A gC1qR prevents white spot syndrome virus replication in the freshwater crayfish Pacifastacus leniusculus. J Virol 2010; 84:10844-51. [PMID: 20686021 DOI: 10.1128/jvi.01045-10] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The gC1qR/p32 protein is a multiple receptor for several proteins and pathogens. We cloned a gC1qR homologue in a crustacean, Pacifastacus leniusculus, and analyzed the expression of P. leniusculus C1qR (PlgC1qR) in various tissues. The gC1qR/p32 transcript was significantly enhanced by white spot syndrome virus (WSSV) infection 6 h after viral infection both in vitro in a hematopoietic tissue cell culture (Hpt) and in vivo compared to appropriate controls. Moreover, PlgC1qR silencing in both the Hpt cell culture and live crayfish enhanced the WSSV replication. In addition, by making a recombinant PlgC1qR protein we could show that if this recombinant protein was injected in a crayfish, Pacifastacus leniusculus, followed by injection of WSSV, this significantly reduced viral replication in vivo. Furthermore, if the recombinant PlgC1qR was incubated with Hpt cells and then WSSV was added, this also reduced viral replication. These experiments clearly demonstrate that recombinant PlgC1qR reduce WSSV replication both in vivo and in vitro. The results from a far-Western overlay and glutathione S-transferase pull-down assays showed that PlgC1qR could bind to VP15, VP26, and VP28. Altogether, these results demonstrate a role for PlgC1qR in antiviral activity against WSSV.
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The wild-type hepatitis C virus core inhibits initiation of antigen-specific T- and B-cell immune responses in BALB/c mice. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2010; 17:1139-47. [PMID: 20519445 DOI: 10.1128/cvi.00490-09] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
In this study, the effects of wild-type and deletion mutant hepatitis C virus (HCV) core proteins on the induction of immune responses in BALB/c mice were assessed. p2HA-C145-S23, encoding a core protein with the C-terminal 46 amino acids truncated, significantly produced stronger antibody and cellular responses than p2HA-C191-S23. The induction of immune responses by p2HA-C145-S23 was dose dependent. However, increasing the doses or repeated administration did not enhance immune responses by the wild-type core protein. In addition, p2HA-C191-S23 was apparently able to interfere with the priming of specific immune responses by p2HA-C145-S23 when the two were coadministered. These results demonstrated that the wild-type HCV core protein itself could inhibit the priming of immune responses in the course of a DNA vaccination, whereas the truncated HCV core protein could provide potential applications for the development of DNA- and peptide-based HCV vaccines.
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Horner SM, Gale M. Intracellular innate immune cascades and interferon defenses that control hepatitis C virus. J Interferon Cytokine Res 2010; 29:489-98. [PMID: 19708811 DOI: 10.1089/jir.2009.0063] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Hepatitis C virus (HCV) is a global public health problem that mediates a persistent infection in nearly 200 million people. HCV is efficient in establishing chronicity due in part to the inefficiency of the host immune system in controlling and counteracting HCV-mediated evasion strategies. HCV persistence is linked to the ability of the virus to suppress the RIG-I pathway and interferon production from infected hepatocytes, thus evading innate immune defenses within the infected cell. This review describes the virus and host processes that regulate the RIG-I pathway during HCV infection. An understanding of these HCV-host interactions could lead to more effective therapies for HCV designed to reactivate the host immune response following HCV infection.
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Affiliation(s)
- Stacy M Horner
- Department of Immunology, University of Washington School of Medicine, Seattle, Washington 98195, USA
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56
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Castellanos M, Cinza Z, Dorta Z, Veliz G, Vega H, Lorenzo I, Ojeda S, Dueñas-Carrera S, Alvarez-Lajonchere L, Martínez G, Ferrer E, Limonta M, Linares M, Ruiz O, Acevedo B, Torres D, Márquez G, Herrera L, Arús E. Immunization with a DNA vaccine candidate in chronic hepatitis C patients is safe, well tolerated and does not impair immune response induction after anti-hepatitis B vaccination. J Gene Med 2010; 12:107-16. [PMID: 19866482 DOI: 10.1002/jgm.1407] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND In the present study, we evaluated the safety of CIGB-230, a novel vaccine candidate based on the mixture of a plasmid for DNA immunization, expressing hepatitis C virus (HCV) structural antigens, with a recombinant HCV Core protein. METHODS Fifteen HCV chronically-infected volunteers with detectable levels of HCV RNA genotype 1b, who were nonresponders to previous treatment with interferon plus ribavirin, were intramuscularly injected with CIGB-230 on weeks 0, 4, 8, 12, 16 and 20. Individuals were also immunized at weeks 28, 32 and 36 with a recombinant vaccine against hepatitis B. Adverse events were recorded and analyzed. Blood samples were taken every 4 weeks up to month 12 for hematological, biochemical, virological and immunological analysis. RESULTS All patients completed the treatment with CIGB-230. Adverse events were only slight (83.6%) or moderate (16.4%). No significant differences in hematological and biochemical parameters, including serum aminotransferases, were detected between the baseline and post-treatment state. Induction of a CD4+ T lymphocyte response against a particular region in HCV E1, spanning amino acids 230-312 in HCV polyprotein, was detected in 42.8% of patients during treatment with CIGB-230. The ability of T cells to proliferate in response to mitogenic stimulation was not weakened. Most individuals (78.6%) were seroprotected after anti-hepatitis B vaccination and 42.8% were hyper-responders (antibody titers > 100 UI/ml). No anti-mitochondrial, anti-nuclear and anti-extractable nuclear antigen antibodies were generated during immunization with CIGB-230. CONCLUSIONS Vaccination with CIGB-230 in HCV chronically-infected individuals was safe, well tolerated and did not impair the ability to respond to non-HCV antigens.
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Donlin MJ, Cannon NA, Aurora R, Li J, Wahed AS, Di Bisceglie AM, Tavis JE. Contribution of genome-wide HCV genetic differences to outcome of interferon-based therapy in Caucasian American and African American patients. PLoS One 2010; 5:e9032. [PMID: 20140258 PMCID: PMC2815788 DOI: 10.1371/journal.pone.0009032] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Accepted: 01/11/2010] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Hepatitis C virus (HCV) has six major genotypes, and patients infected with genotype 1 respond less well to interferon-based therapy than other genotypes. African American patients respond to interferon alpha-based therapy at about half the rate of Caucasian Americans. The effect of HCV's genetic variation on treatment outcome in both racial groups is poorly understood. METHODOLOGY We determined the near full-length pre-therapy consensus sequences from 94 patients infected with HCV genotype 1a or 1b undergoing treatment with peginterferon alpha-2a and ribavirin through the Virahep-C study. The sequences were stratified by genotype, race and treatment outcome to identify HCV genetic differences associated with treatment efficacy. PRINCIPAL FINDINGS HCV sequences from patients who achieved sustained viral response were more diverse than sequences from non-responders. These inter-patient diversity differences were found primarily in the NS5A gene in genotype 1a and in core and NS2 in genotype 1b. These differences could not be explained by host selection pressures. Genotype 1b but not 1a African American patients had viral genetic differences that correlated with treatment outcome. CONCLUSIONS & SIGNIFICANCE Higher inter-patient viral genetic diversity correlated with successful treatment, implying that there are HCV genotype 1 strains with intrinsic differences in sensitivity to therapy. Core, NS3 and NS5A have interferon-suppressive activities detectable through in vitro assays, and hence these activities also appear to function in human patients. Both preferential infection with relatively resistant HCV variants and host-specific factors appear to contribute to the unusually poor response to therapy in African American patients.
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Affiliation(s)
- Maureen J. Donlin
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, St. Louis, Missouri, United States of America
- Saint Louis University Liver Center, Saint Louis University School of Medicine, St. Louis, Missouri, United States of America
| | - Nathan A. Cannon
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, St. Louis, Missouri, United States of America
| | - Rajeev Aurora
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, St. Louis, Missouri, United States of America
| | - Jia Li
- Department of Biostatistics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Abdus S. Wahed
- Department of Biostatistics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Adrian M. Di Bisceglie
- Division of Gastroenterology and Hepatology, Saint Louis University School of Medicine, St. Louis, Missouri, United States of America
- Saint Louis University Liver Center, Saint Louis University School of Medicine, St. Louis, Missouri, United States of America
| | - John E. Tavis
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, St. Louis, Missouri, United States of America
- Saint Louis University Liver Center, Saint Louis University School of Medicine, St. Louis, Missouri, United States of America
- * E-mail:
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Moorman J, Dong ZP, Ni L, Zhang C, Borthwick T, Yao ZQ. Abnormal B-cell activation associated with TALL-1 over-expression and SOCS-1 suppression during chronic hepatitis C virus infection. Immunology 2009; 128:227-35. [PMID: 19740379 DOI: 10.1111/j.1365-2567.2009.03106.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Chronic hepatitis C virus (HCV) infection is associated with cirrhosis, autoimmunity and lymphoproliferative disorders. We have previously reported a differential regulation of T and B lymphocytes by HCV core protein in vitro. In this report, we employed a translational approach to characterize the activation status of peripheral B cells from individuals with chronic HCV infection and to explore potential mechanisms for B-cell dysregulation in the setting of HCV infection. In contrast to the T-cell suppression observed in HCV-infected individuals, B cells exhibit a non-specific polyclonal activation phenotype, characterized by significantly higher levels of (1) the early activation marker, CD69, (2) the costimulatory molecule, CD86, and (3) the CCR5 chemokine receptor, CD195, when compared with B cells from healthy donors in response to phytohaemagglutinin (PHA) stimulation. Importantly, tumour necrosis factor- and Apo-L-related leucocyte-expressed ligand-1 (TALL-1), also known as B-lymphocyte stimulator (BLYS), was found to be up-regulated on the surface of B cells from HCV patients in response to PHA as well as HCV core antigen stimulation. This up-regulation of TALL-1 was associated with vigorous memory B-cell responses to viral antigenic stimulation. Additionally, suppressor of cytokine signalling-1 (SOCS-1), a negative feedback immunoregulator that is inhibited in B lymphocytes by HCV core in vitro, was also inhibited in B cells from HCV patients when compared with healthy donors. These findings suggest that TALL-1 over-expression and SOCS-1 suppression are associated with aberrant B-cell activation, providing a plausible basis for the B-cell clonal expansion underlying the lymphoproliferative disorders and autoimmune phenomena observed during chronic HCV infection.
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Rehermann B. Hepatitis C virus versus innate and adaptive immune responses: a tale of coevolution and coexistence. J Clin Invest 2009; 119:1745-54. [PMID: 19587449 DOI: 10.1172/jci39133] [Citation(s) in RCA: 407] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Since the identification of the hepatitis C virus (HCV) 20 years ago, much progress has been made in our understanding of its life cycle and interaction with the host immune system. Much has been learned from HCV itself, which, via decades of coevolution, gained an intricate knowledge of host innate and adaptive immune responses and developed sophisticated ways to preempt, subvert, and antagonize them. This review discusses the clinical, virological, and immunological features of acute and chronic hepatitis C and the role of the immune response in spontaneous and treatment-induced HCV clearance.
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Affiliation(s)
- Barbara Rehermann
- Immunology Section, Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, NIH/DHHS, Bethesda, MD 20892, USA.
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Cummings KL, Rosen HR, Hahn YS. Frequency of gC1qR+CD4+ T cells increases during acute hepatitis C virus infection and remains elevated in patients with chronic infection. Clin Immunol 2009; 132:401-11. [PMID: 19473882 DOI: 10.1016/j.clim.2009.05.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2009] [Revised: 04/22/2009] [Accepted: 05/03/2009] [Indexed: 01/24/2023]
Abstract
CD4+ T cell responses are impaired in chronic HCV infection. To determine factor(s) involved in CD4+ T cell dysregulation, we examined the effect of extracellular core on the alteration of CD4+ T cell responses and the cell surface level of core-binding protein, gC1qR on CD4+ T cells from acute HCV patients with resolved and chronic infection. During the acute phase of infection, the frequency of gC1qR+CD4+ T cells increased in both resolved and chronic HCV infection compared to healthy controls. Notably, 6 months later, the frequency of gC1qR+CD4+ T cells maintained elevated in chronic patients compared to that in resolved patients. In addition, TCR stimulation increased the frequency of gC1qR+CD4+ T cells, resulting in core-induced inhibition of T cell responses in both resolved and chronic patients. These results suggest that HCV infection expands gC1qR+CD4+ T cells, which increase the susceptibility to core-mediated immune dysregulation and facilitate the establishment of HCV persistency.
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Affiliation(s)
- Kara L Cummings
- Beirne Carter Center for Immunology Research and Department of Microbiology, University of Virginia, Charlottesville, VA 22908, USA
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Ruys TA, Nanlohy NM, van den Berg CHSB, Hassink E, Beld M, van de Laar T, Bruisten S, Wit F, Krol A, Prins M, Lange J, van Baarle D. HCV-specific T-cell responses in injecting drug users: evidence for previous exposure to HCV and a role for CD4+ T cells focussing on nonstructural proteins in viral clearance. J Viral Hepat 2008; 15:409-20. [PMID: 18221302 DOI: 10.1111/j.1365-2893.2007.00963.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In order to understand the parameters associated with resolved hepatitis C virus (HCV)-infection, we analysed the HCV-specific T-cell responses longitudinally in 13 injecting drug-users (IDUs) with a prospectively identified acute HCV infection. Seven IDUs cleared HCV and six IDUs remained chronically infected. T-cell responses were followed in the period needed to resolve and a comparable time span in chronic carriers. Ex vivo T-cell responses were measured using interferon-gamma Elispot assays after stimulation with overlapping peptide pools spanning the complete HCV genome. CD4+ memory-T-cell responses were determined after 12-day stimulation with HCV proteins. The maximum response was compared between individuals. The T-cell responses measured directly ex vivo were weak but significantly higher in resolvers compared to chronic carriers, whereas the CD4+ memory-T-cell response was not different between resolvers and chronic carriers. However, HCV Core protein was targeted more often in chronic carriers compared to individuals resolving HCV infection. CD4+ T-cell responses predominantly targeting nonstructural proteins were associated with resolved HCV infection. Interestingly, observation of memory-T-cell responses present before the documented HCV-seroconversion suggests that reinfections in IDUs occur often. The presence of these responses however, were not predictive for the outcome of infection. However, a transition of the HCV-specific CD4+ memory-T-cell response from targeting Core to targeting nonstructural proteins during onset of infection was associated with a favourable outcome. Therefore, the specificity of the CD4+ memory-T-cell responses measured after 12-day expansion seems most predictive of resolved infection.
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Affiliation(s)
- T A Ruys
- Department of Internal Medicine, Division of Infectious Diseases, Tropical Medicine and AIDS, International Antiviral Therapy and Evaluation Center (IATEC) and Academic Medical Center, Amsterdam, The Netherlands
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Yao ZQ, Prayther D, Trabue C, Dong ZP, Moorman J. Differential regulation of SOCS-1 signalling in B and T lymphocytes by hepatitis C virus core protein. Immunology 2008; 125:197-207. [PMID: 18397267 DOI: 10.1111/j.1365-2567.2008.02829.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Hepatitis C virus (HCV) infection is characterized by a strong propensity toward chronicity, autoimmune phenomena and lymphomagenesis, supporting a role for lymphocyte dysregulation during persistent viral infection. We have shown that HCV core protein inhibits T-cell functions through interaction with a complement receptor, gC1qR. Here, we further report that B cells also express gC1qR that can be bound by HCV core protein. Importantly, using flow cytometry, we demonstrated differential regulation of B and T lymphocytes by the HCV core-gC1qR interaction, with down-regulation of CD69 activation in T cells but up-regulation of CD69 activation and cell proliferation in B cells. HCV core treatment led to decreased interferon-gamma production in CD8+ T cells but to increased immunoglobulin M and immunoglobulin G production as well as cell surface expression of costimulatory and chemokine receptors, including CD86 (B7-2), CD154 (CD40L) and CD195 (CCR5), in CD20+ B cells. Finally, we showed down-regulation of suppressor of cytokine signalling-1 (SOCS-1) using real-time reverse transcription-polymerase chain reaction, accompanied by up-regulation of signal transducer and activator of transcription-1 (STAT1) phosphorylation in B cells in response to HCV core protein, with the opposite pattern observed in HCV core-treated T cells. This study demonstrates differential regulation of B and T lymphocytes by HCV core and supports a mechanism by which lymphocyte dysregulation occurs in the course of persistent HCV infection.
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Affiliation(s)
- Zhi Qiang Yao
- Medical Service, James H. Quillen VAMC, and Department of Internal Medicine, Division of Infectious Diseases, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614, USA
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Cummings KL, Waggoner SN, Tacke R, Hahn YS. Role of complement in immune regulation and its exploitation by virus. Viral Immunol 2008; 20:505-24. [PMID: 18158725 DOI: 10.1089/vim.2007.0061] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Complement is activated during the early phase of viral infection and promotes destruction of virus particles as well as the initiation of inflammatory responses. Recently, complement and complement receptors have been reported to play an important role in the regulation of innate as well as adaptive immune responses during infection. The regulation of host immune responses by complement involves modulation of dendritic cell activity in addition to direct effects on T-cell function. Intriguingly, many viruses encode homologs of complement regulatory molecules or proteins that interact with complement receptors on antigen-presenting cells and lymphocytes. The evolution of viral mechanisms to alter complement function may augment pathogen persistence and limit immune-mediated tissue destruction. These observations suggest that complement may play an important role in both innate and adaptive immune responses to infection as well as virus-mediated modulation of host immunity.
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Affiliation(s)
- Kara L Cummings
- Beirne Carter Center for Immunology Research and Department of Microbiology, University of Virginia, Charlottesville, Virginia
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El-Gogo S, Staib C, Lasarte JJ, Sutter G, Adler H. Protective vaccination with hepatitis C virus NS3 but not core antigen in a novel mouse challenge model. J Gene Med 2008; 10:177-86. [DOI: 10.1002/jgm.1144] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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Hepatitis C virus core protein impairs in vitro priming of specific T cell responses by dendritic cells and hepatocytes. J Hepatol 2008; 48:51-60. [PMID: 17998148 DOI: 10.1016/j.jhep.2007.08.008] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2007] [Revised: 08/23/2007] [Accepted: 08/28/2007] [Indexed: 02/06/2023]
Abstract
BACKGROUND/AIMS Hepatitis C virus leads to chronic hepatitis in the majority of infected individuals. The mechanism of viral persistence is not completely understood. Hepatitis C virus core protein is produced within hepatocytes and is secreted during HCV infection. Our study characterizes the effects of core protein on T cell priming in mice. METHODS We used a system of antigen-specific in vitro priming of CD4(+) and CD8(+) T cells by myeloid dendritic cells, hepatoma cells or primary hepatocytes. Core protein was either added to the cultures or expressed by antigen-presenting cells. RESULTS Antigen-presenting cells treated with core protein showed reduced surface expression of major histocompatibility molecules. Myeloid dendritic cells showed also reduced expression of costimulatory molecules. CD4(+) and CD8(+) T cells primed by these cells showed defects in activation, proliferation, and cytokine production. Importantly, CD4(+) and also CD8(+) T cells primed in the presence of core protein showed an increase in interleukin-10 production resembling the phenotype of regulatory T cells. CONCLUSIONS Hepatitis C virus core protein inhibits priming of antigen-specific CD4(+) and CD8(+) T cell responses by downregulation of major histocompatibility molecules and costimulatory molecules on antigen-presenting cells and induces development of IL-10-producing T cells.
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Biswas AK, Hafiz A, Banerjee B, Kim KS, Datta K, Chitnis CE. Plasmodium falciparum uses gC1qR/HABP1/p32 as a receptor to bind to vascular endothelium and for platelet-mediated clumping. PLoS Pathog 2007; 3:1271-80. [PMID: 17907801 PMCID: PMC2323294 DOI: 10.1371/journal.ppat.0030130] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2007] [Accepted: 07/23/2007] [Indexed: 01/11/2023] Open
Abstract
The ability of Plasmodium falciparum–infected red blood cells (IRBCs) to bind to vascular endothelium, thus enabling sequestration in vital host organs, is an important pathogenic mechanism in malaria. Adhesion of P. falciparum IRBCs to platelets, which results in the formation of IRBC clumps, is another cytoadherence phenomenon that is associated with severe disease. Here, we have used in vitro cytoadherence assays to demonstrate, to our knowledge for the first time, that P. falciparum IRBCs use the 32-kDa human protein gC1qR/HABP1/p32 as a receptor to bind to human brain microvascular endothelial cells. In addition, we show that P. falciparum IRBCs can also bind to gC1qR/HABP1/p32 on platelets to form clumps. Our study has thus identified a novel host receptor that is used for both adhesion to vascular endothelium and platelet-mediated clumping. Given the association of adhesion to vascular endothelium and platelet-mediated clumping with severe disease, adhesion to gC1qR/HABP1/p32 by P. falciparum IRBCs may play an important role in malaria pathogenesis. Adhesion of Plasmodium falciparum–infected red blood cells (IRBCs) to the endothelium lining the capillaries of vital host organs can obstruct blood circulation and is an important pathogenic mechanism in malaria. Adhesion of P. falciparum IRBCs to platelets results in the formation of IRBC clumps that can also obstruct blood flow and is implicated in severe malaria. Here, we have identified a novel cytoadherence receptor that is found on both endothelial cells and platelets. We demonstrate, for the first time to our knowledge, that P. falciparum IRBCs use the 32-kDa human protein gC1qR/HABP1/p32 as a receptor to bind to human endothelial cells, including brain microvascular endothelial cells. In addition, we show that P. falciparum IRBCs can bind to gC1qR/HABP1/p32 on platelets to form clumps. Our study has thus identified a novel host receptor that is used for both adhesion to vascular endothelium and platelet-mediated clumping. Given the association of these cytoadherence phenomena with severe disease, our study opens the door to investigations on the role of adhesion of P. falciparum IRBCs to gC1qR/HABP1/p32 in malaria pathogenesis.
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Affiliation(s)
- Anup Kumar Biswas
- Malaria Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Abdul Hafiz
- Malaria Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Bhaswati Banerjee
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Kwang Sik Kim
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Kasturi Datta
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India
- * To whom correspondence should be addressed. E-mail: (KD); (CEC)
| | - Chetan E Chitnis
- Malaria Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
- * To whom correspondence should be addressed. E-mail: (KD); (CEC)
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68
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Domínguez-Villar M, Muñoz-Suano A, Anaya-Baz B, Aguilar S, Novalbos JP, Giron JA, Rodríguez-Iglesias M, Garcia-Cozar F. Hepatitis C virus core protein up-regulates anergy-related genes and a new set of genes, which affects T cell homeostasis. J Leukoc Biol 2007; 82:1301-10. [PMID: 17711976 DOI: 10.1189/jlb.0507335] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Hepatitis C virus (HCV) infection is the main cause for chronic hepatitis, leading to cirrhosis and hepatic carcinoma. Virally induced immune dysfunction has been called as the cause for viral persistence. Previous results demonstrate that CD4 Jurkat cells stably expressing the HCV core protein show an increased activation of NFAT transcription factor and an impaired IL-2 promoter activity, affecting intracellular signaling pathways in a manner that mimics clonal anergy. We had shown previously that NFAT activates a transcriptional program, ensuing in immunological tolerance. In the present work, we have engineered lentiviral vectors expressing the HCV core to analyze the events, which unfold in the initial phase of HCV core-induced anergy. We show that genes initially described to be up-regulated by ionomycin-induced anergy in mice are also up-regulated in humans, not only by ionomycin but also by HCV core expression. We also show that HCV core is sufficient to cause NFAT nuclear translocation and a slow-down in cell-cycle progression, and using whole genome microarrays, we identify novel genes up-regulated in Jurkat cells expressing HCV core. The relevance of our results is highlighted by the presence of HCV in CD4 T cells from HCV chronically infected patients.
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Affiliation(s)
- M Domínguez-Villar
- Puerto Real University Hospital Research Unit, School of Medicine, Department of Biochemistry, Microbiology, and Immunology, University of Cadiz, Cadiz, Spain
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69
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Feng X, Zhang H, Liu H, Song X, Wang G, Chen K, Ling S. Cancerogenic effect of different fragments of the hepatitis C virus core protein. Eur J Cancer Prev 2007; 16:304-11. [PMID: 17554203 DOI: 10.1097/01.cej.0000236252.16855.82] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The hepatitis C virus core protein plays an extremely important role in the hepatocarcinogenesis of hepatitis C virus. Little, however, is known about the oncogenic potency of fragments. Thus, the purpose of the present study is to investigate the cancerogenic effects of the different core protein fragments. Two series of recombinant plasmids containing hepatitis C virus core gene fragments encoding the different-length core protein were constructed using plasmid enhanced green fluorescent protein (pEGFP)-C1 and pcDNA3.1(+), respectively. Human hepatocyte L02 cells transiently transfected with pEGFP-C1-based plasmids were subjected to confocal laser scanning microscopy analysis to determine the localization of the different core protein fragments. The stably transfected L02 cells with the pcDNA3.1(+)-based core protein plasmids were used to investigate the ultrastructural effects of the core protein and the tumorigenicity of L02 cells expressing core protein fragments in athymic nude mice. The full-length core protein and Core130-191 were completely localized in the cytoplasm, while Core1-59 existed exclusively in the nucleus. On the other hand, Core50-140 and Core1-140 were observed in both the nucleus and the cytoplasm. Ultrastructural changes of L02 cells expressing the full-length core protein were comprehensive and included, for example, irregular nuclear, increased nuclear/cytoplasmic ratio and mitochondria swelling. The slight changes were observed in the cells expressing Core50-140 and Core130-191, whereas the ultrastructure of the cells expressing Core1-59 remained normal. All the L02 cells stably expressing different fragments of the core protein, with the exception of the C-terminal truncated fragment Core1-59, could induce the occurrence of tumor in the nude mice. The N-terminal fragment of the core protein, Core1-59, was not oncogenic, while the intermediate and posterior segments of the hepatitis C virus core protein had the cancerogenic potency. In view of the existence of many important immunogenic epitopes in it, the core protein anterior segment might be a safer candidate for the development of hepatitis C virus vaccine.
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Affiliation(s)
- Xiaoyan Feng
- Department of Vaccine Engineering, Beijing Institute of Basic Medical Sciences, Beijing, People's Republic of China.
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70
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Yao ZQ, King E, Prayther D, Yin D, Moorman J. T cell dysfunction by hepatitis C virus core protein involves PD-1/PDL-1 signaling. Viral Immunol 2007; 20:276-87. [PMID: 17603844 DOI: 10.1089/vim.2006.0096] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Reports have shown that a negative T cell costimulatory pathway mediated by PD-1 (programmed death-1) and PDL-1 (programmed death ligand-1) is associated with T cell exhaustion and persistent viral infection. Persistent hepatitis C virus (HCV) infection in humans is also characterized by impaired T lymphocyte function, but the role of the PD-1 and PDL-1 pathway in HCV infection is unknown. Here we report that T cells isolated from chronically HCV-infected patients express significantly higher levels of PD-1 when compared with healthy donors. In addition, PD-1 and PDL-1 expression is upregulated on healthy donor T cells exposed to HCV core, a nucleocapsid protein that is immunosuppressive; upregulation of PD-1 is mediated through interaction of HCV core with the complement receptor, gC1qR. Importantly, T cell functions that are dysregulated by HCV core, including T cell activation, proliferation, and apoptosis, can be restored by blocking PD-1 and PDL-1 engagement. Our results indicate that HCV core can upregulate a key negative T cell signaling pathway associated with viral persistence and highly expressed on the T cells of persistently infected individuals. This upregulation of the PD-1 and PDL-1 pathway in humans represents a novel and perhaps common mechanism by which a virus usurps host machinery to facilitate persistence.
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Affiliation(s)
- Zhi Q Yao
- Department of Internal Medicine, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee 37614, USA
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71
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Chang S, Dolganiuc A, Szabo G. Toll-like receptors 1 and 6 are involved in TLR2-mediated macrophage activation by hepatitis C virus core and NS3 proteins. J Leukoc Biol 2007; 82:479-87. [PMID: 17595379 DOI: 10.1189/jlb.0207128] [Citation(s) in RCA: 163] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Hepatitis C virus (HCV) is a leading cause of end-stage liver disease through sustained inflammation of the liver produced by the host's immune system. The mechanism for HCV evasion or activation of the immune system is not clear. TLRs are cellular activators of the innate immune system. We recently reported that TLR2-mediated innate immune signaling pathways are activated by HCV core and NS3 proteins. TLR2 activation requires homo- or heterodimerization with TLR1 or TLR6. Here, we aimed to determine whether TLR2 coreceptors participated in cellular activation by HCV core or NS3 proteins. By designing small interfering RNAs targeted to TLR2, TLR1, and TLR6, we showed that knockdown of each of these receptors impairs pro- and anti-inflammatory cytokine activation by TLR-specific ligands as well as by HCV core and NS3 proteins in human embryonic kidney-TLR2 cells and in primary human macrophages. We found that HCV core and NS3 proteins induced TNF-alpha and IL-10 production in human monocyte-derived macrophages, which was impaired by TLR2, TLR1, and TLR6 knockdown. Contrary to human data, results from TLR2, TLR1, or TLR6 knockout mice indicated that the absence of TLR2 and its coreceptor TLR6, but not TLR1, prevented the HCV core and NS3 protein-induced peritoneal macrophage activation. In conclusion, TLR2 may use TLR1 and TLR6 coreceptors for HCV core- and NS3-mediated activation of macrophages and innate immunity in humans. These results imply that multiple pattern recognition receptors could participate in cellular activation by HCV proteins.
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Affiliation(s)
- Serena Chang
- Department of Medicine, University of Massachusetts Medical School, LRB 215, 364 Plantation Street, Worcester, MA 01605-2324, USA
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72
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Shi L, Liu S, Fan GX, Sheng L, Ren HX, Yuan YK. Effective Induction of Type 1 Cytotoxic T Cell Responses in Mice with DNA Vaccine Encoding Two Hepatitis C Virus Cytotoxic T Lymphocyte Epitopes. Viral Immunol 2006; 19:702-11. [PMID: 17201665 DOI: 10.1089/vim.2006.19.702] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The aims of this study were to explain whether a multiple cytotoxic T lymphocyte (CTL) epitope-based anti-hepatitis C virus (HCV) DNA vaccine can induce specific CTL responses to each HCV CTL epitope independently and long-term CD8(+) T cell memory responses, and to determine the cytokine secretion pattern and subtype of epitope-specific cytotoxic T cells. A multi-CTL epitope gene, which consists of two epitopes of HCV (H-2(d)-restricted HCV core(133142) and E1(315322)), was cloned into the eukaryotic expression vector pcDNA3.1. BALB/c mice (H-2(d) restricted) were vaccinated intramuscularly with this multi-CTL epitope-based DNA vaccine. The epitope-specific CTLs against target cells (P815,H-2(d) restricted) pulsed with various CTL epitope peptides were detected by lactate dehydrogenase release assay, and the precursor frequency of epitope-specific CTLs was determined by limiting dilution analysis. Cytokines (interleukin [IL]-2, IL-4, and interferon-) in culture supernatants were determined by enzyme-linked immunosorbent assay. The multi-CTL epitope-based DNA vaccine directed against two HCV CTL epitopes could induce specific CTL responses to each of the two CTL epitopes independently and long-term CD8(+) T cell memory responses. The epitope-specific cytotoxic T cells produced helper T cell type 1 cytokines. This work demonstrated that multiepitope DNA vaccination is a potential strategy to control HCV infection.
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Affiliation(s)
- Lin Shi
- Department of Immunology and Microbiology, Xi'an Jiaotong University School of Medicine, Xi'an, PR China
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73
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Wu CG, Budhu A, Chen S, Zhou X, Popescu NC, Valerie K, Wang XW. Effect of hepatitis C virus core protein on the molecular profiling of human B lymphocytes. Mol Med 2006; 12:47-53. [PMID: 16838065 PMCID: PMC1514550 DOI: 10.2119/2006-00020.wu] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2006] [Accepted: 04/05/2006] [Indexed: 12/19/2022] Open
Abstract
Hepatitis C virus (HCV) core protein features many intriguing properties and plays a pivotal role in cellular immunity, cell growth, apoptosis, cell transformation, and eventually in tumor development. However, the role of B cells, the primary players in the humoral immune response, during HCV infection is largely unknown. To explore the molecular effects of HCV core on human B cells, we conducted gene expression profiling of serial RNA samples from B cells that were infected with adenovirus harboring full-length HCV core protein and beta-galactosidase as a reference using a microarray platform containing 22,149 human oligo probes. The entire experiment was performed in duplicate in B lymphocytes that were isolated from two individual donors and incubated for up to 3 days after infection with adenovirus expressing HCV core protein to identify dynamic gene expression patterns. Differential expression of representative genes was validated by quantitative RT-PCR. We found that HCV core significantly inhibited B-lymphocyte apoptosis. We showed a dramatic downregulation of MHC class II molecules in B cells expressing HCV core, whereas the expression of immunoglobulin genes was not significantly altered. Moreover, genes associated with leukemia and B-lymphoma were consistently upregulated by HCV core. In contrast, downregulation of caspase-1 and caspase-4 was found to be associated with core's ability to prevent B-lymphocyte apoptosis. In summary, we have identified several clusters of genes that are differentially expressed in human B lymphocytes expressing HCV core, suggesting a potential impairment of antigen processing and presentation, which may provide more insights into HCV infection in B lymphocytes.
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Affiliation(s)
- Chuan-ging Wu
- Division of Hematology, Center for Biologics Evaluation and Research, Food
and Drug Administration, Bethesda, MD, USA
- Address correspondence and reprint requests to Chuan-ging Wu, Division
of Hematology, HFM-345, Center for Biologics Evaluation and Research, Food
and Drug Administration, 29 Lincoln Dr, Bethesda, MD 20892. Phone: (301) 827-6580; fax: (301) 402-2780; e-mail: . Xin Wei Wang, Laboratory of Human Carcinogenesis, National Cancer Institute, NIH, Bldg 37, Rm 4146, 37 Convent Dr, Bethesda, MD 20892-4255. Phone: (301) 496-2099; fax: (301) 496-0497; e-mail:
| | - Anuradha Budhu
- Laboratory of Human Carcinogenesis, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Sheng Chen
- Autoimmunity Branch, National Institute of Arthritis and Musculoskeletal
and Skin Diseases, NIH, Bethesda, MD, USA
| | - Xiaoling Zhou
- Laboratory of Experimental Carcinogenesis, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Nicholas C. Popescu
- Laboratory of Experimental Carcinogenesis, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Kristoffer Valerie
- Department of Radiation Oncology, Medical College of Virginia, Virginia
Commonwealth University, Richmond, VA, USA
| | - Xin Wei Wang
- Laboratory of Human Carcinogenesis, National Cancer Institute, NIH, Bethesda, MD, USA
- Address correspondence and reprint requests to Chuan-ging Wu, Division
of Hematology, HFM-345, Center for Biologics Evaluation and Research, Food
and Drug Administration, 29 Lincoln Dr, Bethesda, MD 20892. Phone: (301) 827-6580; fax: (301) 402-2780; e-mail: . Xin Wei Wang, Laboratory of Human Carcinogenesis, National Cancer Institute, NIH, Bldg 37, Rm 4146, 37 Convent Dr, Bethesda, MD 20892-4255. Phone: (301) 496-2099; fax: (301) 496-0497; e-mail:
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74
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Kitazawa S, Takenaka A, Kondo T, Mizoguchi A, Kitazawa R. Protruding disordered loop of gC1qR is specifically exposed and related to antiapoptotic property in germ cell lineage. Histochem Cell Biol 2006; 126:665-77. [PMID: 16871385 DOI: 10.1007/s00418-006-0225-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/07/2006] [Indexed: 10/24/2022]
Abstract
We established a monoclonal antibody (MAb), 5G9, with the use of a fixed seminoma tissue from an archival paraffin-embedded specimen, as an immunogen. Without antigen retrieval, positive 5G9-immunohistochemical staining was confined mostly to primordial germ cells, spermatogonia and various germ cell tumors. 5G9 recognized a mitochondrial 32-kD protein with an isoelectric point of pH 4.2, identified as a multifunctional ubiquitous protein, receptor for globular head of C1q (gC1qR), whose epitope was mapped in a disordered loop connecting the beta3 and the beta4 strands. Reflecting the ubiquitous distribution of gC1qR, with antigen retrieval, 5G9 was found reactive to a wide range of normal and tumor tissues. Since several co-precipitated and phosphorylated bands were observed in various human cell lines but not in germ cell tumor cell lines by in vitro phosphorylation assay, we speculate that the epitope of gC1qR is specifically unmasked in the germ cell lineage. By reducing gC1qR by siRNA, a significant increase was observed in the number of apoptotic cells in ITO-II and TCam-2 cell lines, but to a lesser extent in the Colo201 colon cancer cell line, showing an antiapoptotic property of gC1qR in the germ cells. Since protein-protein interaction is partially preserved by fixation, archival paraffin-embedded specimens can be a valuable source of immunogens for generating monoclonal antibodies (MAbs) that recognize tissue-specific protein conformation.
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Affiliation(s)
- Sohei Kitazawa
- Division of Molecular Pathology, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
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75
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Saito K, Meyer K, Warner R, Basu A, Ray RB, Ray R. Hepatitis C virus core protein inhibits tumor necrosis factor alpha-mediated apoptosis by a protective effect involving cellular FLICE inhibitory protein. J Virol 2006; 80:4372-9. [PMID: 16611896 PMCID: PMC1472009 DOI: 10.1128/jvi.80.9.4372-4379.2006] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
We have previously shown that hepatitis C virus (HCV) core protein modulates multiple cellular processes, including those that inhibit tumor necrosis factor alpha (TNF-alpha)-mediated apoptosis. In this study, we have investigated the signaling mechanism for inhibition of TNF-alpha-mediated apoptosis in human hepatoma (HepG2) cells expressing core protein alone or in context with other HCV proteins. Activation of caspase-3 and the cleavage of DNA repair enzyme poly(ADP-ribose) polymerase were inhibited upon TNF-alpha exposure in HCV core protein-expressing HepG2 cells. In vivo protein-protein interaction studies displayed an association between TNF receptor 1 (TNFR1) and TNFR1-associated death domain protein (TRADD), suggesting that the core protein does not perturb this interaction. A coimmunoprecipitation assay also suggested that HCV core protein does not interfere with the TRADD-Fas-associated death domain protein (FADD)-procaspase-8 interaction. Further studies indicated that HCV core protein expression inhibits caspase-8 activation by sustaining the expression of cellular FLICE (FADD-like interleukin-1beta-converting enzyme)-like inhibitory protein (c-FLIP). Similar observations were also noted upon expression of core protein in context to other HCV proteins expressed from HCV full-length plasmid DNA or a replicon. A decrease in endogenous c-FLIP by specific small interfering RNA induced TNF-alpha-mediated apoptotic cell death and caspase-8 activation. Taken together, our results suggested that the TNF-alpha-induced apoptotic pathway is inhibited by a sustained c-FLIP expression associated with the expression of HCV core protein, which may play a role in HCV-mediated pathogenesis.
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Affiliation(s)
- Kousuke Saito
- Department of Internal Medicine, Saint Louis University, 3635 Vista Ave., FDT-8N, St. Louis, Missouri 63110, USA
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76
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Yao ZQ, Waggoner SN, Cruise MW, Hall C, Xie X, Oldach DW, Hahn YS. SOCS1 and SOCS3 are targeted by hepatitis C virus core/gC1qR ligation to inhibit T-cell function. J Virol 2006; 79:15417-29. [PMID: 16306613 PMCID: PMC1315996 DOI: 10.1128/jvi.79.24.15417-15429.2005] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
T cells play an important role in the control of hepatitis C virus (HCV) infection. We have previously demonstrated that the HCV core inhibits T-cell responses through interaction with gC1qR. We show here that core proteins from chronic and resolved HCV patients differ in sequence, gC1qR-binding ability, and T-cell inhibition. Specifically, chronic core isolates bind to gC1qR more efficiently and inhibit T-cell proliferation as well as gamma interferon (IFN-gamma) production more profoundly than resolved core isolates. This inhibition is mediated by the disruption of STAT phosphorylation through the induction of SOCS molecules. Silencing either SOCS1 or SOCS3 by small interfering RNA dramatically augments the production of IFN-gamma in T cells, thereby abrogating the inhibitory effect of core. Additionally, the ability of core proteins from patients with chronic infections to induce SOCS proteins and suppress STAT activation greatly exceeds that of core proteins from patients with resolved infections. These results suggest that the HCV core/gC1qR-induced T-cell dysfunction involves the induction of SOCS, a powerful inhibitor of cytokine signaling, which represents a novel mechanism by which a virus usurps the host machinery for persistence.
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Affiliation(s)
- Zhi Qiang Yao
- Beirne Carter Center for Immunology Research, Department of Microbiology and Pathology, University of Virginia, Charlottesville, VA 22908, USA
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77
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Jin YH, Crispe IN, Park S. Expression of hepatitis C virus core protein in hepatocytes does not modulate proliferation or apoptosis of CD8+ T cells. Yonsei Med J 2005; 46:827-34. [PMID: 16385660 PMCID: PMC2810598 DOI: 10.3349/ymj.2005.46.6.827] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Hepatocytes are the primary targets of the hepatitis C virus (HCV). While immunosuppressive roles of HCV core protein have been found in several studies, it remains uncertain whether core protein expressed in hepatocytes rather than in immune cells affects the CD8+ T cell response. In order to transduce genes selectively into hepatocytes, we developed a baculoviral vector system that enabled primary hepatocytes to express a target epitope for CD8+ T cells, derived from ovalbumin (OVA), with or without HCV core protein. Culture of OVA-specific CD8+ T cells with hepatocytes infected with these baculoviral vectors revealed that core protein has no effect on proliferation or apoptosis of CD8+ T cells. Our results suggest that HCV core protein does not exert its suppressive role on the CD8+ T cell immune response through expression in hepatocytes.
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Affiliation(s)
- Young-Hee Jin
- The David H Smith Center for Vaccine Biology and Immunology, University of Rochester, Rochester, New York 14642, USA
| | - I. Nicholas Crispe
- The David H Smith Center for Vaccine Biology and Immunology, University of Rochester, Rochester, New York 14642, USA
| | - Sun Park
- The David H Smith Center for Vaccine Biology and Immunology, University of Rochester, Rochester, New York 14642, USA
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78
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Szabo G, Dolganiuc A. Subversion of plasmacytoid and myeloid dendritic cell functions in chronic HCV infection. Immunobiology 2005; 210:237-47. [PMID: 16164031 DOI: 10.1016/j.imbio.2005.05.018] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Insufficient elimination of the hepatitis C virus (HCV) during acute infection results in chronic disease in the majority of patients due to weak virus-specific immune responses. Dendritic cells (DC) play a central role in recognition of HCV and in induction of innate and adaptive immune responses. In this study, we evaluated the frequency and functions of plasmacytoid dendritic cells (PDC) and myeloid dendritic cells (MDC) in patients with chronic HCV infection. We found that both the numbers and IFNalpha production capacity of blood PDC were significantly reduced in patients with chronic HCV infection compared to normal controls. While the frequency of MDC was not affected in chronic HCV, the allostimulatory capacity of monocyte-derived MDC was significantly decreased compared to normals. Lipopolysaccharide (LPS)-induced maturation improved the allostimulatory capacity of HCV infected patients' MDC that still remained significantly lower compared to normal controls. Our experiments revealed that MDC defects can be induced by HCV core and NS3 proteins suggesting virus-induced mechanisms for the DC defects in HCV infection. Finally, using toll-like receptor 2 (TLR2) and TLR4 deficient or mutant mice, we demonstrated that TLR2 but not TLR4 was critical in recognition of HCV core and NS3 proteins by innate immune cells. Further, TLR2 recognition of HCV core and NS3 was not augmented by co-expression of the TLR co-receptor, CD14. These data demonstrate that both PDC and MDC functions are impaired in patients with chronic HCV infection and DC defects are likely related to interaction of HCV viral products with innate immune cells.
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Affiliation(s)
- Gyongyi Szabo
- Department of Medicine, University of Massachusetts Medical School, LRB 215, 364 Plantation Street, Worcester, MA 01605-2324, USA.
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79
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Moorman JP, Fitzgerald SM, Prayther DC, Lee SA, Chi DS, Krishnaswamy G. Induction of p38- and gC1qR-dependent IL-8 expression in pulmonary fibroblasts by soluble hepatitis C core protein. Respir Res 2005; 6:105. [PMID: 16164755 PMCID: PMC1243242 DOI: 10.1186/1465-9921-6-105] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2005] [Accepted: 09/15/2005] [Indexed: 01/04/2023] Open
Abstract
Background Recent studies suggest that HCV infection is associated with progressive declines in pulmonary function in patients with underlying pulmonary diseases such as asthma and chronic obstructive pulmonary disease. Few molecular studies have addressed the inflammatory aspects of HCV-associated pulmonary disease. Because IL-8 plays a fundamental role in reactive airway diseases, we examined IL-8 signaling in normal human lung fibroblasts (NHLF) in response to the HCV nucleocapsid core protein, a viral antigen shown to modulate intracellular signaling pathways involved in cell proliferation, apoptosis and inflammation. Methods NHLF were treated with HCV core protein and assayed for IL-8 expression, phosphorylation of the p38 MAPK pathway, and for the effect of p38 inhibition. Results Our studies demonstrate that soluble HCV core protein induces significant increases in both IL-8 mRNA and protein expression in a dose- and time-dependent manner. Treatment with HCV core led to phosphorylation of p38 MAPK, and expression of IL-8 was dependent upon p38 activation. Using TNFα as a co-stimulant, we observed additive increases in IL-8 expression. HCV core-mediated expression of IL-8 was inhibited by blocking gC1qR, a known receptor for soluble HCV core linked to MAPK signaling. Conclusion These studies suggest that HCV core protein can lead to enhanced p38- and gC1qR-dependent IL-8 expression. Such a pro-inflammatory role may contribute to the progressive deterioration in pulmonary function recently recognized in individuals chronically infected with HCV.
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Affiliation(s)
- Jonathan P Moorman
- Department of Internal Medicine, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
- Medical Service, James H. Quillen VAMC, Johnson City, TN, USA
| | - S Matthew Fitzgerald
- Department of Internal Medicine, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
| | - Deborah C Prayther
- Department of Internal Medicine, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
| | - Steven A Lee
- Department of Internal Medicine, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
| | - David S Chi
- Department of Internal Medicine, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
| | - Guha Krishnaswamy
- Department of Internal Medicine, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
- Medical Service, James H. Quillen VAMC, Johnson City, TN, USA
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80
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Falcón V, Acosta-Rivero N, Shibayama M, Chinea G, Gavilondo JV, de la Rosa MC, Menéndez I, Gra B, Dueñas-Carrera S, Viña A, García W, González-Bravo M, Luna-Munoz J, Miranda-Sanchez M, Morales-Grillo J, Kouri J, Tsutsumi V. HCV core protein localizes in the nuclei of nonparenchymal liver cells from chronically HCV-infected patients. Biochem Biophys Res Commun 2005; 329:1320-8. [PMID: 15766571 DOI: 10.1016/j.bbrc.2005.02.107] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2005] [Indexed: 12/28/2022]
Abstract
Understanding the mechanism of hepatitis C virus (HCV) pathogenesis is an important part of HCV research. Recent experimental evidence suggests that the HCV core protein (HCcAg) has numerous functional activities. These properties suggest that HCcAg, in concert with cellular factors, may contribute to pathogenesis during persistent HCV infection. HCV is capable of infecting cells other than hepatocytes. Although the extrahepatic cellular tropism of HCV may play a role in the pathophysiology of this infection, the precise biological significance of the presence of HCV components in different liver cell types presently remains to be established. In this study, HCcAg was detected in nonparenchymal liver cells of six patients out of eight positive for serum HCV RNA. Immunostaining with anti-HCcAg mAbs revealed the presence of this protein in different liver cell types such as lymphocytes, Kupffer, polymorphonuclear, pit, endothelial, stellate, and fibroblast-like cells. Interestingly, HCcAg was immunolabeled not only in the cytoplasm but also in the nucleus of these cells. Remarkably, HCcAg co-localized with large lipid droplets present in stellate cells and with collagen fibers in the extracellular matrix. Moreover, HCcAg was immunolabeled in bile canaliculus suggesting the involvement of the biliary system in the pathobiology of HCV. Data suggest that nonparenchymal liver cells may constitute a reservoir for HCV replication. Besides, HCcAg may contribute to modulate immune function and fibrosis in the liver as well as steatosis.
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Affiliation(s)
- Viviana Falcón
- Biomedicine Division, Center for Genetic Engineering and Biotechnology, P.O. Box 6162, C.P. 10600, Havana, Cuba.
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Abstract
The year 2004 represents a milestone for the biosensor research community: in this year, over 1000 articles were published describing experiments performed using commercially available systems. The 1038 papers we found represent an approximately 10% increase over the past year and demonstrate that the implementation of biosensors continues to expand at a healthy pace. We evaluated the data presented in each paper and compiled a 'top 10' list. These 10 articles, which we recommend every biosensor user reads, describe well-performed kinetic, equilibrium and qualitative/screening studies, provide comparisons between binding parameters obtained from different biosensor users, as well as from biosensor- and solution-based interaction analyses, and summarize the cutting-edge applications of the technology. We also re-iterate some of the experimental pitfalls that lead to sub-optimal data and over-interpreted results. We are hopeful that the biosensor community, by applying the hints we outline, will obtain data on a par with that presented in the 10 spotlighted articles. This will ensure that the scientific community at large can be confident in the data we report from optical biosensors.
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Affiliation(s)
- Rebecca L Rich
- Center for Biomolecular Interaction Analysis, University of Utah, Salt Lake City, UT 84132, USA
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