151
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Elliot LN, Lloyd AR, Ziegler JB, Ffrench RA. Protective immunity against hepatitis C virus infection. Immunol Cell Biol 2006; 84:239-49. [PMID: 16509830 DOI: 10.1111/j.1440-1711.2006.01427.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
There is increasing evidence that a small percentage of individuals exposed to the hepatitis C virus have the capacity to generate a strong cellular immune response against the virus and avoid persistent infection, and perhaps do so repeatedly after re-exposure. This article reviews the evidence that the responses identified in this unique group of individuals represent the protective immunity that will need to be elicited by hepatitis C virus vaccines.
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Affiliation(s)
- Lisa N Elliot
- School of Women's and Children's Health, The University of New South Wales, Sydney, New South Wales, Australia
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152
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Gallegos-Orozco JF, Arenas JI, Vargas HE, Kibler KV, Wilkinson JK, Nowicki M, Radkowski M, Nasseri J, Rakela J, Laskus T. Selection of different 5' untranslated region hepatitis C virus variants during post-transfusion and post-transplantation infection. J Viral Hepat 2006; 13:489-98. [PMID: 16792543 DOI: 10.1111/j.1365-2893.2006.00724.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
BACKGROUND Hepatitis C virus (HCV) translation is initiated in a cap-independent manner by an internal ribosome entry site (IRES) located within the 5' untranslated region (5'UTR). Sequence changes in this region could affect translation efficiency and presumably viral replication. AIM To determine translation efficiency of 5'UTR variants developing during post-transfusion hepatitis C in two immunocompetent subjects and in two immunosuppressed liver recipients with recurrent HCV. METHODS Sequential samples were screened for 5'UTR changes by single-strand conformation polymorphism followed by cloning and sequencing whenever band pattern suggested sequence changes. 5'UTR variants were tested for IRES activity using a bicistronic dual luciferase expression plasmid transfected into HepG2 and Huh7 cell-lines. RESULTS In the transfused patients, translation efficiency of 5'UTR variants from early post-transfusion samples was 5.1- to 13.7-fold higher than that of predominant variants found in late follow-up samples. Post-transplant variants in the other two patients had 2.6- to 5.9-fold higher translation efficiency than those present only in pretransplant samples. CONCLUSION In the immunocompetent host there may be selection of low translation efficiency HCV variants over the course of infection. However, in immunosuppressed subjects the opposite seems to be true as low translation efficiency variants are superseded by high translation efficiency variants.
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Affiliation(s)
- J F Gallegos-Orozco
- Division of Transplantation Medicine, Mayo Clinic, Scottsdale, AZ 85259, USA.
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153
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Katsoulidou A, Sypsa V, Tassopoulos NC, Boletis J, Karafoulidou A, Ketikoglou I, Tsantoulas D, Vafiadi I, Hatzis G, Skoutelis A, Akriviadis E, Vasiliadis T, Kitis G, Magiorkinis G, Hatzakis A. Molecular epidemiology of hepatitis C virus (HCV) in Greece: temporal trends in HCV genotype-specific incidence and molecular characterization of genotype 4 isolates. J Viral Hepat 2006; 13:19-27. [PMID: 16364078 DOI: 10.1111/j.1365-2893.2005.00649.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
This study aimed to estimate the overall HCV genotype distribution and to reconstruct the HCV genotype-specific incidence in Greece during the recent decades. It also focused at the identification of genotype 4 subtype variability in Greek isolates. A total of 1686 chronically infected HCV patients with detectable serum HCV RNA by RT-PCR, belonging to different risk groups were studied. Amplified products from the 5'-noncoding region were typed using a commercially available assay based on the reverse hybridization principle. The HCV genotype-specific incidence was estimated using a previously described back calculation method. HCV genotype 1 was the most prevalent (46.9%) followed by genotype 3 (28.1%), 4 (13.2%), 2 (6.9%) and 5 (0.4%). A high prevalence of genotype 1 (66.3%) in haemophilia patients was recorded whereas HCV genotype 3 was found mainly among patients infected by I.V. drug use (58.2%). Data on the temporal patterns of HCV genotype-specific incidence in Greece revealed a moderate increase (1.3-1.6 times) for genotypes 1 and 4, and a decrease (1.5 times) for genotype 2 from 1970 to 1990, whereas there was a sharp (13-fold) increase for genotype 3. The molecular characterization of 41 genotype 4 HCV isolates belonging to various risk groups revealed that, subtype 4a was the most frequently detected (78%). Phylogenetic comparison of the Greek 4a isolates with all HCV-4a isolates reported worldwide so far revealed a topology which does not discriminate Greek isolates from the others. HCV-4 does not represent a recent introduction in Greece.
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Affiliation(s)
- A Katsoulidou
- Department of Hygiene and Epidemiology, Athens University Medical School, Athens, Greece
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154
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Sun ZH, Ma WL, Zhang B, Peng YF, Zheng WL. Application of restriction display PCR technique in the preparation of cDNA microarray probes. World J Gastroenterol 2005; 11:7579-84. [PMID: 16437681 PMCID: PMC4727234 DOI: 10.3748/wjg.v11.i48.7579] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2005] [Revised: 07/10/2005] [Accepted: 07/15/2005] [Indexed: 02/06/2023] Open
Abstract
AIM To develop a simplified and efficient method for the preparation of hepatitis C virus (HCV) cDNA microarray probes. METHODS With the technique of restriction display PCR (RD-PCR), restriction enzyme Sau3A I was chosen to digest the full-length HCV cDNAs. The products were classified and re-amplified by RD-PCR. We separated the differential genes by polyacrylamide gel electrophoresis and silver staining. Single bands cut out from the polyacrylamide gel were isolated. The third-round PCR was performed using the single bands as PCR template. The RD-PCR fragments were purified and cloned into the pMD18-T vector. The recombinant plasmids were extracted from positive clones, and the target gene fragments were sequenced. The cDNA microarray was prepared by spotting RD-PCR products to the surface of amino-modified glass slides using a robot. We validated the detection of microarray by hybridization and sequence analysis. RESULTS A total of 24 different cDNA fragments ranging from 200 to 800 bp were isolated and sequenced, which were the specific gene fragments of HCV. These fragments could be further used as probes in microarray preparation. The diagnostic capability of the microarray was evaluated after the washing and scanning steps. The results of hybridization and sequence analysis showed that the specificity, sensitivity, accuracy, reproducibility, and linearity in detecting HCV RNA were satisfactory. CONCLUSION The RD-PCR technique is of great value in obtaining a large number of size-comparable gene probes, which provides a speedy protocol in generating probes for the preparation of microarrays. Microarray prepared as such could be further optimized and applied in the clinical diagnosis of HCV.
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Affiliation(s)
- Zhao-Hui Sun
- Institute of Genetic Engineering, Southern Medical University, Guangzhou 510515, Guangdong Province, China
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155
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Itakura J, Nagayama K, Enomoto N, Hamano K, Sakamoto N, Fanning LJ, Kenny-Walsh E, Shanahan F, Watanabe M. Viral load change and sequential evolution of entire hepatitis C virus genome in Irish recipients of single source-contaminated anti-D immunoglobulin*. J Viral Hepat 2005; 12:594-603. [PMID: 16255760 DOI: 10.1111/j.1365-2893.2005.00645.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
In hepatitis C virus (HCV) infection, serum viral load is important in the prediction of therapeutic efficacy. However, factors that affect the viral load remain poorly understood. To identify viral genomic elements responsible for the viral load, we investigated samples from a population of Irish women who were iatrogenically infected from a single HCV source by administration of HCV 1b-contaminated anti-D immune globulin between 1977 and 1978 (Kenny-Walsh, N Engl J Med 1999; 340: 1228). About 15 patients were divided into two groups, viral load increasing group (11 patients) and decreasing group (4 patients). Pairs of sera were collected from each patient at interval between 1.1 and 5.8 years. Full-length sequences of HCV genome were determined, and analyzed for changes in each patient. Sliding window analysis showed that the decreasing group had significantly higher mutation rates in a short segment of NS5B region that may affect the activity of RNA-dependent RNA polymerase. By comparing each coding regions, significantly higher mutation numbers were accumulated in NS5A region in the increasing group than the decreasing group (0.92 vs 0.16 nucleotides/site/year, P = 0.021). The mutation in certain positions of the HCV genome may be determinant factors of the viral load in a relatively homogeneous patient population.
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Affiliation(s)
- J Itakura
- Department of Gastroenterology and Hepatology, Tokyo Medical and Dental University, Tokyo, Japan
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156
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Mizokami M, Tanaka Y, Miyakawa Y. Spread Times of Hepatitis C Virus Estimated by the Molecular Clock Differ among Japan, the United States and Egypt in Reflection of Their Distinct Socioeconomic Backgrounds. Intervirology 2005; 49:28-36. [PMID: 16166786 DOI: 10.1159/000087260] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Infection with hepatitis C virus (HCV) is taking an ever increasing role in the development of hepatocellular carcinoma (HCC) over the world. Dynamics of HCV infection were determined by the molecular clock, estimating the dissemination time when HCV entered the country and the "spread time" when it started to grow exponentially on a national scale. A comparison of HCV dynamics in Japan, the United States and Egypt has disclosed different dissemination and spread times among the three countries. Furthermore, they faithfully mirror socioeconomic as well as medical and paramedical events inherent to each country responsible for the wide spread of HCV infection during the past. Epidemic histories of HCV would enable us to predict what is going to happen in the future for HCV infection, in special reference to HCC associated with it. Population dynamics of HCV need to be determined in other countries where HCV prevails and compared with those in the three countries described. These studies should help foresee what will happen in the near future for HCV infection in a given country, time the future development of HCC and take measures for preventing it.
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Affiliation(s)
- Masashi Mizokami
- Department of Clinical Molecular Informative Medicine, Nagoya City University Graduate School of Medical Sciences, Nagoya 467-8601, Japan.
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157
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Ray SC, Fanning L, Wang XH, Netski DM, Kenny-Walsh E, Thomas DL. Divergent and convergent evolution after a common-source outbreak of hepatitis C virus. ACTA ACUST UNITED AC 2005; 201:1753-9. [PMID: 15939791 PMCID: PMC2213258 DOI: 10.1084/jem.20050122] [Citation(s) in RCA: 160] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The genomic sequences of viruses that are highly mutable and cause chronic infection tend to diverge over time. We report that these changes represent both immune-driven selection and, in the absence of immune pressure, reversion toward an ancestral consensus. Sequence changes in hepatitis C virus (HCV) structural and nonstructural genes were studied in a cohort of women accidentally infected with HCV in a rare common-source outbreak. We compared sequences present in serum obtained 18–22 yr after infection to sequences present in the shared inoculum and found that HCV evolved along a distinct path in each woman. Amino acid substitutions in known epitopes were directed away from consensus in persons having the HLA allele associated with that epitope (immune selection), and toward consensus in those lacking the allele (reversion). These data suggest that vaccines for genetically diverse viruses may be more effective if they represent consensus sequence, rather than a human isolate.
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Affiliation(s)
- Stuart C Ray
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA.
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158
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Affiliation(s)
- Stefan F Wieland
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
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159
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Zehender G, De Maddalena C, Bernini F, Ebranati E, Monti G, Pioltelli P, Galli M. Compartmentalization of hepatitis C virus quasispecies in blood mononuclear cells of patients with mixed cryoglobulinemic syndrome. J Virol 2005; 79:9145-56. [PMID: 15994809 PMCID: PMC1168762 DOI: 10.1128/jvi.79.14.9145-9156.2005] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The aim of this study was to investigate the quasispecies heterogeneity of hepatitis C virus (HCV) in the plasma, cryoprecipitate, and peripheral lymphocytes of chronically infected HCV patients with mixed cryoglobulinemia (MC). We studied 360 clones from 10 HCV-positive patients with MC and 8 age-, gender- and HCV genotype-matched subjects with chronic HCV infection but without MC. A partial nucleotide sequence encompassing the E1/E2 region, including hypervariable region 1 (HVR1), was amplified and cloned from plasma, cryoprecipitates, and peripheral blood mononuclear cells (PBMC), and the genetic diversity and complexity and synonymous and nonsynonymous substitution rates were determined. Heterogeneous selection pressure at codon sites was evaluated. Compartmentalization was estimated by phylogenetic and phenetic (Mantel's test) approaches. The patients with MC had 3.3 times lower nonsynonymous substitution rates (1.7 versus 5.7 substitutions/100 sites). Among the subjects with HCV genotype 1, the MC patients had significantly less complexity than the controls, whereas the diversity and complexity were similar in the genotype 2 patients and controls. Site-specific selection analysis confirmed the low frequency of MC patients showing positive selection. There was a significant correlation between positive selection and the infecting HCV genotype. The quasispecies were less heterogeneous in PBMC than in plasma. Significant compartmentalization of HCV quasispecies was observed in the PBMC of four of nine subjects (three with MC) and seven of nine cryoprecipitates. In one subject with MC, we detected a 5-amino-acid insertion at codons 385 to 389 of HVR1. Our results suggest reduced quasispecies heterogeneity in MC patients that is related to a low selection pressure which is probably due to an impaired immune response, the HCV genotype, and/or the duration of the infection. The frequent HCV quasispecies compartmentalization in patients' PBMC suggests a possible pathogenetic significance.
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Affiliation(s)
- Gianguglielmo Zehender
- Istituto di Malattie Infettive e Tropicali, Università di Milano c/o Ospedale L. Sacco, Via G.B. Grassi 74, 20157 Milan, Italy.
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160
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Ludmerer SW, Graham DJ, Boots E, Murray EM, Simcoe A, Markel EJ, Grobler JA, Flores OA, Olsen DB, Hazuda DJ, LaFemina RL. Replication fitness and NS5B drug sensitivity of diverse hepatitis C virus isolates characterized by using a transient replication assay. Antimicrob Agents Chemother 2005; 49:2059-69. [PMID: 15855532 PMCID: PMC1087645 DOI: 10.1128/aac.49.5.2059-2069.2005] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The innate genetic variability characteristic of chronic hepatitis C virus (HCV) infection makes drug resistance a concern in the clinical development of HCV inhibitors. To address this, a transient replication assay was developed to evaluate the replication fitness and the drug sensitivity of NS5B sequences isolated from the sera of patients with chronic HCV infection. This novel assay directly compares replication between NS5B isolates, thus bypassing the potential sequence and metabolic differences which may arise with independent replicon cell lines. Patient-derived NS5B sequences were similar to those of the established HCV genotypes, but isolates from each patient shared genetic variability specific to that patient, with additional genetic variability observed across the individual isolates. Every sample provided functional NS5B isolates which supported subgenomic replication, frequently to levels comparable to that of laboratory-optimized replicons. All isolates were equivalently sensitive to an active-site nucleoside inhibitor, but the sensitivities to a panel of nonnucleoside inhibitors which targeted three distinct sites on NS5B varied among the isolates. In con1, the original laboratory-optimized replicon, the NS5B S282T substitution confers resistance to the nucleoside inhibitor but impairs replication. This substitution was engineered into both genotype 1a and genotype 1b isolates. Replication was severely debilitated, demonstrating that no compensatory residues were encoded within these genetically diverse sequences to increase the replication fitness of the mutated replicons. This work describes a transient replicon-based assay that can support the clinical development of compounds which target NS5B and demonstrates its utility by examining several patient-derived NS5B isolates for replication fitness and differential sensitivity to NS5B inhibitors.
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Affiliation(s)
- Steven W Ludmerer
- Department of Antiviral Research, Merck Research Laboratories, P.O. Box 4, Sumneytown Pike, West Point, PA 19486, USA
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161
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Boulestin A, Sandres-Saune K, Alric L, Pipy B, Dubois M, Vinel JP, Izopet J. Evolution of Hepatitis C Virus Quasispecies during Therapy with Il2 Combinated to Alpha Interferon and Ribavirin. Antivir Ther 2005. [DOI: 10.1177/135965350501000408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
This study analyses the impact of interleukin 2 (IL2) combined with alpha interferon (IFN-α) and ribavirin on the heterogeneity of hepatitis C virus (HCV). We studied 10 patients who took part in a clinical trial that assessed the effects of retreatment with IL2, IFN-α and ribavirin in patients who failed to clear the virus after a previous bitherapy. The heterogeneity of HCV quasispecies was assessed by cloning and sequencing the hypervariable region 1 (HVR1) in samples obtained at baseline (W0), after 12 weeks of treatment with IFN-α and ribavirin (W12), after a cycle of administration of IL2 in combination with the classical bitherapy (W21 and W24) in the eight patients who failed to clear the virus under treatment. The mean viral load at W21 and at W24 was not different from that at W12. The heterogeneity of HVR1 quasispecies after the administration of IL2 was not different from that at baseline or after 12 weeks of bitherapy. Furthermore, the proportion of nonsynonymous substitutions was unchanged after the IL2 cycles. Thus, the efficacy of the tritherapy with IL2, IFN-α and ribavirin is similar to that of the classical bitherapy. Treatment with IL2 in combination with IFN-α and ribavirin had no effect on the selective pressure on HCV quasispecies. IL2 is not the best option to treat hepatitis C.
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Affiliation(s)
- Anne Boulestin
- Laboratoire de Virologie EA 2046, IFR30, Toulouse, France
| | | | - Laurent Alric
- Service de Médecine Interne, Fédération Digestive, Toulouse, France
- Laboratoire des Macrophages, Médiateurs de l'Inflammation et Interactions cellulaires, Institut Louis Bugnard, Toulouse, France
| | - Bernard Pipy
- Laboratoire des Macrophages, Médiateurs de l'Inflammation et Interactions cellulaires, Institut Louis Bugnard, Toulouse, France
| | - Martine Dubois
- Laboratoire de Virologie EA 2046, IFR30, Toulouse, France
| | - Jean-Pierre Vinel
- Service d'Hépato-Gastroentérologie, Fédération Digestive, Toulouse, France
| | - Jacques Izopet
- Laboratoire de Virologie EA 2046, IFR30, Toulouse, France
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162
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Kato N, Nakamura T, Dansako H, Namba K, Abe KI, Nozaki A, Naka K, Ikeda M, Shimotohno K. Genetic variation and dynamics of hepatitis C virus replicons in long-term cell culture. J Gen Virol 2005; 86:645-656. [PMID: 15722525 DOI: 10.1099/vir.0.80479-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Hepatitis C virus (HCV) genomic sequences are known to vary widely among HCV strains, but to date there have been few reports on the genetic variations and dynamics of HCV in an experimental system of HCV replication. In this study, a genetic analysis of HCV replicons obtained in long-term culture of two HCV replicon cells (50-1 and 1B-2R1), which were established from two HCV strains, 1B-1 and 1B-2, respectively, was performed. One person cultured 50-1 cells for 18 months, and two people independently cultured 50-1 cells for 12 months. 1B-2R1 cells were also cultured for 12 months. The whole nucleotide sequences of the three independent replicon RNA clones obtained at several time points were determined. It was observed that genetic mutations in both replicons accumulated in a time-dependent manner, and that the mutation rates of both replicons were approximately 3·0×10−3 base substitutions/site/year. The genetic diversity of both replicons was also enlarged in a time-dependent manner. The colony formation assay by transfection of total RNAs isolated from both replicon cells at different time points into naïve HuH-7 cells revealed that the genetic mutations accumulating with time in both replicons apparently improved colony formation efficiency. Taken together, these results suggest that the HCV replicon system is useful for the analysis of evolutionary dynamics and variations of HCV. Using this replicon cell culture system, it was demonstrated further that neither ribavirin nor its derivative mizoribine accelerated the mutation rate or the increase in the genetic diversity of HCV replicon.
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Affiliation(s)
- Nobuyuki Kato
- Department of Molecular Biology, Okayama University Graduate School of Medicine and Dentistry, 2-5-1 Shikata-cho, Okayama 700-8558, Japan
| | - Takashi Nakamura
- Department of Molecular Biology, Okayama University Graduate School of Medicine and Dentistry, 2-5-1 Shikata-cho, Okayama 700-8558, Japan
| | - Hiromichi Dansako
- Department of Molecular Biology, Okayama University Graduate School of Medicine and Dentistry, 2-5-1 Shikata-cho, Okayama 700-8558, Japan
| | - Katsuyuki Namba
- First Department of Internal Medicine, Okayama University Graduate School of Medicine and Dentistry, 2-5-1 Shikata-cho, Okayama 700-8558, Japan
| | - Ken-Ichi Abe
- Department of Molecular Biology, Okayama University Graduate School of Medicine and Dentistry, 2-5-1 Shikata-cho, Okayama 700-8558, Japan
| | - Akito Nozaki
- Department of Molecular Biology, Okayama University Graduate School of Medicine and Dentistry, 2-5-1 Shikata-cho, Okayama 700-8558, Japan
| | - Kazuhito Naka
- Department of Molecular Biology, Okayama University Graduate School of Medicine and Dentistry, 2-5-1 Shikata-cho, Okayama 700-8558, Japan
| | - Masanori Ikeda
- Department of Molecular Biology, Okayama University Graduate School of Medicine and Dentistry, 2-5-1 Shikata-cho, Okayama 700-8558, Japan
| | - Kunitada Shimotohno
- Department of Viral Oncology, Institute for Virus Research, Kyoto University, 53 Kawara-cho Shogo-in, Sakyo-ku, Kyoto 606-8507, Japan
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163
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164
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Bartenschlager R, Frese M, Pietschmann T. Novel insights into hepatitis C virus replication and persistence. Adv Virus Res 2005; 63:71-180. [PMID: 15530561 DOI: 10.1016/s0065-3527(04)63002-8] [Citation(s) in RCA: 227] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Hepatitis C virus (HCV) is a small enveloped RNA virus that belongs to the family Flaviviridae. A hallmark of HCV is its high propensity to establish a persistent infection that in many cases leads to chronic liver disease. Molecular studies of the virus became possible with the first successful cloning of its genome in 1989. Since then, the genomic organization has been delineated, and viral proteins have been studied in some detail. In 1999, an efficient cell culture system became available that recapitulates the intracellular part of the HCV life cycle, thereby allowing detailed molecular studies of various aspects of viral RNA replication and persistence. This chapter attempts to summarize the current state of knowledge in these most actively worked on fields of HCV research.
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Affiliation(s)
- Ralf Bartenschlager
- Department of Molecular Virology, University of Heidelberg, Im Neuenheimer Feld 345, 69120 Heidelberg, Germany
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165
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166
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Burioni R, Mancini N, Carletti S, Perotti M, Grieco A, Canducci F, Varaldo PE, Clementi M. Cross-reactive pseudovirus-neutralizing anti-envelope antibodies coexist with antibodies devoid of such activity in persistent hepatitis C virus infection. Virology 2004; 327:242-8. [PMID: 15351212 DOI: 10.1016/j.virol.2004.06.042] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2004] [Revised: 05/17/2004] [Accepted: 06/18/2004] [Indexed: 12/09/2022]
Abstract
Most RNA viruses have evolved mechanisms to avoid neutralizing antibody responses, and it is generally believed that variability of envelope-encoding regions is the major molecular basis of this phenomenon. However, it has been hypothesized that other mechanisms can be involved. Recent experimental data indicate that in hepatitis C virus (HCV) infection, the anti-envelope humoral response includes cross-reactive antibody clones able to neutralize vesicular stomatitis virus (VSV) pseudotypes containing HCV E1 and E2 glycoproteins (HCV/VSV pseudotype) as well as other clones devoid of such activity. In this work, we demonstrate that natural infection with a large variety of HCV isolates belonging to different genotypes elicits HCV/VSV pseudotype-neutralizing cross-reactive anti-envelope antibodies together with clones unable to neutralize this pseudovirus. This was shown by designing a novel strategy for quantitation of serum antibodies binding selectively to single viral cross-reactive conformational epitopes. These data can be useful not only for a better understanding of the virus-host interplay in important viral diseases, but also for the development of an effective anti-HCV vaccine.
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Affiliation(s)
- Roberto Burioni
- Istituto di Microbiologia, Facoltà di Medicina e Chirurgia, Università di Ancona, 60020 Ancona, Italy.
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167
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Laskus T, Wilkinson J, Gallegos-Orozco JF, Radkowski M, Adair DM, Nowicki M, Operskalski E, Buskell Z, Seeff LB, Vargas H, Rakela J. Analysis of hepatitis C virus quasispecies transmission and evolution in patients infected through blood transfusion. Gastroenterology 2004; 127:764-76. [PMID: 15362033 DOI: 10.1053/j.gastro.2004.06.005] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND & AIMS Studies on hepatitis C virus (HCV) quasispecies dynamics in the natural course of infection are rare owing to difficulties in obtaining samples from the early phase of infection. METHODS We studied 15 patients from the Transfusion-Transmitted Viruses Study who seroconverted to anti-HCV after receiving infected blood. Follow-up serum samples were collected every 2-3 weeks for 6 months, at 10 months, and at 11-16 years. Viral quasispecies in the second envelope hypervariable region 1 (E2/HVR1) and 5' untranslated region (5'UTR) were analyzed with single-strand conformation polymorphism (SSCP) and heteroduplex mobility assay (HMA). RESULTS Seven patients cleared infection within 7-24 weeks (mean, 14.0 wk) and 3 patients eventually became anti-HCV negative. In 6 patients with resolving hepatitis the SSCP band pattern remained stable, whereas in one patient minor changes appeared before clearance. In contrast, in all 8 patients progressing to chronicity, major changes in the E2/HVR1 quasispecies developed at 8-22 weeks (mean, 13.1 wk). Shannon entropy and medium mobility shift values derived from HMA gels remained stable in patients with resolving hepatitis but changed in those who developed chronic infection. Only 2 patients showed minor changes in 5'UTR. A decrease in E2/HVR1 complexity at the time of transmission (bottleneck) was found in 5 patients altogether. CONCLUSIONS Changes in E2/HVR1 quasispecies 8-22 weeks after infection, likely caused by mounting immune pressure, were predictive of ensuing chronic infection, whereas stability was associated with resolution. Our study also showed that composition of HCV quasispecies may be preserved during transmission from host to host.
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Affiliation(s)
- Tomasz Laskus
- Department of Medicine, Mayo Clinic Scottsdale, Scottsdale, Arizona, USA
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168
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Fernandez J, Taylor D, Morhardt DR, Mihalik K, Puig M, Rice CM, Feinstone SM, Major ME. Long-term persistence of infection in chimpanzees inoculated with an infectious hepatitis C virus clone is associated with a decrease in the viral amino acid substitution rate and low levels of heterogeneity. J Virol 2004; 78:9782-9. [PMID: 15331711 PMCID: PMC514970 DOI: 10.1128/jvi.78.18.9782-9789.2004] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2004] [Accepted: 05/18/2004] [Indexed: 01/04/2023] Open
Abstract
Two chimpanzees, 1535 and 1536, became persistently infected following inoculation with RNA transcripts from cDNA clones of hepatitis C virus (HCV). Analysis of the HCV genomes from both animals showed an accumulation of amino acid substitutions over time. The appearance of substitutions in the envelope genes was associated with increased antienvelope antibody titers. However, extensive mutations were not incorporated into hypervariable region 1 (HVR1). A comparison of the nonsynonymous substitution rate/synonymous substitution rate was made at various time points to analyze selective pressure. The highest level of selective pressure occurred during the acute phase and decreased as the infection continued. The nonsynonymous substitution rate was initially higher than the synonymous substitution rate but decreased over time from 3.3 x 10(-3) (chimpanzee 1535) and 3.2 x 10(-3) (chimpanzee 1536) substitutions/site/year at week 26 to 1.4 x 10(-3) (chimpanzee 1535) and 1.7 x 10(-3) (chimpanzee 1536) at week 216, while the synonymous substitution rate remained steady at approximately 1 x 10(-3) substitutions/site/year. Analysis of PCR products using single-stranded conformational polymorphism indicated a low level of heterogeneity in the viral genome. The results of these studies confirm that the persistence of infection is not solely due to changes in HVR1 or heterogeneity and that the majority of variants observed in natural infections could not arise simply through mutation during the time period most humans and chimpanzees are observed. These data also indicate that immune pressure and selection continue throughout the chronic phase.
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Affiliation(s)
- Javier Fernandez
- Laboratory of Hepatitis Viruses, Division of Viral Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Building 29A, Room 1D10, HVM 448, 8800 Rockville Pike, Bethesda, MD 20892, USA
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169
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Frelin L, Ahlén G, Alheim M, Weiland O, Barnfield C, Liljeström P, Sällberg M. Codon optimization and mRNA amplification effectively enhances the immunogenicity of the hepatitis C virus nonstructural 3/4A gene. Gene Ther 2004; 11:522-33. [PMID: 14999224 DOI: 10.1038/sj.gt.3302184] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
We have recently shown that the NS3-based genetic immunogens should contain also hepatitis C virus (HCV) nonstructural (NS) 4A to utilize fully the immunogenicity of NS3. The next step was to try to enhance immunogenicity by modifying translation or mRNA synthesis. To enhance translation efficiency, a synthetic NS3/4A-based DNA (coNS3/4A-DNA) vaccine was generated in which the codon usage was optimized (co) for human cells. In a second approach, expression of the wild-type (wt) NS3/4A gene was enhanced by mRNA amplification using the Semliki forest virus (SFV) replicon (wtNS3/4A-SFV). Transient tranfections of human HepG2 cells showed that the coNS3/4A gene gave 11-fold higher levels of NS3 as compared to the wtNS3/4A gene when using the CMV promoter. We have previously shown that the presence of NS4A enhances the expression by SFV. Both codon optimization and mRNA amplification resulted in an improved immunogenicity as evidenced by higher levels of NS3-specific antibodies. This improved immunogenicity also resulted in a more rapid priming of cytotoxic T lymphocytes (CTLs). Since HCV is a noncytolytic virus, the functionality of the primed CTL responses was evaluated by an in vivo challenge with NS3/4A-expressing syngeneic tumor cells. The priming of a tumor protective immunity required an endogenous production of the immunogen and CD8+ CTLs, but was independent of B and CD4+ T cells. This model confirmed the more rapid in vivo activation of an NS3/4A-specific tumor-inhibiting immunity by codon optimization and mRNA amplification. Finally, therapeutic vaccination with the coNS3/4A gene using gene gun 6-12 days after injection of tumors significantly reduced the tumor growth in vivo. Codon optimization and mRNA amplification effectively enhances the overall immunogenicity of NS3/4A. Thus, either, or both, of these approaches should be utilized in an NS3/4A-based HCV genetic vaccine.
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Affiliation(s)
- L Frelin
- Division of Clinical Virology, Karolinska Institutet at Huddinge University Hospital, Stockholm, Sweden
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170
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Lyra AC, Fan X, Di Bisceglie AM. Molecular biology and clinical implication of hepatitis C virus. Braz J Med Biol Res 2004; 37:691-5. [PMID: 15107931 DOI: 10.1590/s0100-879x2004000500010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Hepatitis C virus (HCV) was first described in 1989 as the putative viral agent of non-A non-B hepatitis. It is a member of the Flaviviridae family and has been recognized as the major causative agent of chronic liver disease, including chronic active hepatitis, cirrhosis and hepatocellular carcinoma. HCV is a positive RNA virus with a genome containing approximately 9500 nucleotides. It has an open reading frame that encodes a large polyprotein of about 3000 amino acids and is characterized by extensive genetic diversity. HCV has been classified into at least 6 major genotypes with many subtypes and circulates within an infected individual as a number of closely related but distinct variants known as quasispecies. This article reviews aspects of the molecular biology of HCV and their clinical implication.
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Affiliation(s)
- A C Lyra
- Serviço de Gastro-Hepatologia e Laboratório de Biologia Molecular, Hospital São Rafael e Universidade Federal da Bahia, Salvador, BA, Brazil.
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171
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Krönke J, Kittler R, Buchholz F, Windisch MP, Pietschmann T, Bartenschlager R, Frese M. Alternative approaches for efficient inhibition of hepatitis C virus RNA replication by small interfering RNAs. J Virol 2004; 78:3436-46. [PMID: 15016866 PMCID: PMC371081 DOI: 10.1128/jvi.78.7.3436-3446.2004] [Citation(s) in RCA: 133] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Persistent infection with hepatitis C virus (HCV) is a leading cause of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. It has recently been shown that HCV RNA replication is susceptible to small interfering RNAs (siRNAs), but the antiviral activity of siRNAs depends very much on their complementarity to the target sequence. Thus, the high degree of sequence diversity between different HCV genotypes and the rapid evolution of new quasispecies is a major problem in the development of siRNA-based gene therapies. For this study, we developed two alternative strategies to overcome these obstacles. In one approach, we used endoribonuclease-prepared siRNAs (esiRNAs) to simultaneously target multiple sites of the viral genome. We show that esiRNAs directed against various regions of the HCV coding sequence as well as the 5' nontranslated region (5' NTR) efficiently block the replication of subgenomic and genomic HCV replicons. In an alternative approach, we generated pseudotyped retroviruses encoding short hairpin RNAs (shRNAs). A total of 12 shRNAs, most of them targeting highly conserved sequence motifs within the 5' NTR or the early core coding region, were analyzed for their antiviral activities. After the transduction of Huh-7 cells containing a subgenomic HCV replicon, we found that all shRNAs targeting sequences in domain IV or nearby coding sequences blocked viral replication. In contrast, only one of seven shRNAs targeting sequences in domain II or III had a similar degree of antiviral activity, indicating that large sections of the NTRs are resistant to RNA interference. Moreover, we show that naive Huh-7 cells that stably expressed certain 5' NTR-specific shRNAs were largely resistant to a challenge with HCV replicons. These results demonstrate that the retroviral transduction of HCV-specific shRNAs provides a new possibility for antiviral intervention.
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Affiliation(s)
- Jan Krönke
- Department of Molecular Virology, Hygiene Institute, University of Heidelberg, D-69120 Heidelberg, Germany
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172
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Nakayama H, Sugai Y, Ikeya S, Inoue J, Nishizawa T, Okamoto H. Molecular investigation of interspousal transmission of hepatitis C virus in two Japanese patients who acquired acute hepatitis C after 40 or 42 years of marriage. J Med Virol 2004; 75:258-66. [PMID: 15602741 DOI: 10.1002/jmv.20265] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A 65-year-old woman (C1I) and a 65-year-old man (C2I) contracted acute hepatitis C 40 or 42 years after marriage, respectively, in Japan. They had no discernible risk factors for acquiring hepatitis C virus (HCV) infection, except that they had monogamous sexual relationships with their spouses (C1S [66-year-old] with hepatocellular carcinoma and C2S [64-year-old] with liver cirrhosis, respectively) who were infected with HCV of the same genotype (1b) and had a high-titer HCV RNA in the serum (bDNA probe assay, 17 Meq/ml [C1S] and 15 Meq/ml [C2S]). The HCV isolates from Patients C1I and C1S and those from Patients C2I and C2S shared identity of 99.9% and 99.1%, respectively, in the 1,087-nucleotide (nt) sequence of the NS5B region, although these four isolates were only 91.7%-96.2% identical to the 94 reported genotype 1b isolates including those from Japanese patients. To confirm the high degree of genetic relatedness among ten HCV clones from each spouse within each pair of spouses, the E1 and E2 junctional region sequence (268 or 271 nt) including hypervariable region 1 (HVR-1) was analyzed. There was a close relationship between clones obtained from each spouse within each couple. Regarding the HVR-1 amino acid sequence, nine of the ten C1I clones were 100% identical with six of the ten C1S clones, and one each of the C2I and C2S clones differed by only one amino acid residue. This study indicates that two Japanese patients with acute hepatitis C had acquired HCV infection most probably by interspousal sexual transmission during a long-lasting marriage.
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Affiliation(s)
- Haruo Nakayama
- Department of Internal Medicine, Iwaki Kyoritsu General Hospital, Fukushima-Ken, Japan
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173
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Takeda T, Tatsumi N, Nakayama Y, Yasuda T, Nishiguchi S, Seki S. Mode of HCV infection examined by polymorphism of hypervariable region-1 in cases of acute hepatitis C after accidental exposure to blood-borne pathogens. J Med Virol 2004; 75:35-41. [PMID: 15543585 DOI: 10.1002/jmv.20233] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Acute hepatitis C is known to respond better to interferon therapy than chronic hepatitis C. The reason for this difference remains unclear. The present study was undertaken to examine HCV quasispecies in blood from patients with acute hepatitis C caused by accidental exposure to blood-borne pathogens and in blood from the source patients. Three patients who developed hepatitis C (recipient patients; R-Pt.) and two patients who served as a source of HCV infection (source patients; S-Pt.) were the subjects of this study. The number of quasispecies and the genetic diversity in hypervariable region-1 (HVR-1) were examined on the basis of fluorescence single-strand conformation polymorphism and sequence analysis (FSSA). On the day of the accident, the number of quasispecies and genetic diversity were 13 and 36 in S-Pt.1 and 6 and 20 in S-Pt.3, respectively. At the time of diagnosis of acute hepatitis, the number of quasispecies and nucleotide diversity were 2 and 2 in R-Pt.1, 2 and 0 in R-Pt.2, and 4 and 0 in R-Pt.3, respectively. Immediately before the start of treatment, the number of quasispecies and genetic diversity were 4 and 4 in R-Pt.1, 2 and 0 in R-Pt.2, and 3 and 0 in R-Pt.3., respectively. In three R-Pts, interferon therapy resulted in eradication of HCV. These findings indicate that in the early stage of HCV infection, only a portion of HCV transmitted from S-Pts to R-Pts can proliferate. The low number of quasispecies of HCV appears to be one of the reasons why acute hepatitis responds well to interferon therapy.
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Affiliation(s)
- Tadashi Takeda
- Department of Hepatology, Graduate School of Medicine, Osaka City University, 1-4-3 Asahimachi Abeno-ku, Osaka 545-8585, Japan.
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174
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Bartosch B, Bukh J, Meunier JC, Granier C, Engle RE, Blackwelder WC, Emerson SU, Cosset FL, Purcell RH. In vitro assay for neutralizing antibody to hepatitis C virus: evidence for broadly conserved neutralization epitopes. Proc Natl Acad Sci U S A 2003; 100:14199-204. [PMID: 14617769 PMCID: PMC283569 DOI: 10.1073/pnas.2335981100] [Citation(s) in RCA: 241] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Our understanding of the humoral immune response to hepatitis C virus (HCV) is limited because the virus can be studied only in humans and chimpanzees and because previously described neutralization assays have not been robust or simple to perform. Nevertheless, epidemiologic and laboratory studies suggested that neutralizing Ab to HCV might be important in preventing infection. We have recently described a neutralization assay based on the neutralization of pseudotyped murine retrovirus constructs bearing HCV envelope glycoproteins on their surface. We have applied the assay to well characterized clinical samples from HCV-infected patients and chimpanzees, confirmed the existence of neutralizing Ab to HCV, and validated most previously reported neutralizations of the virus. We did not find neutralizing anti-HCV in resolving infections but did find relatively high titers (>1:320) of such Ab in chronic infections. Neutralizing Ab was directed not only to epitope(s) in the hypervariable region of the E2 envelope protein but also to one or more epitopes elsewhere in the envelope of the virus. Neutralizing Ab was broadly reactive and could neutralize pseudotype particles bearing the envelope glycoproteins of two different subgenotypes (1a and 1b). The ability to assay neutralizing anti-HCV should permit an assessment of the prospects for successful Ab-mediated passive and active immunoprophylaxis against hepatitis C.
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Affiliation(s)
- Birke Bartosch
- Laboratoire de Vectorologie Rétrovirale et Thérapie Génique, Institut National de la Santé et de la Recherche Médicale U412, IFR 128, Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, 69364 Lyon Cedex 07, France
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175
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Kaplan M, Gawrieh S, Cotler SJ, Jensen DM. Neutralizing antibodies in hepatitis C virus infection: a review of immunological and clinical characteristics. Gastroenterology 2003; 125:597-604. [PMID: 12891562 DOI: 10.1016/s0016-5085(03)00882-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Mitchell Kaplan
- Department of Internal Medicine, Rush Presbyterian St. Luke's Medical Center, Rush University, Chicago, IL 60612, USA
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176
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Gaudy C, Moreau A, Veillon P, Temoin S, Lunel F, Goudeau A. Significance of pretreatment analysis of hepatitis C virus genotype 1b hypervariable region 1 sequences to predict antiviral outcome. J Clin Microbiol 2003; 41:3615-22. [PMID: 12904364 PMCID: PMC179854 DOI: 10.1128/jcm.41.8.3615-3622.2003] [Citation(s) in RCA: 13] [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 heterogeneity of hypervariable region 1 (HVR1), located at the amino terminus of the E2 envelope, may be involved in resistance to alpha interferon (IFN-alpha) treatment. We investigated whether peculiar HVR1 domain profiles before treatment were associated with the maintenance of sensitivity or the appearance of resistance to treatment. Fifteen patients infected with hepatitis C virus genotype 1b and treated with IFN with or without ribavirin were selected. Ten responded to treatment (groups R1 and R2) and five did not (group NR). The amino acid sequences of 150 naturally occurring HVR1 variants present in the serum before therapy were compared in relation to treatment outcome. HVR1 variants from the NR group contained a constant nonantigenic amino acid segment that was not found in HVR1 variants from the R groups.
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Affiliation(s)
- Catherine Gaudy
- Département de Microbiologie Médicale et Moléculaire EA 3250, Université François Rabelais, F37044 Tours Cedex, France
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177
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Malet I, Belnard M, Agut H, Cahour A. From RNA to quasispecies: a DNA polymerase with proofreading activity is highly recommended for accurate assessment of viral diversity. J Virol Methods 2003; 109:161-70. [PMID: 12711059 DOI: 10.1016/s0166-0934(03)00067-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
RNA viruses are characterized by their high rates of genetic variation. Their genetic diversity is generally studied by reverse transcription (RT) followed by polymerase chain reaction (PCR) amplification and nucleotide (nt) sequence determination. The misinterpretation of viral diversity due to copy errors introduced by the enzymes used in this two-step protocol has not yet been assessed systematically. In order to investigate the impact of such errors, we sought to bypass the intrinsic viral heterogeneity by starting from a homogeneous cDNA template. With this in mind, the hepatitis C virus (HCV) 5' non-coding region (5'NCR) was amplified either by PCR starting from a homopolymeric cDNA template or by RT-PCR starting from the in vitro RNA transcript derived from the same original cDNA template. Amplicons were cloned and the 17-20 individual clones were sequenced in each assay. Different quasispecies patterns were obtained with various commercially available DNA polymerases, resulting in different computed error rates. The non-proofreading Taq DNA polymerase provided the highest error rate which was seven times higher than that obtained with the most reliable of the proofreading polymerases tested. We, therefore, emphasize that the misleading interpretation of the observed heterogeneity for a given viral sample could be due to ignorance of the fidelity of the polymerase used for viral genome amplification, and thus that proofreading DNA polymerases should be preferred for the investigation of natural genetic diversity of RNA viruses.
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Affiliation(s)
- Isabelle Malet
- Laboratoire de Virologie, C.E.R.V.I., UPRES EA 2387, Groupe Hôpital Pitié-Salpêtrière, 83 Bd de l'hôpital, 75651 Paris Cedex 13, France
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178
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Frelin L, Alheim M, Chen A, Söderholm J, Rozell B, Barnfield C, Liljeström P, Sällberg M. Low dose and gene gun immunization with a hepatitis C virus nonstructural (NS) 3 DNA-based vaccine containing NS4A inhibit NS3/4A-expressing tumors in vivo. Gene Ther 2003; 10:686-99. [PMID: 12692597 DOI: 10.1038/sj.gt.3301933] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The hepatitis C virus (HCV) protease and helicase encompasses the nonstructural (NS) 3 protein and the cofactor NS4A, which targets the NS3/4A-complex to intracellular membranes. We here evaluate the importance of NS4A in NS3-based genetic immunogens. A full-length genotype 1 NS3/4A gene was cloned into a eucaryotic expression vector in the form of NS3/4A and NS3 alone. Transient transfections revealed that the inclusion of NS4A increased the expression levels of NS3. Subsequently, immunization with the NS3/4A gene primed 10- to 100-fold higher levels of NS3-specific antibodies as compared to immunization with the NS3 gene. Humoral responses primed by the NS3/4A gene had a higher IgG2a/IgG1 ratio (>20) as compared to the NS3 gene (3.0), suggesting a T helper 1-skewed response. Low dose i.m. (10 microg) immunization with the NS3/4A gene inhibited the growth of NS3/4A-expressing tumor cells in vivo, whereas the NS3 gene alone or NS3 protein did not. We then evaluated the efficiency of the NS3/4A gene administered by the gene gun, at the same doses used for humans, in priming cytotoxic T lymphocyte (CTL) responses. Three to four 4 microg doses of the NS3/4A gene primed CTL at a precursor frequency of 2-4%, which inhibited the growth of NS3/4A-expressing tumor cells in vivo. Thus, NS4A enhances the expression levels and immunogenicity of NS3, and an NS3/4A gene delivered transdermally could be a therapeutic vaccine candidate.
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Affiliation(s)
- L Frelin
- Karolinska Institutet at Huddinge University Hospital, Stockholm, Sweden
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179
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Abstract
Hepatitis C virus (HCV) is an emerging virus of medical importance. A majority of HCV infections become chronic and lead to chronic hepatitis, liver cirrhosis and hepatocellular carcinoma. HCV usually induces robust immune responses, but it frequently escapes the immune defense to establish persistent infection. The fact that HCV exists as an evolving quasispecies plays an important role in the selection of escape mutants. Furthermore, several viral proteins interfere with cellular functions, in particular, those involved in the immune response of the host. Several HCV proteins also modulate cell signalling through interaction with different effectors involved in cell proliferation and apoptosis, or in the interferon-signalling pathway. In addition, HCV infects immune cells such as B and T cells, and thus affects their normal functions. These various strategies used by HCV to counter the immune response of the host are reviewed here. A better understanding of these mechanisms would help design new therapeutic targets.
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Affiliation(s)
- Nicole Pavio
- Department of Molecular Microbiology, University of Southern California, Keck School of Medicine, Los Angeles, CA 90033, USA
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180
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Cantaloube JF, Biagini P, Attoui H, Gallian P, de Micco P, de Lamballerie X. Evolution of hepatitis C virus in blood donors and their respective recipients. J Gen Virol 2003; 84:441-446. [PMID: 12560577 DOI: 10.1099/vir.0.18642-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
This paper describes the study of hepatitis C virus (HCV) evolution in the largest cohort of HCV-infected blood donors (BDs)/blood recipients (BRs) reported to date (25 pairs). A molecular analysis of partial sequences in the E1 (envelope) and NS5-B (polymerase) genes was performed. Phylogenetic reconstruction showed that the evolution of dominant strains was qualitatively and quantitatively different in BDs and BRs. The evolutionary rate was significantly higher in BRs, in which, in addition, most substitutions observed were antonymous. These findings corroborate the hypothesis that a large part of virus evolution - which was evaluated to be equivalent to approximately 20 years of chronic evolution - is acquired during the early phase of infection. These findings should be taken into account for the modelling of the long-term evolution of HCV and their possible contribution to improve our understanding of HCV natural history is discussed.
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Affiliation(s)
- Jean-François Cantaloube
- Unité des Virus Emergents, Etablissement Français du Sang Alpes-Méditerranée, EA32/92-IFR48, Université de la Méditerranée, Faculté de Médecine, 27 Bd J. Moulin, F-13005 Marseille, France
| | - Philippe Biagini
- Unité des Virus Emergents, Etablissement Français du Sang Alpes-Méditerranée, EA32/92-IFR48, Université de la Méditerranée, Faculté de Médecine, 27 Bd J. Moulin, F-13005 Marseille, France
| | - Houssam Attoui
- Unité des Virus Emergents, Etablissement Français du Sang Alpes-Méditerranée, EA32/92-IFR48, Université de la Méditerranée, Faculté de Médecine, 27 Bd J. Moulin, F-13005 Marseille, France
| | - Pierre Gallian
- Unité des Virus Emergents, Etablissement Français du Sang Alpes-Méditerranée, EA32/92-IFR48, Université de la Méditerranée, Faculté de Médecine, 27 Bd J. Moulin, F-13005 Marseille, France
| | - Philippe de Micco
- Unité des Virus Emergents, Etablissement Français du Sang Alpes-Méditerranée, EA32/92-IFR48, Université de la Méditerranée, Faculté de Médecine, 27 Bd J. Moulin, F-13005 Marseille, France
| | - Xavier de Lamballerie
- Unité des Virus Emergents, Etablissement Français du Sang Alpes-Méditerranée, EA32/92-IFR48, Université de la Méditerranée, Faculté de Médecine, 27 Bd J. Moulin, F-13005 Marseille, France
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181
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Abstract
HCV infection becomes persistent in many patients who are otherwise immune competent. There is increasing support for potential contribution of innate immune response and viral interference with its components to the subsequent outcome. As for the adaptive immune response, humoral immunity may be largely ineffective despite evidence for neutralizing antibody response directed to the E2 HVR region, perhaps due to rapid selection of antibody escape variants. Cellular immune response does seem to play a role in the virologic outcome during acute infection based on strong association of a sustained vigorous and multispecific antiviral CD4 and CD8 T cell response with HCV clearance during acute infection. Following clearance, vigorous CD4 T cell response to HCV is maintained for many years, whereas the memory CD8 T cell response may be maintained with variable efficiency. If unable to clear the virus quickly, the T cell response (particularly if focused) may also select for T cell escape variants that are poorly recognized by the circulating T cells or even actively inactivate them through T cell antagonism. In established chronic infection. HCV-specific T cell response is quantitatively weak, providing only minimal selection pressure for further escape mutation. Although earlier studies using conventional in vitro techniques suggest that this low-frequency T cell response may help control the virus and liver disease progression, the role and nature of these apparently defective T cells in the outcome of chronic HCV infection remains to be fully determined. In summary, much progress has been made in the field of HCV immune pathogenesis since the initial identification of HCV. Although more work is needed to define the mechanism of HCV persistence and liver cell injury, there is considerable hope as well as challenge for potential development of vaccine and immunotherapy for HCV infection (see article by Drs. Inchaupsé and Feinstone). A better understanding of the relevant host and viral factors for clinical and virologic outcome, and the mechanism of selective immune defect against HCV, will be invaluable in our ability to treat the many patients infected with HCV.
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Affiliation(s)
- Kyong-Mi Chang
- University of Pennsylvania, University Avenue, A212/Medical Research, Philadelphia, PA 19104, USA.
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182
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Tanaka Y, Hanada K, Mizokami M, Yeo AET, Shih JWK, Gojobori T, Alter HJ. A comparison of the molecular clock of hepatitis C virus in the United States and Japan predicts that hepatocellular carcinoma incidence in the United States will increase over the next two decades. Proc Natl Acad Sci U S A 2002; 99:15584-9. [PMID: 12438687 PMCID: PMC137760 DOI: 10.1073/pnas.242608099] [Citation(s) in RCA: 260] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/30/2002] [Indexed: 12/12/2022] Open
Abstract
The prevalence of hepatitis C virus (HCV)-related hepatocellular carcinoma (HCC) is considerably lower in the U.S. than in Japan. To elucidate this difference, we determined the time origin of the HCV epidemic in each country by using molecularly clocked long-term serial samples obtained from HCV carriers of genotypes 1a and 1b. The molecular clock estimated that HCV genotype 1 first appeared in Japan in around 1882, whereas emergence in the U.S. was delayed until around 1910. In addition, by statistical analysis using coalescent theory, the major spread time for HCV infection in Japan occurred in the 1930s, whereas widespread dissemination of HCV in the U.S. occurred in the 1960s. These estimates of viral spread time are consistent with epidemiologic observations and predict that the burden of HCC in the U.S. will increase in the next two to three decades, possibly to equal that currently experienced in Japan.
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Affiliation(s)
- Yasuhito Tanaka
- Department of Transfusion Medicine, Warren Grant Magnuson Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA.
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183
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Fabrizi F, Lunghi G, Poordad FF, Martin P. Genetic variability of hepatitis C virus in dialysis: the implications. Int J Artif Organs 2002; 25:1034-48. [PMID: 12487391 DOI: 10.1177/039139880202501102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- F Fabrizi
- Division of Nephrology, Dialysis and Renal Transplantation, Maggiore Hospital, Policlinico IRCCS, Milano, Italy.
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184
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García-Retortillo M, Forns X. [Genomic variability and natural history of hepatitis C virus infection]. GASTROENTEROLOGIA Y HEPATOLOGIA 2002; 25:514-20. [PMID: 12361535 DOI: 10.1016/s0210-5705(02)70303-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- M García-Retortillo
- Unidad de Hepatología, Institut de Malalties Digestives (IMD), Hospital Clínic e IDIBAPS, Universitat de Barcelona, España
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185
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Boulestin A, Sandres-Sauné K, Payen JL, Alric L, Dubois M, Pasquier C, Vinel JP, Pascal JP, Puel J, Izopet J. Genetic heterogeneity of the envelope 2 gene and eradication of hepatitis C virus after a second course of interferon-alpha. J Med Virol 2002; 68:221-8. [PMID: 12210411 DOI: 10.1002/jmv.10192] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The heterogeneity of the envelope 2 (E2) gene of the hepatitis C virus (HCV) was involved in the sensitivity of HCV to interferon-alpha (IFN-alpha). To assess the factors leading to virus eradication by IFN-alpha, patients whose first treatment by IFN-alpha failed and who had virus eradication after a second treatment were studied. These patients were paired with subjects in whom both treatments failed. The phosphorylation homology domain of the E2 gene (E2-PHD) had no sequence variation between the two stages in both groups of patients. Therefore, this region has no clinical predictive value within a specific genotype. The hypervariable region 1 (HVR1) was analyzed by cloning and sequencing 20 clones per sample. Comparison of samples showed that the change in quasispecies induced by the first IFN-alpha therapy could be associated with virus elimination obtained after a second treatment. The greater proportion of nonsynonymous mutations that was noted before the second treatment in responders suggest that pretherapeutic immune response is a major factor determining virus elimination and that the immune status of these patients changed between the first and the second treatment.
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Affiliation(s)
- Anne Boulestin
- Laboratoire de Virologie, Hôpital Purpan, Toulouse Cedex, France.
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186
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Contreras AM, Hiasa Y, He W, Terella A, Schmidt EV, Chung RT. Viral RNA mutations are region specific and increased by ribavirin in a full-length hepatitis C virus replication system. J Virol 2002; 76:8505-17. [PMID: 12163570 PMCID: PMC136407 DOI: 10.1128/jvi.76.17.8505-8517.2002] [Citation(s) in RCA: 152] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
High rates of genetic variation ensure the survival of RNA viruses. Although this variation is thought to result from error-prone replication, RNA viruses must also maintain highly conserved genomic segments. A balance between conserved and variable viral elements is especially important in order for viruses to avoid "error catastrophe." Ribavirin has been shown to induce error catastrophe in other RNA viruses. We therefore used a novel hepatitis C virus (HCV) replication system to determine relative mutation frequencies in variable and conserved regions of the HCV genome, and we further evaluated these frequencies in response to ribavirin. We sequenced the 5' untranslated region (5' UTR) and the core, E2 HVR-1, NS5A, and NS5B regions of replicating HCV RNA isolated from cells transfected with a T7 polymerase-driven full-length HCV cDNA plasmid containing a cis-acting hepatitis delta virus ribozyme to control 3' cleavage. We found quasispecies in the E2 HVR-1 and NS5B regions of untreated replicating viral RNAs but not in conserved 5' UTR, core, or NS5A regions, demonstrating that important cis elements regulate mutation rates within specific viral segments. Neither T7-driven replication nor sequencing artifacts produced these nucleotide substitutions in control experiments. Ribavirin broadly increased error generation, especially in otherwise invariant regions, indicating that it acts as an HCV RNA mutagen in vivo. Similar results were obtained in hepatocyte-derived cell lines. These results demonstrate the potential utility of our system for the study of intrinsic factors regulating genetic variation in HCV. Our results further suggest that ribavirin acts clinically by promoting nonviable HCV RNA mutation rates. Finally, the latter result suggests that our replication model may be useful for identifying agents capable of driving replicating virus into error catastrophe.
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Affiliation(s)
- Ana Maria Contreras
- Gastrointestinal Unit, Massachusetts General Hospital and Department of Medicine, Harvard Medical School, Boston, Massachusetts 02114, USA
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187
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Zhao X, Tang ZY, Klumpp B, Wolff-Vorbeck G, Barth H, Levy S, von Weizsäcker F, Blum HE, Baumert TF. Primary hepatocytes of Tupaia belangeri as a potential model for hepatitis C virus infection. J Clin Invest 2002; 109:221-32. [PMID: 11805134 PMCID: PMC150834 DOI: 10.1172/jci13011] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Hepatitis C virus (HCV) is a major cause of chronic hepatitis worldwide, but the study of HCV infection has been hampered by the lack of an in vitro or in vivo small animal model. The tree shrew Tupaia belangeri is susceptible to infection with a variety of human viruses in vivo, including hepatitis viruses. We show that primary Tupaia hepatocytes can be infected with serum- or plasma-derived HCV from infected humans, as measured by de novo synthesis of HCV RNA, analysis of viral quasispecies evolution, and detection of viral proteins. Production of infectious virus could be demonstrated by passage to naive hepatocytes. To assess whether viral entry in Tupaia hepatocytes was dependent on the recently isolated HCV E2 binding protein CD81, we identified and characterized Tupaia CD81. Sequence analysis of cloned Tupaia cDNA revealed a high degree of homology between Tupaia and human CD81 large extracellular loops (LEL). Cellular binding of E2 and HCV infection could not be inhibited by anti-CD81 antibodies or soluble CD81-LEL, suggesting that viral entry can occur through receptors other than CD81. Thus, primary Tupaia hepatocytes provide a potential model for the study of HCV infection of hepatocytes.
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MESH Headings
- Animals
- Antigens, CD/biosynthesis
- Antigens, CD/genetics
- Antigens, CD/metabolism
- Base Sequence
- Cells, Cultured
- DNA, Complementary/analysis
- Hepacivirus/classification
- Hepacivirus/genetics
- Hepacivirus/physiology
- Hepatocytes/cytology
- Hepatocytes/metabolism
- Hepatocytes/virology
- Humans
- Membrane Proteins
- Models, Biological
- Molecular Sequence Data
- RNA, Viral/analysis
- Receptors, Virus/biosynthesis
- Receptors, Virus/genetics
- Receptors, Virus/metabolism
- Sequence Homology, Nucleic Acid
- Tetraspanin 28
- Tupaia
- Viral Envelope Proteins/metabolism
- Viral Proteins/biosynthesis
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Affiliation(s)
- Xiping Zhao
- Department of Medicine II, University of Freiburg, Freiburg, Germany
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188
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Zhao X, Tang ZY, Klumpp B, Wolff-Vorbeck G, Barth H, Levy S, Weizsäcker FV, Blum HE, Baumert TF. Primary hepatocytes of Tupaia belangeri as a potential model for hepatitis C virus infection. J Clin Invest 2002. [DOI: 10.1172/jci0213011] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
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189
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Grant MD. Antibody convergence along a common idiotypic axis in immunodeficiency virus and hepatitis C virus infections. J Med Virol 2002; 66:13-21. [PMID: 11748653 DOI: 10.1002/jmv.2105] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The anti-idiotypic antibody 1F7 selectively binds antibodies against human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) gag, pol, and env proteins. We tested anti-hepatitis C virus (HCV) antibodies to investigate selection of the 1F7 idiotype on antibodies against other chronic pathogens. Twelve of 15 HCV-seropositive individuals co-infected with HIV had detectable antibodies against recombinant HCV core, 4 against HCV NS4 protein, and 3 against HCV NS3 protein. All four HCV-seropositive, non-HIV-infected individuals had antibodies against HCV core and NS4, while 3 had antibodies against NS3. The 1F7 idiotype was frequently present on antibodies against each of the HCV antigens in the HIV co-infected and non-HIV-infected groups. Antibodies against HCV, including antibodies recognizing the putative principal neutralizing determinant of HCV E2 protein, displayed skewed kappa/lambda light chain usage consistent with clonal dominance. These observations extend the association between expression of the 1F7 idiotype and abnormal B cell clonal dominance in HIV and SIV infection to HCV infection and suggest that early establishment of an oligoclonal antibody response against HCV may freeze the B cell repertoire, impair adaptation to emergent HCV variants, and favor escape from neutralizing antibodies. We also demonstrated that expression of the 1F7 idiotype extends beyond antibodies against multiple antigens of AIDS-causing retroviruses to include antibodies against multiple antigens of an unrelated chronic hepatitis virus. Thus, distinct pathogens establishing chronic infection in the face of strong humoral immune responses select antibodies along a common idiotypic axis of the immune network.
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Affiliation(s)
- Michael D Grant
- Immunology Program, Division of Basic Medical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NF Canada.
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190
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Abstract
Hepatitis C virus, a recently identified member of the family Flaviviridae, is an important cause of chronic viral hepatitis and cirrhosis. There are similarities in the nature of the immune response to this pathogen with immunity in other flavivirus and hepatotropic virus infections, such as hepatitis B. However, the high rate of viral persistence after primary hepatitis C infection, and the observation that neutralizing antibodies are not protective, would suggest that there are a number of important differences between hepatitis C, other flaviviruses, and hepatitis B. The phenomenon of quasispecies evolution and other viral factors have been proposed to contribute to immune evasion by hepatitis C virus. In the face of established persistent infection, virus-specific cytotoxic T lymphocytes may exert some control over viral replication. However, these same effectors may also be responsible for the progressive liver damage characteristic of chronic hepatitis C infection. The nature of protective immunity, including the role of innate immune responses early after hepatitis C exposure, remains to be defined.
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Affiliation(s)
- A J Freeman
- Viral Hepatitis Research, Gastrointestinal and Liver Unit, The Prince of Wales Hospital, Randwick, New South Wales, Australia.
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191
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Cabot B, Martell M, Esteban JI, Piron M, Otero T, Esteban R, Guardia J, Gómez J. Longitudinal evaluation of the structure of replicating and circulating hepatitis C virus quasispecies in nonprogressive chronic hepatitis C patients. J Virol 2001; 75:12005-13. [PMID: 11711591 PMCID: PMC116096 DOI: 10.1128/jvi.75.24.12005-12013.2001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In previous cross-sectional studies, we demonstrated that, in most patients with chronic hepatitis C, the composition and complexity of the circulating hepatitis C virus (HCV) population do not coincide with those of the virus replicating in the liver. In the subgroup of patients with similar complexities in both compartments, the ratio of quasispecies complexity in the liver to that in serum (liver/serum complexity ratio) of paired samples correlated with disease stage. In the present study we investigated the dynamic behavior of viral population parameters in consecutive paired liver and serum samples, obtained 3 to 6 years apart, from four chronic hepatitis C patients with persistently normal transaminases and stable liver histology. We sequenced 359 clones of a genomic fragment encompassing the E2(p7)-NS2 junction, in two consecutive liver-serum sample pairs from the four patients and in four intermediate serum samples from one of the patients. The results show that the liver/serum complexity ratio is not stable but rather fluctuates widely over time. Hence, the liver/serum complexity ratio does not identify a particular group of patients but a particular state of the infecting quasispecies. Phylogenetic analysis and signature mutation patterns showed that virtually all circulating sequences originated from sequences present in the liver specimens. The overall behavior of the circulating viral quasispecies appears to originate from changes in the relative replication kinetics of the large mutant spectrum present in the infected liver.
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Affiliation(s)
- B Cabot
- Liver Unit, Department of Internal Medicine, Hospital General Universitari Vall d'Hebron, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain
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192
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Abstract
Because hepatitis C virus is etiologically involved in about half the cases of the world's most common cancer, hepatocellular carcinoma, and because this virus is likely to continue to spread in most of the developing world for many years, the authors believe that development of a prophylactic vaccine is imperative. Numerous approaches are available to overcome the many impediments which make the development of an HCV vaccine difficult. Such impediments include the many viral genotypes and quasispecies of HCV and the association of virions with host lipids. It is likely that overcoming these impediments will require a vaccine which induces a strong cell-mediated response. The most promising approach seems to be DNA-based immunization or a prime-boost regimen with DNA priming and boosting with a viral vector. Potentiation of responses with adjuvant strategies will probably be necessary. Hepatitis C virus immunization is in an early stage of development. Given the explosive growth in the understanding of immunology, progress should be rapid.
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Affiliation(s)
- A M Prince
- Lindsley F. Kimball Research Institute, New York Blood Center, New York, New York, USA.
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193
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Abstract
Although recent evidence indicates that the quasispecies nature of HCV constitutes a critical strategy for the virus to survive in the host, the mechanisms of viral persistence remain unknown. Similarly, the correlates of immune protection in a limited proportion of individuals who succeed in clearing HCV are still largely undefined. Understanding the mechanisms of sterilizing immunity is essential for devising preventive measures against HCV and unraveling how the virus eludes such immunity. As in other viral infections, the complex interactions between the virus and the host early in the course of HCV infection probably determine the outcome of the disease (i.e., resolution or persistence). The evidence now accumulated on HCV and other models of viral infection is compatible with the hypothesis that both cellular and humoral components are needed for definitive viral clearance. Nevertheless, detailed studies of the specific cellular and humoral immune responses during the incubation period and the acute phase of hepatitis C, in relation to the viral quasispecies evolution and the clinical outcome, are still lacking both in humans and in the chimpanzee model. Until such studies are performed, most ideas of viral clearance mechanisms remain hypothetical, and the immunologic basis of HCV clearance will continue to be inferred from associations rather than from causal relationships.
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Affiliation(s)
- P Farci
- Department of Medical Sciences, University of Cagliari, Cagliari, Italy.
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194
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Stamenkovic G, Zerjav S, Velickovic ZM, Krtolica K, Samardzija VL, Jemuovic L, Nozic D, Dimitrijevic B. Distribution of HCV genotypes among risk groups in Serbia. Eur J Epidemiol 2001; 16:949-54. [PMID: 11338127 DOI: 10.1023/a:1011060505152] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Blood samples from 190 patients that were anti-hepatitis C virus (HCV) positive were genotyped and 165 were found to contain HCV-RNA. Genotyping was performed by PCR based on type-specific primers (117 isolates) and LiPA test (48 isolates) and verifying by sequencing. In Serbia, the most frequent genotype was 1b (49.1%), followed by genotype 3 (21.2%) and genotype 1a (8.5%). The frequency of genotypes 2 and 4 was below 5% and mixed infections were encountered in 9.1% of cases. Distribution of genotypes was monitored in different risk groups: intravenous drug abusers, patients under blood transfusion, patients with previous history of surgery, patients undergoing hemodialysis and those with unknown risk factors. Genotype distribution is essentially the same in all the groups, except for the patients undergoing hemodialysis and those with previous history of surgery where significant difference exists compared with the group with unknown route of transmission (p < 0.001 and p < 0.05, respectively). There exists significant age-dependent genotype 3 distribution in Serbian population (p < 0.01).
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Affiliation(s)
- G Stamenkovic
- Institute for Nuclear Sciences Vinca, Belgrade, Yugoslavia.
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195
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Abstract
Hepatitis C virus (HCV) binds to platelets in chronically infected patients where free HCV constitutes only about 5% of total circulating virus. Free HCV preferentially binds to human mononuclear cell lines but free and complexed virus binds equally to platelets. The extent of free HCV binding to human Molt-4 T cells (which express CD81) and to human promonocytic U937 cells or to platelets (which do not express CD81) was similar. The binding of free HCV to the cell lines was saturated at a virus dose of 1 IU HCV RNA per cell but binding to platelets was not saturable. Human anti-HCV IgG, but not anti-CD81, markedly inhibited HCV binding to target cells in a dose-dependent manner. Human antibodies to HCV hypervariable region 1 of E2 glycoprotein partially inhibited viral binding to target cells. Recombinant E2 also inhibited viral binding to target cells in a dose-dependent manner, with the efficacy of this decreasing in the rank order of Molt-4 cells more than U937 cells more than platelets. In contrast to HCV, recombinant E2 bound to Molt-4 cells to an extent markedly greater than that apparent with U937 cells or platelets. These results suggest that the binding of HCV to blood cells is mediated by multiple cell surface receptors and that recombinant E2 binding may not be representative of the interaction of the intact virus with target cells.
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196
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Hamaia S, Li C, Allain JP. The dynamics of hepatitis C virus binding to platelets and 2 mononuclear cell lines. Blood 2001; 98:2293-300. [PMID: 11588022 DOI: 10.1182/blood.v98.8.2293] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Hepatitis C virus (HCV) binds to platelets in chronically infected patients where free HCV constitutes only about 5% of total circulating virus. Free HCV preferentially binds to human mononuclear cell lines but free and complexed virus binds equally to platelets. The extent of free HCV binding to human Molt-4 T cells (which express CD81) and to human promonocytic U937 cells or to platelets (which do not express CD81) was similar. The binding of free HCV to the cell lines was saturated at a virus dose of 1 IU HCV RNA per cell but binding to platelets was not saturable. Human anti-HCV IgG, but not anti-CD81, markedly inhibited HCV binding to target cells in a dose-dependent manner. Human antibodies to HCV hypervariable region 1 of E2 glycoprotein partially inhibited viral binding to target cells. Recombinant E2 also inhibited viral binding to target cells in a dose-dependent manner, with the efficacy of this decreasing in the rank order of Molt-4 cells more than U937 cells more than platelets. In contrast to HCV, recombinant E2 bound to Molt-4 cells to an extent markedly greater than that apparent with U937 cells or platelets. These results suggest that the binding of HCV to blood cells is mediated by multiple cell surface receptors and that recombinant E2 binding may not be representative of the interaction of the intact virus with target cells.
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Affiliation(s)
- S Hamaia
- Division of Transfusion Medicine, Department of Haematology, University of Cambridge, Cambridge, United Kingdom
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197
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198
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Bugli F, Mancini N, Kang CY, Di Campli C, Grieco A, Manzin A, Gabrielli A, Gasbarrini A, Fadda G, Varaldo PE, Clementi M, Burioni R. Mapping B-cell epitopes of hepatitis C virus E2 glycoprotein using human monoclonal antibodies from phage display libraries. J Virol 2001; 75:9986-90. [PMID: 11559832 PMCID: PMC114571 DOI: 10.1128/jvi.75.20.9986-9990.2001] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Clinical and experimental evidence indicates that the hepatitis C virus (HCV) E2 glycoprotein (HCV/E2) is the most promising candidate for the development of an effective anti-HCV vaccine. Identification of the human epitopes that are conserved among isolates and are able to elicit protective antibodies would constitute a significant step forward. This work describes the mapping of the B-cell epitopes present on the surface of HCV/E2, as recognized by the immune system during infection, by the analysis of the reciprocal interactions of a panel of human recombinant Fabs derived from an HCV-infected patient. Three unrelated epitopes recognized by antibodies with no neutralization-of-binding (NOB) activity were identified; a fourth, major epitope was defined as a clustering of minor epitopes recognized by Fabs endowed with strong NOB activity.
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Affiliation(s)
- F Bugli
- Istituti di Microbiologia, Facoltà di Medicina e Chirurgia, Università Cattolica del S. Cuore, 00168 Rome, Italy
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199
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Owsianka A, Clayton RF, Loomis-Price LD, McKeating JA, Patel AH. Functional analysis of hepatitis C virus E2 glycoproteins and virus-like particles reveals structural dissimilarities between different forms of E2. J Gen Virol 2001; 82:1877-1883. [PMID: 11457993 DOI: 10.1099/0022-1317-82-8-1877] [Citation(s) in RCA: 154] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Structure-function analysis of the hepatitis C virus (HCV) envelope glycoproteins, E1 and E2, has been difficult due to the unavailability of HCV virions. Truncated soluble forms of E2 have been used as models to study virus interaction with the putative HCV receptor CD81, but they may not fully mimic E2 structures on the virion. Here, we compared the CD81-binding characteristics of truncated E2 (E2(660)) and full-length (FL) E1E2 complex expressed in mammalian cells, and of HCV virus-like particles (VLPs) generated in insect cells. All three glycoprotein forms interacted with human CD81 in an in vitro binding assay, allowing us to test a panel of well-characterized anti-E2 monoclonal antibodies (MAbs) for their ability to inhibit the glycoprotein-CD81 interaction. MAbs specific for E2 amino acid (aa) regions 396-407, 412-423 and 528-535 blocked binding to CD81 of all antigens tested. However, MAbs specific for regions 432-443, 436-443 and 436-447 inhibited the interaction of VLPs, but not of E2(660) or the FL E1E2 complex with CD81, indicating the existence of structural differences amongst the E2 forms. These findings underscore the need to carefully select an appropriate ligand for structure-function analysis.
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Affiliation(s)
- Ania Owsianka
- MRC Virology Unit, Institute of Virology, Church Street, Glasgow G11 5JR, UK1
| | - Reginald F Clayton
- MRC Virology Unit, Institute of Virology, Church Street, Glasgow G11 5JR, UK1
| | | | - Jane A McKeating
- University of Reading, School of Animal & Microbial Sciences, PO Box 228, Reading, UK3
| | - Arvind H Patel
- MRC Virology Unit, Institute of Virology, Church Street, Glasgow G11 5JR, UK1
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200
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Bigger CB, Brasky KM, Lanford RE. DNA microarray analysis of chimpanzee liver during acute resolving hepatitis C virus infection. J Virol 2001; 75:7059-66. [PMID: 11435586 PMCID: PMC114434 DOI: 10.1128/jvi.75.15.7059-7066.2001] [Citation(s) in RCA: 324] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Hepatitis C virus (HCV) poses a worldwide health problem in that the majority of individuals exposed to HCV become chronically infected and are predisposed for developing significant liver disease. DNA microarray technology provides an opportunity to survey transcription modulation in the context of an infectious disease and is a particularly attractive approach in characterizing HCV-host interactions, since the mechanisms underlying viral persistence and disease progression are not understood and are difficult to study. Here, we describe the changes in liver gene expression during the course of an acute-resolving HCV infection in a chimpanzee. Clearance of viremia in this animal occurred between weeks 6 and 8, while clearance of residual infected hepatocytes did not occur until 14 weeks postinfection. The most notable changes in gene expression occurred in numerous interferon response genes (including all three classical interferon antiviral pathways) that increased dramatically, some as early as day 2 postinfection. The data suggest a biphasic mechanism of viral clearance dependent on both the innate and adaptive immune responses and provide insight into the response of the liver to a hepatotropic viral infection.
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Affiliation(s)
- C B Bigger
- Department of Virology and Immunology, Southwest Regional Primate Research Center, Southwest Foundation for Biomedical Research, San Antonio, Texas 78227, USA
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