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Hiroishi K, Ito T, Imawari M. Immune responses in hepatitis C virus infection and mechanisms of hepatitis C virus persistence. J Gastroenterol Hepatol 2008; 23:1473-82. [PMID: 18761560 DOI: 10.1111/j.1440-1746.2008.05475.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Immune responses against hepatitis C virus (HCV) play a crucial role in the pathogenesis of chronic hepatitis C. HCV infection often persists and leads to chronic hepatitis and eventually cirrhosis. Accumulated data suggest that HCV proteins suppress host immune responses through the suppression of functions of immune cells, such as cytotoxic T lymphocytes, natural killer cells, and dendritic cells. They also suppress the type 1 interferon signaling system. The resulting insufficient immune responses against HCV lead to the sustained infection. The appropriate control of immune responses would contribute to the eradication of HCV and the improvement of hepatitis, but there are still many issues to be clarified. This review describes the scientific evidence to support these emerging concepts, and will touch on the implications for improving antiviral therapy.
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Affiliation(s)
- Kazumasa Hiroishi
- Department of Gastroenterology, Showa University School of Medicine, Tokyo, Japan.
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Hakamada T, Funatsuki K, Morita H, Ugajin T, Nakamura I, Ishiko H, Matsuzaki Y, Tanaka N, Imawari M. Identification of novel hepatitis C virus-specific cytotoxic T lymphocyte epitopes by ELISpot assay using peptides with human leukocyte antigen-A*2402-binding motifs. J Gen Virol 2004; 85:1521-1531. [PMID: 15166436 DOI: 10.1099/vir.0.79801-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The human leukocyte antigen (HLA)-A*2402 is common in Asians. The authors attempted to identify epitopes for HLA-A*2402-restricted, hepatitis C virus (HCV)-specific CD8+ T cells by an enzyme-linked immunospot (ELISpot) assay using peripheral blood CD8+ T cells from HLA-A*2402-positive hepatitis C patients and synthetic HCV peptides based on HLA-A*2402-binding motifs and the amino acid sequence of type 1b HCV. Ten novel epitopes were identified in five of seven HLA-A*2402-positive patients with acute or short-term chronic HCV infection (<3 years), but in none of four with longer-term chronic infection (>10 years). Only one of the ten epitopes proved to be definitely HLA-A*2402-restricted. Another epitope was identified in one of two HLA-A*2402-negative acute hepatitis C patients. In two of the six patients with positive CD8+ T cell responses, the targeted epitopes were multiple. The same epitope was targeted in two patients. When patients with unresolved acute HCV infection were treated with alpha interferon, peripheral blood HCV-specific CD8+ T cells decreased with resolution of the hepatitis. In conclusion, CD8+ T cell responses to HCV infection are heterogeneous. One definite HLA-A*2402-restricted and ten probably non-HLA-A*2402-restricted epitopes were identified. Patients with short-term HCV infection are suitable for searching for novel HCV epitopes, but peripheral blood HCV-specific CD8+ T cells decrease markedly after loss of antigenic stimulation.
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Affiliation(s)
- Taku Hakamada
- Division of Gastroenterology, Institute of Clinical Medicine, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8575, Japan
| | - Kiyomi Funatsuki
- Research & Development Department, Mitsubishi Kagaku Bio-Clinical Laboratories Inc., 3-30-1 Shimura, Itabashi-ku, Tokyo 174-8555, Japan
| | - Hiroki Morita
- Division of Gastroenterology, Omiya Medical Center, Jichi Medical School, 1-847 Amanuma-cho, Omiya-ku, Saitama 330-8503, Japan
| | - Takuhiro Ugajin
- Division of Gastroenterology, Omiya Medical Center, Jichi Medical School, 1-847 Amanuma-cho, Omiya-ku, Saitama 330-8503, Japan
| | - Ikuo Nakamura
- Division of Gastroenterology, Omiya Medical Center, Jichi Medical School, 1-847 Amanuma-cho, Omiya-ku, Saitama 330-8503, Japan
| | - Hiroaki Ishiko
- Research & Development Department, Mitsubishi Kagaku Bio-Clinical Laboratories Inc., 3-30-1 Shimura, Itabashi-ku, Tokyo 174-8555, Japan
| | - Yasushi Matsuzaki
- Division of Gastroenterology, Institute of Clinical Medicine, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8575, Japan
| | - Naomi Tanaka
- Division of Gastroenterology, Institute of Clinical Medicine, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8575, Japan
| | - Michio Imawari
- Second Department of Internal Medicine, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8666, Japan
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Zhou YL, Wang SY, Zhang JY, Peng XX. Analysis of hepatitis B virus-immunoglobulin isotype complexes by a novel immuno-capture polymerase chain reaction method. Scand J Immunol 2003; 57:391-6. [PMID: 12662303 DOI: 10.1046/j.1365-3083.2003.01240.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Hepatitis B virus (HBV) can be present in the circulating blood either as free virus or as a virion-immunoglobulin (Ig) complex. Presently, it remains unclear what specific role each Ig plays in the clearance of HBV. In this study, a novel method that combined immuno-capture and polymerase chain reaction (PCR) amplification was used for detecting and distinguishing different HBV-Ig complexes. Three isotypes of Ig (IgM, IgG and IgA) bound to HBV were detected in the four clinically defined stages of HBV infection in 108 patients. The results showed that all the three isotypes of Ig could bind to HBV, and the patterns of HBV-Ig complexes varied according to disease categories. Interestingly, the frequency of HBV DNA-Ig complexes in hepatitis B e antigen (HBeAg)-positive patients was significantly lower than that in HBeAg-negative patients. All the data suggest that the three isotypes of HBV DNA-Ig circulating immune complex (CIC) may have different biological meanings. In summary, HBV bound to an antibody is a common feature of hepatitis B, and immuno-capture PCR is a valuable method for the analysis of the composition of the immune complexes. The detection of HBV-Ig complexes may provide new and valuable insights into HBV pathogenesis.
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Affiliation(s)
- Y L Zhou
- The Key Laboratory of Education Ministry for Cell Biology and Tumour Cell Engineering, Department of Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361 005, PR China
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