2001 Fiscal Year Final Research Report Summary
Analysis of cellular immune responses in perihperal blood and liver tissues in HCV infection
| Project/Area Number |
11470136
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Gastroenterology
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| Research Institution | Jichi Medical School |
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Principal Investigator |
IMAWARI Michio Jichi Medical School, Departmet of Medicine, Professor, 医学部, 教授 (70134228)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAMURA Ikuo Jichi Medical School, Department of Medicine, Lecturer, 医学部, 講師 (40251243)
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| Project Period (FY) |
1999 – 2001
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| Keywords | hepatitis C virus / immunology / helper T cell / cytotoxic T lymphocyte / interferon-γ / interleukin-4 / interleukin-10 / ELISpot |
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| Research Abstract |
Hepatitis C virus (HCV) infection frequently persists, progresses to chronic hepatitis and cirrhosis, and finally develops hepatocellular carcinoma. Although viruses in the infected cells are eliminated by virus-specific cytotoxic T lymphocytes (CTLs) that recognize endogenously synthesized, processed viral proteins presented by HLA and lyse the cells, the CTL responses are regulated by helper T cells and immunomodulatory cytokines. In the present study, we investigated mainly the helper T cell and immunomodulatory cytokine responses in peripheral blood ant liver tissues of patients with chronic HCV infection. In chronic HCV infection, type 1 helper T cell responses that produced interferon-γin response to HCV proteins dominated type 2 helper T cell responses that produced interleukin-4. However, HCV proteins stimulated the production of immunosuppressive interleukin-10. In the peripheral blood of patients with chronic hepatitis C, the number of HCV-stimulated interleukin-10-producing cells was larger than that of HCV-stimulated interferon-γ-producing cells. Thus, the anti-HCV responses seemed to be suppressed in the peripheral blood. HCV-specific helper T cells were concentrated in the liver tissues. The number of HCV-stimulated interferon-γ-producing cells in the peripheral blood was inversely correlated with serum HCV RNA levels. Interferon treatment decreased the number of peripheral blood HCV-stimulated interferon-γ-producing cells at 3 month, but the number returned to the pretreatment level later. There were regions in HCV proteins that stimulated of production of interferon-γ and interleukin-10 by peripheral blood mononuclear cells of patients with chronic HCV infection in common. Finally we identified an epitope in HCV recognized by CTLs in association with HLA-A^*0206.
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