Research on cytotoxic T cell responses to hepatitis C virus infection

丙型肝炎病毒(丙型肝炎病毒)感染经常持续，并导致慢性肝炎、肝硬化，最终导致肝细胞癌。在普遍使用一次性医疗器械和引入血液制品丙型肝炎病毒检测后，急性丙型肝炎病毒感染大幅下降。通过干扰素治疗，可以消除慢性丙型肝炎患者体内的丙型肝炎病毒。然而，仍有许多患者对该疗法没有反应。由于细胞毒性T淋巴细胞(CTL)在清除感染病毒的过程中起着重要作用，因此增强丙型肝炎病毒特异性CTL反应的治疗对这类患者可能是有效的。我们开发了评估外周血对丙型肝炎病毒全抗原的CTL反应的系统。使用该系统，我们发现接受干扰素治疗的患者的丙型肝炎病毒特异性CTL应答与血清中丙型肝炎病毒的下降相一致，而治疗的暂时中断通过再次出现的丙型肝炎病毒刺激增强了CTL应答。我们还试图鉴定出尽可能多的丙型肝炎病毒特异性CTL表位，为未来丙型肝炎病毒多肽疫苗的开发奠定基础。利用含有HLA-A24结合基序的丙型肝炎病毒多肽或包含整个丙型肝炎病毒蛋白的重叠多肽，我们通过干扰素-‘，ELISpot实验鉴定了16个新的丙型肝炎病毒特异性CTL表位。我们还利用CTL表位多肽-HLAA24-Ig二聚体和细胞表面标志物分析了丙型肝炎病毒特异性CTL的表型，发现外周血中丙型肝炎病毒特异性CTL活性低，分化程度不同。

Hepatitis C virus (HCV) infection frequently persists, and leads to chronic hepatitis, cirrhosis, and eventually hepatocellular carcinoma. Acute HCV infection has decreased dramatically after universal use of disposable medical instruments and introduction of HCV test for blood products. Elimination of HCV from chronic hepatitis C patients became possible by interferon therapies. However there are still many patients who do not respond to the therapy. Since cytotoxic T lymphocytes (CTL) play an important role in elimination of infected viruses, the therapy that augments HCV-specific CTL responses may be effective for such patients. We developed the system that assesses CTL responses of peripheral blood to whole HCV antigens. Using the system, we found that HCV-specific CTL responses of patients treated with interferon decreased in accord with the decrease of HCV in serum, and that a temporary interruption of the therapy augmented CTL responses by stimulation with re-appeared HCV. We also attempted to identify HCV-specific CTL epitopes as many as possible for future development of HCV peptide vaccines. Using HCV peptides with HLA-A24-binding motif or overlapping peptides encompassing the whole HCV protein, we identified 16 novel HCV-specific CTL epitopes by interferon-', ELISpot assay. We also analyzed the phenotypes of HCV-specific CTL using CTL epitope peptide-HLA-A24-Ig dimers and cell surface markers, and found that HCV-specific CTL in the peripheral blood were poorly activated and differentiated variously.