Identification and clinical application for the role of NKT cells in patients with chronic hepatitis and hepatocellualr carcinoma infected hepatitis virus

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Natural killer T (NKT) cells share features of both classical T cells and NK cells. NKT cells are heterogenous populations, and recognize glycolipids associated with CD1d molecule. We investigated Th1/Th2 cytokine production as well as frequency and phenotype of circulating NKT cells in patients with chronic hepatitis (CH) and hepatocellular carcinoma (HCC) infected with hepatitis C virus (HCV). Peripheral blood mononuclear cells (PBMC) were obtained befor and 2 weeks later IFN/ribavirin and radiofrequency ablation therapy for CH and HCC, respectively. PBMC were cultured with α galactosylceramide (α GalCer) and IL-2. Frequency and cytokine production of NKT cells were analyzed with flow cytometry. IFN-γ production of Vα 24+CD3+ T cells did not differ among groups, but became greater after treatment in contrast to lowered IL-4 production.The function of dendritic cells (DCs) appears to be decreased in patients with chronic hepatitis C. However, we have no strategy to modulate its functi … More on. Thus we wanted to induce maturated DC by activating V α 24+ NKT cells. We cultured peripheral blood CD14+ cells in the presence of GMCSF and IL-4. Simultaneously CD3+ T cells were cultured with α GalCer + IL-2. After 5-day culture, they are mixed and cultured with GMCSF, α GalCer and IL-2 for further 2 days. This method induced matured, functional DC.Cytotoxic T lymphocyes (CTLs) are thought to be major effectors for clearing viruses in acute infections including hepatitis B virus (HBV). Persistent HBV infection is characterized by a lack of or a weak CTL response to HBV, which is thought to reflect tolerance to HBV antigens. We found that α GalCer, a ligand for V α 14+ NKT cells in mice, strongly enhanced the induction and proliferation of HBV-specific CTLs by HBsAg. In HbsAg transgenic mice, which are thought to be tolerant to HBV-encoded antigens, administration of HbsAg or α GalCer alone failed to HbsAg-specific CTLs, but they were induced by administration of both compounds. A blocking experiment using antibodies to cytokines and CD4O ligand showed that IL-2 mediates the enhancement of CTL induction caused by α GalCer through NKT activation. Less