EARLY DETECTION OF THE METASTASIS AND IMMUNETHERAPY TARGETING TUMOR-REJECTION ANTIGENS IN HUMAN HEPATOCELLULARA CARCINOMA

我们已经明确肿瘤排斥抗原，如MAGE-1、MAGE-3和NY-ESO-1在人类肝细胞癌（HCC）中以mRNA和蛋白水平显著表达。除睾丸外，这些基因在正常体细胞中不表达。尽管我们已经尝试在HLA-A2阳性的健康志愿者和HCC患者中检测针对MAGE-3或NY-ESO-1衍生的多片段的细胞毒性t细胞反应，但迄今为止我们无法检测到。由于已有报道在黑色素瘤患者血清中检测到针对NY-ESO-1的IgG抗体，因此我们也试图检测HCC患者的血清抗体。结果，100例HCC患者中有2例出现IgG抗体。这一结果提示肝癌患者对NY-ESO-1产生免疫应答，NY-ESO-1衍生肽可用于肝癌患者的疫苗治疗。相反，我们分析了抗原加工和抗原呈递分子的表达，如LMP-2、-7、热休克蛋白、TAP、β2-微球蛋白、HLA - i类和B7-1和-2。我们已经阐明，共刺激分子B7-1和-2的表达在HCC中显著缺失，HLA - i类分子的表达也较少减少。这些结果表明，HCC通过这些分子的丢失，特别是通过B7分子的丢失，逃避免疫监视。对于HCC患者免疫治疗的下一步，我们必须确定转染树突状细胞中的B7分子作为APC或HCC细胞作为靶细胞是否可以引发针对肿瘤排斥抗原的CTL反应。此外，我们进行了SEREX，并确定了四个分子在HCC中异常表达。我们也在研究人类HCC样本中y -tes -1基因的表达，该基因是我校发现的癌睾丸抗原之一。

We have clarified that tumor-rejection antigens such as MAGE-1, MAGE-3 and NY-ESO-1 are expressed in a significant proportion of human hepatocellular carcinoma(HCC)at mRNA and protein levels. These genes are not expressed normal somatic cells except for testis. Although we have attempted to detect cytotoxic T-cell responses against MAGE-3 or NY-ESO-1 derived peplides in HLA-A2 positive healthy volunteers and HCC patients, we could not detect it to date. Since it has been reported that CTL activity against NY-ESO-1 was detected in melanoma patients in whom IgG antibodies against NY-ESO-1 was found in serum, we have also tried to detect serum antibodies in HCC patients. As a result, the IgG antibodies were observed in two of 100 patients with HCC.This result suggests that immune response against NY-ESO-1 is developed in HCC patients and NY-ESO-1 derived peptides can be used for vaccine therapy in HCC patients. In contrast, we have analyzed the expression of antigen-processing and antigen-presenting molecules, e.g., LMP-2, -7, Heat shock protein, TAP, β2-microglobulin, HLA class-I and B7-1 and -2. We have clarified that the expression of co-stimulatory molecules, B7-1 and -2 was lost in a significant proportion of HCC and that of HLA class-I molecule was also reduced in less frequency. These results indicate that HCC escape from immune surveillance via the losses of these molecules especially via the loss of B7 molecules. For the next step for immunotherapy in HCC patients, we have to determine whether the transfection of B7 molecules in dendritic cells as APC or HCC cells as the target cells can elicit CTL responses against tumor-rejection antigens. Further, we have carried out SEREX and identified four molecules are aberrantly expressed in HCC.We are also examining the expression of OY-TES-1 gene in human HCC samples, which was discovered as one of cancer-testis antigens in our university.