负载不同形式肝癌抗原的树突状细胞抑瘤功能的比较

目的：探讨不同形式的肝癌抗原修饰的树突状细胞(DC)的抑瘤功能。方法：分别用肝癌H22冻融抗原、H22小分子抗原肽和Hsp70-H22抗原肽复合物修饰DC；用MTT比色法分析DC激活的CTL对H22细胞的杀伤能力，并用RT-PCR法测定脾脏T细胞中IFN-γ mRNA的表达水平；用不同修饰的DC免疫小鼠，观察其对H22肝癌的生长抑制作用。结果：单独的H22肝癌抗原肽修饰的DC不能激活CTL。Hsp70-H22肽复合物修饰的DC激活CTL的能力强于H22肝癌冻融抗原修饰的DC，对H22细胞的杀伤率分别为47．3％和18．3％。各组T细胞中IFN-γ表达水平的变化与杀伤率的变化相一致。用H22肝癌冻融抗原和Hsp70-H22肽复合物修饰的DC免疫小鼠后，均可抑制H22细胞生长，但后者的抑制作用更强，成瘤率仅40％。其他各组的成瘤率均为100％。结论：Hsp70-H22肽复合物是一种DC的强致敏物．可通过激活CTL、诱导CD4^ T细胞分化成Th1型细胞而参与肝癌的免疫排斥。

Comparison of antitumor effects of dendritic cells modified with different forms of hepatocellular cancer antigens

AIM: To explore the antitumor effects of dendritic cells (DCs) modified with different forms of hepatocellular cancer antigens. METHODS: DCs were modified with freeze-thawed H22 cell lysate, small molecular H22 peptides and Hsp70-H22 peptide complex, respectively. The cytotoxicity of DCs-activated CTLs to H22 cells was detected by MTT colorimetry. The expression level of IFN-gamma mRNA in splenocytes was detected by RT-PCR. The DCs modified with different antigens were used to immunize mice and then the suppressive effects on the growth of tumor were measured. RESULTS: The DCs modified with H22 peptides alone could not activate CTLs. The ability to activate CTLs by DCs modified with Hsp70-H22 peptide complex was stronger than that by DCs modified with freeze-thawed H22 lysate, with the killing rates of CTLs being 47.3% and 18.3%, respectively. The expression level of IFN-gamma mRNA in 3 groups of splenocytes was consistent with the killing rate of CTLs.The growth of H22 cells in mice immunized with DCs modified with freeze-thawed H22 lysate or Hsp70-H22 peptide complex was suppressed, but the suppressive effect of the latter was stronger than that of the former. The tumorigenesis rate in the Hsp70-22 peptide complex group was only 40%, whereas the tumorigenesis rates in the other two groups were 100%. CONCLUSION: Hsp70-H22 peptide complex is a strong sensitizer for DCs, which participates in immune rejection of tumor through activating CTLs and inducing CD4 (+) T cells to differentiate into Th1 cells.