中文摘要：

目的：分析从中国槲寄生中提取的55 kD凝集素诱导T淋巴细胞增殖和肿瘤细胞凋亡的免疫学活性。方法：通过CM-Sepharose和ConA柱分离和纯化了分子量为55 kD的槲寄生凝集素。用流式细胞术和ELISA检测纯化的槲寄生凝集素诱导T淋巴细胞表型和细胞因子分泌格局。并经Annexin V染色法研究其诱导肿瘤细胞凋亡的免疫学机制。结果：从中国槲寄生中分离纯化了由两个30 kD亚基组成的55 kD槲寄生凝集素蛋白,其具有特异诱导人γδT细胞扩增和以Caspase依赖途径诱导Jurkat细胞凋亡,并能促进TNFα-释放和抑制IL-10的释放的作用。结论：中国槲寄生凝集素具有免疫学调节作用和诱导肿瘤细胞凋亡作用。在研究抗肿瘤和免疫学机制中具有应用价值。

英文摘要：

Objective：To explore immuno-modulation of a migtletoe lectin（ML）.Methods：In this study,a 55 kD ML was purified from Chinese mistletoe and its effects on haman γδT cell cytotoxicity,the modulation in cytokine network and apoptosis induction was studied.FACS and ELISA analysis were applied to quantify translocation of the cell membrane phospholipid phosphatidylserine and nuclear DNA fragmentation during apoptosis.The cytotoxic properties of γδT cells was evaluated by using a ^51 Cr release test.Results：It was found that：ML induced apoptosis in both a Caspasedependent and CD95-dependent manner;ML could effectively stimulate γδT cell proliferation in a dose-and time-dependent manner;ML increased γδT cell cytotoxicity;ML could modulate lipopolysaccharide-induced cytokine release in a pro-inflammatory manner by increasing release of tumor necrosis factor-α release and inhibiting the release of anti-inflammatory interleukin-10.Conclusion：The results indicate that ML is a potent immunomodulator to human γδT cell cytotoxicity,cytokine production and apoptosis of tumor cells.