转染B7-1基因的Raji和Jurkat细胞诱导细胞因子mRNA表达的研究

为探讨B7共刺激分子在T细胞活化和分化中的作用，利用脂质体导的转基因技术将B7基因导入恶性血液病细胞系Raji和Jrkat细胞，用流式细胞术检测转基因前，后B7-1基因的表达，用RT-PCR检测T细胞表面细胞因子IL-2，IL-4和IFN-γmRNA的表达及这3种细胞因子在转基因后4，12，20及48小时的时间动态变化，结果发现，B7^ Raji细胞可诱导T细胞分泌细胞因子IL-2，IL-4和IFN-γ，B7^ Jurkat细胞可诱导IL-2和IFN-γ的分泌，而B7^-Raji细胞及B7^-Jurkat细胞均未诱导细胞因子的分泌，IL-2和IL-4在T细胞活化4小时即可检测到，IFN-γ在T细胞活化12小时可检测到，在20小时出现峰值，结论：B7-1基因的导入可有效地增强肿瘤细胞的免疫原性，激活T细胞，B7-1在T细胞活化和分化中起着更主要的作用。

Study on Expression of Cytokines mRNA Induced by B7-1-transfected Raji and Jurkat Cells

To investigate the function of B7 co-stimulator in activation and differentiation of T cell,B7 gene was transfected into Raji and Jurkat cells by liposome,B7 expression in tumor cells was detected with flow cytometry,and expression of IL-2,IL-4 and IFN-ymRNA was detected by RT-PCR.Kinetics of secretion of three cytokines were also analyzed at 4,12,20 and 48 hours after gene transfection.The results showed that B7+ Raji cells could induce mRNA expression of IL-2,IL-4 and IFN-y on T cell surface; B7+ Jurkat cells could induce secretion of IL-2 and IFN-y.However,B7 Raji and B7 Jurkat cells could not induce secretion of cytokines.Kinetics of the three cytokines secretion were different,IL-2 and IL-4 were only detectable after 4 hours of T cell activation,whereas IFN-y was detectable after 12 hours of stimulation.The peak levels of IL-2,IL-4 and IFN-y were found at 20 hours after activation.It was concluded that tumor cell lines transfected B7 gene could enhance their immunocompetence,activating T cell efficiently and B7-1 play more critical role in T cell activation and differentiation.