布鲁菌S_2株诱导小鼠腹腔巨噬细胞凋亡及免疫激活的研究

Study on apoptosis and immune activation of macrophage of mice induced by Brucella S_2

目的:研究猪布鲁菌S2株诱导巨噬细胞(Mφ)的凋亡、活化及对T淋巴细胞的激活作用。方法:用猪布鲁菌S2株体外感染Mφ,并以大肠埃希菌作为对照,采用瑞氏-姬姆萨染色观察细胞形态学变化;流式细胞仪测定感染后24小时Mφ的凋亡率;ELISA法检测感染后不同时间点Mφ培养上清中IL-12和TNF-α及感染后Mφ与T细胞共培养上清中IFN-γ的含量的变化。结果:瑞氏-姬姆萨染色显示布鲁菌S2株感染Mφ后1小时体积明显增大,突起增多,胞浆内可见大量布鲁菌;6小时细胞内细菌减少,但胞膜仍完整;至12小时细胞核固缩,胞膜失去完整性。流式细胞仪检测结果显示,感染后24小时Mφ的凋亡率均明显高于正常对照组及大肠埃希菌感染组(P<0.05)。ELISA结果显示S2株感染Mφ12、24、48小时的上清中IL-12和TNF-α含量均明显高于正常对照组(P<0.01),S2株感染后Mφ与T细胞共培养24、48、72小时产生的IFN-γ量高于正常对照组(P<0.05),但低于大肠埃希菌感染组(P<0.01)。结论:S2株可以引起Mφ的凋亡,同时可诱导Mφ活化,产生IL-12和TNF-α;布鲁菌感染后的Mφ可诱导T细胞活化,产生IFN-γ免疫应答。

Objective：To study the apoptosis and activation of macrophages and their abilities to initiate immune actvation induced by B.suis S2.Methods： The macrophages infected by B.suis S2 were compared with Escherichia coli in vitro.The cell morphology changes were observed by Wrights-Giemsa stain and the cell apoptosis rates at 24 h post-infected were determined by Flow Cytometry.The IL-12 and TNF-α levels secreted by macrophages and the IFN-γ levels in the supernatants of T cells co-cultured with macrophages at different time points were detected by ELISA.Results： After 1 h infected by B.suis S2,the volume of macrophages was significantly expanded.The protuberances were increased and there were a large number of B.suis S2 in the cytoplasm of macrophages;the number of B.suis S2 decreased and the cell membranes remained intact after 6 h;the macrophages appeared karyopyknosis and the membranes were not intact after 12 h.The apoptosis rates of macrophages at 24 h post-infected by B.suis S2 were significantly higher than those of control group and Escherichia coli group（P〈0.05）.The IL-12 and TNF-α levels of macrophages infected by B.suis S2 were significantly higher than those of the control group at 12,24 and 48 h（P〈0.01）.The IFN-γ levels released from T cells co-cultured with macrophages at 24,48 and 72 h were also significantly higher than those of the control group（P〈0.05）,but lower than those of Escherichia coli group（P〈0.01）.Conclusion： B.suis S2 can induce Mφ apoptosis,activation and secretion of IL-12 and TNF-α;Mφ infected by B.suis S2 can induce IFN-γ production of T cell.