布鲁菌S2感染后死亡的巨噬细胞启动T细胞应答的作用

目的研究布鲁菌S2感染死亡的巨噬细胞在启动细胞免疫应答中的作用。方法以布鲁菌S2株体外感染小鼠腹腔巨噬细胞，并以未感染的正常细胞作为对照，感染后1h用不含血清的RPMI1540培养基饥饿培养5d，待细胞完全死亡后与骨髓源性树突状细胞共培养24h后，ELISA法检测细胞上清中IL-12、TNF—α水平；同时将树突状细胞与淋巴结T细胞共培养，在共培养的不同时间点ELISA法检测培养上清中IFN-γ含量。结果正常死亡的巨噬细胞和S2株感染死亡的巨噬细胞与树突状细胞共培养后均可刺激树突状细胞分泌TNF—α，但S2株感染死亡组的TNF—α分泌水平明显高于正常死亡组（P〈0．05），但不刺激IL-12分泌，且与T细胞共培养各时间点IFN-γ的分泌水平均高于对照组（P〈0．05）。结论感染布鲁菌S2株死亡的巨噬细胞可激活树突状细胞，并可使其提呈抗原、诱导T细胞产生IFN-γ。

Studies on the effects of dead macrophage infected by Brucella suis S2 to prime T cell response

Objective To study the effects of dead macrophage infected by B. suis S2 to prime T cell immune response. Methods Macrophage was infected for 1 h by B. suis S2 in vitro and the normal macrophge acted as control, and was cultured with serum-free medium for 5 d untill the cell completly dead. The dead macrphage was co-cultured with murine bone marrow-derived dendritic cells （BMDC） for 24 h. The IL-12, TNF-α secreted by BMDC were detected with indirected ELISA. Meanwhile the BMDC was co-cultured with T cells, and the IFN-γ content in the culture supernatant was detected by ELISA. Results Both normal dead macrophages and B. suis S2 infected dead macrophages could induce BMDC TNF-α secretion and the TNF-α secretion of BMDC in B. suis S2 infected group was significantly increased than that of control group（P〈0.05）, but IL-12 was not produced. The levels of IFN-γ of T cell in B. suis S2 infected group were significantly higher than those of control group at 24 h, 48 h and 72 h （P 〈 0.05）. Conclusion The dead macrophage infected by B. suis S2 canactivvate DC to secret TNF-α and present antigen to T cell and result in T cell IFN-γ secretion.