布鲁菌S_2株感染巨噬细胞与树突状细胞的比较

Comparison of macrophages and dendritic cells infected by Brucella S_2

目的比较猪布鲁菌S2菌株感染巨噬细胞和树突状细胞(DC)的特点。方法采用瑞氏-吉姆萨染色法观察细胞形态并计算吞噬率;用ELISA法测定细胞培养上清中的IL-12和TNF-α以及与T细胞共培养上清中IFN-γ和IL-4的含量;用annexin-Ⅴ-FITC/PI双染,流式细胞仪检测细胞凋亡率。结果感染S2菌株1 h后巨噬细胞的吞噬率为(43.6±4.8)%,显著高于DC的吞噬率(13.08±2.36)%(P<0.05);正常巨噬细胞凋亡率为(3.09±1.21)%感染S2菌株后6、12和24 h的凋亡率分别为(19.89±1.36)%、(22.73±2.21)%和(42.44±3.12)%,明显高于DC感染后相同时间点的凋亡率(P<0.05),正常DC凋亡率为(1.82±0.01)%,DC感染S2菌株6、12、24 h凋亡率分别为(3.76±0.13)%、(7.87±0.56)%和(9.08±0.23)%。巨噬细胞在感染S2菌株后24、48 h分泌的IL-12均明显低于DC分泌IL-12的量(P<0.05);24、48、72 h分泌的TNF-α量均明显低于DC(P<0.01);在24、48、72 h与T细胞共培养分泌的IFN-γ含量均明显低于DC(P<0.01)。结论巨噬细胞吞噬猪布鲁菌S2菌株的能力高于DC,猪布鲁菌S2感染后巨噬细胞的凋亡率高于DC,感染S2菌株后DC的活化及提呈抗原并激活T细胞的能力强于巨噬细胞。

Objective To make a comparison of the characteristics between macrophages and dendritic cells （DC） infected by Brucella suis （ B. suis） S2. Methods Wrights-Giemsa＇s stainning was used to observe the cell morphology and calculate the phagocytic rate. ELISA was employed to detect the expressions of IL-12 and TNF-α in cell culture supernatants as well as the contents of IFN-γ and IL-4 in the co-culture with T cells. With annexin-V-FITC/PI double staining, the cell apoptosis rate was determined by flow cytometry. Results 1h after infected by B. suis S2, the phagocytic rate of macrophages was （43.6 ± 4.8） %, which was significantly higher than that of the DC （ 16.3 ± 2. ？） % （ P 〈 0.05）. The apoptosis rates of normal macro- phages and macrophages 6, 12 and 24 h after infected by B. suis S2 were （3.09 ± 1.21 ）%, （ 19.89 ± 1.36）%, （22. 73 ± 2.2]） % and （42. 44 ± 3.12）%, respectively, which were dramatically higher than those of the DC at the corresponding time points, being （1.82 ±0.01）%, （3.76 ±0.13）%, （7.87 ±0.56）% and （9.08 ±0.23）%, respectively （P〈0.05）. The levels of IL-12 secreted by macrophages 24 and 48 h after infected by B. suis S2 were significantly lower than those by the DC （ P 〈 0.01 ）. At 24, 48 and 72 h, the levels of TNF-α secreted by macrophages were dramatically lower than those by the DC （ P 〈 0.01 ）, and the levels of IFN-γ in the co-culture supematants of macrophages and T cells were significantly lower than those in DC and T cell co-culture （ P 〈 0.01 ）. Conclusion Macrophages have a better ability in phagocytosing B. suis S2 than DC and the apoptosis rate of macrophages is higher than that of DC after infected by B. suis S2, but in activating and inducing the cellular immune response and presenting antigen, DC are stronger than macrophages.