巨噬细胞对不同生长时相鼠伤寒沙门氏菌的免疫应答反应

The immune response of macrophage to Salmonella typhimurium in different growth phases

目的观察鼠伤寒沙门氏菌不同生长时相鞭毛的表达规律，并研究鞭毛蛋白表达水平与巨噬细胞免疫应答反应的相关性。方法RT-PCR检测沙门菌在对数期和稳定期鞭毛蛋白基因表达，半固体培养基穿刺接种实验检测沙门菌鞭毛动力水平，乳酸脱氢酶释放实验和荧光染料染色法测定沙门菌诱导的巨噬细胞的焦亡率，Westernblotting实验检测感染后巨噬细胞caspase-1、IL-1β的表达水平，从而评价炎性复合体的激活状态。结果对数期沙门菌鞭毛基因表达以及鞭毛动力均高于稳定期沙门菌，对数期沙门菌可促进感染后巨噬细胞caspase-1、IL-1β的表达并且诱导大量巨噬细胞焦亡，而稳定期沙门菌则无此现象发生。结论鼠伤寒沙门氏菌在对数期鞭毛蛋白高表达，激活炎性复合体免疫反应，且能诱导大量巨噬细胞发生焦亡。

Objective To explore the regulation of flagella expression of Salmonella typhimurium in different growth phases and to investigate the relationship between flagella and immune response. Methods Flagella expression in the logarithmic phase and the stationary phase was measured by RT-PCR. Swimming mo- tility was evaluated by motility assay. Macrophage pyroptosis rate was calculated by LDH assay and fluorescent dye staining. The expression of caspase-1 and IL-1 β was detected by Western blotting assay. Results Flagella expression and swimming motility of Salmonella typhimurium in the logarithmic phase was higher than that in the stationary phase. Salmonella typhimurium in the logarithmic phase could induce expression of caspase-1 and IL-1 β and trigger rapid macrophage pyroptosis,while salmonella in the stationary phase did not show this capa- bility. Conclusion The high expression level of flagella in Salmonella typhimurium in the logarithmic phase could activate inflammasome and induce macrophage pyroptosis.