TLR2及其相关细胞因子在军团菌感染中作用

目的 通过体外实验探讨Toll样受体2(TLR2)及肿瘤坏死因子-α(TNF-α)、白介素1β(IL-1β)、白介素6(IL-6)在军团菌感染中的作用.方法 分离30名健康人外周血单核细胞(PBMC),将每名健康人PBMC分为对照组和军团菌刺激组,军团菌刺激组加入500 μL 2×10⁷/mL军团菌悬液,对照组加入500 μL磷酸盐缓冲液(PBS),分别在18、24、72 h时获取细胞及上清液,采用real-time PCR法测定细胞中TLR2、MyD88 mRNA的表达水平,ELISA法检测细胞培养上清液IL-6、IL-1β及TNF-α含量.结果 与对照组比较,18h军团菌刺激组MyD88 mRNA △Ct值(1.414 0±0.044 9)低于对照组(1.684 4±0.042 6),24h军团菌刺激组TLR2 mRNA△Ct值(1.347 9±0.056 2)低于对照组(1.425 9±0.038 7),72h军团菌刺激组TLR2 mRNA和MyD88 mRNA △Ct值 [(1.504 9±0.018 9)和(1.540 0±0.031 9)]均高于对照组[(1.410 5±0.025 5)和(1.339 2±0.032 2)],差异均有统计学意义(均P< 0.05);18、24、72h军团菌刺激组细胞上清液中TNF-α、IL-1β、IL-6浓度均高于对照组,差异均有统计学意义(均P< 0.05).结论 TLR2及TNF-α、IL-1β、IL-6等相关炎性因子可有效抵制军团菌感染,TLR2介导的天然免疫可能是军团菌感染的保护因素.

Role of TLR2 and its related cytokines in Legionella infection

Objective To explore the role of Toll like receptor 2(TLR2) and its related cytokines in Legionella infection by in vitro experiment.Methods Peripheral blood mononuclear cells(PBMCs) were obtained from healthy subjects(n=30) and were stimulated with live Legionella pneumophila(Lp) for 18,24,and 72 hours.The mRNA expression levels of TLR2 and myeloid differentiation factor 88(MyD88) in PBMCs were determined using real-time reverse transeription PCR(RT-PCR).The expression levels of tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β),and interleukin-6(IL-6) were measured with enzyme-linked immunosorbent assay(ELISA).Results TLR2 mRNA expression level was not significantly different between stimulation group and control group in 18 hours(P >0.05).TLR2 mRNA expression level of stimulation group was significantly higher than that of control group(1.3479±0.0562 vs.1.4259±0.0387,P <0.05) in 24 hours.The MyD88 mRNA expression level of stimulation group was significantly higher than that of control group(1.4140±0.0449 vs.1.6844±0.0426,P <0.05) in 18 hours.The MyD88 mRNA expression level was not statistically significantly different between stimulation group and control group in 24 hours(P >0.05).TLR2 mRNA and MyD88 mRNA expression levels of stimulation group were significantly lower than those of control group(P <0.05) in 72 hours.The concentration of TNF-α,IL-1β and IL-6 for Legionella stimulation group were significantly higher than those of the control group(P <0.05) in 18,24 and 72 hours.Conclusion Our study showed that TLR2 and its related inflammatory cytokines TNF-α,IL-1β and IL-6 can effectively resist Legionella infection and TLR2 mediated innate immunity may be a protective factor for Legionella infection.