TLR2信号在沙眼衣原体生殖道感染中介导了早期炎症细胞因子的产生

TLR2 signaling mediates early inflammatory cytokine production following Chlamydia trachomatis genital tract infection in mice

目的探讨TLR2和TLR4在小鼠沙眼衣原体生殖道感染免疫应答中的作用。方法用沙眼衣原体小鼠肺炎株(Mo Pn,1×104IFUs)经生殖道感染野生型小鼠(WT,11只)、TLR2基因缺陷小鼠(TLR2 KO,14只)和TLR4基因缺陷小鼠(TLR4 KO,11只),复制生殖道沙眼衣原体感染模型。于感染后不同时间点取生殖道分泌物,部分用于免疫荧光法检测衣原体包涵体数量,部分用于炎症细胞因子IL-1α、IL-6和MIP-2水平检测。在感染后第70天,处死小鼠,无菌分离腹腔巨噬细胞,于体外衣原体Mo Pn感染,培养24 h后,测定上清液中IL-1α、IL-6和MIP-2含量。细胞因子含量测定均采用ELISA法。结果 TLR2 KO或TLR4 KO小鼠与WT小鼠在每一个检测时间点下生殖道带菌量无差异,且带菌持续时间相同,截止到感染后第38天,3种基因型所有小鼠均清除了下生殖道感染的衣原体。TLR2基因缺失小鼠巨噬细胞产生的炎症细胞因子IL-1α、IL-6和MIP-2水平均明显低于野生型WT小鼠(P<0.01),而TLR4基因缺失小鼠巨噬细胞产生的3种炎症细胞因子水平均与野生型WT小鼠无差异(P>0.05);TLR2基因缺失小鼠棉拭子标本同样具有较低水平的炎症细胞因子(P<0.05)。结论在沙眼衣原体生殖道感染中,TLR2介导了早期炎症细胞因子的产生。沙眼衣原体诱导的早期免疫应答部分依赖于TLR2,而不依赖TLR4。

To evaluate the roles of TLR2 and TLR4 in immune responses to Chlamydia trachomatis genital tract infection in mice, wild-type mice（n=11） and mice deficient in TLR2（n=14） or TLR4（n=11） were infected intravaginally with 1×104IFUs of live C. muridarum organisms（Mo Pn） to establish the models of Chlamydia trachomatis genital tract infection in mice. The vaginal swabs were collected on different days after infection. A part of each vaginal swab sample was used to monitor live organism shedding using an immunofluorescence assay. The other part of each sample was used for inflammatory cytokines IL-1α, IL-6 and MIP-2 measurement. All mice were sacrificed on day 70 post infection. Macrophages were harvested from the peritoneal cavity and were then infected with C. muridarum for 24 h.The supernatants from infected macrophages were used for inflammatory cytokines IL-1α, IL- 6 and MIP-2measurement. All cytokines were measured using ELISA. There was no significant difference in the number of IFUs recovered from the vaginal swabs（at any time points post infection） among WT, TLR2 KO and TLR4 KO. All mice regardless of the genotypes displayed live organism shedding with similar time course and cleared infection by day 38 post infection. Macrophages lacking TLR2 produced significantly decreased amounts of IL-1α, IL-6, and MIP-2compared with those in WT mice（P〈0.01）; however there was no significant difference between WT and TLR4 KO mice（P〈0.05）. Mice lacking TLR2 also produced lower levels of inflammatory cytokines（P〈0.05）, which was consistent with measured results from macrophages. These results demonstrate that TLR2 signaling mediates earlyinflammatory cytokine production following Chlamydia trachomatis genital tract infection in mice and that early immune responses triggered by Chlamydia trachomatis partially depend on TLR2, but not on TLR4.