Zhang Xiao-yun, Li Ji-long, Dong Ming-gang, Gao Li-fen, Zhong Guang-ming
Department of Biochemistry, Hebei North University, Zhangjiakou 075000, China.
Beijing Da Xue Xue Bao Yi Xue Ban. 2010 Oct 18;42(5):509-13.
To evaluate the early interleukin-17 (IL-17) production in airway upon Chlamydia trachomatis infection and its relationship with the secretion of interleukin-6 (IL-6) and macrophage inflammatory protein 2 (MIP-2) in local site.
In vivo, a murine model of pneumonia induced by intranasal inoculation with Chlamydia trachomatis mouse pneumonitis (MoPn, now classified as a new species C. muridarum) was used for the study. Chlamydial growth in the lung was assessed by inoculating HeLa cell monolayer with lung homogenates followed by enzyme-linked immunosorbent assay (IFA). IL-17, IL-6 and MIP-2 were measured by enzyme-linked immunosorbent assay (ELISA). Mice without infection acted as the control group. In vitro, L929 cells were pretreated with recombinant murine IL-17 (rmIL-17) at a dose ranging from 20, 100 to 500 μg/L for 24 h then infected with MoPn for 24 h. The supernatants were harvested and tested for IL-6 and MIP-2 concentration using ELISA. The cells were assayed for the number of inclusion-forming unit (IFU) by IFA. L929 cells without pretreatment with rmIL-17 but infected with MoPn was the control group.
The study showed that in vivo, Chlamydial growth in the lung was found on day 1 after infection, and reached its peak at day 8 (6.49±0.19, lg IFU/lung) with subsequent decline in quantity. IL-17 peaked at 48 h (83.0 ng/L±35.8 ng/L) while IL-6 peaked on day 3 [(3.98±0.04) μg/L], MIP-2 peaked on day 8 [(2.19±0.71) μg/L]. The study showed that in vitro, compared with control group [(55.10±16.54) ng/L for IL-6 production and (13.71±0.84) ng/L for MIP-2], L929 cells pretreated with rmIL-17 at the different concentrations of 20, 100 and 500 μg/L for 24 h then infected with MoPn for 24 h, could significantly increase IL-6 (P <0.01) and MIP-2 secretion (P <0.05). The productions of IL-6 in the supernatants were (531.65±24.40), (629.95±7.71), and (646.51±35.92) ng/L. Meanwhile, the productions of MIP-2 were (107.21±28.40), (181.95±25.51), and (221.90±17.32) ng/L, respectively. RmIL-17 alone had no effect on IL-6 and MIP-2 secretion, and no direct effect on growth of chlamydial inclusion body was demonstrated either.
IL-17 was produced early in airway upon Chlamydia trachomatis, and rmIL-17could induce IL-6 and MIP-2 production in L929 cells after infection with MoPn. These suggest that an early IL-17 response may play an important role by inducing the secretion of IL-6 and MIP-2 in initiating host defense against infection with Chlamydia trachomatis in the airway.
评估沙眼衣原体感染后气道中白细胞介素-17（IL-17）的早期产生情况及其与局部白细胞介素-6（IL-6）和巨噬细胞炎性蛋白2（MIP-2）分泌的关系。
在体内，采用经鼻接种沙眼衣原体鼠肺炎株（MoPn，现归类为新种鼠衣原体）诱导的小鼠肺炎模型进行研究。通过将肺匀浆接种到HeLa细胞单层上，随后进行酶联免疫吸附测定（IFA）来评估肺中的衣原体生长情况。采用酶联免疫吸附测定（ELISA）法检测IL-17、IL-6和MIP-2。未感染的小鼠作为对照组。在体外，将L929细胞用剂量为20、100至500μg/L的重组鼠IL-17（rmIL-17）预处理24小时，然后感染MoPn 24小时。收集上清液，使用ELISA检测IL-6和MIP-2浓度。通过IFA检测细胞中包涵体形成单位（IFU）的数量。未用rmIL-17预处理但感染MoPn的L929细胞作为对照组。
研究表明，在体内，感染后第1天在肺中发现衣原体生长，并在第8天达到峰值（6.49±0.19，lg IFU/肺），随后数量下降。IL-17在48小时达到峰值（83.0 ng/L±35.8 ng/L），而IL-6在第3天达到峰值[（3.98±0.04）μg/L]，MIP-2在第8天达到峰值[（2.19±0.71）μg/L]。研究表明，在体外，与对照组[IL-6产生量为（55.10±16.54）ng/L，MIP-2产生量为（13.71±0.84）ng/L]相比，用20、100和500μg/L不同浓度的rmIL-17预处理24小时然后感染MoPn 24小时的L929细胞，可显著增加IL-6（P<0.01）和MIP-2分泌（P<0.05）。上清液中IL-6的产生量分别为（531.65±24.40）、（629.95±7.71）和（646.51±35.92）ng/L。同时，MIP-2的产生量分别为（107.21±28.4）、（181.95±25.51）和（221.90±17.32）ng/L。单独的rmIL-17对IL-6和MIP-2分泌无影响，也未显示对衣原体包涵体生长有直接影响。
沙眼衣原体感染后气道中早期产生IL-17，rmIL-17可在感染MoPn后的L929细胞中诱导IL-6和MIP-2产生。这些结果表明，早期IL-17反应可能通过诱导IL-6和MIP-2的分泌在启动宿主对气道沙眼衣原体感染的防御中发挥重要作用。
