摘要目的 探讨γδT细胞在沙眼衣原体呼吸道感染中的作用以及对衣原体特异性适应性免疫应答的影响.方法 WT(C57 BL/6)小鼠和TCRδ-/-小鼠(C57BL/6背景)经鼻腔吸入1×103 IFU的沙眼衣原体小鼠肺炎菌株(Chlamydia muridarum,Cm),建立沙眼衣原体小鼠呼吸道感染模型.酶免疫法检测感染不同时间的小鼠肺组织衣原体生长情况,用衣原体包涵体形成单位(IFU)代表衣原体繁殖;ELISA法测定脾细胞培养上清中IFN-γ和IL-17的产生;细胞内细胞因子染色检测小鼠肺组织CD3+ CD4+T细胞IFN-γ(Th1免疫应答)及CD3+ CD4+T细胞IL-17(Th17免疫应答)的水平,确定γδT细胞对宿主特异性抵抗衣原体的Th1、Th17免疫应答的调节作用.结果 经鼻腔吸入一定剂量Cm诱导小鼠沙眼衣原体肺炎,与WT小鼠比较,TCRδ-小鼠感染Cm早期体重下降更明显,但是两组小鼠肺组织衣原体繁殖水平未见显著差异.ELISA结果显示,WT与TCRδ-/-小鼠在Cm呼吸道感染后的第3天和第7天IFN-γ分泌无显著差异,感染第7天TCRδ-/-小鼠IL-17分泌显著低于WT小鼠;细胞内细胞因子染色结果提示感染第3天和第7天TCRδ-/-小鼠CD3+ CD4+T细胞分泌IL-17的量显著低于WT小鼠,IFN-γ未见显著差异.结论 γδT细胞通过促进抗衣原体特异性的Th17应答发挥免疫保护作用.

abstractsObjective To investigate the functions of γδT cells in a mouse model of Chlamydia muridarum (Cm) lung infection and their effects on Chlamydia-specific immunity.Methods Wild type (WT) and TCRδ-/-mice were infected with 1 × 103 inclusion forming units (IFU) of Cm by nasal inhalation to establish the murine model of Chlamydia respiratory infection.The bodyweight of each mouse was monitored daily.The growth of Chlamydia strains in lung tissues was measured by using enzyme immunoassay (EIA) and represented by IFU.ELISA was used to measure the levels of IFN-γand IL-17 in the supernatants of spleen cell culture.The levels of IFN-γ and IL-17 secreted by CD3+CD4+ T cells were determined by using the intracellular cytokine staining assay for evaluating the roles and mechanisms of γδT cells in regulating the Th1 and Th17 immune responses to Chlamydia strains.Results The murine model of Chlamydia pneumonitis was established by nasal inhalation of Cm strains.Compared with the WT mice,the TCR-/-mice showed a significant decrease in bodyweight after Cm infection.No significant difference in the growth of Chlamydia strains in lung tissues was observed between mice from the two groups.Results of the ELISA showed that the levels of IFN-γ in the supernatants of spleen cell culture from WT mice group were similar to those form TCRδ-/-mice groups on days 3 and 7 after Cm infection,but less IL-17 was secreted in TCRδ-/-mice than in WT mice on day 7.The intracellular cytokine staining analysis further indicated that the secretion of IL-17 by CD3+CD4+ T cells in TCRδ-/-mice was significantly decreased as compared with that in WT mice on days 3 and 7 after Cm infection.Conclusion γδT cells protect mice from Chlamydia respiratory infection by promoting the Chlamydia-specific Th17 immune responses.