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【目的】对沙眼衣原体在BALB/c小鼠肺部感染过程中CD4+CD25+Foxp3+调节性T细胞(regulatory T cells,Treg)与Th17反应关系进行初步探讨。【方法】取6-8周龄的BALB/c小鼠,鼻腔吸入25μL含5×103IFU的沙眼衣原体鼠肺炎菌株(Chlamydia muridarum,Cm),建立沙眼衣原体小鼠肺感染模型。监测感染后不同时期小鼠体重变化;检测肺组织衣原体包涵体形成单位(IFU)及肺组织病理改变;利用流式细胞术检测Cm感染后小鼠体内Treg细胞百分率;ELISA检测肺组织上清液IL-6、TGF-β、IL-17、IL-2细胞因子的的表达;qRT-PCR检测KC(keratinocyte derived chemokine)mRNA和MIP-2(macrophage inflammatory protein-2)mRNA的表达差异。【结果】用5xl03IFU Cm经鼻腔吸入感染后小鼠发生沙眼衣原体肺炎,表现为体重下降、肺组织大量炎症细胞浸润并可检测到衣原体繁殖。Cm感染后第3天,小鼠体内Treg细胞占CD4+T细胞的百分比明显降,随后开始恢复,第7天恢复原来水平,一直持续到衣原体清除。TGF-β、IL-2的表达与Treg细胞动态变化一致。与Th17相关细胞因子IL-6、IL-17和Th17相关趋化因子KC、MIP-2的表达于第3天开始升高,至第7天达到最高水平,随后逐渐减少。【结论】在衣原体感染BALB/c小鼠过程中,Treg可能通过提供TGF-β并在IL-6帮助下促进Th17应答产生。
【Objective】 To investigate the relationship between CD4 + CD25 + Foxp3 + regulatory T cells (Tregs) and Th17 response during C. pneumoniae infection in BALB / c mice. 【Methods】 BALB / c mice of 6-8 weeks old were inoculated with 25 μL of Chlamydia muridarum (Cm) containing 5 × 103 IFU into the nasal cavity to establish a lung infection model of Chlamydia trachomatis mice. The body weight of mice in different periods after infection was monitored. IFU and histopathological changes of lung tissues were detected. The percentage of Treg cells in mice was detected by flow cytometry. The expression of IL-6, TGF-β, IL-17 and IL-2 cytokines were detected by qRT-PCR. The differences of mRNA expression of KIP and macrophage inflammatory protein-2 were detected by qRT-PCR. [Results] Chlamydia trachomatis pneumonia was found in mice infected with 5xl03IFU Cm via nasal inhalation, manifested as body weight loss, a large number of infiltration of inflammatory cells in lung tissue and the detection of chlamydia reproduction. On day 3 after infection with Cm, the percentage of Treg cells in CD4 + T cells was significantly decreased in mice, and then began to recover. On the 7th day, the percentage of Treg cells returned to its original level until the clearance of Chlamydia. TGF-β, IL-2 expression and Treg cell dynamic changes. The expression of Th17-associated cytokines IL-6, IL-17 and Th17 related chemokines KC and MIP-2 began to rise on the 3rd day and reached the highest level on the 7th day, then decreased gradually. 【Conclusion】 Treg may contribute to TGF-β during the infection of chlamydial BALB / c mice and promote the production of Th17 with the help of IL-6.