Unique Chemokine Profiles of Lung Tissue Distinguish Post-chemotherapeutic Persistent and Chronic Tuberculosis in a Mouse Model. Mus musculus

To identify the immunological status of the persistent and chronic stages, we analysed immunological genes in lung tissues from mice infected with M. tuberculosis. Based on the cDNA microarray results, 11 candidate cytokine genes, which were obviously up-regulated during the chronic stage compared with those during the persistent stage, were selected and clustered into three groups: 1) chemokine genes, except those of monocyte chemoattractant proteins (MCPs) (CXCL9, CXCL10, CXCL11, CCL5, CCL19); 2) MCP genes (CCL2, CCL7, CCL8, CCL12); and 3) TNF and IFN-γ genes. Results from the cDNA microarray and quantitative RT-PCR analyses revealed that the mRNA expression of the selected cytokine genes was significantly higher in lung tissues of the chronic stage than of the persistent stage. Three chemokines (CCL5, CCL19 and CXCL9) and three MCPs (CCL7, CCL2 and CCL12) were noticeably increased in the chronic stage compared with the persistent stage. Overall design: We present a new experimental animal model, in which the reactivation of tuberculosis is induced without administration of immunosuppressive agents, which might disturb immune responses. From lung tissue of chronic or persistent stage of tuberculosis, gene expression was screened using cDNA microarray analysis and confirmed by quantitative RT-PCR.

为明确结核分枝杆菌（Mycobacterium tuberculosis，缩写M. tuberculosis）感染小鼠肺组织在持续感染期与慢性感染期的免疫状态，我们对免疫相关基因展开了分析。基于cDNA微阵列（cDNA microarray）检测结果，筛选出11个在慢性感染期较持续感染期显著上调的候选细胞因子基因，并将其聚类为3组：1）趋化因子基因（不含单核细胞趋化蛋白（monocyte chemoattractant proteins，MCPs）），涵盖CXCL9、CXCL10、CXCL11、CCL5、CCL19；2）单核细胞趋化蛋白（MCP）基因，涵盖CCL2、CCL7、CCL8、CCL12；3）肿瘤坏死因子（TNF）与干扰素γ（IFN-γ）基因。cDNA微阵列与定量逆转录聚合酶链反应（quantitative RT-PCR）分析结果显示，慢性感染期小鼠肺组织中上述候选细胞因子基因的mRNA表达水平显著高于持续感染期。其中3种趋化因子（CCL5、CCL19与CXCL9）及3种MCP（CCL7、CCL2与CCL12）在慢性感染期的表达量较持续感染期显著升高。实验设计概述：本研究构建了一种新型实验动物模型，可在不使用免疫抑制剂的情况下诱导结核病复发，避免了免疫抑制剂对免疫应答的干扰。研究分别从结核病慢性期与持续期感染小鼠的肺组织中获取样本，通过cDNA微阵列分析筛选差异表达基因，并采用定量RT-PCR对筛选结果进行验证。