Prabha C, Rajashree P, Sulochana D Das
Department of Immunology, Tuberculosis Research Centre (ICMR), Mayor V.R. Ramanathan Road, Chetput, Chennai 600031, India.
Immunol Lett. 2008 Apr 15;117(1):26-34. doi: 10.1016/j.imlet.2007.11.002. Epub 2007 Dec 3.
Toll-like receptors (TLRs) play an important role in mediating the down stream signaling of immune response in tuberculosis. The predominance of Th1 response in tuberculous pleurisy prompted us to study the expression profiles of TLR2 and TLR4 on different immune cells and on subsets of T cells obtained from the site of infection. Our results showed that TLR2 was up-regulated on the monocytes from pleural fluid indicating a prominent role for this receptor in anti-tuberculous immunity. Notably, TLR2 and TLR4 expression were also enhanced on IFN-gamma secreting CD4(+)T cells. However, their expression was down-regulated on activated and IL-4 secreting CD4(+)T cells from the site of infection indicating that TLR expression is differentially modulated on the different subsets of T cells depending on their activation status and cytokine expression. The down-regulation of both TLRs on the natural regulatory T cells despite their higher number at the site of infection might be a mechanism to maintain their suppressive activity.
Toll样受体（TLRs）在介导结核病免疫反应的下游信号传导中起重要作用。结核性胸膜炎中Th1反应的优势促使我们研究TLR2和TLR4在不同免疫细胞以及从感染部位获得的T细胞亚群上的表达谱。我们的结果表明，胸腔积液中的单核细胞上TLR2上调，表明该受体在抗结核免疫中起重要作用。值得注意的是，分泌IFN-γ的CD4(+)T细胞上TLR2和TLR4的表达也增强。然而，来自感染部位的活化且分泌IL-4的CD4(+)T细胞上它们的表达下调，这表明TLR表达根据T细胞不同亚群的激活状态和细胞因子表达而受到差异调节。尽管天然调节性T细胞在感染部位数量较多，但这两种TLR在其上的下调可能是维持其抑制活性的一种机制。
