Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, 100193, Beijing, People's Republic of China.
Inflammation. 2015;38(3):1337-46. doi: 10.1007/s10753-014-0105-x.
The TB9.8 of Mycobacterium bovis can induce strong antigen-specific T-cell responses in proliferation assays and IFN-γ assays. However, whether and how TB9.8 activates innate immune cells remain unclear. Therefore, recombinant protein TB9.8 (rTB9.8)-induced proinflammatory cytokine profile by RAW264.7 cells was investigated and the related signaling pathway was studied. Stimulation with rTB9.8 triggered RAW264.7 cells to produce IL-6 and IL-12 p40. In addition, rTB9.8 activated the mitogen-activated protein kinase (MAPK) cascade in RAW264.7 cells by inducing the phosphorylation of extracellular signal-regulated kinase (ERK) and p38 kinase (p38) and also promoted nuclear translocation of phosphorylated p38 and ERK1/2. Furthermore, rTB9.8 activated nuclear factor κB (NF-κB) signaling pathway by inducing p65 translocation into the nucleus and the phosphorylation of IκBα in the cytosol. Blocking assays showed that specific inhibitors of ERK1/2, p38, and IκBα can significantly reduce the expression of IL-6 and IL-12 p40, which demonstrated that rTB9.8-mediated cytokine production is dependent on the activation of these kinases. Thus, this study demonstrates that rTB9.8 can activate RAW264.7 and trigger IL-6 and IL-12 p40 production via the ERK, p38, and NF-κB signaling pathways.
牛分枝杆菌 TB9.8 可在增殖试验和 IFN-γ 试验中诱导强烈的抗原特异性 T 细胞反应。然而，TB9.8 是否以及如何激活先天免疫细胞尚不清楚。因此，研究了重组蛋白 TB9.8（rTB9.8）诱导 RAW264.7 细胞产生促炎细胞因子的特性，并研究了相关的信号通路。rTB9.8 刺激 RAW264.7 细胞产生 IL-6 和 IL-12 p40。此外，rTB9.8 通过诱导细胞外信号调节激酶（ERK）和 p38 激酶（p38）的磷酸化，激活 RAW264.7 细胞中的丝裂原激活蛋白激酶（MAPK）级联反应，并促进磷酸化 p38 和 ERK1/2 的核易位。此外，rTB9.8 通过诱导 p65 向核内易位和细胞质中 IκBα 的磷酸化激活核因子κB（NF-κB）信号通路。阻断实验表明，ERK1/2、p38 和 IκBα 的特异性抑制剂可显著降低 IL-6 和 IL-12 p40 的表达，表明 rTB9.8 介导的细胞因子产生依赖于这些激酶的激活。因此，本研究表明 rTB9.8 可通过 ERK、p38 和 NF-κB 信号通路激活 RAW264.7 并触发 IL-6 和 IL-12 p40 的产生。
