He Haiqi, Genovese Kenneth J, Nisbet David J, Kogut Michael H
Southern Plains Agricultural Research Center, USDA-ARS, College Station, 2881 F&B Road, TX 77845, USA.
Mol Immunol. 2007 May;44(12):3234-42. doi: 10.1016/j.molimm.2007.01.034. Epub 2007 Mar 6.
Toll-like receptors (TLRs) recognize microbial components and initiate the innate immune responses that control microbial infections. We have investigated the innate immune response of chicken monocytes to ligands of TLR3 and TLR9, poly I:C (an analog of viral double-stranded RNA) and CpG-ODN (a CpG-motif containing oligodeoxydinucleotide) by measuring the induction of nitric oxide (NO) synthesis in chicken monocytes. Our results show that poly I:C and CpG-ODN synergized the induction of NO. When stimulated separately, CpG-ODN induced significant NO production in the chicken monocytes; whereas, poly I:C stimulated very little NO production. In combination, CpG-ODN and poly I:C induced significantly higher level of NO in chicken monocytes than either agonist alone. The addition of poly I:C prior to or simultaneously with CpG-ODN was required for the synergy. No synergistic effects on NO production were observed when monocytes were stimulated with combinations of CpG-ODN or poly I:C with other TLR agonists. Unlike chicken monocytes, cells of a chicken macrophage cell line, HD11, were readily stimulated to produce NO by both CpG-ODN and poly I:C with no synergism on NO induction when HD11 cells were stimulated by a combination of CpG-ODN and poly I:C. Using a pharmacological inhibitor, we also demonstrated that double-stranded RNA-dependent protein kinase (PKR) is indispensable for stimulation of NO production by CpG-ODN alone or in combination with poly I:C in both chicken peripheral blood monocytes and HD11 macrophage cells. Our results show that a combination of bacterial DNA and dsRNA induces an enhanced inflammatory immune response that has both antiviral and antibacterial activity in primary chicken monocytes.
Toll样受体（TLRs）可识别微生物成分并启动控制微生物感染的固有免疫反应。我们通过检测鸡单核细胞中一氧化氮（NO）合成的诱导情况，研究了鸡单核细胞对TLR3和TLR9配体、聚肌胞苷酸（poly I:C，一种病毒双链RNA类似物）和CpG-寡脱氧核苷酸（CpG-ODN，一种含CpG基序的寡脱氧核苷酸）的固有免疫反应。我们的结果表明，poly I:C和CpG-ODN协同诱导NO的产生。单独刺激时，CpG-ODN可诱导鸡单核细胞产生大量NO；而poly I:C刺激产生的NO很少。联合使用时，CpG-ODN和poly I:C诱导鸡单核细胞产生的NO水平显著高于单独使用任一激动剂时。协同作用需要在CpG-ODN之前或同时添加poly I:C。当单核细胞用CpG-ODN或poly I:C与其他TLR激动剂联合刺激时，未观察到对NO产生的协同作用。与鸡单核细胞不同，鸡巨噬细胞系HD11细胞很容易被CpG-ODN和poly I:C刺激产生NO，当HD11细胞用CpG-ODN和poly I:C联合刺激时，对NO诱导没有协同作用。使用一种药理抑制剂，我们还证明双链RNA依赖性蛋白激酶（PKR）对于单独或与poly I:C联合刺激鸡外周血单核细胞和HD11巨噬细胞产生NO是必不可少的。我们的结果表明，细菌DNA和双链RNA的组合可诱导增强的炎症免疫反应，在原代鸡单核细胞中具有抗病毒和抗菌活性。
