Involvement of the toll-like receptor 9 signaling pathway in the induction of innate immunity by baculovirus
Involvement of the toll-like receptor 9 signaling pathway in the induction of innate immunity by baculovirus
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DOI：
10.1128/jvi.79.5.2847-2858.2005
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发表时间：
2005-03-01
影响因子：
5.4
通讯作者：
Matsuura, Y
中科院分区：
文献类型：
--
作者：
Abe, T;Hemmi, H;Matsuura, Y
我们以前已经表明，小鼠鼻内接种野生型杆状病毒（苜蓿银纹夜蛾核型多角体病毒[AcNPV]）的保护，从致命的攻击流感病毒。然而，AcNPV处理诱导这种保护性免疫应答的确切机制仍不清楚。在这里，我们表明，AcNPV激活免疫细胞通过Toll样受体9（TLR 9）/MyD 88依赖的信号通路。MyD 88或TLR 9缺陷小鼠的腹腔巨噬细胞（佩奇）和脾脏CD 11 c（+）树突状细胞（DC）与AcNPV共同培养后，炎性细胞因子的产生显著减少。相比之下，显著量的α干扰素（IFN-α.）在这些小鼠的佩奇和DC中，在用AcNPV刺激后仍然可以检测到IFN-α，这表明TLR 9/MyD 88非依赖性信号通路也可能参与AcNPV产生IFN-α。由于先前的工作表明TLR 9配体包括细菌DNA和含有未甲基化CpG二核苷酸的某些寡核苷酸，我们还研究了杆状病毒DNA对先天免疫诱导的影响。用杆状病毒DNA转染小鼠巨噬细胞系RAW 264.7导致产生炎性细胞因子，而从病毒颗粒中去除包膜糖蛋白，UV照射病毒，并用纯化的杆状病毒包膜蛋白或内体成熟抑制剂进行预处理，减少了AcNPV诱导的免疫应答。总之，这些结果表明，病毒DNA通过病毒包膜糖蛋白介导的膜融合内化，以及内体成熟（将病毒基因组释放到表达TLR 9的细胞区室中），对于诱导先天性免疫反应是必要的AcNPV。
We have previously shown that mice inoculated intranasally with a wild-type baculovirus (Autographa californica nuclear polyhedrosis virus [AcNPV]) are protected from a lethal challenge by influenza virus. However, the precise mechanism of induction of this protective immune response by the AcNPV treatment remained unclear. Here we show that AcNPV activates immune cells via the Toll-like receptor 9 (TLR9)/MyD88-dependent signaling pathway. The production of inflammatory cytokines was severely reduced in peritoneal macrophages (PECs) and splenic CD11c(+) dendritic cells (DCs) derived from mice deficient in MyD88 or TLR9 after cultivation with AcNPV. In contrast, a significant amount of alpha interferon (IFN-alpha.) was still detectable in the PECs and DCs of these mice after stimulation with AcNPV, suggesting that a TLR9/MyD88-independent signaling pathway might also participate in the production of IFN-alpha by AcNPV. Since previous work showed that TLR9 ligands include bacterial DNA and certain oligonucleotides containing unmethylated CpG dinucleotides, we also examined the effect of baculoviral DNA on the induction of innate immunity. Transfection of the murine macrophage cell line RAW264.7 with baculoviral DNA resulted in the production of the inflammatory cytokine, while the removal of envelope glycoproteins from viral particles, UV irradiation of the virus, and pretreatment with purified baculovirus envelope proteins or endosomal maturation inhibitors diminished the induction of the immune response by AcNPV. Together, these results indicate that the internalization of viral DNA via membrane fusion mediated by the viral envelope glycoprotein, as well as endosomal maturation, which releases the viral genome into TLR9-expressing cellular compartments, is necessary for the induction of the innate immune response by AcNPV.