H5N1 avian influenza virus without 80-84 amino acid deletion at the NS1 protein hijacks the innate immune system of dendritic cells for an enhanced mammalian pathogenicity
H5N1 avian influenza virus without 80-84 amino acid deletion at the NS1 protein hijacks the innate immune system of dendritic cells for an enhanced mammalian pathogenicity
复制标题
H5N1 禽流感病毒 NS1 蛋白上没有 80-84 个氨基酸缺失，劫持树突状细胞的先天免疫系统，从而增强哺乳动物的致病性
DOI：
10.1111/tbed.13904
复制
发表时间：
2020-11-17
影响因子：
4.3
通讯作者：
Liu, Xiufan
中科院分区：
文献类型：
--
作者：
Chen, Sujuan;Miao, Xinyu;Liu, Xiufan
NS基因通常被认为与高致病性禽流感病毒（AIV）的毒力有关。近年来，在从哺乳动物分离的H5N1亚型AIV中，在NS1蛋白的80 - 84位添加了5个氨基酸的毒株已变得流行。然而，这种模式在哺乳动物中的致病性和机制仍不清楚。本研究利用NS1蛋白缺失的H5N1亚型禽流感病毒（rNS（Delta 5aa））和NS1蛋白未缺失的突变病毒（rNS（5aa-R））对小鼠进行了致病性测定。结果表明，rNS（5aa-R）在小鼠体内和体外均具有较rNS（Delta 5aa）强的致病性，并伴有IL-6、MX1和CXCL10的高表达。此外，我们发现rNS（5aa-R）增强了树突状细胞（DCs）的感染能力。此外，与rNS（Delta 5aa）相比，rNS（5aa-R）增强DC的表型标志物（CD80、CD86、CD40和MHCII）、活化标志物CD69、炎性细胞因子（IL-6、TNF-α和IL-10）的表达，并拮抗干扰素（IFN-α）。rNS（5aa-R）通过上调CCR7的表达，诱导DCs快速迁移至颈淋巴结附近，并在迁移的DCs上高表达CD86。我们还发现rNS（5aa-R）感染的DC显著促进同种异体CD4（+）T细胞的增殖。这些结果表明，rNS（5aa-R）较rNS（Delta 5aa）能更强地诱导天然免疫应答，有利于激活广泛的免疫应答，导致强烈的细胞因子风暴，增强H5N1亚型AIV在哺乳动物中的致病性。
NS gene is generally considered to be related to the virulence of highly pathogenic avian influenza virus (AIV). In recent years, the strains with five amino acids added to the 80-84 positions of the NS1 protein have become prevalent in H5N1 subtype AIVs isolated from mammals. However, the pathogenicity and mechanism of this pattern in mammals remain unclear. In this study, H5N1 subtype AIVs without 80-84 amino acids of the NS1 protein (rNS(Delta 5aa)) and a mutant virus (rNS(5aa-R)) with no deletion of 80-84 amino acids of the NS1 protein were used to determine the pathogenicity in mice. Our results showed that rNS(5aa-R) possessed an enhanced pathogenicity compared with rNS(Delta 5aa) in vivo and in vitro, which was accompanied by high expression of IL-6, MX1 and CXCL10 in murine lungs. Furthermore, we found that rNS(5aa-R) increased the infection ability to dendritic cells (DCs). Besides, rNS(5aa-R) enhanced the expression of phenotypic markers (CD80, CD86, CD40 and MHCII), activation marker CD69, inflammatory cytokines (IL-6, TNF-alpha and IL-10) and antagonized interferon (IFN-alpha) of DCs, in comparison to rNS(Delta 5aa). Moreover, rNS(5aa-R) induced DCs to quickly migrate into nearby cervical lymph nodes by highly upregulating CCR7, and CD86 showed a high expression on the migrated DCs. We also found that rNS(5aa-R)-infected DCs significantly promoted the allogeneic CD4(+) T-cell proliferation. These findings suggested that rNS(5aa-R) strongly induced the innate immune response compared with the rNS(Delta 5aa), which is conducive to activate a wide immune response, resulting in a strong cytokine storm and causing an enhanced pathogenicity of H5N1 subtype AIVs in mammals.