The Lack of Maturation of Ebola Virus-Infected Dendritic Cells Results from the Cooperative Effect of at Least Two Viral Domains
The Lack of Maturation of Ebola Virus-Infected Dendritic Cells Results from the Cooperative Effect of at Least Two Viral Domains
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DOI：
10.1128/jvi.03316-12
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发表时间：
2013-07-01
影响因子：
5.4
通讯作者：
Bukreyev, Alexander
中科院分区：
文献类型：
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作者：
Lubaki, Ndongala M.;Ilinykh, Philipp;Bukreyev, Alexander
埃博拉病毒（EBOV）感染的特征在于T淋巴细胞应答缺陷、T淋巴细胞凋亡和在不存在T淋巴细胞直接感染的情况下的淋巴细胞减少症。相比之下，树突状细胞（DC）被感染，但未能适当成熟，从而削弱了T细胞反应。我们通过产生表达增强型绿色荧光蛋白并携带影响几个潜在免疫调节结构域的突变的重组病毒来研究EBOV蛋白在调节DC成熟中的贡献。它们包括包膜糖蛋白（GP）结构域，以及先前在VP 24和VP 35蛋白中鉴定的先天反应拮抗剂结构域（IRAD）。发现由不相关的载体而非野生型EBOV表达的GP强烈诱导DC成熟，并且用携带使GP功能结构域失效的突变的重组EBOV感染不能恢复DC成熟。相反，携带突变的每种病毒使VP 35中的任何IRAD失效，诱导DC成熟标志物的显著上调。这是依赖于感染，但不与GP的相互作用。IRAD的禁用还导致细胞因子和趋化因子的分泌增加高达几百倍。此外，这些突变诱导形成同型DC簇，这代表了其成熟的密切相关性，并可能促进抗原从迁移DC转移到淋巴结DC。因此，单个IRAD不足以抑制DC成熟;相反，在EBOV感染期间观察到的DC成熟的抑制和“免疫麻痹”是由两种或更多种单个IRAD的协同作用引起的。
Ebola virus (EBOV) infections are characterized by deficient T lymphocyte responses, T lymphocyte apoptosis, and lymphopenia in the absence of direct infection of T lymphocytes. In contrast, dendritic cells (DC) are infected but fail to mature appropriately, thereby impairing the T cell response. We investigated the contributions of EBOV proteins in modulating DC maturation by generating recombinant viruses expressing enhanced green fluorescent protein and carrying mutations affecting several potentially immunomodulating domains. They included envelope glycoprotein (GP) domains, as well as innate response antagonist domains (IRADs) previously identified in the VP24 and VP35 proteins. GP expressed by an unrelated vector, but not the wild-type EBOV, was found to strongly induce DC maturation, and infections with recombinant EBOV carrying mutations disabling GP functional domains did not restore DC maturation. In contrast, each of the viruses carrying mutations disabling any IRAD in VP35 induced a dramatic upregulation of DC maturation markers. This was dependent on infection, but not interaction with GP. Disabling of IRADs also resulted in up to a several hundredfold increase in secretion of cytokines and chemokines. Furthermore, these mutations induced formation of homotypic DC clusters, which represent close correlates of their maturation and presumably facilitate transfer of antigen from migratory DC to lymph node DC. Thus, an individual IRAD is insufficient to suppress DC maturation; rather, the suppression of DC maturation and the "immune paralysis" observed during EBOV infections results from a cooperative effect of two or more individual IRADs.