Influence of RCMV-encoded vXCL1 on XCR1+ DC

RCMV 编码的 vXCL1 对 XCR1 DC 的影响

• 批准号: 240143179
• 负责人: Professor Dr. Sebastian Voigt
• 金额: --
• 依托单位: Institut für Virologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/240143179?language=en
• 关键词: Influence; RCMV; encoded; vXCL1; XCR1+

Cytomegaloviruses (CMV) use multiple strategies to modulate the immune response. One of these strategies is the expression of virus-encoded chemokines that interfere with the hosts chemokine network which plays an important role in initiating and organizing leukocyte trafficking. The English and Berlin isolates of rat CMV (MuHV-8) encode the so far only known viral gamma-chemokine. Its similar sequence to the endogenous rat, mouse, and human gamma-chemokine XCL1 resulted in its designation as viral XCL1 (vXCL1). To better understand vXCL1 function and investigate a putative competition with the host chemokine, expression of host XCL1 as well as binding of both chemokines to XCR1 was characterized. Rat XCL1 is mostly secreted by CD8+ T cells, NKT cells and NK cells as has been shown for human and mouse XCL1. Both host rat XCL1 and vXCL1 have chemokine-like properties, bind to the corresponding receptor XCR1 and attract exclusively CD4- rat DC that express XCR1. Hence, they function similarly. The receptor XCR1 is expressed on about 80% of splenic CD4- XCR1+ rat DC. Both viral XCL1 and human XCL1 are selective agonists that only activate their species-specific receptors rXCR1 and hXCR1, respectively. In contrast, host rat XCL1 is an agonist that activates both receptors. Viral XCL1 appears to be a super agonist that exhibits superior binding to rXCR1 than the endogenous rXCL1 chemokine. To further study the interaction between vXCL1 and XCR1 in rodents an xcr1 knockout rat was generated to study receptor function in the context of viral infection. In the current proposal, we will initially characterize the knockout rat and examine its response to infection. We plan to investigate if vXCL1 only activates rat XCR1 or if there is cross reactivity or antagonistic activity to XCR1 of different species. Further, we intend to infect XCR1+ DC and analyze their infection capacity. We then plan to infect animals and analyze host XCL1 expression upon infection using wild-type, vxcl1 mutant and revertant viruses. We speculate that vXCL1 attracts XCR1+ CD4- DC to benefit viral dissemination or to impair cross-presentation to circumvent cytotoxic immune responses exerted by CD8+ T lymphocytes. To examine this, we will characterize an IE1 immunodominant epitope, identify an expressed MHC allele presenting a viral peptide and ultimately test if vXCL1 is involved in blocking cross-presentation.

巨细胞病毒（CMV）使用多种策略来调节免疫应答。这些策略之一是表达病毒编码的趋化因子，其干扰在启动和组织白细胞运输中起重要作用的宿主趋化因子网络。大鼠CMV的英国和柏林分离株（MuHV-8）编码迄今为止唯一已知的病毒γ-趋化因子。其与内源性大鼠、小鼠和人γ-趋化因子XCL 1的相似序列导致其被命名为病毒XCL 1（vXCL 1）。为了更好地理解vXCL 1功能并研究与宿主趋化因子的推定竞争，表征了宿主XCL 1的表达以及两种趋化因子与XCR 1的结合。大鼠XCL1主要由CD8 + T细胞、NKT细胞和NK细胞分泌，如人和小鼠XCL1所示。宿主大鼠XCL 1和vXCL 1都具有趋化因子样特性，与相应的受体XCR 1结合，并专门吸引表达XCR 1的CD4-大鼠DC。因此，它们的功能相似。受体XCR1在约80%的脾CD4-XCR1+大鼠DC上表达。病毒XCL1和人XCL1都是选择性激动剂，分别仅激活其物种特异性受体rXCR1和hXCR1。相比之下，宿主大鼠XCL 1是激活两种受体的激动剂。病毒XCL 1似乎是一种超级激动剂，表现出比内源性rXCL 1趋化因子更上级的rXCR 1结合。为了进一步研究啮齿动物中vXCL 1和XCR 1之间的相互作用，产生了xcr 1敲除大鼠，以研究病毒感染背景下的受体功能。在目前的提议中，我们将首先描述基因敲除大鼠的特征，并检查其对感染的反应。我们计划研究vXCL 1是否仅激活大鼠XCR 1，或者是否对不同物种的XCR 1具有交叉反应性或拮抗活性。此外，我们打算感染XCR1 + DC并分析其感染能力。然后，我们计划感染动物，并分析宿主XCL1表达感染后使用野生型，vxcl1突变体和回复突变病毒。我们推测vXCL1吸引XCR1 + CD4-DC以利于病毒传播或削弱交叉呈递以规避CD8 + T淋巴细胞产生的细胞毒性免疫应答。为了检验这一点，我们将表征IE1免疫显性表位，鉴定呈递病毒肽的表达的MHC等位基因，并最终测试vXCL1是否参与阻断交叉呈递。