Host influence on cell tropism and immune response to MERS-CoV

宿主对中东呼吸综合征冠状病毒细胞趋向性和免疫反应的影响

• 批准号: RGPIN-2016-05280
• 负责人: Falzarano, Darryl
• 金额: $ 2.62万
• 依托单位: University of Saskatchewan
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=708501
• 关键词: Host; influence; cell; tropism; immune

Zoonotic viruses, such as Middle East respiratory syndrome coronavirus (MERS-CoV) can cause severe pathology in humans, but in reservoir hosts, little to no evidence of disease may be present. In camels, which serve as a amplifying host, a primarily upper respiratory tract infection has been experimentally observed with little pathology and no longer term consequences, despite high levels of virus shedding. In humans, and nonhuman primate and mouse animal models, mild to severe disease is served, with virus primarily targeting the lower respiratory tract for replication. Understanding how a virus interacts with different hosts, where there is significant differences in viral replication, shedding and ultimately disease can provide many insights into beneficial and detrimental virus-host interactions. My lab is in the process of establishing a surrogate animal model for camels, using alpacas, to allow us to study virus replication, shedding, transmission, tissue tropism and pathogenesis to compare and contrast reservoir and disease models. Preliminary data indicates that alpacas and camels are comparable models. As a comparator, we will use transgenic mice that express human dipeptidyl peptidase 4 (hDPP4), the receptor for MERS-COV. This model recapitulates severe disease comparable to that observed in humans. Studying the virus interplay with the host in both these two widely different models will allow us to dissect out mechanisms of how virus spread, cellular tropism and the host response varies in different model systems. This will help us to understand the mechanisms that both the virus and the host use to influence virus replication and tropism which ultimately determines whether infection results in a relatively reservoir-like state suitable for transmitting the virus on to new hosts or disease-like state that results in significant illness and/or death. First we will define the cellular tropism of MERS-CoV in the mouse and alpaca models, determining receptor distribution and quantifying virus output in primary cell cultures of respiratory tract tissues. In vitro findings will be confirmed in the animal model. As all MERS-CoV viruses to date have been passaged in monkey cells, we will generate a camelid-adapted virus in a camel cells line, with subsequent genomic and growth kinetic characterization to determine effects on tropism and pathogenesis. Next, we will determine differences in immune cell recruitment and activity in respiratory tract tissues in both animal models using cell type specific gene markers, determining levels of inflammatory cytokines and identifying what cells are recruited to sites of infection. Last, we will determine the mechanism of virus spread in respiratory tissues. The kinetics of infection under different conditions that favour either release and diffusion or cell-to-cell spread with determine if virus spread in the lung is primarily cell-to-cell.

人畜共患病毒，如中东呼吸综合征冠状病毒（MERS-CoV）可在人类中引起严重病理，但在宿主中，可能几乎没有证据表明存在疾病。在作为扩增宿主的骆驼中，实验观察到主要是上呼吸道感染，尽管病毒大量脱落，但几乎没有病理和长期后果。在人类、非人类灵长类动物和小鼠动物模型中，病毒主要以下呼吸道为复制目标，服务于轻度至重度疾病。了解病毒如何与不同宿主相互作用，在病毒复制、脱落和最终疾病方面存在显著差异，可以为病毒与宿主的有益和有害相互作用提供许多见解。我的实验室正在用羊驼建立骆驼的替代动物模型，使我们能够研究病毒的复制、脱落、传播、组织趋向性和发病机制，以比较和对比病毒库和疾病模型。初步数据表明羊驼和骆驼是可比较的模型。作为比较，我们将使用表达MERS-COV受体人二肽基肽酶4 （hDPP4）的转基因小鼠。该模型概括了与在人类中观察到的类似的严重疾病。在这两种截然不同的模型中研究病毒与宿主的相互作用，将使我们能够剖析病毒在不同模型系统中如何传播、细胞趋向性和宿主反应的机制。这将有助于我们了解病毒和宿主用来影响病毒复制和向性的机制，这最终决定了感染是导致相对类似于储存库的状态，适合将病毒传播给新的宿主，还是导致严重疾病和/或死亡的类似疾病状态。