Evaluating the Progression of Pneumonic Plague

描述（由申请方提供）：鼠疫是由吸入鼠疫耶尔森氏菌引起的。由于其致命性、疾病进展迅速以及通过雾化传播的能力，Y。鼠疫被美国疾病控制中心列为最有可能在生物恐怖袭击中使用的六种A类制剂之一。尽管它作为人类病原体的致命性和历史，但关于肺鼠疫的发病机制知之甚少，因为大多数工作都集中在淋巴腺感染和弱毒力或无毒力菌株。在小鼠感染模型中，肺鼠疫表现为两个不同的阶段。在疾病的前36小时内，在没有宿主炎症或疾病病理的情况下，细菌在肺中复制到大的负荷。36-48小时后，开始强烈的炎症期，导致严重的支气管扩张症。为了生存，Y。鼠疫必须适应哺乳动物肺中这两种非常不同的环境，最初逃避/抑制免疫力，随后经受住宿主炎症的冲击。本申请的最终目标是通过鉴定细菌毒力因子和靶宿主细胞，更全面地了解肺鼠疫的进展。Y.表达绿色荧光蛋白（GFP）的鼠疫菌将用于鼻内感染小鼠，并且在整个感染过程中的不同时间，将收获肺并通过流式细胞术分析以鉴定被Y.以及这些种群如何随时间变化。为了确定疾病进展中涉及的细菌因素，将使用定量实时PCR来评估288 Y的转录。鼠疫基因先前显示在感染后48小时受到调节。将在感染期间的多个时间点评价目标基因的转录。高度调控或在感染阶段之间表现出差异调控的基因将被删除，并在小鼠感染模型中评估突变株，以确定它们在肺鼠疫中的作用。

DESCRIPTION (provided by applicant): Pneumonic plague results from the inhalation of the bacterium Yersinia pestis. Due to its lethality, rapid disease progression, and ability to be disseminated via aerosolization, Y. pestis is categorized by the U.S. Centers for Disease Control as one of the six Category A agents most likely to be used during a biological terrorist attack. Despite its lethality and history as a human pathogen, very little is known regarding pneumonic plague pathogenesis, as a majority of work has focused on bubonic infection and with less virulent or avirulent strains. In a mouse infection model pneumonic plague was shown to progress in two distinct phases. During the first 36 hours of disease bacteria replicate to large burdens in the lung in the absence of host inflammation or disease pathology. After 36-48 hours, an intense inflammatory phase is initiated, resulting in severe bronchopneumonia. In order to survive, Y. pestis must adapt to these two very different environments in the mammalian lung, initially evading/suppressing immunity and subsequently withstanding the host inflammatory onslaught. The ultimate goal of this application is to obtain a more complete understanding of the progression of pneumonic plague by identifying bacterial virulence factors and target host cells. Y. pestis expressing green fluorescent protein (GFP) will be used to infect mice intranasally, and at different times throughout infection lungs will be harvested and analyzed by flow cytometry to identify cell populations targeted by Y. pestis, and how those populations change over time. To identify bacterial factors involved in disease progression, quantitative real-time PCR will be used to evaluate the transcription of 288 Y. pestis genes previously shown to be regulated at 48 hours post-infection. The transcription of genes of interest will be evaluated at multiple time points during infection. Genes that are highly regulated or demonstrate differential regulation between phases of infection will be deleted, and mutant strains evaluated in a mouse model of infection to determine their role in pneumonic plague.