Host: Pathogen Interaction in Plague

我们的项目以前集中在开发新的疫苗和治疗策略， 鼠疫耶尔森菌模型。我们检查了脂质A模拟物（氨基烷基氨基葡糖苷磷酸盐，AGPs）、Toll样 受体（TLR）4激动剂。我们发现AGPs可以直接预防肺鼠疫， 增强抗生素治疗，并且是鼻内（i.n.）或皮下（s.c.） 含Y.鼠疫荚膜（F1）和/或V-抗原。我们的疫苗接种方案导致快速 和持续的获得性TH 1免疫应答，在小鼠和大鼠模型中起到保护作用。我们也 描述了几个新发现的Y.鼠疫毒力因子及其调控重大进展 通过筛选减毒株， 利用先进的生物信息学分析，全面的转座子库，并通过动物和 秀丽隐杆线虫模型。我们在本提案中的具体目标是在这些成功的基础上加以扩展： 具体目标1：进一步检查天然免疫诱导与TLR之间的过渡 激动剂和针对肺鼠疫的特异性免疫。AGP的产品开发 需要描述鼠和人免疫应答之间的差异。转基因 人源化TLR 4/MD-2小鼠将用于评估对作为治疗剂和作为疫苗的AGP的应答 佐剂此外，我们将研究各种TLR激动剂的组合以增加保护。 具体目标2：确定调控基因和表面/胞外蛋白在Y.鼠疫 感染和/或跳蚤媒介维持。我们将系统地描述调控突变，细胞 表面/细胞外蛋白和葡萄糖调节基因在毒力中的作用，最终目标是 为产品开发确定新的目标。 具体目标3：确定自然突变（假基因）是必不可少的Y。鼠疫 发病机制我们将检验这样一个假设，即细菌毒力的增加部分是由于进化 在适应宿主的过程中遗传信息的丢失。我们将使用生物信息学来识别丢失的和/或 灭活Y染色体组中的功能。鼠疫菌株在密切相关但较少的 致病性耶尔森氏菌这些鉴定了Y.鼠疫“假基因”将被修复，以确定是否 这种恢复减弱了毒性。我们把这个过程称为“逆分子科赫假设”。

Our project previously focused on the development of novel vaccine and therapeutic strategies using Yersinia pestis models. We examined lipid A mimetics (aminoalkyl glucosaminide phosphates, AGPs), Tolllike receptor (TLR) 4 agonists. We found that AGPs directly protect against pneumonic plague, dramatically augment antibiotic therapy, and are efficacious adjuvants for either intranasal (i.n.) or subcutaneous (s.c.) vaccines containing Y. pestis capsular (F1) and/or V-antigens. Our vaccination regimen results in a rapid and sustained acquired TH1 immune response which protects in mouse and rat models. We also are characterizing several newly identified Y. pestis virulence factors and their regulation. Significant advances have been made toward identifying additional virulence mechanisms by screening for attenuated strains using advanced bioinformatic analyses, comprehensive transposon libraries, and through animal and Caenorhabditis elegans models. Our specific aims in this proposal expand on these successes: Specific Aim 1: To further examine the transition between induction of innate immunity with TLR agonists and specific immunity directed against pneumonic plague. The product development of AGPs requires delineation of the differences between murine and human immune responses. Transgenic humanized TLR4/MD-2 mice will be used to assess responses to AGPs as therapeutics and as vaccine adjuvants. In addition we will examine combinations of various TLR agonists to increase protection. Specific Aim 2: Determine the role of regulatory genes and surface/extracellular proteins in Y. pestis infection and/or flea vector maintenance. We will systematically characterize regulatory mutations, cell surface/extracellular proteins, and glucose-regulated genes for their role in virulence with the ultimate goal of identifying novel targets for product development. Specific Aim 3: Identify natural mutations (pseudogenes) that are essential for Y. pestis pathogenesis. We will test the hypothesis that increased bacterial virulence is, in part, due to evolutionary loss of genetic information during adaptation to the host. We will use bioinformatics to identify the lost and/or inactivated functions in the genomes of Y. pestis strains which are functional in the closely related but less virulent Yersinia enteropathogens. These identified Y. pestis 'pseudogenes' will be repaired to determine if this restoration attenuates virulence. We refer to this process as 'reverse molecular Koch's postulates'.