Defining early entry mechanisms of Mycobacterium avium paratuberculosis into the host

约翰氏病（JD）是由副结核分枝杆菌（MAP）引起的反刍动物常见的慢性肠道疾病。在感染后的早期阶段，动物几乎没有显示出疾病的证据，这使得很难检测到感染，并且很容易在不知不觉中传播。JD对牛和羊的健康和福利有重大影响，经济损失与慢性阶段的生产力降低和高死亡率有关。JD在英国和世界范围内是一个潜在的和日益严重的问题，除了测试和屠宰外，没有有效的牛控制措施。这部分是因为MAP是能够隐藏和操纵免疫系统，但也反映了相对缺乏和整合的研究人员在该地区，MAP的缓慢增长和高成本的实验研究在目标hosts.We建议调查MAP如何与宿主细胞在肠道中相互作用在感染不同毒力的MAP菌株的早期阶段。我们将使用一系列方法来确定MAP进入肠道的关键细胞类型和机制。这些包括易处理的小鼠模型，肠肠和外科肠循环提供了独特的概述MAP-宿主相互作用。此外，我们建议确定MAP基因在生存和复制中的作用。这些研究将解决目前知识的根本差距，并将促进控制和治疗MAP感染的策略的合理设计。我们的建议汇集了具有互补专业知识，建立感染模型和经过验证的合作记录的研究人员。我们有三个相互关联的目标：1）使用小鼠模型定义MAP穿过肠粘膜转运所涉及的细胞类型，以准确识别进入的细胞门户2）使用肠和外科肠环模型表征MAP穿过牛肠道的机制，以识别进入的关键途径和机制3）使用靶向和随机诱变方法识别宿主组织侵袭和存活所需的关键MAP基因该项目汇集了一支在MAP，牛免疫学，粘膜免疫应答和细胞内细菌方面具有专业知识的独特团队。主要产出将是确定控制进入的关键宿主和病原体因素，这些因素可能是未来疾病控制干预战略的目标。

Johne's disease (JD) is a common and chronic disease of the gut of ruminants caused by infection with the pathogen Mycobacterium avium subspecies paratuberculosis (MAP). At early stages following infection animals show little evidence of the disease, making it difficult to detect and easy for infection to spread unnoticed. JD has a significant impact on the health and welfare of cattle and sheep, with economic losses associated with reduced productivity and high mortality in the chronic stage. JD is an insidious and increasing problem in the UK and world-wide, with no effective control measures in cattle other than test and slaughter. This is partly because MAP is able to hide from and manipulate the immune system but also reflects the relative paucity and integration of researchers in the area, slow growth of MAP and high cost of experimental studies in target hosts.We propose to investigate how MAP interacts with host cells in the gut at early stages following infection with strains of MAP of varying virulence. We will use a combination of methods to determine the critical cell types and mechanisms utilised by MAP for entry into the gut. These include tractable murine models, gut enteroids and surgical gut loops providing a unique overview of the MAP-host interaction. Moreover, we propose to define the role of MAP genes in survival and replication. These studies will address fundamental gaps in current knowledge and will facilitate the rational design of strategies to control and treat MAP infections.Our proposal brings together researchers with complimentary expertise, established models of infection and a proven record of collaboration. We have three inter-linked objectives:1) Define the cell types involved in transit of MAP across the gut mucosa using mouse models to accurately identify the cellular portal of entry2) Characterise the mechanisms by which MAP transits the bovine gut using enteroids and surgical gut loop models to identify critical pathways and mechanisms of entry3) Identify critical MAP genes required for host tissue invasion and survival using targeted and random mutagenesis approaches This project brings together a unique team with expertise in MAP, bovine immunology, mucosal immune responses and intracellular bacteria. The major output will be the definition of key host, and pathogen factors that control entry and that could be targets for future intervention strategies for disease control.