Listeria-induced cytosolic response and host immunity

描述（由申请人提供）：本提案的长期目标是了解宿主如何识别和区分生活在不同细胞区室中的微生物，引发病原体特异性免疫反应，并产生保护性免疫。单核增生李斯特菌是一种细胞内细菌，在巨噬细胞中激活两组不同的转录反应：在细胞表面和空泡识别期间启动的myd88依赖性反应和在细胞质进入期间启动的irf3依赖性反应。该细菌将被用作模型微生物，以确定IRF3依赖性胞质反应在急性感染和长期免疫过程中所起的作用。单核细胞增生乳杆菌突变体改变了多药耐药转运体的表达，从而诱导不同程度的胞质基因表达，将被用来确定感染期间胞质反应的影响。第一个具体目标将检查在急性单核细胞增生乳杆菌感染期间，在缺乏tlr介导的反应中，胞质反应的贡献。第二个特定目标的目标是阐明细胞质反应是否参与树突状细胞成熟和T细胞启动。最后，第三个具体目标将解决是否胞质反应有助于产生T细胞介导的保护性免疫反应。揭示irf3介导的对单核增生乳杆菌的胞质反应的作用可能揭示一种对保护性免疫产生重要的新的先天免疫机制，这将有助于疫苗的开发。疫苗设计的主要挑战是如何引起免疫反应，建立针对特定致病微生物的长期保护性免疫。本提案中概述的研究将研究单核细胞增生李斯特菌感染的早期炎症反应如何导致免疫记忆的产生，从而防止再次感染。这项工作将有助于理解炎症如何产生长期记忆，并可能为开发安全有效的疫苗的方法提供新的见解。

DESCRIPTION (provided by applicant): The long-term objectives of this proposal are to understand how the host recognizes and discriminates between microbes that live in distinct cellular compartments, elicits a pathogen-specific immunological response, and generates protective immunity. Listeria monocytogenes is an intracellular bacterium that activates two distinct sets of transcriptional responses in macrophages: a MyD88-dependent response initiated during cell surface and vacuolar recognition and an IRF3-dependent response initiated during cytosolic entry. This bacterium will be used as a model microorganism to determine what role the IRF3- dependent cytosolic response plays during acute infection and long-term immunity. L. monocytogenes mutants that have altered expression of multidrug resistance transporters and consequently induce varying magnitudes of cytosolic gene expression will be exploited to determine the effect of the cytosolic response during infection. The first specific aim will examine the contribution ofthe cytosolic response during acute L. monocytogenes infection in the absence of the TLR-mediated responses. The goal of the second specific aim is to elucidate whether the cytosolic response is involved in dendritic cell maturation and T cell priming. Finally, the third specific aim will address whether the cytosolic response contributes to the generation of T- cell mediated protective immune responses. Uncovering the role of the IRF3-mediated cytosolic response to L. monocytogenes could reveal a new innate immune mechanism important for the generation of protective immunity, knowledge that would be instrumental for vaccine development. The major challenge of vaccine design is how to elicit an immune response that establishes long-term protective immunity against a specific pathogenic microorganism. The research outlined in this proposal will examine how the early inflammatory response to infection with the bacterium Listeria monocytogenes leads to the generation of immunological memory that protects against reinfection. This work will contribute to the understanding of how inflammation generates long-term memory and may reveal new insights on methods to develop safe and effective vaccines.