Differentiation and function of intestinal tissue-resident memory T cells

T细胞在消除病原体中起着关键作用，记忆T细胞的产生是防止继发感染的重要组成部分。记忆T细胞可以根据其位置分为两组，那些能够在整个身体中循环的细胞和那些驻留在组织中的细胞，准备对继发性感染迅速做出反应。组织驻留记忆T细胞（Trm）细胞保留在组织中，并且在感染消退后不被循环细胞补充。循环T细胞通常不足以保护免受继发感染;因此，确定Trm细胞如何产生并随时间维持其功能具有重要意义。只有少数微生物需要突破粘膜表面才能引发疾病。适应性免疫细胞在大型复杂组织中定位病原体并在它们传播到更深的组织之前将其消除的能力是保护性免疫的必要组成部分。我们已经使用肠道病原体假结核耶尔森氏菌的感染，以检查病原体特异性的CD 8 + Trm在感染过程中，并使用该模型，我们已经发现了显着的表型异质性在肠道Trm细胞，与整合素CD 103的表达定义这些人口。T细胞接近肠组织内的感染区域调节Trm分化，炎症和转录因子STAT 4的活化导致CD 103 Trm细胞数量增加。该提案将确定调节CD 103 Trm亚群的分化和维持的潜在机制。我们已经证明了CD 103 Trm细胞在原发性感染期间控制病原体复制中的关键作用，并且我们已经开发了新的工具来分析继发性感染期间Trm亚群之间的分工。这些发现将解决我们关于Trm细胞在继发感染期间控制肠道定植的功能的知识中的根本性空白。此外，目前还不清楚单独的Trm亚群是否足以提供保护，我们将确定Trm细胞的完整补体是否是强大免疫所必需的。这项工作将确定策略，以最大限度地提高Trm细胞的数量和持久性，这是任何成功的疫苗接种策略的重要组成部分，以靶向粘膜病原体。

T cells play a critical role eliminating pathogens and the generation of memory T cells is an important component in protection from secondary infection. Memory T cells can be divided into two groups based on their location, those that are capable of circulating throughout the body and those that are lodged in tissues, poised to respond rapidly to secondary infection. Tissue-resident memory T cells (Trm) cells remain in the tissue and are not replenished by circulating cells after infection is resolved. Circulating T cells are often not sufficient to protect from secondary infection; therefore, it is of significant interest to determine how Trm cells are generated and maintain their function over time. Only a small number of microbes need to breach the mucosal surface to initiate disease. The ability of adaptive immune cells to locate pathogens in large, complex tissues and eliminate them before they disseminate to deeper tissues is a necessary component of protective immunity. We have used infection with the intestinal pathogen Yersinia pseudotuberculosis to examine pathogen-specific CD8+ Trm during infection, and using this model we have uncovered significant phenotypic heterogeneity in intestinal Trm cells, with expression of the integrin CD103 defining these populations. Proximity of T cells to areas of infection within the intestinal tissue regulates Trm differentiation, with inflammation and activation of the transcription factor STAT4 leading to increased numbers of CD103 Trm cells. This proposal will identify the underlying mechanisms that regulate the differentiation and maintenance of the CD103 Trm subset. We have already shown a critical role for CD103 Trm cells in controlling pathogen replication during primary infection, and we have developed new tools to analyze the division of labor between Trm subsets during secondary infection. These findings will address a fundamental gap in our knowledge regarding the function of Trm cells in controlling intestinal colonization during secondary infection. Additionally, it is currently unclear whether either Trm subset alone is sufficient to confer protection, and we will determine if the full complement of Trm cells is necessary for robust immunity. This work will identify strategies to maximize the number and persistence of Trm cells, an important component of any successful vaccination strategy to target mucosal pathogens.