GUT INFLUENCES ON IMMUNE DEVELOPMENT IN EARLY LIFE

 描述(由申请人提供)：据观察，早期生活是产生耐受性反应的重要时期。这段时间也与肠道微生物区系的建立有关，这也是耐受性发展所必需的。然而，目前尚不清楚为什么耐受性在生命早期建立得最好，以及微生物区系如何对免疫系统产生影响。在这里，我展示了在生命早期，肠道内的细菌自发地从肠腔转移到肠系膜淋巴结。这一过程是正常发育的一部分，但这一现象的细节仍未确定。成年小鼠可以通过使用抗生素来诱导细菌易位，这需要杯状细胞相关抗原传代(GAP)和CX3CR1+抗原提呈细胞(APC)。在这笔赠款中，我将通过对早期生命中的小鼠器官进行16S深度测序，定义细菌在早期生命中何时发生易位，哪些物种易位，这些物种起源于哪里，以及哪些器官物种易位到哪些器官。我还将调查早期生命中的细菌易位是否需要GAP和CX3CR1+APC，就像成年小鼠一样，以及操纵GAP或CX3CR1+APC是否会使用转基因小鼠扰乱细菌易位以及对GAP的药理学操作。最后，我将使用流式细胞术和全身性炎症的迟发性超敏反应模型来评估细菌易位在调节性T细胞和全身耐受性的发展中所起的作用。该项目的完成将定义LFE早期生理性细菌易位的新过程，它是如何调节的，它对免疫系统有什么影响，提供关于肠道微生物区系如何促进耐受发展的洞察，以及早期生命中细菌易位中断对终身免疫反应的影响。

 DESCRIPTION (provided by applicant): It has been observed early life is an important time for the development of tolerogenic responses. This time is also correlated to the establishment of the intestinal microbiota, which is also necessary for the development of tolerance. However, it is unclear why tolerance is established best during early life and how the microbiota confers an effect on the immune system. Here I show gut resident bacteria spontaneously translocate from the intestinal lumen to the mesenteric lymph nodes during early life. This process occurs as part of normal development, yet the details of this phenomenon remain undefined. Adult mice can be manipulated through the use of antibiotics to induce bacterial translocation, which requires goblet-cell-associated antigen passages (GAPs) and CX3CR1+ antigen presenting cells (APCs). In this grant I will define when bacterial translocation occurs during early life, what species translocate, from where the species originate, and to which organs species translocate using 16S deep sequencing of murine organs throughout early life. I will also investigate if bacterial translocation during early life requires GAPs and CX3CR1+ APCs, similar to adult mice, and if manipulation of GAPs or CX3CR1+ APCs disrupt bacterial translocation using transgenic mice and pharmacological manipulation of GAPs. Finally, I will evaluate the role bacterial translocation has in the development of regulatory T cells and systemic tolerance using flow cytometry and a delayed type hypersensitivity model of systemic inflammation. Completion of this project will define the novel process of physiologic bacterial translocation during early lfe, how it is regulated and what effects it has on the immune system, providing insight into how the intestinal microbiota contributes to the development of tolerance and the effect disruption of bacterial translocation during early life has on lifelong immune responses.