Intestinal CD4 T cell responses to dietary and microbial antigens

项目摘要 高度特化的肠道免疫系统负责维持对来自肠道的无害刺激的耐受性。 细菌和食物，同时提供对病原体的保护性免疫。这种失调 临界平衡可导致炎症性肠病、食物过敏或增加对肠道疾病的易感性。 病原体CD 4 + T细胞是肠道内稳态的关键参与者，在抗原水平上微调反应 识别和功能分化。在肠上皮（IE）和下层固有层（LP）中， 组织适应性促炎（即，Th 17，Th 1）和调节（Treg）和上皮内（CD 8aa + CD 4 IEL）CD 4 + T细胞协调免疫和耐受各种肠道刺激。尽管如此，它仍然有待定义。 TCR库及其特异性如何转化为响应微生物抗原LP和IEL两者的功能。 此外，对饮食抗原特异性肠道T细胞的特征知之甚少。口服 耐受性是肠道内稳态的关键机制，由此口服给予抗原导致局部免疫耐受和局部免疫耐受。 以及对该抗原的系统耐受性，已知依赖于TcB。然而，多克隆的克隆动态 T细胞在耐受性环境中的反应仍不清楚。最后，在免疫或过敏的背景下， 特异性识别食物蛋白质的T细胞还有待鉴定。根据最近公布的数据， 作为在当前资助周期中获得的初步数据，我们假设组织线索与 来自肠道微生物和食物的TCR驱动信号决定了肠道T细胞的功能分化， 状态，而感染或过敏原导致的正常T细胞应答的破坏导致不适当的克隆性T细胞应答。 动力学包括病理性T细胞的扩增。目标1将定义微生物群或肠道刺激如何 病毒影响TCR库和肠CD 4 T细胞的功能分化。目标2将描述 饮食抗原在耐受性、肠道感染或食物过敏的背景下的作用影响TCR库， 肠CD 4 T细胞的功能分化。我们将联合收割机单细胞转录组学与新的命运结合起来- 选择性标记外周T细胞的定位策略，这些外周T细胞在各种微生物刺激下被募集到肠道， 和饮食挑战。最近开发的LIPSTIC工具允许肠上皮细胞（IEC）标记 将利用相互作用的细胞来定义IEL募集/扩增的潜在机制， 非自我刺激最近产生的具有固定TCR Vb链的鼠品系，或携带微生物群特异性的 TCR与互补的四聚体和无菌策略相结合，将用于特异性地跟踪和 在肠道中的T细胞迁移和分化过程中定义识别特性。新型“超四聚体”和 饮食操作，结合炎症挑战将用于定义食物抗原特异性T细胞 以及在食物过敏或过敏性疾病中肠道CD 4 + T细胞对饮食抗原的应答如何改变。 感染背景。通过结合粘膜免疫学中的这些创新方法和概念， 这将有助于更好地确定非自身抗原刺激在肠道T细胞库和功能中的作用。

Project Summary The highly specialized intestinal immune system is charged with maintaining tolerance to harmless stimuli from commensal bacteria and food, while providing protective immunity against pathogens. Dysregulation of this critical balance can lead to inflammatory bowel disease, food allergy, or increased susceptibility to enteric pathogens. CD4+ T cells are key players in intestinal homeostasis, finely tuning responses at the level of antigen recognition and functional differentiation. In the intestinal epithelium (IE) and underlying lamina propria (LP), tissue adapted pro-inflammatory (ie. Th17, Th1) and regulatory (Treg) and intraepithelial (CD8aa+ CD4IEL) CD4+ T cells coordinate immunity and tolerance to diverse intestinal stimuli. Nevertheless, it remains to be defined how TCR repertoire and its specificity translate to function of both LP and IELs in response to microbial antigens. Additionally, very little is known about the characteristics of dietary antigen-specific intestinal T cells. Oral tolerance, a critical mechanism of gut homeostasis whereby oral administration of antigen results in both local and systemic tolerance to that antigen, is known to depend on Tregs. However, the clonal dynamics of polyclonal T cell responses in the setting of tolerance remain unclear. Finally, outside the context of immunization or allergy, T cells that specifically recognize food protein have yet to be identified. Based on data recently published as well as preliminary data obtained during the current funding cycle, we hypothesize that tissue cues combined with TCR-driven signals from commensal microbes and food dictate intestinal T cell functional differentiation in steady state, while disruption of normal T cell responses by infections or allergens results in inappropriate clonal dynamics including expansion of pathological T cells. Aim 1 will define how stimulation by microbiota or enteric viruses impact TCR repertoire and functional differentiation of intestinal CD4 T cells. Aim 2 will characterize the role of dietary antigens in the context of tolerance, enteric infections, or food allergy, affect TCR repertoire and functional differentiation of intestinal CD4 T cells. We combine single cell transcriptomics with a novel fate- mapping strategy to selectively label peripheral T cells that are recruited to the intestine under various microbial and dietary challenges. A recently developed LIPSTIC tool that allows intestinal epithelial cells (IECs) labeling of interacting cells will be utilized to define potential mechanisms of IEL recruitment/expansion in response to nonself stimuli. Recently generated murine strains with fixed TCR Vb chain, or that carry microbiota-specific TCRs, combined with complementary tetramer and gnotobiotic strategies will be used to specifically track and define recognition properties during T cell migration and differentiation in the gut. Novel “super-tetramer” and dietary manipulations, combined with inflammatory challenges will be used to define food antigen-specific T cells during steady state and how intestinal CD4+ T cell responses to dietary antigen are altered in a food allergic or infection context. By combining these innovative approaches and concepts in mucosal immunology, this proposal will help better defining the role of nonself antigen stimulation in T cell repertoire and function in the intestine.