Mucosal T cell memory to pathogens

项目总结 反复的T细胞刺激可导致衰老、衰竭或死亡(SED)，正如在慢性病毒感染期间观察到的那样 感染，某些异源加强(HPB)疫苗接种研究，或癌症。知道是否有 T细胞克隆性扩增的公理限度是与多种疾病免疫治疗相关的知识的一个关键缺口 以及对免疫生物学的基本了解。在8年前开始的试点实验中，我们 确定了一种刺激策略，揭示了记忆CD8 T细胞群体本质上是无限可扩展的， 我们最年长的人群在3200天内经历了38次加强免疫(比任何老鼠都长 生命)，并有效地生产&gt；1030后代。我们假设这种原则性的、极端的性质 实验揭示了基本的T细胞生物学与我们对免疫系统和 提供了可用于医学相关目的的意外观察。我们将利用这一点 独特的资源(ISTC，反复刺激的T细胞)，以探索反复刺激对T细胞的影响 细胞生物学。我们将讨论在反复刺激下避免SED的规则，ISTC的相关性 在不表现出功能衰竭的情况下表达与疲劳相关的基因，以及通过 其中ISTCs持久地保留了血液和粘膜组织之间循环的独特效应器性质。 目的1.明确ISTC分化程序的调控和演变。我们将1)定义 使用生物信息学和计算生物学方法在单细胞水平上的ISTC的进化，2)定义 通过修改我们的刺激策略的参数来避免T细胞SED的规则，以及3)来自 在分子水平上比较耗竭T细胞(TeX)和连续的基因表达模式 一代代的ISTC。我们将检验这样的假设：1)永久的扩散能力取决于避免 ‘茎’群体的末端分化，2)短时间内过度分裂促进末端分化 分化，以及3)尽管与耗尽的细胞共享关键特征，但功能ISTC将显示出离散的 基因表达的模式，从而完善了疲劳的分子定义。 目的2.明确ISTC再循环的特性、免疫监视机制和 抗菌功能。ISTC代表了一个独特的机会来询问非淋巴疾病的机制 组织再循环。我们将1)定义使用异种共生手术的ISTC的迁移特性， 可光激活的小鼠系和扰动的归巢分子，2)评估ISTC在 一个LM-N挑战模型，以及3)将这些发现扩展到“脏”小鼠(已经反复暴露的小鼠 对自然病原体)和人类。我们将检验以下假设：1)ISTC通过NLT循环，2)ISTC 可以防止病原体的攻击，以及3)可以在“脏”的小鼠和人类中发现ISTCs。

PROJECT SUMMARY Iterative T cell stimulation can result in senescence, exhaustion, or death (SED) as observed during chronic viral infections, certain heterologous prime boost (HPB) vaccination studies, or cancer. Knowing whether there are axiomatic limits to T cell clonal expansion is a critical gap in knowledge relevant for immunotherapy of diverse diseases as well as fundamental understanding of immunobiology. In pilot experiments that began >8y ago, we identified a stimulation strategy revealing that memory CD8 T populations are essentially infinitely expansible, our oldest population having gone through 38 booster immunizations over 3200 days (longer than any mouse lives) and effectively producing >1030 progeny. We hypothesize that this proof-of-principle, extreme-of-nature experiment reveals fundamental T cell biology highly relevant to our understanding of the immune system and provides unexpected observations that could be exploited for medically relevant purposes. We will leverage this unique resource (ISTCs, iteratively stimulated T cells) to explore the consequences of iterative stimulation on T cell biology. We will address the rules for avoiding SED despite repeated stimulation, the relevance of ISTCs expressing exhaustion-associated genes without appearing functionally exhausted, and the mechanisms by which ISTCs durably retain the unique effector-like property of circulation between blood and mucosal tissues. Aim 1. To define the regulation and evolution of the ISTC differentiation program. We will 1) define the evolution of ISTCs at the single cell level using bioinformatic and computational biology approaches, 2) define rules for avoiding T cell SED by modifying the parameters of our stimulation strategy, and 3) contrast ISTCs from exhausted T cells (Tex) on a molecular level by comparing gene expression patterns of Tex and consecutive generations of ISTCs. We will test the hypotheses that 1) everlasting proliferative capacity depends on avoiding terminal differentiation of a ‘stem’ population, 2) excessive division over a short period of time promotes terminal differentiation, and 3) despite sharing key features with exhausted cells, functional ISTCs will reveal discrete patterns of gene expression thus refining the molecular definition of exhaustion. Aim 2. To define ISTC recirculation properties, mechanisms of immunosurveillance, and antimicrobial functions. ISTCs represent a unique opportunity to interrogate mechanisms of nonlymphoid tissue recirculation. We will 1) define the migration properties of ISTCs using parabiosis surgeries, photoactivatable mouse lines, and perturbing homing molecules, 2) assess the protective potential of ISTCs in a LM-N challenge model, and 3) extend these findings to ‘dirty’ mice (mice which have been iteratively exposed to natural pathogens) and humans. We will test the hypotheses that 1) ISTCs recirculate through NLTs, 2) ISTCs can protect against pathogen challenge, and 3) ISTCs can be identified in ‘dirty’ mice and humans.