TCR-dependent activation, functional differentiation and memory formation of CD4+ T cells following infection

项目摘要 由于它们的频率升高，自我更新能力和快速获得效应器功能 在再激活后，记忆T细胞具有增强的保护免受二次攻击的能力。的 记忆T细胞的产生是许多疫苗和免疫策略的焦点。最 （90-95%）效应T细胞在病原体清除后死亡，但那些注定成为记忆细胞的T细胞可能会死亡。 在初级效应反应期间鉴定，表明活化的T细胞接受分化提示， 在对感染的主要反应中影响记忆命运分化。我们最近的研究表明 T细胞受体（TCR）信号在驱动CD 4+记忆T细胞分化中起关键作用。TCR是 能够在持续的相互作用中与MHC II类结合抗原（pMHCII）结合的抗原偏向于 长期记忆的形成，而与抗原进行短期相互作用的TCR是有偏见的。 向终端效应细胞分化。我们将在这些研究的基础上， 为了定义导致以下形成的TCR依赖性激活和转录程序的方面， 淋巴驻留、循环和组织驻留CD 4+记忆T细胞。我们提出三个关键问题。第一、 TCR信号强度在记忆T细胞形成中的作用是什么？我们将探讨一个假设， 体内增加TCR信号强度驱动末端效应T细胞分化，而较弱的TCR信号强度驱动末端效应T细胞分化。 强度允许记忆T细胞形成。第二，TCR结合参数是什么， 记忆T细胞发育我们将测量2D亲和力和键寿命与力的应用， TCR是效应器偏置或记忆偏置的。我们将检验一个假设，即键的寿命将预测 TCR依赖的记忆分化。第三，控制记忆的转录程序是什么 阵型？我们将测试在记忆T细胞中差异表达的分子的机制作用， 初级效应器反应期间的前体，包括TCF-1。我们预计， 本研究中提出的问题将提供一个框架，用于更详细地确定 记忆T细胞形成并鉴定直接调节CD 4+效应子和记忆T细胞的治疗方法 体内细胞分化。

Project Summary Because of their elevated frequency, ability to self-renew and rapid acquisition of effector function following re-activation, memory T cells have an enhanced ability to protect from secondary challenge. The generation of memory T cells is the focal point of numerous vaccine and immunotherapeutic strategies. Most (90-95%) effector T cells die after pathogen clearance, but those fated to become memory cells can be identified during the primary effector response, showing that activated T cells receive differentiation cues during the primary response to infection that influence memory fate differentiation. We have recently shown that T cell receptor (TCR) signals play a key role in driving CD4+ memory T cell differentiation. TCRs that are able to engage MHC Class II-bound antigen (pMHCII) in sustained interactions are biased towards the formation of long-lived memory, while TCRs that engage in short-lived interactions with antigen are biased towards terminal effector cell differentiation. We will build on those studies by using diverse infectious models to define aspects of the TCR-dependent activation and transcriptional program that leads to the formation of lymphoid-resident, circulating and tissue-resident CD4+ memory T cells. We pose three key questions. First, what is the role of TCR signal strength in the formation of memory T cells? We will explore the hypothesis that increasing TCR signal strength in vivo drives terminal effector T cell differentiation, while weaker TCR signal strength allows memory T cell formation. Second, what are the TCR binding parameters associated with memory T cell development? We will measure 2D affinity and bond lifetime with the application of force for TCRs at that are effector-biased or memory-biased. We will test the hypothesis that bond lifetimes will predict TCR-dependent memory differentiation. Third, what are the transcriptional programs that control memory formation? We will test the mechanistic role of molecules that are differentially expressed in memory T cell precursors during the primary effector response, including TCF-1. We anticipate that resolution of the questions posed in this study will provide a framework for determining in greater mechanistic detail how memory T cells form and identify therapeutic approaches for directly modulating CD4+ effector and memory T cell differentiation in vivo.