Expression and function of the TLRs on T cells

描述（由申请人提供）：Toll样受体（TLR）是高度保守的蛋白质，在先天性和适应性免疫中发挥不可或缺的作用。9个特征性哺乳动物TLR是整合病原体相关分子模式（PAMP）的模式识别受体，提供了区分自我和非自我的手段。TLR的连接激活先天性免疫系统的细胞，诱导诸如吞噬作用和IFN-α和IFN-b分泌的功能。TLR-连接还充当先天性和适应性免疫系统之间的桥梁。DC和巨噬细胞的TLR刺激诱导炎性细胞因子如IL-12的产生，以及MHC II类和共刺激配体如CD40和CD86的上调。虽然在APC上的作用已经很好地建立，但令人惊讶的是，关于它们在T细胞上的表达和潜在功能知之甚少。我们实验室的新研究表明，几个TLR的表达后激活na？ve CD4 + CD25-T细胞。这些TLR通过其适当的PAMP的连接激活几种已知的下游信号传导途径，包括NF-κ B、p38 JNK和ERK。在功能上，这导致增强的T细胞存活，并且还可以提供与次优TCR连接的共刺激。我们的工作假设是T细胞上的TLR信号传导是细胞免疫应答的重要贡献者，并且是耐受性发展的阻碍。为此，本研究计划的长期目标是确定T细胞上TLR的表达和功能。在具体目标#1中，我们将表征控制T细胞上TLR表达和上调的信号，以及TLR用于介导其作用的下游信号传导途径。具体目标#2将使用来自TCR转基因小鼠的细胞与体外和体内过继转移系统偶联，以详细检查T细胞的TLR活化对活化和共刺激分子的诱导、细胞因子产生或偏斜以及效应子/记忆分化和响应性的影响。这种方法将允许精确定义TLR刺激T细胞可以做什么。在具体目标#3中，我们将询问目标#2中针对TLR鉴定的功能在体内免疫应答期间是否起作用。为此，我们将创建体内模型，其中只有T细胞缺乏TLR信号传导，以评估TLR信号在体内免疫应答期间对T细胞的特定作用。具体的模型包括过继转移、骨髓嵌合体和在TLR3或MyD88缺陷背景下使用TCR转基因小鼠的移植

DESCRIPTION (provided by applicant): Toll-like receptors (TLRs) are highly conserved proteins which play an integral role in innate and adaptive immunity. The nine characterized mammalian TLRs are pattern recognition receptors for integral pathogen associated molecular patterns (PAMPs), providing a means to discriminate between self and non-self. Ligation of TLRs activates cells of the innate immune system, inducing functions such as phagocytosis and IFN-a and IFN-b secretion. TLR-ligation also serves as a bridge between the innate and adaptive immune systems. TLR stimulation of DCs and macrophages induces the production of inflammatory cytokines such as IL-12, and upregulation of MHC class II and costimulatory ligands such as CD40 and CD86. While roles if or TLRs on APCs are well-established, surprisingly little is known about their expression and potential function on T cells. New studies from our laboratory show that several TLRs are expressed following activation of na?ve CD4+CD25- T cells. Ligation of these TLRs by their appropriate PAMPs activates several known downstream signaling pathways, including NF-kB, p38 JNK, and ERK. Functionally, this leads to enhanced T cell survival and may also provide costimulation with sub-optimal TCR ligation. Our workinq hypothesis is that TLRs signaling on T cells is an important contributor to cellular immune responses, and a block to the development of tolerance. To this end, the long-term goals of this research program are to define the expression and function of TLRs on T cells. In specific aim #1 we will characterize the signals which govern the expression and upregulation of TLRs on T cells, and the downstream signaling pathways which TLRs use to mediate their effects. Specific aim #2 will use cells from TCR transgenic mice coupled with in vitro and in vivo adoptive transfer systems to conduct a detailed examination of the effects of TLR activation of T cells on induction of activation and costimulatory molecules, cytokine production or skewing, and effector/memory differentiation and responsiveness. This approach will allow for precise definition of what TLR stimulation of T cells can do. In specific aim #3 we will then ask which if the functions identified for TLRs in aim #2 are operative during in vivo immune responses. To do so, we will create in vivo models in which only T cells are deficient in TLR signaling, in order to assess the specific role of TLR signals on T cells during in vivo immune responses. Specific models include adoptive transfers, bone-marrow chimeras, and transplantation using TCR transgenic mice on TLR3- or MyD88-deficient backgrounds