Cytokine-induced modulation of T lymphocyte responses to antigens

细胞因子诱导的 T 淋巴细胞对抗原反应的调节

• 批准号: RGPIN-2014-04692
• 负责人: Ilangumaran, Subburaj
• 金额: $ 2.55万
• 依托单位: Université de Sherbrooke
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=611187
• 关键词: Cytokine; induced; modulation; lymphocyte; responses

Background: Activation of ‘naïve’ (antigen-inexperienced) CD8 T cells requires two signals. Signal 1 is delivered via the T cell antigen (Ag) receptor (TCR), and signal 2 is delivered via co-stimulatory receptors. Contrary to this two signal paradigm, we have shown that certain inflammatory cytokines produced during innate immune response (IL-6, IL-21) can synergize with homeostatic cytokines (IL-7, IL-15) to induce Ag non-specific proliferation of naïve CD8 T cells (Cell. Signal. 2007,19:806). We have also shown that a brief exposure of naïve CD8 T cells to IL-21 or IL-6 in the presence of IL-7 or IL-15 markedly decreases the TCR signaling threshold required for activation (J. Immunol. 2008,180: 7958). We refer to this cytokine-mediated increase in TCR responsiveness as ‘cytokine priming’, and have proposed that this pathway may bridge innate and adaptive immune responses (Crit. Rev. Immunol. 2009,29: 219). Progress: During the current grant period, we have shown that cytokine priming reduces the expression of CD5, a negative regulator of TCR signaling (Immunol. Cell. Biol. 2010,88: 451). We have also shown that cytokine-primed cells acquire the capacity to respond to weak TCR ligands, and that cytokine priming could occur in vivo using mouse models of autoimmunity (J. Immunol. 2010, 185:357; ibid. 2011,186:5131). Our recent findings indicate that (i) cytokine priming increases the lipid raft content and CD45, two key components of the TCR signaling machinery, (ii) cytokine priming induces a memory cell phenotype and attenuates Ag-induced exhaustion, (iii) cytokine-primed cells display show elevated spare mitochondrial respiratory capacity. Hypothesis: We hypothesize that the functional consequences of cytokine priming arise from spatial and temporal changes in TCR signaling along with modulation of differentiation pathways and cellular energy metabolism, and that specific changes in gene/protein expression underlie these alterations. Objectives: The long-term objective of this research program is to understand the mechanisms and the significance of cytokine priming in physiological and pathological immune responses. Our short-term goals for the next 5 years are: 1. Characterize the TCR signaling dynamics in cytokine-primed naive CD8 T cells. 2. Elucidate how cytokine priming modulates their energy metabolism. 3. Define the changes in gene/protein expression induced by the priming cytokines. 4. Determine the role of priming cytokines in CD8 T cell responses to weak TCR ligands in vivo. Methodology: As experimental system, we will use TCR transgenic mice to obtain a uniform population of naïve CD8 T cells. 1) We will use confocal microscopy to visualize the spatial and temporal distribution of lipid rafts, CD45 and key TCR signaling events at the immune synapse formed between T cells and Ag-loaded dendritic cells. 2) We will use the Seahorse® cell metabolism analyzer to measure oxygen consumption rate (a measure of ATP synthesis via mitochondrial electron transport chain) and extracellular acidification rate (a measure of glycolysis that generates building blocks needed for cell proliferation). 3) We will carry out gene expression analysis using microarrays, and proteomic analysis by mass spectrometry. 4) We will use a virus expressing either the cognate Ag recognized by the transgenic TCR, or a weak agonist, to infect wild type or specific cytokine deficient mice, and evaluate activation and functional differentiation of Ag-specific CD8 T cells in vivo. Significance: This research program will provide insight into the mechanisms by which inflammatory cytokines ‘prime’ naïve CD8 T cells for the ensuing encounter with Ags of invading pathogens.

背景：激活“幼稚”（抗原 - 内X8）CD8 T细胞需要两个信号。信号1通过T细胞抗原（Ag）受体（TCR）传递，信号2通过共刺激受体传递。与这两个信号范式相反，我们已经表明，在先天免疫响应（IL-6，IL-21）期间产生的某些炎症细胞因子可以与稳态细胞因子（IL-7，IL-15）协同化，以诱导AG非特异性诱导NaïveCD8T细胞的非特异性繁殖。我们还表明，在存在IL-7或IL-15的情况下，将幼稚的CD8 T细胞短暂暴露于IL-21或IL-6，显着降低了激活所需的TCR信号阈值（J.Immunol。2008,180：7958）。我们将这种细胞因子介导的TCR反应性增加称为“细胞因子启动”，并提出该途径可能会弥合先天和适应性免疫调查（Crit。Crit。Rev.Immunol。2009,29：219）。 进展：在当前赠款期间，我们表明细胞因子启动降低了CD5的表达，CD5是TCR信号传导的负调节剂（Immunol。Cell。Biol。2010,88：451）。我们还表明，细胞因子裂化的细胞具有对弱TCR配体反应的能力，并且使用自身免疫的小鼠模型在体内可能发生细胞因子启动（J. Immunol。2010，185：357;同上2011年，2011年186：5131）。我们最近的发现表明，（i）细胞因子启动增加了脂质筏含量和CD45，这是TCR信号机械的两个关键组成部分，（ii）细胞因子启动诱导记忆细胞表型，并减弱AG诱导的衰竭，（III）细胞因子培养细胞显示出较高的备用备用能力。 假设：我们假设细胞因子启动的功能后果是由TCR信号传导的空间和临时变化以及分化途径和细胞能代谢的调节以及基因/蛋白质表达的特定变化是这些改变的。 目标：该研究计划的长期目标是了解细胞因子启动在物理和病理免疫调查中的机制和重要性。 我们未来5年的短期目标是： 1。表征细胞因子引发的幼稚CD8 T细胞中的TCR信号传导动力学。 2。阐明细胞因子启动如何调节其能量代谢。 3。定义启动细胞因子诱导的基因/蛋白质表达的变化。 4。确定启动细胞因子在体内对弱TCR配体的CD8 T细胞反应中的作用。 方法论：作为实验系统，我们将使用TCR转基因小鼠获得CD8 T细胞的均匀种群。 1）我们将使用共聚焦显微镜可视化脂质筏，CD45和键TCR信号事件的空间和临时分布，在T细胞和Ag负载的树突状细胞之间形成的免疫突触中。 2）我们将使用Seahorse®细胞代谢分析仪来测量氧的消耗率（通过线粒体电子传输链的ATP合成的度量）和细胞外酸化速率（糖酵解产生细胞增殖所需的构件的量度）。 3）我们将使用微阵列进行基因表达分析，并通过质谱法进行蛋白质组学分析。 4）我们将使用表达被转基因TCR或弱激动剂识别的同源Ag的病毒，以感染的野生型或特定的细胞因子特异性小鼠，并评估体内Ag特异性CD8 T细胞的激活和功能分化。 意义：该研究计划将洞悉炎症细胞因子“ Prime”幼稚CD8 T细胞的机制，以与随之而来的入侵病原体的AG相遇。