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: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=654224
• 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 Seahorser 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：“初始”（未经历抗原）CD8 T 细胞的激活需要两个信号，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。两种信号范式，我们已经证明先天免疫反应过程中产生的某些炎症细胞因子（IL-6、IL-21）可以与稳态细胞因子（IL-7、IL-7）协同作用。 IL-15) 诱导幼稚 CD8 T 细胞的 Ag 非特异性增殖 (Cell. Signal. 2007,19:806) 我们还表明，幼稚 CD8 T 细胞短暂暴露于 IL-21 或 IL-6 中。 IL-7或IL-15的存在显着降低了激活所需的TCR信号阈值（J.Immunol.2008，180：7958）。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桥接先天性免疫反应和适应性免疫反应（Crit.Rev.Immunol.2009,29:219）。**进展：在当前资助期内，我们已经证明细胞因子引发会降低 CD5 的表达，CD5 是 TCR 信号传导的负调节因子（Immunol. Cell. Biol. 2010,88：我们还表明，细胞因子引发的细胞获得了对弱 TCR 配体作出反应的能力，并且细胞因子引发可以使用自身免疫小鼠模型在体内发生（J.Immunol.2010, 185:357；同上，2011， 186:5131)。我们最近的研究结果表明 (i) 细胞因子引发会增加脂筏含量和 CD45，这是 TCR 信号传导的两个关键组成部分。机器，(ii) 细胞因子引发诱导记忆细胞表型并减弱 Ag 诱导的衰竭，(iii) 细胞因子引发的细胞显示出备用线粒体呼吸能力升高。**假设：我们发现细胞因子引发的功能后果来自于空间TCR 信号传导的时间变化以及分化途径和细胞能量代谢的调节，以及基因/蛋白质表达的特定变化是这些变化的基础。**目标：该研究计划的长期目标是了解机制和细胞因子引发在生理和病理性免疫反应中的重要性*我们未来 5 年的短期目标是：*1. 表征细胞因子引发的初始 CD8 T 细胞中的 TCR 信号动力学。*2。 *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 CD8 T 细胞对弱 TCR 配体的反应中的作用。体内。**方法：作为实验系统，我们将使用 TCR 转基因小鼠获得均匀的初始 CD8 T 细胞群 *1) 我们将使用共聚焦显微镜来可视化脂筏、CD45 和关键 TCR 的空间和时间分布。 T 细胞和负载 Ag 的树突状细胞之间形成的免疫突触的信号传导事件 *2) 我们将使用 Seahorser 细胞代谢分析仪来测量耗氧率（通过线粒体合成 ATP 的方法）。 *3) 我们将使用微阵列进行基因表达分析，并通过质谱进行蛋白质组分析 *4) 我们将使用表达转基因 TCR 识别的同源 Ag 或弱激动剂的病毒来感染野生型或特定型。细胞因子缺陷小鼠，并评估 Ag 特异性 CD8 T 细胞的激活和功能分化体内.**意义：该研究计划将深入了解炎症细胞因子“启动”幼稚 CD8 T 细胞随后遭遇入侵病原体 Ag 的机制。