T cell costimulation through the immunological synapse

通过免疫突触进行 T 细胞共刺激

• 批准号: 7333667
• 负责人: JIM F Miller
• 金额: $ 15.79万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-01 至 2009-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7333667
• 关键词: Accounting; Address; Adhesions; Age; Aging; Aging-Related Process; Antigens; Attenuated; CD28 gene; CD4 Positive T Lymphocytes; Calcium; Cell Aging; Chromosome Pairing; Defect; Development; Elements; Enhancers; Event; Exclusion; Genetic Transcription; Goals; Immune response; Individual; Interleukin-2; Kinetics; Life; Mediating; Messenger RNA; Microscopy; Molecular; Molecular Analysis; Mus; Numbers; PTPRC gene; Peripheral; Phosphoric Monoester Hydrolases; Process; Proteins; Recruitment Activity; Secretory Component; Signal Transduction; Signaling Molecule; Site; Synapses; T-Cell Activation; T-Lymphocyte; Talin; Testing; Transgenic Organisms; Up-Regulation; age effect; cell age; cellular imaging; immunological synapse; receptor; response

DESCRIPTION (provided by applicant): The immune response is dramatically attenuated during aging. There are a number of factors that contribute to this phenomenon, one of which is an intrinsic defect in CD4 T cell activation. T cell activation takes place in the context of the immunological synapse, where receptors, cytoskeletal elements, and signaling molecules are organized into discreet domains at the T cell: APC interaction site. In the mature synapse the central region, cSMAC, contains the TCR, CD28, signaling components (PKCtheta), and secretory components. The peripheral region, pSMAC, contains LFA-1 and associated proteins talin and RAPL. The phosphatase, CD45, is recruited to the site of T cell: APC interaction, but largely excluded from the synapse. Recent evidence indicates that TCR signaling takes place in microclusters that form at the outside of the synapse and the cSMAC is a site of downmodulation of TCR signaling. In contrast, we have found that CD28 costimulation occurs within the cSMAC region, through the recruitment of PKCtheta and upregulation of IL-2 transcription. In addition, we have found that LFA-1-dependent formation of the pSMAC is required for the exclusion of the CD45 and this correlates with an increase in proximal signaling through the TCR. Thus, T cell costimulation through CD28 and LFA-1 may be mediated through the organization of proteins within the immunological synapse. There is good evidence that CD28 and LFA-1 functions are diminished in T cells from aged individuals. Thus the central hypothesis of this application is that aging results in a specific defect in the ability to target CD28 and/or LFA-1, or their associated proteins, to the cSMAC or pSMAC respectively and this results in a decrease in proximal T cell signaling that will account in part for the intrinsic defect in T cell activation in CD4 T cells from aged individuals. We will test this central hypothesis in 2 Aims: (1) Determine whether CD28 signaling within and/or outside the immunological synapse is downmodulated in T cells from aged mice and (2) Determine whether LFA-1 adhesion and/or immunological synapse organization is disrupted in T cells from aged mice. We will use TCR transgenic, CD28-deficient and LFA-1-deficient mice and a combination of immunofluorescent microscopy, live cell imaging, and molecular analysis. We will determine whether aging effects T cell: APC adhesion the kinetics, efficiency, or magnitude of recruitment and organization of TCR, LFA-1, CD28, or associated proteins into the immunological synapse. We will determine whether there is a corresponding defect in LFA-1 and/or CD28-associated signaling events and whether there is an alteration in the functional consequences these costimulatory signals. Finally, if a defect is noted in any of these events we will address the specific molecular process that accounts for a loss in LFA-1 and/or CD28 function during aging. The immune response is dramatically attenuated during aging in part due to a defect in T cell signaling. The overall goal of this project is to determine the precise cellular and molecular events that account for this defect. We hope that understanding the mechanism behind this aging process will facilitate the development of specific immuno-enhancers that can counteract these events and promote effect immune responses in older individuals.

描述（由申请人提供）：衰老期间免疫反应大大减弱。有许多因素导致这种现象，其中一种是CD4 T细胞激活中的固有缺陷。 T细胞激活发生在免疫突触的背景下，其中受体，细胞骨架元素和信号分子被组织到T细胞的谨慎域：APC相互作用位点。在成熟的突触中，中央区域CSMAC包含TCR，CD28，信号成分（PKCTHETA）和分泌组件。周围区域PSMAC包含LFA-1和相关的蛋白质塔林和Rapl。磷酸酶CD45被募集到T细胞的位点：APC相互作用，但在很大程度上被排除在突触之外。最近的证据表明，TCR信号发生在突触外部形成的微量群体中发生，而CSMAC是TCR信号传导下调的位置。相比之下，我们发现CD28共刺激发生在CSMAC区域内，通过募集PKCTHETA和IL-2转录的上调。此外，我们发现PSMAC的LFA-1依赖性形成是排除CD45所必需的，并且与通过TCR近端信号传导的增加相关。因此，通过CD28和LFA-1进行T细胞共刺激可以通过免疫突触中的蛋白质组织来介导。有充分的证据表明，来自老年个体的T细胞中CD28和LFA-1功能会降低。因此，该应用的中心假设是，衰老导致靶向CD28和/或LFA-1或其相关蛋白的特定缺陷分别与CSMAC或PSMAC相关的蛋白质，这会导致近端T细胞信号传导的近端T细胞信号降低，该信号会降低CD4 T细胞活化中CD4 T细胞活化中CD4 T细胞活化中CD4 T细胞中的内在缺陷的降低。我们将在2个目标中检验该中心假设：（1）确定在老年小鼠的T细胞中，免疫突触内和/或外部的CD28信号传导是否在T细胞中降低，并且（2）确定LFA-1粘附和/或免疫突触组织是否在T细胞中破坏了来自年龄小鼠的T细胞中的T细胞。我们将使用TCR转基因，CD28缺陷型和LFA-1缺陷型小鼠，以及免疫荧光显微镜，活细胞成像和分子分析的组合。我们将确定衰老效应T细胞：APC粘附是TCR，LFA-1，CD28的募集和组织的动力学，效率或幅度，还是相关的蛋白质中的动力学和组织中的动力学。我们将确定在LFA-1和/或CD28相关的信号事件中是否存在相应的缺陷，以及功能后果是否发生了变化。最后，如果在这些事件中的任何一个中都注意到缺陷，我们将解决衰老过程中LFA-1和/或CD28功能损失的特定分子过程。在衰老期间，由于T细胞信号传导缺陷，免疫反应会大大减弱。该项目的总体目标是确定解释此缺陷的精确细胞和分子事件。我们希望了解这种衰老过程背后的机制将有助于开发特定的免疫增强剂，这些免疫增强剂可以抵消这些事件并促进老年人的影响免疫反应。