Local Retinal Antigen Presentation

描述：免疫应答依赖于抗原呈递，这是免疫的中心事件。在淋巴组织中能够执行这种功能的细胞是深入研究的主题，并且越来越多地发现是树突状细胞。相反，在非淋巴组织，特别是包括视网膜和CNS的神经组织中呈递抗原的细胞没有得到很好的表征。这些细胞功能的基础知识对于理解这些敏感组织中的炎症至关重要。我们先前在视网膜中的免疫细胞的抗原呈递能力的体外测定中几乎没有发现活性。在体内，我们发现了导致视网膜炎症的抗原呈递可以由从循环中募集的细胞提供的证据。我们还发现，少量的分离树突状细胞进入眼睛，显著增加了自身反应性T细胞对视网膜抗原的致病反应的强度。因此，我们提出，在视网膜中启动CD 4 T细胞介导的免疫应答所需的抗原呈递依赖于从循环中募集的抗原呈递细胞，而不是局部细胞。这一假说与目前视网膜和CNS中抗原呈递的范例显著不同，该范例断言血管周围细胞是负责诱导CD 4 T细胞介导的神经系统免疫应答的抗原呈递细胞。因此，需要检查视网膜免疫生物学的基本方面。该假设分为两部分。A部分提出，启动CD 4 T细胞介导的实验性自身免疫性葡萄膜视网膜炎所需的抗原呈递依赖于从循环中募集的抗原呈递细胞，而不是依赖于驻留的小胶质细胞或缓慢翻转的骨髓源性血管周围细胞。B部分提出视网膜小胶质细胞和血管周围细胞在该模型中发挥减轻视网膜炎症的调节作用。为了解决这些假设，将对视网膜抗原特异性的自身反应性CD 4 T细胞接种到具有或缺乏以下各项的小鼠中：1.树突状细胞;或2. MHC II类分子对视网膜免疫细胞亚群的影响将测试循环抗原呈递细胞或其前体替代抗原呈递中的这些缺陷的能力。

DESCRIPTION: Immune responses are dependent on antigen presentation, a central event in immunity. The cells capable of performing this function in lymphoid tissues are the subject of intense study, and are increasingly found to be dendritic cells. Conversely, the cells which present antigen in non-lymphoid tissues, especially neural tissues including retina and CNS, are not well-characterized. Fundamental knowledge of the function of these cells is critical to understanding inflammation in these sensitive tissues. Our previous in vitro assays of the antigen presenting abilities of immune cells in retina found virtually no activity. In vivo, we found evidence that antigen presentation leading to retinal inflammation could be provided by cells recruited from the circulation. We also found that inoculating small numbers of isolated dendritic cells into the eye dramatically increased the strength of the pathogenic response of autoreactive T cells to a retinal antigen. As a result, we propose that the antigen presentation required to initiate CD4 T cell-mediated immune responses in retina is dependent on antigen presenting cells recruited from the circulation, rather than local cells. This hypothesis differs significantly from the current paradigm of antigen presentation in retina and CNS, which asserts that perivascular cells are the antigen presenting cells responsible for induction of CD4 T cell mediated nervous system immune responses. Consequently, basic aspects of retinal immunobiology need to be examined. The hypothesis is divided into two parts. Part A proposes that the antigen presentation required to initiate CD4 T cell-mediated experimental autoimmune uveoretinitis is dependent on antigen presenting cells recruited from the circulation, rather than on the resident microglia, or on bone marrow-derived perivascular cells that turn over slowly. Part B proposes that retinal microglia and perivascular cells play regulatory roles that attenuate retinal inflammation in this model. To address these hypotheses, autoreactive CD4 T cells specific for a retinal antigen will be inoculated into mice that either possess or lack: 1. dendritic cells; or 2. MHC class II on subsets of immune cells in the retina. The ability of circulating antigen presenting cells, or their precursors, to replace these deficiencies in antigen presentation will be tested.