Gamma/delta T cells in autoimmune keratitis

描述(申请人提供)：到目前为止，所有被检查的颌骨脊椎动物都携带α/β和伽马/德尔塔TCR基因，这表明这两种T细胞类型都存在，并且对生存很重要。虽然许多动物的伽马/德尔塔T细胞和阿尔法/贝塔T细胞的数量大致相同，但在小鼠和人类的淋巴器官中，伽玛/德尔塔T细胞的数量比阿尔法/贝塔T细胞少得多。小鼠和人类的免疫系统之间还有许多相似之处，因此，也许在两者中，伽马/德尔塔T细胞都已沦为最基本的功能。已证明，γ/Delta T细胞在清除感染性病原体、破坏肿瘤细胞以及控制免疫和炎症反应方面具有重要作用。在这项研究中，我们将检查是什么导致C57BL/10品系缺乏伽马/Delta T细胞(B10.TCRDelta-/-)的雌性小鼠发生角膜炎症的频率很高。这些小鼠自发发生角膜炎的事实表明，通常需要伽马/德尔塔T细胞来防止对眼睛的免疫攻击。我们的初步数据表明，这些小鼠的角膜炎不是传染性的，而是自身免疫性的，并且是由自身侵袭性的ab T细胞介导的。此外，我们还表明，过继转移特定的伽马/德尔塔T细胞亚群可降低角膜炎的发生率。在这项提案中，我们将测试免疫调节性伽马/德尔塔T细胞通常阻止角膜特异性自身反应性阿尔法/贝塔T细胞攻击角膜的假设。因此，B10.TCRDelta-/-小鼠容易患角膜炎，因为这些调节性伽马/Delta T细胞缺失。该项目的具体目标是：特定目标1-测试B10.TCRDelta-/-小鼠中导致角膜炎的α/βT细胞是角膜特异性自身侵袭性细胞的假设。我们将研究渗入角膜炎B10.TCRDelta-/-小鼠角膜的α/βT细胞的特征，检测它们在激活时产生的细胞因子，并在体外测试它们对角膜抗原的反应。我们还将确定哪些α/βT细胞是传播疾病所必需的，并通过活体成像确定它们是否直接攻击角膜中的细胞。具体目标2-检验预防角膜炎的伽马/德尔塔T细胞耐受致病的α/β细胞的假设。我们将描述一组通常存在于角膜中的伽马/德尔塔T细胞，并检查降低角膜炎发病率的脾伽马/德尔塔T细胞是否含有类似的细胞。我们还将测试伽马/德尔塔T细胞在角膜中是否发挥其保护作用，确定它们产生的哪些细胞因子对其效果至关重要。它们是否直接作用于α/βT细胞将通过活体角膜成像进行检查。我们还将研究它们诱导调节性α/βT细胞的能力，以及 以促进角膜炎期间的角膜愈合。这个项目既有创新性，又有针对性。 因为它专注于一种新的自发性自身免疫性角膜炎的小动物模型，该模型缺乏现有小动物模型的缺点和局限性。伽马/德尔塔T细胞已经被其他人认为与人类眼病有关。因此，该项目可能会改进或改进人类角膜疾病的治疗，并将有助于我们了解眼睛的免疫特免权。此外，它的发现可能会揭示伽马/德尔塔T细胞的独特属性，这可能有助于解释为什么它们在进化上是保守的。

DESCRIPTION (provided by applicant): All jawed vertebrates so far examined carry both alpha/beta and gamma/delta TCR genes, suggesting that both T cells types are present and important to survival. Although many animals have approximately equal numbers of gamma/delta and alpha/beta T cells, in the lymphoid organs of both mice and humans, the gamma/delta T cells are much less numerous than are alpha/beta T cells. There are a host of additional similarities between the mouse and human immune systems, so perhaps in both, gamma/delta T cells have been reduced to their most essential functions. Gamma/delta T cells have been shown to be important in clearing infectious agents, in the destruction of tumor cells, and in controlling immune and inflammatory responses. In this study, we will examine what causes a high frequency of female mice of the C57Bl/10 strain lacking gamma/delta T cells (B10.TCRdelta-/-) to develop inflammation of the cornea. The fact that keratitis arises spontaneously in these mice suggests that gamma/delta T cells are normally needed to prevent an immune attack on the eye. Our preliminary data indicate that keratitis in these mice is not infectious, but is instead autoimmune, and is mediated by auto aggressive ab T cells. Also, we showed that adoptively transferring a particular gamma/delta T cell subset reduces the incidence of keratitis. In this proposal, we will test the hypothesis that immunoregulatory gamma/delta T cells normally prevent cornea-specific autoreactive alpha/beta T cells from attacking the cornea. Thus, B10.TCRdelta-/- mice would be susceptible to keratitis because these regulatory gamma/delta T cells are missing. The specific aims of this project are: Specific Aim 1 - to test the hypothesis that keratitis-inducing alpha/beta T cells in B10.TCRdelta-/-mice are cornea-specific auto aggressive cells. We will investigate the characteristics of alpha/beta T cells that infiltrate the corneas of keratitic B10.TCRdelta-/- mice, examine the cytokines they produce when activated, and test whether they respond in vitro to corneal antigen. We will also determine which alpha/beta T cells are necessary to transfer the disease, and by intravital imaging whether they directly attack cells in the cornea. Specific Aim 2- to test the hypothesis that gamma/delta T cells which protect against keratitis tolerize disease-inducing alpha/beta cells. We will characterize a population of gamma/delta T cells that normally resides in the cornea, and examine whether splenic gamma/delta T cells that reduce the incidence of keratitis contain similar cells. We will also test whether gamma/delta T cells carry out their protective rol while in the cornea, determine which of the cytokines they produce are critical for their effect. Whether they act directly on alpha/beta T cells will be examined by intravital imaging of the cornea. We will also investigate their ability to induce regulatory alpha/beta T cells, and as well as to promote healing of the cornea during keratitis. This project is both innovative and relevant because it focuses on a new small animal model for spontaneous autoimmune keratitis which lacks the drawbacks and limitations of existing small animal models for this disease. Gamma/delta T cells have already been implicated by others in human eye diseases. This project could therefore lead to improvements or refinements in the treatment of corneal disease in humans, and will contribute towards our understanding of immune privilege in the eye. In addition, its findings are likely to reveal unique attributes of gamma/delta T cells that may help o explain why they have been evolutionarily conserved.