Gamma/delta T cells in autoimmune keratitis

描述（由申请人提供）：到目前为止，所有颌骨脊椎动物都携带α / β和γ / δ 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。尽管许多动物的γ / δ和α / β T细胞数量大致相等，但在小鼠和人类的淋巴器官中，γ / δ T细胞的数量远少于α / β T细胞。在小鼠和人类免疫系统之间还有许多其他的相似之处，所以也许在两者中，γ / δ T细胞已经减少到它们最基本的功能。γ / δ T细胞已被证明在清除感染因子、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，我们将研究导致缺乏γ / δ T细胞（b10 . tcrδ -/-）的C57Bl/10菌株的雌性小鼠发生角膜炎症的原因。角膜炎在这些小鼠中自发产生的事实表明，通常需要γ / δ 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，由自身侵袭性ab T细胞介导。此外，我们还发现过继性转移特定的γ / δ T细胞亚群可降低角膜炎的发生率。在这个提议中，我们将检验免疫调节性γ / δ T细胞通常阻止角膜特异性自身反应性α / β T细胞攻击角膜的假设。因此,B10。tcrδ -/-小鼠易患角膜炎，因为这些调节性γ / δ T细胞缺失。本项目的具体目的是：具体目的1 -验证B10中诱导角膜炎的α / β T细胞的假设。tcrδ -/-小鼠是角膜特异性的自体侵袭细胞。我们将研究α / β T细胞浸润角膜B10的特征。TCRdelta-/-小鼠，检测它们在激活时产生的细胞因子，并测试它们是否对角膜抗原有反应。我们还将确定哪些α / β T细胞是转移疾病所必需的，并通过活体成像确定它们是否直接攻击角膜细胞。特异性目的2-验证抗角膜炎的γ / δ T细胞耐受诱导疾病的α / β细胞的假设。我们将描述通常存在于角膜中的γ / δ T细胞群的特征，并检查减少角膜炎发生率的脾脏γ / δ T细胞是否含有类似的细胞。我们还将测试γ / δ T细胞是否在角膜中发挥其保护作用，确定它们产生的哪些细胞因子对其作用至关重要。它们是否直接作用于α / β T细胞将通过角膜活体成像检查。我们还将研究它们诱导调节性α / β T细胞的能力

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. PUBLIC HEALTH RELEVANCE: We recently discovered that female mice of a certain background, when unable to produce a rare type of T cell known as gamma/delta T lymphocytes, spontaneously develop an inflammation of the cornea of the eye, or keratitis, at a very high rate. This disease, which can become very severe, appears to stem from an autoimmune attack by conventional T cells, or alpha/beta T cells, on the cornea. We hypothesize that gamma/delta T cells normally suppress these autoimmune alpha beta T cells and prevent keratitis. We believe these mice represent a useful disease model for autoimmune keratitis, and propose to further investigate the cells that are responsible for and those that prevent this disease.