Chemokines and T Cell Recruitment in High Risk Corneal Allograft Rejection

描述（由主要研究者提供）：由于免疫排斥反应，“高危”血管化角膜床受体的角膜移植物存活率很低。我们的假设是，这些移植物的命运类似于其他实体器官血管化同种异体移植物，需要积极的全身免疫抑制，以提高生存。同种异体移植物的排斥反应是通过同种异体特异性T细胞的协调募集和浸润介导的。最近，研究实体血管化器官同种异体移植物的免疫排斥反应的研究表明，手术后移植部位的选择性趋化因子的早期诱导是T细胞进入排斥性同种异体移植物的最佳募集所必需的。我们的数据显示，T细胞进入移植物的募集在高风险血管化角膜移植物的排斥反应中也是至关重要的。这与中性粒细胞趋化因子CXCL 1/KC的早期产生和T细胞趋化因子CXCL 9/Mig（由IFN-3诱导的单核因子）和CXCL 10/IP 10（IFN-3诱导蛋白）的晚期上调相关。尽管CXCL 1/KC的体内中和导致移植物存活增加，但我们最近的数据显示CXCL 10/IP 10的中和导致更快和更强的排斥。在本申请中，我们将测试高风险血管化角膜的行为与血管化实体器官移植相似的假设。CXCL 1/KC的早期产生对于T细胞化学引诱物的后期诱导是至关重要的，所述T细胞化学引诱物是将同种异体特异性效应或调节性CD 4 T细胞募集到移植物中所必需的。本申请中提出的实验的总体目标是了解血管化角膜环境如何调节早期CXC趋化因子的产生以及引发的同种异体特异性效应细胞和调节性T细胞向移植物中的募集以介导排斥反应。在目标1中，我们将使用一种追踪抗原特异性T细胞的新系统进行测试，以监测同种异体特异性T细胞的启动，并测试这是由高风险血管化角膜同种异体移植物改变的，以这种方式，有更多的T细胞具有不同的表型，优化了招募。在目标2中，我们将鉴定CXCL 1/KC的细胞来源，并检测CXCL 1/KC如何通过增加产生IFN-β的CXCR 2+细胞的浸润来诱导T细胞化学引诱物的晚期产生。目标3中的实验将使用中和抗体和CXCL/9/Mig缺陷的小鼠来测试这种T细胞化学引诱物是T细胞增加募集到移植物中的原因。我们还将利用荧光标记的效应和调节性T细胞的新型动物模型来测试移植物内趋化因子如何改变它们的募集和移植结果。本提案中描述的实验结果将确定用于开发新型治疗试剂和策略的靶点，以抑制T细胞浸润到高风险同种异体移植物中。这将最终提高移植物存活率，同时减少对目前可用的普遍和衰弱的免疫抑制方案的依赖。角膜移植是治疗严重角膜瘢痕导致失明的主要方法。不幸的是，在角膜瘢痕形成与血管形成相关的患者中，移植的排斥率很高。本申请中提出的实验将研究趋化因子信号对免疫细胞的募集如何负责移植物排斥。我们相信，这些趋化因子的局部中和将是一种新的治疗形式，以保持角膜移植物的清晰和改善患者的视力结果与血管化瘢痕角膜。

DESCRIPTION (provided by principal investigator): The survival rate of corneal allografts in "high risk" vascularized corneal bed recipients is poor due to immune rejection. Our hypothesis is that these grafts are similar to the fate of other solid organ vascularized allogeneic grafts that require aggressive systemic immune-suppression to improve survival. The rejection of allografts is mediated through the coordinated recruitment and infiltration of allo-specific T cells. Most recently, studies investigating the immunological rejection of solid vascularized organ allotransplants have shown that the early induction of selective chemokines at the site of transplantation after surgery is required for the optimal recruitment of T cells into rejecting allografts. Our data shows that recruitment of T cells into the graft is also critical in rejection of high risk vascularized corneal allografts. This correlates to the early production of the neutrophil chemoattractant CXCL1/KC and late up-regulation of the T cell chemoattractants: CXCL9/Mig (monokine induced by IFN-3) and CXCL10/IP10 (IFN-3-inducible protein). Although the in vivo neutralization of CXCL1/KC results in increased graft survival, our recent data shows that neutralization of CXCL10/IP10 causes a faster and robust rejection. In this application we will test the hypothesis that a high risk vascularized cornea behaves like a vascularized solid organ transplant. The early production of CXCL1/KC is crucial to the late induction of T cell chemoattractants necessary for the recruitment of allo-specific effector or regulatory CD4 T cells into the graft. The overall goal of the experiments proposed in this application is to understand how the vascularized corneal environment regulates early CXC chemokine production and the recruitment of primed allo-specific effector and regulatory T cells into the graft to mediate rejection reactions. In Aim 1, we will test using a novel system of tracking antigen specific T cells, to monitor allo-specific T cells priming and test this is altered by high risk vascularized corneal allografts in such a way that there are more T cells with a different phenotype optimized for recruitment. In Aim 2, we will identify the cell source of CXCL1/KC and test how CXCL1/KC induces the late production of T cell chemoattractants by increasing infiltration of CXCR2+ cells that produce IFN-?. Experiments in Aim 3 will use neutralizing antibodies and mice deficient in CXCL/9/Mig to test that this T cell chemoattractant is responsible for the increased recruitment of T cells into the graft. We will also utilize novel animal models with fluorescently labeled effector and regulatory T cells to test how intragraft chemokines alter their recruitment and graft outcome. The results from experiments described in this proposal will identify targets for the development of novel therapeutic reagents and strategies to inhibit T cell infiltration into high risk allografts. This will ultimately improve graft survival while decreasing the dependence on the generalized and debilitating immunosuppressive regimens currently available. PUBLIC HEALTH RELEVANCE The main treatment for blindness caused by severe corneal scarring is corneal transplantation. Unfortunately, in patients where corneal scarring is associated with blood vessel formation, the rejection rate of the transplant is high. The experiments proposed in this application will examine how the recruitment of immune cells by chemokine signals is responsible for graft rejection. We believe that the local neutralization of these chemokines will be a novel form of therapy to keep corneal transplants clear and improve the visual outcome in patients with vascularized scarred corneas.