Composite Allografting for Promoting Survival of Corneal Transplants

描述（由申请人提供）：角膜移植是角膜失明患者恢复视力的主要方式，角膜失明是全球第二大致盲原因。然而，在炎症（或“高风险”）移植床中，超过50%的角膜异体移植失败，尽管最大程度的免疫抑制。这种发生率完全被简单（或“低风险”）移植床的成功移植率所掩盖，在局部类固醇的掩护下，移植失败率仅为10%。同种异体角膜移植的上皮在同种异体免疫中具有“矛盾”的特性：虽然它作为功能性屏障和构成性炎症调节/抑制因子，但它也携带着显著的同种异体抗原负荷。后一种特性导致宿主对移植物的同种异体抗原敏感，重要的是，这些同种异体抗原与移植物角膜内皮共享，这是排斥反应的关键靶点。因此，复合移植物，由异体供体上皮覆盖的同种异体内皮组成，可能会使受体对移植物内皮不共享的第三方同种异体抗原敏感。因此，我假设在高风险移植模型中，这种策略将减少对移植物内皮的同种异体敏化，并促进移植物的存活。此外，这将提供上皮屏障功能以及免疫调节因子的补充，以最大限度地促进同种异体移植物的存活。因此，这项研究的长期目标是使用这种复合移植物来促进移植物的存活，这是与国家眼科研究所的使命相关的目标，也是临床领域高度可行的策略。在Specific Aim 1中，我建议研究移植物上皮与基质内皮在高危宿主中的作用。这将在体内通过原位鉴定同种异体致敏，以及通过开发体外试验来测量同种异体致敏，随后在体内环境中进行验证。在Specific Aim 2中，我提议测试这种复合移植物是否能促进角膜移植存活。这将通过测量移植物中T细胞的浸润，通过过继转移试验评估效应T细胞的体内功能，最后通过生物显微镜测量移植物的存活率来测试。描述：对于严重炎症的眼睛（所谓的“高风险”宿主），角膜移植的成功率非常低。这些眼睛很容易移植失败，因为在移植器官上产生了一种叫做“异体抗原”的蛋白质。在本提案中，我将测试排除这些同种异体抗原的移植重建是否会促进小鼠的移植存活。C

DESCRIPTION (provided by applicant): Keratoplasty is the principal modality by which vision is restored in corneal blindness-the 2nd leading cause of blindness worldwide. Nevertheless, greater than 50% of corneal allografts placed in inflamed (or 'high-risk') graft beds fail despite maximal immune suppression. This incidence is completely overshadowed by the successful transplantation rates experienced in uncomplicated (or 'low-risk') graft beds, which boast a failure rate of only10% under cover of topical steroids. The epithelium of a corneal allograft has 'paradoxical' properties in alloimmunity: while it serves as a functional barrier and constitutive inflammation regulator/suppressor, it also carries a significant alloantigenic load. The latter property results in sensitization of the host against alloantigens of the graft, and importantly, these alloantigens are shared by the graft corneal endothelium-the critical target in rejection. It is therefore likely that composite grafts, consisting of allogeneic stoma-endothelium covered by an allodisparate 3rd-party donor epithelium, will sensitize the recipient to 3rd-party alloantigens-which are not shared by graft endothelium. I therefore hypothesize that this strategy will diminish allosensitization to graft endothelium and promote graft survival in a model of high-risk transplantation. Furthermore, this will provide epithelial barrier function along with the compliment of immunoregulatory factors to maximally promote allograft survival. Hence, the long-term objective of this study, which is to use such composite grafts to promote graft survival, is a goal relevant to the National Eye Institute mission and a highly feasible strategy in the clinical realm. In Specific Aim 1, I propose to examine the poorly understood roles of graft epithelium versus stroma- endothelium in high-risk hosts. This will be tested in vivo by identifying allosensitization in situ, as well as through the development of an in vitro assay to measure allosensitization, and subsequently verified in an in vivo setting. In Specific Aim 2, I propose to test whether such composite grafts promote corneal transplant survival. This will be tested by measuring T cell infiltration into the graft, assessing in vivo function of effector T cells via adoptive transfer assays, and finally the measurement of graft survival via biomicroscopy. LAY DESCRIPTION: Success rates for corneal transplantation are very poor in eyes with severe inflammation (so-called 'high-risk' hosts). These eyes are prone to graft failure by arousing certain proteins called 'alloantigens' on the transplant. In this proposal, I will test whether the reconstruction of transplants to exclude such alloantigens will promote transplant survival in mice. C