The Effects of Cytomegalovirus on Organ Transplant Rejection

项目摘要 移植慢性排斥反应占心脏移植后患者死亡的30%。的标志 实体器官移植慢性排斥反应（CR）的病变是移植血管硬化（TVS）。TVS加速 移植部位的炎症和免疫反应。影响炎症免疫的因素很多 移植物附近的环境，以促进慢性排斥反应。其中一个特别感兴趣的因素是感染 人巨细胞病毒（HCMV）。因为大约75%的人类移植供体/受体 当人群对HCMV呈阳性时，开发减轻HCMV影响的新疗法对于 治疗接受HCMV+供体器官的移植受者，以提高移植物存活率并预防CR。然而，在这方面， 与HCMV加速同种异体移植物TVS和CR相关的病毒机制知之甚少。一 更好地理解这些机制对于提高移植存活率和生活质量至关重要 患者 目前的文献表明，增强对病毒和移植物的免疫应答是 导致早期移植物破坏和促进同种异体移植疾病的病毒加速。主机 趋化因子通过募集和激活免疫细胞促进移植排斥反应，从而表明病毒性 编码的趋化因子也可能在促进移植排斥中起作用。已知HCMV可调节 通过诱导感染后的趋化因子表达来调节趋化因子轴，并编码多种趋化因子， 趋化因子受体，包括趋化因子UL 128和UL 130。然而，这些趋化因子 在病毒发病机制和加速移植排斥反应中的作用仍然知之甚少， 我们的研究。我们将使用体外试验模拟大鼠心脏移植来研究这些关系 用RCMV感染的模型和移植前对心脏组织的细胞浸润的体内研究， 利用HCMV UL 130的RCMV同源物，RCMV R131。特别是，我们假设病毒- 编码的CC-趋化因子R131促进免疫细胞迁移并增加免疫细胞浸润， 移植，这可能会导致炎症和加速TVS移植后，在体内 大鼠心脏移植模型我们的第二个假设是R131在PEC中具有与UL 130相似的作用。 介导的进入巨噬细胞和内皮细胞，这可能会促进病毒在体内的广泛传播。 同种异体移植物，增强移植物疾病。我们将在具体目标1中通过定义后处理这些假设。 通过鉴定RCMV R131内存在的介导迁移的基序， 在体外和体内。我们的目标是产生一组缺乏趋化活性的病毒突变体。具体目标 2、明确R131在巨噬细胞和内皮细胞中的作用以及R131对巨噬细胞和内皮细胞的影响。 体内致病突变。在具体目标3中，我们将确定R131突变的程度， 可能影响心脏移植物的存活和病理学。

Project Summary Transplant chronic rejection accounts for 30% of patient deaths following cardiac transplantation. The hallmark lesion of solid-organ allograft chronic rejection (CR) is transplant vascular sclerosis (TVS). TVS is accelerated by inflammation and immune response at graft sites. Many factors influence the inflammatory immune environment near a graft to promote chronic rejection. One such factor of particular interest is infection with Human Cytomegalovirus (HCMV). Because approximately 75% of the human transplant donor/recipient population is positive for HCMV, the development of novel therapies that mitigate HCMV effects is critical to treat transplant recipients receiving HCMV+ donor organs to increase graft survival and prevent CR. However, the viral mechanisms associated with HCMV-acceleration of allograft TVS and CR are poorly understood. A better understanding of these mechanisms is critical to improving survival and quality of life for transplant patients. Current literature suggests that enhancement of the immune response both against the virus and the graft are leading candidates for early graft destruction and promote viral-acceleration of allograft disease. Host chemokines promote graft rejection by recruiting and activating immune cells, thereby suggesting that virally encoded chemokines may also play a role in promoting graft rejection. HCMV is known to modulate the chemokine axis by inducing chemokine expression following infection, and to encode multiple chemokines and chemokine receptors, including the chemokines UL128 and UL130. However, the role that these chemokines play in viral pathogenesis and acceleration of transplant rejection remains poorly understood, and is the focus of our research. We will investigate these relationships using in vitro assays mimicking a rat cardiac transplant model with RCMV infection and in vivo studies for cellular infiltrate to cardiac tissue prior to transplantation, utilizing the RCMV homologue of HCMV UL130, RCMV R131. In particular, we hypothesize that the virally- encoded CC-chemokine R131 promotes immune cell migration and increases immune cell infiltrate prior to transplantation, which may lead to inflammation and acceleration of TVS following transplantation in an in vivo rat cardiac transplantation model. Our second hypothesis is that R131 has a similar role as UL130 in PEC- mediated entry into macrophages and endothelial cells, which may foster widespread viral dissemination in the allograft, enhancing graft disease. We will address these hypotheses in Specific Aim 1 by defining post- translational modifications to R131 and by identifying motifs present within RCMV R131 that mediate migration in vitro and in vivo. Our goal is to generate a panel of viral mutants that lack chemotactic activity. In Specific Aim 2, we will define the role of R131 in entry into macrophages and endothelial cells and the impacts of R131 mutations in pathogenesis in vivo. In Specific Aim 3, we will determine the degree to which mutations in R131 may affect survival of and pathology in cardiac allografts.