Chronic DTH and IFN-gamma in Human Graft Arterioscleros*

慢性迟发型超敏反应和干扰素-γ在移植物动脉硬化中的作用移植物动脉硬化(GA)是一种宿主抗移植物免疫介导的病变，以内膜扩张、血管重构(病理性重塑)和异常的血管调节为特征。GA是同种异体心脏移植物慢性排斥反应的基础，也是移植物失败的主要原因。目前还没有有效的治疗方法或手段来早期诊断这种不可抗拒的进行性疾病。GA的免疫致病机制(S)尚不清楚。我们早期对同种异体心脏移植物动脉的免疫细胞化学分析表明，动脉内膜中存在由非细胞溶解T细胞介导的慢性迟发性超敏反应(DTH)，似乎对永久性移植物内皮细胞(EC)表达的同种异体抗原发生反应。由于啮齿动物T细胞与EC的相互作用与人类截然不同，啮齿动物移植模型在探索免疫致病机制方面可能是有限的。我们最近的工作表明，干扰素-伽马，一种由T细胞产生的细胞因子，介导迟发性高血压(即Th1细胞)可以导致人类动脉的内膜扩张。在本项目中，我们将使用人动脉细胞和器官培养模型以及人动脉移植到SCID小鼠体内(由Core B生产)，以研究抗EC DTH的发展和慢性DTH对人血管的影响(项目1)，并阐明干扰素-γ诱导人动脉内膜扩张和其他变化的机制(项目2)。我们将通过与使用常规形态学(包括免疫荧光、免疫细胞化学和原位杂交)的人类GA样本(由Core D分析)以及激光捕获显微镜/逆转录聚合酶链式反应的比较来验证这些模型。这些研究将与形态计量学相辅相成，以评估血管重构和内膜连锁反应。这些研究将与形态计量学相补充，以评估血管重塑和内膜增生(由Core C进行)、血管功能的生理学评估(由Core C进行)以及分子表达谱分析(分别由项目3、Core D和Core进行的多肽噬菌体展示、SELDI/蛋白质芯片分析和RNA阵列分析)。最后，我们将使用我们的人体动脉异种移植和其他模型来开发基于病理生理过程而不是终末期结构变化的早期非侵入性GA的新方法(项目3)。这一主题整合计划的结果将为解决慢性同种异体移植排斥反应问题的新的和更有效的方法提供科学基础。

Chronic DTH and IFN-gamma in Human Graft Arteriosclerosis. Graft arteriosclerosis (GA) is a host anti-graft immune-mediated lesion characterized by intimal expansion, vessel construction (pathological remodeling) and abnormal vasoregulation. GA is the underlying basis of chronic cardiac allograft rejection and the leading cause of allograft failure. There is currently no effective therapy or means of early diagnosis of this inexorably progressive disease. The immunopathogenetic mechanism(s) of GA is unknown. Our early immunocytochemical analysis of cardiac allograft allograft arteries suggested the presence of a chronic delayed type hypersensitivity (DTH) reaction mediated by non-cytolytic T cells within the arterial intima that appeared to be reacting to alloantigens expressed on persistent graft endothelial cells (EC). Since interactions of rodent T cells with EC are profoundly different from those that occur in humans, rodent transplant models may be of limited us in exploring immune pathogenetic mechanisms. Our more recent work has suggested that IFN-gamma, a cytokine made by T cells that mediate DTH (I.e. TH1 cells) can cause intimal expansion of human arteries. In this program project we will employ human artery cell and organ culture models as well as human arteries xenografted into SCID mice (produced by Core B) to investigate the development of anti-EC DTH and effects of chronic DTH on human vessels (Project 1) and to elucidate the mechanisms by which IFN-gamma induces intimal expansion and other changes of human arteries (Project 2). We will validate these models by comparisons to human GA specimens (analyzed by Core D) using conventional morphology (including immunofluorescence, immunocytochemistry and in situ hybridization) as well as laser capture microscopy/reverse transcription- polymerase chain reaction. These studies will be complemented with morphometry to assess both vascular remodeling and intimal chain reaction. These studies will be complemented with morphometry to assess both vascular remodeling and intimal hyperplasia (conducted by Core C) and physiological assessment of vessel function (conducted by Core C) and molecular expression profiling (via peptide phage display, SELDI/ProteinChip analysis and RNA array analysis (conducted by Project 3, Core D and Core, respectively). Finally, we will use our human artery xenografts and other models to develop new approaches for early non-invasive of GA based upon pathophysiologic processes rather than end stage structural changes (Project 3). The results of this thematically integrated program will provide a scientific basis for new and more effective approaches to address the problem of chronic allograft rejection.