Virus Infections In The Eye

我们对病毒和寄生虫在眼睛微环境中复制时发生的各种病毒学和免疫病理过程的研究包括五个方面：(1)病毒诱导的视网膜退化过程；(2)病毒在人类疾病中的可能作用；(3)人类巨细胞病毒(CMV)感染的分子诊断和发病机制；(4)眼睛的疱疹病毒感染；(5)视网膜的弓形虫感染。我们已经建立了一个研究视网膜退行性疾病的模型系统-实验性冠状病毒视网膜病变(ECR)。该病毒能够在存在轻度视网膜血管炎症的情况下引发急性感染。最初的视网膜损伤之后是感染性病毒的清除和进行性的视网膜变性。这是第一个显示病毒引起的变性、病毒持久性、对病毒引起的组织损伤的遗传易感性和病毒引发的自身免疫反应的视网膜模型。我们的目标是确定视网膜退行性疾病的病理生理机制，并确定与之相关的基因。在过去的一年里，我们取得了以下重要发现。我们证明了非溶细胞性视网膜抗病毒反应的重要性和关键作用。这些研究表明，T细胞渗入视网膜产生的干扰素-g是免疫机制的重要组成部分，该免疫机制负责将传染性病毒从视网膜上清除出去。此外，这些研究突出了干扰素-g药物对不可再生细胞中病毒的非细胞溶解清除的明显优势。人类巨细胞病毒是一种疱疹病毒，是先天性感染儿童和免疫功能受损儿童失明的主要原因。人类巨细胞病毒潜伏期的研究比较困难。因此，CMV复制和潜伏期的细胞培养模型可能为替代治疗方式提供理论基础。为了了解巨细胞病毒在视网膜组织中的趋向性，我们扩展了我们最初对巨细胞病毒在hRPE中复制的研究，以评估反义治疗策略。针对CMV的反义寡核苷酸已经被开发出来，并针对与CMV的主要即时早期转录单位互补的病毒mRNA。我们的研究表明，hRPE细胞对ISIS第一代和第二代反义寡核苷酸的抗病毒作用明显比成纤维细胞敏感。这些寡核苷酸在hRPE细胞中的增强效力可能与病毒基因转录的延迟以及病毒在这些细胞中的缓慢复制和传播有关。这些研究表明，该CMV RPE细胞模型系统可用于评估病毒复制和反义寡核苷酸抗病毒治疗的有效性。 我们已经开发了使用聚合酶链式反应分析检测疱疹病毒的分子诊断方法。这些检测方法被用来区分感染性和免疫性眼球后段炎症。

Our studies of various virologic and immunopathologic processes that occur when viruses and parasites replicate in the ocular microenvironment comprise five areas: (1) virus induced retinal degenerative processes; (2) the possible roles of viruses in human diseases; (3) molecular diagnosis and pathogenesis of cytomegalovirus (CMV) infections in man; (4) herpesvirus infections of the eye and (5) Toxoplasma gondii infections of the retina. We have established a model system for studying retinal degenerative diseases, experimental coronavirus retinopathy (ECR). The virus is capable of inducing an acute infection in the presence of mild retinal vascular inflammation. Initial retinal damage is followed by clearance of infectious virus and progressive retinal degeneration. This is the first retinal model to demonstrate a virus induced degeneration, viral persistence, a genetic predisposition to virus induced tissue damage and a virus triggered autoimmune response. Our goal is to determine the pathophysiological mechanisms and to identify genes involved in the retinal degenerative disease. During the past year we have made the following key findings. We demonstrated the importance and critical role of the non-cytolytic retinal antiviral responses. These studies indicate that generation of IFN-g by T cells infiltrating the retina is an essential part of an immune mechanism responsible for noncytolytic clearance of infectious virus from the retina. Moreover, these studies highlight the distinct advantage of IFN-g medicated noncytolytic clearance of virus from cells that are non-renewable. Human CMV is a herpesvirus that is a major cause of blindness in children born with congenital infections and in immunocompromised individuals. It is difficult to study CMV latency in man. Therefore cell culture models of CMV replication and latency may provide insight into a rationale for alternative treatment modalities. In order to understand the retinal tissue tropism for CMV, we have extended our original studies of CMV replication in HRPE to evaluate antisense treatment strategies. Antisense oligonucleotides specific for treatment of CMV have been developed and target the viral mRNA complementary to the major immediate early transcription unit of CMV. Our studies demonstrate that HRPE cells were significantly more sensitive than fibroblasts to the antiviral actions of ISIS 1st and 2nd generation antisense oligonucleotides. The enhanced potency of these oligonucleotides in HRPE cells may be associated with a delay in viral gene transcription and slow viral replication and spread in these cells. These studies demonstrate the utility of this CMV RPE cell model system to evaluate virus replication and efficacy of antiviral therapy with antisense oligonucleotides. We have developed molecular diagnostic methods using PCR analysis to detect herpesviruses. These assays are being used to distinguish between infectious and immunopathogenic posterior segment intraocular inflammation.