Virus Infections In The Eye

我们对病毒和寄生虫在眼部微环境中复制时发生的各种病毒学和免疫病理学过程的研究包括四个领域：（1）病毒诱导的视网膜变性过程;（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;以及（4）眼部疱疹病毒感染。我们建立了一个研究视网膜变性疾病的模型系统-实验性冠状病毒视网膜病变（ECOR）。该病毒能够在存在轻度视网膜血管炎症的情况下诱导急性感染。最初的视网膜损伤之后是感染性病毒的清除和进行性视网膜变性。这是第一个证明病毒诱导的变性、病毒持续存在、对病毒诱导的组织损伤的遗传易感性和病毒触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变性疾病的病理生理机制，并确定相关基因。在过去一年中，我们取得了以下主要成果。 我们评估了非常早期的细胞因子和趋化因子谱，作为冠状病毒感染的视网膜变性易感和视网膜变性抵抗背景的小鼠中免疫反应强度的量度。 这些研究确定了两种小鼠品系产生的早期免疫应答的明显差异。 这些差异在IFN-γ和由IFN-γ触发的两种趋化因子CXCL 9和CXCL 10的产生中被注意到。 在PI第2天和第3天，BALB/c小鼠在其血清中具有高水平的IFN-γ、CXCL 9和CXCL 10。 同时，在CD-1小鼠的血清中检测到这些分子的水平显著较低。 此外，视网膜的真实的时间PCR分析鉴定，与CD-1小鼠相比，来自BABL/c小鼠的视网膜中的CXCL 9和CXCL 10基因表达显著更高。 这些研究确实令人兴奋，并确定了可能的机制，使BALB/c小鼠具有强大的免疫反应，可以触发自身免疫成分。 CXCL 9和CXCL 10是与活化的T细胞和NK细胞上存在的CXCR 3相互作用的强效趋化因子。 它们引导这些细胞的迁移并刺激其粘附。 这些T细胞参与针对视网膜内的感染和自身靶标的免疫反应。 这些趋化因子已被证明是病毒感染如HSV角膜炎和SARS的关键因素。 事实上，在SARS中，感染后早期检测到的CXCL 10血清浓度是疾病结局的独立预后指标。 角膜疱疹感染会引发强烈的炎症反应，并最终导致潜伏病毒频繁重新激活的后遗症，从而导致危及视力的基质角膜炎。 单纯疱疹性角膜基质炎的病因被认为是异常的Th 1细胞因子介导的免疫病理学。我们评估了HSV感染人角膜上皮细胞和角膜成纤维细胞。我们发现HSV DNA导致TLR-3和9基因表达和IL-6释放增加。由于病毒通常以中和的病毒免疫复合物的形式存在，因此评价了这些免疫复合物与TLR相互作用并触发IL-6产生的能力。我们发现HSV-抗HSV IgG复合物在诱导IL-6的能力方面与HSV DNA一样有效。这些现象通过增强TLR-3和.9基因表达介导。 这些研究表明，沉积在角膜基质中的病毒DNA和/或免疫复合物可能在最初的急性病毒损伤消退很长时间后，通过TLR 3和9释放过量的细胞因子继续引发基质炎症。

Our studies of various virologic and immunopathologic processes that occur when viruses and parasites replicate in the ocular microenvironment comprise four 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; and (4) herpesvirus infections of the eye. We have established a model system for studying retinal degenerative diseases, experimental coronavirus retinopathy (ECOR). 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 evaluated very early cytokine and chemokine profiles as a measure of intensity of immune reactivity in coronavirus infected mice with a retinal degeneration susceptible and a retinal degeneration resistant background. These studies identified a distinct difference in the early immune response that is generated by the two mouse strains. These differences are noted in the production of IFN-gamma and the two chemokines triggered by IFN-gamma, CXCL9 and CXCL10. At day 2 and 3 PI, BALB/c mice have high levels of IFN-gamma, CXCL9 and CXCL10 in their sera. At the same time, significantly lower levels of these molecules are detected in sera from CD-1 mice. Moreover, real time PCR analysis of retinas identified that CXCL9 and CXCL10 gene expression is significantly greater in retinas from BABL/c mice in comparison to CD-1 mice. These studies are truly exciting and identify possible mechanisms that allow the BALB/c mouse to have a robust immune response that could trigger an autoimmune component. CXCL9 and CXCL10 are potent chemokines that interact with CXCR3 present on activated T cells and NK cells. They direct the migration and stimulate the adhesion of these cells. These T cells participate in immune reactivity against infected and self targets within the retina. These chemokines have been shown to be key elements in virus infections such as HSV keratitis and SARS. In fact, in SARS, serum concentrations of CXCL10 detected early after infection is an independent prognostic indicator of disease outcome. Corneal herpes infection elicits a robust inflammatory response and eventually leads to a vision-threatening stromal keratitis as a sequela of frequent reactivation of latent virus. The aetiology of herpetic stromal keratitis is thought to be an aberrant Th1 cytokine mediated immunopathology. We evaluated HSV infection in human corneal epithelial and corneal fibroblast cells. We found that HSV DNA resulted in augmented TLR-3 and 9 gene expression and IL-6 release. As virus is frequently in the form of neutralized virus immune complexes, the ability of these immune complexes to interact with TLRs and trigger IL-6 production was evaluated. We found that HSV-anti-HSV IgG complexes were as potent as HSV DNA in their ability to induce IL-6. These phenomena were mediated via augmented TLR-3 and .9 gene expression. These studies indicate that viral DNA and/or immune complexes deposited in corneal stroma may continue to trigger stromal inflammation by excessive cytokine release via TLR3 and 9 long after the initial acute viral insult has subsided.