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。在过去的一年中，我们继续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抗性背景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细胞上的CXCR 3相互作用的强效趋化因子。这些T细胞参与针对视网膜内感染和自身靶点的免疫反应。 角膜疱疹病毒感染引起强烈的炎症反应，并最终导致危及视力的基质角膜炎，这是潜伏病毒频繁再激活的后遗症。 单纯疱疹性角膜基质炎（HSK）的病因被认为是异常的TH 1细胞因子介导的免疫病理学。 最近，我们发现HSV-DNA和HSV-IgG IC在眼部微环境中的持续存在可能有助于在HSK中观察到的血管生成和炎症，并且细胞因子和TLR可能是潜在的干预靶点。在过去的一年中，我们已经确定了协会的HHV-6和/或其他人类疱疹病毒在角膜炎症使用聚合酶链反应（PCR）。 我们评估了22例角膜炎症患者。 其中HHV-6阳性14例，HSV-1阳性9例。 仅5例患者疱疹病毒DNA阴性。 这些结果表明，大多数角膜炎症与疱疹病毒有关，并且HHV-6与疾病的关联比与其他疱疹病毒的关联更频繁。 而47例正常人泪液中未检出HHV-6 DNA。 当HSV-1触发角膜炎症时，浸润的T细胞或巨噬细胞可能携带HHV-6。 HHV-6诱导的免疫抑制活性可能进一步促进HSV-1的复制。 我们还观察到HHV-6，但不是HSV-1的DNA在涂片标本从12例患者中的5。 这些后者的数据表明，HHV-6本身可能是角膜炎症的另一种致病因子。 HHV-6是旁观者还是真正的病理因子的问题仍有待进一步阐明。

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 continued to 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 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.These T cells participate in immune reactivity against infected and self targets within the retina. 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 (HSK) is thought to be an aberrant TH1 cytokine mediated immunopathology. Recently, we identified that the continued presence of HSV-DNA and HSV-IgG IC within the ocular microenvironment may contribute to angiogenesis and inflammation observed in HSK, and cytokines and TLRs may be potential targets for intervention. During the past year we have determined the association of HHV-6 and/or other human herpesviruses in corneal inflammation using polymerase chain reaction (PCR). We evaluated 22 patients with corneal inflammation. Among them, HHV-6 was positive in 14 out of 22 patients, and HSV-1 was found in 9 of those patients. Only 5 patients were negative for herpesvirus DNA. These results indicated that the majority of the corneal inflammation was related to herpesviruses, and that the association of HHV-6 with disease was more frequent that with other herpesviruses. In contrast, HHV-6 DNA was not detected in 47 tear samples obtained from normal individuals. When HSV-1 triggers corneal inflammation, infiltrated T cells or macrophages may carry HHV-6. The immune suppressive activities induced by HHV-6 may further facilitate HSV-1 replication. We also observed HHV-6 but not HSV-1 DNA in smear samples from 5 of 12 patients. These latter data indicate that HHV-6 may be another causative agent by itself in corneal inflammation. The issue of whether HHV-6 is a bystander or true pathological agent remains to be further elucidated.