Antiviral activity of leflunomide against respiratory syncytial virus

呼吸道同步病毒(RSV)是导致婴儿和婴儿肺部疾病的主要原因，通常严重，危及生命 幼儿，免疫抑制的器官移植接受者，囊性纤维化患者， 先天性心脏病和老年人。目前还没有有效的疫苗可以预防呼吸道合胞病毒 疾病。利巴韦林，唯一被批准的抗病毒药物，必须雾化吸入12至18年 每天持续3至7天，仅有轻微效果，并未被证明能显著降低死亡率 与呼吸道合胞病毒病有关。而用高免球蛋白或单抗进行被动免疫预防 抗体已被证明在某些情况下可以减轻疾病的严重程度，但令人满意的抗病毒治疗尚未到位。 已实现。来氟米特是一种嘧啶合成和蛋白激酶活性的抑制剂，是一种抗炎药物。 一种被批准用于治疗类风湿性关节炎的药物，目前正在作为免疫抑制剂进行临床试验 在移植受者身上。这种药物已被证明对巨细胞病毒有很强的抗病毒活性。 在体外和体内，以及在体外和体内抗RSV的初步研究。这样做的具体目的是 研究旨在验证来氟米特降低RSV病毒载量和相关毛细支气管炎的假设 并从分子水平阐明其抗病毒机制。棉鼠接种RSV和 用来氟米特、利巴韦林、帕利维珠单抗或这些药物的组合治疗将在 不同的时间间隔。病毒载量将通过肺匀浆空斑分析、组织损伤和 肺部炎症将通过肺组织的组织学和免疫组织化学分析进行评估。 呼吸道合胞病毒感染动物的免疫状态将通过脾细胞增殖反应来评估 RSV抗原。分子抗病毒机制将通过病毒的实时定量RT-PCR检测来阐明 病毒蛋白的基因组RNA合成与转录、免疫沉淀及蛋白质印迹分析 合成和磷酸化，以及免疫金电子显微镜。这些研究产生的数据包括 预计将证明来氟米特在降低病毒载量和 主要引起呼吸道合胞病毒病的严重炎症反应同时减弱 表现形式。此外，阐明这种药物的分子抗病毒机制可能会识别出新的 未来抗病毒药物开发的目标。

Respiratory synctial virus (RSV) is a major cause of often serious, life-threatening lung disease in infants and young children, immunosuppressed organ transplant recipients, patients suffering from cystic fibrosis, congenital heart disease, and the elderly. No effective vaccine is currently available for prevention of RSV disease. Ribavirin, the only approved antiviral therapy, which must be administered by aerosol for 12 to 18 hours/day for 3 to 7 days, is only marginally effective and has not been shown to significantly reduce mortality associated with RSV disease. While passive immunoprophylaxis with hyperimmune globulin or monoclonal antibody has been shown to reduce disease severity in some cases, satisfactory antiviral therapy has yet to be achieved. Leflunomide, an inhibitor of pyrimidine synthesis and protein kinase activity, is an anti-inflammatory agent approved for treatment of rheumatoid arthritis and is currently in clinical trials as an immunosuppressant in transplant recipients. This agent has been shown to exert powerful antiviral activity against cytomegalovirus in vitro and in vivo, and in preliminary in vitro and in vivo studies against RSV. The specific aims of this investigation are to test the hypothesis that leflunomide reduces RSV viral load and associated bronchiolitis in vivo, and to elucidate its antiviral mechanisms at the moleclular level. Cotton rats inoculated with RSV and treated with leflunomide, ribavirin, Palivizumab, or combinations of theses agents will be euthanized at various intervals. Viral loads will be quantitated by plaque assay of lung homogenates, and tissue injury and pulmonary inflammation will be assessed by histologic and immunohistochemical analysis of lung tissue. Immune status of RSV-infected animals will be assessed by proliferation assays of splenocyte responses to RSV antigen. Molecular antiviral mechanisms will be elucidated by quantitative real time rtPCR assays of viral genomic RNA synthesis and transcription, immunoprecipitation and western blot analysis of viral protein synthesis and phosphorylation, and immunogold electron microscopy. Data generated by these studies are anticipated to demonstrate the bifunctional utility of leflunomide in both the reduction in viral load and the concurrent attenuation of the severe inflammatory reaction primarily responsible for RSV disease manifestations. Furthermore, elucidation of the molecular antiviral mechanisms of this agent may identify novel targets for future antiviral drug development.