Inhibition of respiratory syncytial virus in vitro and in vivo by the immunosuppressive agent leflunomide
Inhibition of respiratory syncytial virus in vitro and in vivo by the immunosuppressive agent leflunomide
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DOI：
10.3851/imp1763
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发表时间：
2011-01-01
影响因子：
1.2
通讯作者：
Waldman, W. James
中科院分区：
文献类型：
--
作者：
Dunn, Melinda C. Cox;Knight, Deborah A.;Waldman, W. James
背景：呼吸道合胞病毒（RSV）是全世界婴幼儿毛细支气管炎和肺炎的主要原因，并且常常是骨髓、实体器官移植、囊性纤维化和先天性心脏病患者以及老年人呼吸道疾病的感染原因。治疗选择仅限于效果有限的利巴韦林和非常昂贵的被动免疫预防。免疫抑制剂来氟米特已被证明对多种疱疹病毒和多瘤病毒 BK 具有有效的抗病毒活性。在当前的研究中，我们测试了来氟米特对 RSV 具有抗病毒活性的假设。方法：用 RSV 接种人 Hep-2 或小气道上皮细胞，并用来氟米特的活性代谢物 A77 1726 处理。通过免疫组织化学染色评估合胞体形成，并通过噬斑测定测量病毒产量。棉鼠鼻内接种 RSV，用来氟米特灌胃处理，并通过肺匀浆斑块测定法测量肺部病毒载量。 结果：相差显微镜和免疫组织化学染色表明，在用 A77 1726（来氟米特的活性代谢物）处理的感染培养物中，RSV 诱导的合胞体形成显着减弱。 RSV 接种细胞培养物中病毒产量的空斑测定表明，A77 介导的有效、剂量依赖性抗病毒活性。同样，即使来氟米特治疗延迟到接种后第 3 天，与媒介物处理的对照组相比，来氟米特接种 RSV 接种的棉鼠的肺部病毒载量也减少了 3 个对数以上。 结论：这些发现表明，来氟米特有望成为不断增长的抗病毒治疗库中一种方便的口服补充药物。虽然具体的抗病毒机制仍有待阐明，但来氟米特显示出独特的双功能潜力，既可以减少病毒载量，又可以凭借其有据可查的抗炎活性，减轻与 RSV 疾病相关的破坏性炎症。
Background: Respiratory syncytial virus (RSV) is the primary cause of bronchiolitis and pneumonia in infants and young children worldwide and is often the cause of infections in bone marrow, solid organ transplant, cystic fibrosis and congenital heart disease patients, as well as respiratory tract disease in elderly adults. Treatment options are limited to ribavirin, which is only marginally effective, and passive immunoprophylaxis, which is very expensive. The immunosuppressive agent leflunomide has been shown to exert potent antiviral activity against several herpesviruses and polyomavirus BK. In the current study we have tested the hypothesis that leflunomide exerts antiviral activity against RSV.Methods: Human Hep-2 or small airway epithelial cells were inoculated with RSV and treated with A77 1726, the active metabolite of leflunomide. Syncytia formation was assessed by immunohistochemical staining, and virus yield was measured by plaque assay. Cotton rats were intranasally inoculated with RSV, treated with leflunomide by gavage, and pulmonary viral loads were measured by plaque assay of lung homogenates.Results: Phase contrast microscopy and immunohistochemical staining demonstrated profound attenuation of RSV-induced syncytia formation in infected cultures treated with A77 1726, the active metabolite of leflunomide. Plaque assays of virus yield in RSV-inoculated cell cultures demonstrated potent, dose-dependent A77-mediated antiviral activity. Likewise, pulmonary viral loads in RSV-inoculated cotton rats were reduced by >3 log by leflunomide compared with vehicle-treated controls, even when leflunomide treatment was delayed until day 3 post-inoculation.Conclusions: These findings suggest promise for leflunomide as a convenient, orally administered addition to the growing arsenal of antiviral therapeutics. While specific antiviral mechanisms remain to be elucidated, leflunomide shows unique bifunctional potential to both reduce viral load and, by virtue of its well-documented anti-iniflammatory activity, attenuate the destructive inflammation associated with RSV disease.