Novel mechanism of inhibition of cytomegalovirus by the experimental immunosuppressive agent leflunomide.
Novel mechanism of inhibition of cytomegalovirus by the experimental immunosuppressive agent leflunomide.
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DOI：
10.1097/00007890-199909270-00014
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发表时间：
1999-09
期刊：
影响因子：
6.2
通讯作者：
Waldman Wj;Deborah A. Knight;N. Lurain;Daniel M. Miller;Daniel D. Sedmak;James W. Williams;Anita S. Chong
中科院分区：
文献类型：
--
作者：
Waldman Wj;Deborah A. Knight;N. Lurain;Daniel M. Miller;Daniel D. Sedmak;James W. Williams;Anita S. Chong
尽管抗病毒化疗取得了进展，但巨细胞病毒（CMV）仍然是免疫抑制器官移植受者发病和死亡的主要原因，临床医生经常在平衡移植物保存与控制CMV疾病之间进行斗争。来氟米特是一种蛋白激酶活性和嘧啶合成抑制剂，是一种实验性免疫抑制剂，在动物模型中可有效对抗急性和慢性同种异体移植排斥反应。由于已知许多CMV蛋白质被磷酸化，我们测试了该试剂可能对CMV发挥抑制活性的假设。方法和结果空斑试验表明，来氟米特处理的人成纤维细胞和内皮细胞（体内CMV感染的常见靶细胞）中多种临床CMV分离株的产生呈显著的剂量依赖性衰减。如北方印迹分析和免疫组化染色所示，来氟米特既不干扰即刻早期或晚期病毒基因的转录，也不干扰相应蛋白的表达。CMV特异性DNA斑点印迹和生化酶分析表明，与目前批准的抗CMV药物相比，来氟米特对感染细胞中病毒DNA的积累或病毒DNA聚合酶活性没有抑制作用。相反，如通过透射电子显微镜观察到的，该药剂似乎通过防止病毒核衣壳获得被膜而在病毒体组装的后期起作用。最后，我们证明了来氟米特对多药耐药CMV分离株的等效抑制活性。结论：这些发现表明，来氟米特，一种有效的免疫抑制剂，显示出潜在的同时减轻免疫抑制的主要并发症，CMV疾病，通过一种新的抗病毒活性机制。
BACKGROUND Despite progress in antiviral chemotherapy, cytomegalovirus (CMV) remains a major cause of morbidity and mortality among pharmacologically immunosuppressed organ transplant recipients, frequently engaging the clinician in a struggle to balance graft preservation with control of CMV disease. Leflunomide, an inhibitor of protein kinase activity and pyrimidine synthesis, is an experimental immunosuppressive agent effective against acute and chronic allograft rejection in animal models. Because a number of CMV proteins are known to be phosphorylated, we tested the hypothesis that this agent might exert inhibitory activity against CMV. METHODS AND RESULTS Plaque assays demonstrated dramatic dose-dependent attenuation of production of multiple clinical CMV isolates in leflunomide-treated human fibroblasts and endothelial cells, common targets for CMV infection in vivo. As shown by Northern blot analysis and immunohistochemical staining, leflunomide neither interferes with transcription of immediate early or late viral genes, nor with expression of corresponding proteins. CMV-specific DNA dot blots and biochemical enzyme assays indicated that, in contrast to currently approved anti-CMV drugs, leflunomide exerts no inhibitory effect on the accumulation of viral DNA in infected cells, or on viral DNA polymerase activity. Rather, as visualized by transmission electron microscopy, this agent appears to act at a late stage in virion assembly by preventing tegument acquisition by viral nucleocapsids. Finally we have demonstrated equivalent inhibitory activity of leflunomide against multi-drug-resistant CMV isolates. CONCLUSIONS These findings imply that leflunomide, an effective immunosuppressive agent, shows potential to concurrently attenuate a major complication of immunosuppression, CMV disease, by a novel mechanism of antiviral activity.