Yang Guang, Pevear Daniel C, Davies Marc H, Collett Marc S, Bailey Tom, Rippen Susan, Barone Linda, Burns Chris, Rhodes Gerry, Tohan Sanjeev, Huggins John W, Baker Robert O, Buller R L Mark, Touchette Erin, Waller Kem, Schriewer Jill, Neyts Johan, DeClercq Erik, Jones Kevin, Hruby Dennis, Jordan Robert
ViroPharma, Inc., Exton, Pennsylvania, USA.
J Virol. 2005 Oct;79(20):13139-49. doi: 10.1128/JVI.79.20.13139-13149.2005.
ST-246 is a low-molecular-weight compound (molecular weight = 376), that is potent (concentration that inhibited virus replication by 50% = 0.010 microM), selective (concentration of compound that inhibited cell viability by 50% = >40 microM), and active against multiple orthopoxviruses, including vaccinia, monkeypox, camelpox, cowpox, ectromelia (mousepox), and variola viruses. Cowpox virus variants selected in cell culture for resistance to ST-246 were found to have a single amino acid change in the V061 gene. Reengineering this change back into the wild-type cowpox virus genome conferred resistance to ST-246, suggesting that V061 is the target of ST-246 antiviral activity. The cowpox virus V061 gene is homologous to vaccinia virus F13L, which encodes a major envelope protein (p37) required for production of extracellular virus. In cell culture, ST-246 inhibited plaque formation and virus-induced cytopathic effects. In single-cycle growth assays, ST-246 reduced extracellular virus formation by 10 fold relative to untreated controls, while having little effect on the production of intracellular virus. In vivo oral administration of ST-246 protected BALB/c mice from lethal infection, following intranasal inoculation with 10x 50% lethal dose (LD(50)) of vaccinia virus strain IHD-J. ST-246-treated mice that survived infection acquired protective immunity and were resistant to subsequent challenge with a lethal dose (10x LD(50)) of vaccinia virus. Orally administered ST-246 also protected A/NCr mice from lethal infection, following intranasal inoculation with 40,000x LD(50) of ectromelia virus. Infectious virus titers at day 8 postinfection in liver, spleen, and lung from ST-246-treated animals were below the limits of detection (<10 PFU/ml). In contrast, mean virus titers in liver, spleen, and lung tissues from placebo-treated mice were 6.2 x 10(7), 5.2 x 10(7), and 1.8 x 10(5) PFU/ml, respectively. Finally, oral administration of ST-246 inhibited vaccinia virus-induced tail lesions in Naval Medical Research Institute mice inoculated via the tail vein. Taken together, these results validate F13L as an antiviral target and demonstrate that an inhibitor of extracellular virus formation can protect mice from orthopoxvirus-induced disease.
ST - 246是一种低分子量化合物（分子量 = 376），具有强效（抑制病毒复制50%的浓度 = 0.010微摩尔）、选择性（抑制细胞活力50%的化合物浓度 = >40微摩尔），且对多种正痘病毒具有活性，包括痘苗病毒、猴痘病毒、骆驼痘病毒、牛痘病毒、埃可病毒（鼠痘病毒）和天花病毒。在细胞培养中选择出的对ST - 246具有抗性的牛痘病毒变体，其V061基因发生了单个氨基酸变化。将此变化重新引入野生型牛痘病毒基因组可赋予其对ST - 246的抗性，这表明V061是ST - 246抗病毒活性的靶点。牛痘病毒V061基因与痘苗病毒F13L同源，后者编码产生细胞外病毒所需的一种主要包膜蛋白（p37）。在细胞培养中，ST - 246抑制蚀斑形成和病毒诱导 cytopathic 效应。在单周期生长试验中，相对于未处理的对照，ST - 246使细胞外病毒形成减少了10倍，而对细胞内病毒的产生影响很小。在体内，经鼻接种10×50%致死剂量（LD(50)）的痘苗病毒株IHD - J后，口服ST - 246可保护BALB/c小鼠免受致死性感染。感染后存活的经ST - 246处理的小鼠获得了保护性免疫，并且对随后用致死剂量（10×LD(50)）的痘苗病毒进行的攻击具有抗性。经鼻接种40,000×LD(50)的埃可病毒后，口服ST - 246也可保护A/NCr小鼠免受致死性感染。在感染后第8天，经ST - 246处理的动物肝脏、脾脏和肺中的感染性病毒滴度低于检测限（<10 PFU/ml）。相比之下，安慰剂处理小鼠的肝脏、脾脏和肺组织中的平均病毒滴度分别为6.2×10(7)、5.2×10(7)和1.8×10(5) PFU/ml。最后，口服ST - 246可抑制通过尾静脉接种的海军医学研究所小鼠中痘苗病毒诱导的尾部病变。综上所述，这些结果验证了F13L作为抗病毒靶点，并证明细胞外病毒形成抑制剂可保护小鼠免受正痘病毒诱导的疾病。
