Structure-function analysis of hepatitis C virus envelope-CD81 binding
Structure-function analysis of hepatitis C virus envelope-CD81 binding
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DOI：
10.1128/jvi.74.10.4824-4830.2000
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发表时间：
2000-05-01
影响因子：
5.4
通讯作者：
Grandi, G
中科院分区：
文献类型：
--
作者：
Petracca, R;Falugi, F;Grandi, G
丙型肝炎病毒（HCV）是导致慢性肝病的主要人类病原体。我们最近发现人类 CD81 的大细胞外环 (LEL) 与 HCV 结合。这一发现促使我们通过使用重组 E2 蛋白和重组可溶形式的 CD81 LEL 来评估 HCV-CD81 相互作用的结构功能特征。我们发现 HCV-E2 结合 CD81 LEL，K-d 为 1.8 nM； CD81可以介导E2在肝细胞上的附着；即使在 12 小时后，CD81 的参与也仅介导 30% 的 CD81 分子的内化； CD81 LEL的四个半胱氨酸形成两个二硫桥，其完整性对于CD81-HCV相互作用是必需的。总而言之，我们的数据表明，旨在干扰HCV与人类细胞结合的中和抗体应具有高于10(-9) M的亲和力，HCV与肝细胞的结合可能不完全依赖于CD81，CD81是介导病毒进入能力较差的附着受体，并且还原环境不利于CD81-HCV相互作用。这些研究提供了对 CD81-HCV 相互作用的更好理解，因此应有助于阐明病毒生命周期并开发旨在干扰 HCV 与人类细胞结合的新策略。
Hepatitis C virus (HCV) is a major human pathogen causing chronic liver disease. We have recently found that the large extracellular loop (LEL) of human CD81 binds HCV. This finding prompted us to assess the structure-function features of HCV-CD81 interaction by using recombinant E2 protein and a recombinant soluble form of CD81 LEL. We have found that HCV-E2 binds CD81 LEL with a K-d of 1.8 nM; CD81 can mediate attachment of E2 on hepatocytes; engagement of CD81 mediates internalization of only 30% of CD81 molecules even after 12 h; and the four cysteines of CD81 LEL form two disulfide bridges, the integrity of which is necessary for CD81-HCV interaction. Altogether our data suggest that neutralizing antibodies aimed at interfering with HCV binding to human cells should have an affinity higher than 10(-9) M, that HCV binding to hepatcytes may not entirely depend on CD81, that CD81 is an attachment receptor with poor capacity to mediate virus entry, and that reducing environments do not favor CD81-HCV interaction. These studies provide a better understanding of the CD81-HCV interaction and should thus help to elucidate the viral life cycle and to develop new strategies aimed at interfering with HCV binding to human cells.