Functional characterization of intracellular and secreted forms of a truncated hepatitis C virus E2 glycoprotein
Functional characterization of intracellular and secreted forms of a truncated hepatitis C virus E2 glycoprotein
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DOI：
10.1128/jvi.74.2.702-709.2000
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发表时间：
2000-01-01
影响因子：
5.4
通讯作者：
McKeating, JA
中科院分区：
文献类型：
--
作者：
Flint, M;Dubuisson, J;McKeating, JA
丙型肝炎病毒(HCV)的E2蛋白被认为是一种病毒粒子表面糖蛋白，是抗病毒疫苗的候选成分。最近发现一个截短的可溶版本的E2与CD81相互作用，这表明该蛋白可能是丙型肝炎病毒受体的一个组成部分。当在真核细胞中表达时，相当大比例的E2会形成错误折叠的聚集体。为了分析E_2与CD81相互作用的特异性，用高压液相色谱分离了截短的E_2糖蛋白(E_2(661))的聚集态和单体形式，并分析了它与CD81的结合。非聚集形式的E2优先结合CD81和一些构象依赖的单抗(MAb)。此外，细胞内形式的E2(661)与CD81结合的亲和力高于细胞外形式。细胞内和分泌型E2(661)与单抗和人血清的反应性也不同，这与抗原性的不同是一致的。综上所述，这些数据表明，E2的适当折叠对于其与CD81的相互作用是重要的，并且多糖的修饰可以调节这种相互作用。确定具有生物活性的E2形式将有助于未来设计预防丙型肝炎病毒感染的疫苗。
The E2 protein of hepatitis C virus (HCV) is believed to be a virion surface glycoprotein that is a candidate for inclusion in an antiviral vaccine. A truncated soluble version of E2 has recently been shown to interact with CD81, suggesting that this protein may be a component of the receptor for HCV. When expressed in eukaryotic cells, a significant proportion of E2 forms misfolded aggregates. To analyze the specificity of interaction between E2 and CD81, the aggregated and monomeric forms of a truncated E2 glycoprotein (E2(661)) were separated by high-pressure liquid chromatography and analyzed for CD81 binding. Nonaggregated forms of E2 preferentially bound CD81 and a number of conformation-dependent monoclonal antibodies (MAbs). Furthermore, intracellular forms of E2(661) were found to bind CD81 with greater affinity than the extracellular forms. Intracellular and secreted forms of E2(661) were also found to differ in reactivity with MAbs and human sera, consistent with differences in antigenicity. Together, these data indicate that proper folding of E2 is important for its interaction with CD81 and that modifications of glycans can modulate this interaction. Identification of the biologically active forms of E2 will assist in the future design of vaccines to protect against HCV infection.