Identification of human neutralizing antibodies that bind to complex epitopes on dengue virions
Identification of human neutralizing antibodies that bind to complex epitopes on dengue virions
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DOI：
10.1073/pnas.1200566109
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发表时间：
2012-05-08
影响因子：
11.1
通讯作者：
de Silva, Aravinda M.
中科院分区：
文献类型：
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作者：
de Alwis, Ruklanthi;Smith, Scott A.;de Silva, Aravinda M.
登革热是一种蚊媒黄病毒，正在以前所未有的速度传播，并已发展成为50多个国家的主要健康和经济负担。尽管感染个体产生有效且持久的表型特异性中和抗体（Abs），但尚未鉴定出人中和Abs所接合的表位。在这里，我们证明了登革病毒（DENV）特异性血清抗体反应在人类中由大部分的交叉反应，中和性差的抗体和一小部分的特异性，强效抑制抗体。尽管许多小鼠产生的强中和性单克隆抗体（mAb）识别存在于重组DENV包膜（E）蛋白上的表位，但出乎意料地，人免疫血清中的大多数中和性Ab与完整病毒体结合，但不与纯化的可溶性E蛋白的胞外域结合。用来自DENV免疫个体的新产生的人mAb证实了多克隆Ab的这些结论。三种强中和性人单克隆抗体中有两种与E蛋白表位结合，这些表位保留在病毒体上，但不保留在重组E（rE）蛋白上。我们提出，人类产生的抗体，通过结合一个复杂的，四级结构的表位，只有当E蛋白组装在病毒颗粒上表达中和登革病毒感染。作图研究表明，该表位具有跨越相邻E蛋白二聚体的足迹，并且包括E蛋白的结构域I和II之间的铰链处的残基。这些结果对DENV抗体和疫苗领域具有重要意义。
Dengue is a mosquito-borne flavivirus that is spreading at an unprecedented rate and has developed into a major health and economic burden in over 50 countries. Even though infected individuals develop potent and long-lasting serotype-specific neutralizing antibodies (Abs), the epitopes engaged by human neutralizing Abs have not been identified. Here, we demonstrate that the dengue virus (DENV)-specific serum Ab response in humans consists of a large fraction of cross-reactive, poorly neutralizing Abs and a small fraction of serotype-specific, potently inhibitory Abs. Although many mouse-generated, strongly neutralizing monoclonal antibodies (mAbs) recognize epitopes that are present on recombinant DENV envelope (E) proteins, unexpectedly, the majority of neutralizing Abs in human immune sera bound to intact virions but not to the ectodomain of purified soluble E proteins. These conclusions with polyclonal Abs were confirmed with newly generated human mAbs derived from DENV-immune individuals. Two of three strongly neutralizing human mAbs bound to E protein epitopes that were preserved on the virion but not on recombinant E (rE) protein. We propose that humans produce Abs that neutralize DENV infection by binding a complex, quaternary structure epitope that is expressed only when E proteins are assembled on a virus particle. Mapping studies indicate that this epitope has a footprint that spans adjacent E protein dimers and includes residues at the hinge between domains I and II of E protein. These results have significant implications for the DENV Ab and vaccine field.