Identification of Continuous Human B-Cell Epitopes in the VP35, VP40, Nucleoprotein and Glycoprotein of Ebola Virus
Identification of Continuous Human B-Cell Epitopes in the VP35, VP40, Nucleoprotein and Glycoprotein of Ebola Virus
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DOI：
10.1371/journal.pone.0096360
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发表时间：
2014-06-10
期刊：
影响因子：
3.7
通讯作者：
Leroy, Eric M.
中科院分区：
文献类型：
--
作者：
Becquart, Pierre;Mahlakoiv, Tanel;Leroy, Eric M.
埃博拉病毒(EBOV)是一种高毒力的人类病原体。感染患者的康复与有效的EBOV特异性免疫球蛋白G(IgG)反应有关，而致命结果与体液免疫缺陷有关。由于EBOV上的B细胞表位定义不明确，我们试图确定四种EBOV蛋白(糖蛋白(GP)、核蛋白(NP)和基质病毒蛋白(VP)40和VP35)中的特定表位。我们首次检测了无症状个体和有症状的加蓬幸存者在早期体液反应(症状结束后7天)和记忆后期(感染后7-12年)收集的EBOV IgG+血清。我们还测试了EBOV阳性患者的血清，这些患者从未出现过出血热的临床症状或生活在非流行地区(无症状受试者)。我们发现，无症状个体的血清对VP40肽的反应比对GP、NP或VP35的反应更强。有趣的是，来自无症状患者的抗EBOV抗体针对VP40的三个免疫优势区域，据报道在病毒组装和萌发中发挥关键作用。相比之下，三次疫情中大多数幸存者的血清是在症状结束后几天收集的，主要与GP多肽反应。然而，在无症状的受试者中，在GP中发现了最长的免疫优势结构域，对GP晶体结构的分析表明，这些结构域覆盖了由三个GP(1)亚基组成的圣杯的更大表面积。我们在EBOV VP35、VP40、NP和GP蛋白中确定的B细胞表位可能是了解该病毒的体液反应和开发新的基于抗体的治疗或检测方法的重要工具。
Ebola virus (EBOV) is a highly virulent human pathogen. Recovery of infected patients is associated with efficient EBOV-specific immunoglobulin G (IgG) responses, whereas fatal outcome is associated with defective humoral immunity. As B-cell epitopes on EBOV are poorly defined, we sought to identify specific epitopes in four EBOV proteins (Glycoprotein (GP), Nucleoprotein (NP), and matrix Viral Protein (VP)40 and VP35). For the first time, we tested EBOV IgG+ sera from asymptomatic individuals and symptomatic Gabonese survivors, collected during the early humoral response (seven days after the end of symptoms) and the late memory phase (7-12 years post-infection). We also tested sera from EBOV-seropositive patients who had never had clinical signs of hemorrhagic fever or who lived in non-epidemic areas (asymptomatic subjects). We found that serum from asymptomatic individuals was more strongly reactive to VP40 peptides than to GP, NP or VP35. Interestingly, anti-EBOV IgG from asymptomatic patients targeted three immunodominant regions of VP40 reported to play a crucial role in virus assembly and budding. In contrast, serum from most survivors of the three outbreaks, collected a few days after the end of symptoms, reacted mainly with GP peptides. However, in asymptomatic subjects the longest immunodominant domains were identified in GP, and analysis of the GP crystal structure revealed that these domains covered a larger surface area of the chalice bowl formed by three GP(1) subunits. The B-cell epitopes we identified in the EBOV VP35, VP40, NP and GP proteins may represent important tools for understanding the humoral response to this virus and for developing new antibody-based therapeutics or detection methods.