Institute of Preventive Medicine, National Defense Medical Center, Taipei 11490, Taiwan.
Department and Graduate Institute of Microbiology and Immunology, National Defense Medical Center, Taipei 11490, Taiwan.
Viruses. 2020 Mar 19;12(3):336. doi: 10.3390/v12030336.
The Japanese encephalitis virus (JEV) is the major cause of an acute encephalitis syndrome in many Asian countries, despite the fact that an effective vaccine has been developed. Virus-like particles (VLPs) are self-assembled multi-subunit protein structures which possess specific epitope antigenicities related to corresponding native viruses. These properties mean that VLPs are considered safe antigens that can be used in clinical applications. In this study, we developed a novel baculovirus/mosquito (BacMos) expression system which potentially enables the scalable production of JEV genotype III (GIII) VLPs (which are secreted from mosquito cells). The mosquito-cell-derived JEV VLPs comprised 30-nm spherical particles as well as precursor membrane protein (prM) and envelope (E) proteins with densities that ranged from 30% to 55% across a sucrose gradient. We used IgM antibody-capture enzyme-linked immunosorbent assays to assess the resemblance between VLPs and authentic virions and thereby characterized the epitope specific antigenicity of VLPs. VLP immunization was found to elicit a specific immune response toward a balanced IgG2a/IgG1 ratio. This response effectively neutralized both JEV GI and GIII and elicited a mixed Th1/Th2 response in mice. This study supports the development of mosquito cell-derived JEV VLPs to serve as candidate vaccines against JEV.
日本脑炎病毒（JEV）是许多亚洲国家急性脑炎综合征的主要原因，尽管已经开发出有效的疫苗。病毒样颗粒（VLPs）是自我组装的多亚基蛋白结构，具有与相应天然病毒相关的特定表位抗原性。这些特性意味着 VLPs 被认为是安全的抗原，可以用于临床应用。在这项研究中，我们开发了一种新型杆状病毒/蚊子（BacMos）表达系统，该系统可能能够大规模生产 JEV 基因型 III（GIII）VLPs（从蚊子细胞中分泌）。蚊子细胞衍生的 JEV VLPs 由 30nm 球形颗粒以及前膜蛋白（prM）和包膜（E）蛋白组成，在蔗糖梯度中的密度范围为 30%至 55%。我们使用 IgM 抗体捕获酶联免疫吸附试验来评估 VLPs 与真实病毒粒子之间的相似性，从而表征 VLPs 的表位特异性抗原性。VLP 免疫被发现引发针对平衡 IgG2a/IgG1 比的特异性免疫反应。这种反应有效地中和了 JEV GI 和 GIII，并在小鼠中引发了混合 Th1/Th2 反应。这项研究支持开发蚊子细胞衍生的 JEV VLPs 作为针对 JEV 的候选疫苗。
