Virus-like particle (VLP) is a self-assembled nanostructure incorporating key viral structural proteins. VLP resembles molecular and morphological features of authentic viruses but is non-infectious and non-replicating due to lack of genetic materials. Successful applications of VLP has been shown in vaccinological and virological research. As an accessibly safe and relevant substitute of naturally pathogenic viruses, the construction of SARS-CoV-2 VLPs is much in demand in the ongoing fight against 2019 Coronavirus disease (COVID-19) pandemics. In the current study, using mammalian expression system, which is advantageous in maintaining correct protein glycosylation patterns, we efficiently constructed SARS-CoV-2 VLPs. We showed that among four SARS-CoV-2 structural proteins, expression of membrane protein (M) and small envelope protein (E) are essential for efficient formation and release of SARS-CoV-2 VLPs. Moreover, the corona-like structure presented in SARS-CoV-2 VLPs from Vero E6 cells is more stable and unified, as compared to those from HEK-293T cells. Our data demonstrate that SARS-CoV-2 VLPs possess molecular and morphological properties of native virion particles, which endow such VLPs with a promising vaccine candidate and a powerful tool for the research of SARS-CoV-2.

中文翻译：

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哺乳动物表达系统构建SARS-CoV-2病毒样颗粒

病毒样颗粒 (VLP) 是一种自组装纳米结构，结合了关键的病毒结构蛋白。VLP 类似于真实病毒的分子和形态特征，但由于缺乏遗传物质而具有非传染性和非复制性。VLP 的成功应用已在疫苗学和病毒学研究中得到证明。作为天然致病病毒的可及安全且相关的替代品，在与 2019 年冠状病毒病 (COVID-19) 大流行的持续斗争中，对构建 SARS-CoV-2 VLP 的需求很大。在目前的研究中，我们使用哺乳动物表达系统，有利于维持正确的蛋白质糖基化模式，有效地构建了 SARS-CoV-2 VLP。我们发现，在四种 SARS-CoV-2 结构蛋白中，膜蛋白 (M) 和小包膜蛋白 (E) 的表达对于 SARS-CoV-2 VLP 的有效形成和释放至关重要。此外，与来自 HEK-293T 细胞的结构相比，来自 Vero E6 细胞的 SARS-CoV-2 VLP 中呈现的冠状样结构更加稳定和统一。我们的数据表明，SARS-CoV-2 VLPs 具有天然病毒粒子的分子和形态学特性，这为此类 VLPs 提供了有希望的候选疫苗和研究 SARS-CoV-2 的强大工具。