Laboratory of Immunology, Center of Excellence in Infectious Disease and Inflammation, Office of Biotechnology Products, Center for Drug Evaluation and Research, Food and Drug Administration, Silver Spring, MD, United States.
Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, United States.
Front Immunol. 2022 Jul 28;13:919815. doi: 10.3389/fimmu.2022.919815. eCollection 2022.
Since first reported in 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is rapidly acquiring mutations, particularly in the spike protein, that can modulate pathogenicity, transmission and antibody evasion leading to successive waves of COVID19 infections despite an unprecedented mass vaccination necessitating continuous adaptation of therapeutics. Small animal models can facilitate understanding host-pathogen interactions, target selection for therapeutic drugs, and vaccine development, but availability and cost of studies in BSL3 facilities hinder progress. To generate a BSL2-compatible system that specifically recapitulates spike protein mediated disease we used replication competent, GFP tagged, recombinant Vesicular Stomatitis Virus where the VSV glycoprotein was replaced by the SARS-CoV-2 spike protein (rVSV-SARS2-S). We show that infection requires hACE2 and challenge of neonatal but not adult, K18-hACE2 transgenic mice (hACE2tg) leads to productive infection of the lungs and brains. Although disease progression was faster in SARS-CoV-2 infected mice, infection with both viruses resulted in neuronal infection and encephalitis with increased expression of Interferon-stimulated Irf7, Bst2, Ifi294, as well as CxCL10, CCL5, CLC2, and LILRB4, and both models were uniformly lethal. Further, prophylactic treatment targeting the Spike protein (Receptor Binding Domain) with antibodies resulted in similar levels of protection from lethal infection against rVSV-SARS2-S and SARS-CoV-2 viruses. Strikingly, challenge of neonatal hACE2tg mice with SARS-CoV-2 Variants of Concern (SARS-CoV-2-α, -β, ϒ, or Δ) or the corresponding rVSV-SARS2-S viruses (rVSV-SARS2-Spike-α, rVSV-SARS2-Spike-β, rVSV-SARS2-Spike-ϒ or rVSV-SARS2-Spike-Δ) resulted in increased lethality, suggesting that the Spike protein plays a key role in determining the virulence of each variant. Thus, we propose that rVSV-SARS2-S virus can be used to understand the effect of changes to SARS-CoV-2 spike protein on infection and to evaluate existing or experimental therapeutics targeting spike protein of current or future VOC of SARS-CoV-2 under BSL-2 conditions.
自 2019 年首次报告以来，严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）迅速发生突变，特别是在刺突蛋白中，这可以调节致病性、传播和抗体逃逸，导致 COVID19 感染的连续浪潮，尽管进行了前所未有的大规模疫苗接种，但需要不断调整治疗方法。小动物模型可以促进宿主-病原体相互作用的理解、治疗药物的靶点选择和疫苗开发，但在 BSL3 设施中进行研究的可用性和成本阻碍了进展。为了生成一种专门模拟刺突蛋白介导疾病的 BSL2 兼容系统，我们使用了具有复制能力的、GFP 标记的、重组的水疱性口炎病毒，其中 VSV 糖蛋白被 SARS-CoV-2 的刺突蛋白取代（rVSV-SARS2-S）。我们表明，感染需要 hACE2，并且挑战新生但不是成年的、K18-hACE2 转基因小鼠（hACE2tg）会导致肺部和大脑的有效感染。虽然 SARS-CoV-2 感染的小鼠疾病进展更快，但两种病毒的感染都会导致神经元感染和脑炎，干扰素刺激的 Irf7、Bst2、Ifi294 以及 CxCL10、CCL5、CLC2 和 LILRB4 的表达增加，两种模型都是致死性的。此外，针对 Spike 蛋白（受体结合域）的预防性治疗用抗体导致对 rVSV-SARS2-S 和 SARS-CoV-2 病毒的致死性感染的保护水平相似。引人注目的是，用 SARS-CoV-2 关注变体（SARS-CoV-2-α、-β、ϒ或Δ）或相应的 rVSV-SARS2-S 病毒（rVSV-SARS2-Spike-α、rVSV-SARS2-Spike-β、rVSV-SARS2-Spike-ϒ或 rVSV-SARS2-Spike-Δ）挑战新生的 hACE2tg 小鼠会导致更高的致死率，这表明 Spike 蛋白在决定每个变体的毒力方面起着关键作用。因此，我们提出 rVSV-SARS2-S 病毒可用于了解 SARS-CoV-2 刺突蛋白变化对感染的影响，并在 BSL-2 条件下评估针对当前或未来 SARS-CoV-2 VOC 刺突蛋白的现有或实验性治疗方法。
