State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, 610041, China.
Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, China.
J Nanobiotechnology. 2021 Jan 29;19(1):33. doi: 10.1186/s12951-021-00768-w.
The outbreak and pandemic of coronavirus SARS-CoV-2 caused significant threaten to global public health and economic consequences. It is extremely urgent that global people must take actions to develop safe and effective preventions and therapeutics. Nanobodies, which are derived from single‑chain camelid antibodies, had shown antiviral properties in various challenge viruses. In this study, multivalent nanobodies with high affinity blocking SARS-CoV-2 spike interaction with ACE2 protein were developed.
Totally, four specific nanobodies against spike protein and its RBD domain were screened from a naïve VHH library. Among them, Nb91-hFc and Nb3-hFc demonstrated antiviral activity by neutralizing spike pseudotyped viruses in vitro. Subsequently, multivalent nanobodies were constructed to improve the neutralizing capacity. As a result, heterodimer nanobody Nb91-Nb3-hFc exhibited the strongest RBD-binding affinity and neutralizing ability against SARS-CoV-2 pseudoviruses with an IC value at approximately 1.54 nM.
The present study indicated that naïve VHH library could be used as a potential resource for rapid acquisition and exploitation of antiviral nanobodies. Heterodimer nanobody Nb91-Nb3-hFc may serve as a potential therapeutic agent for the treatment of COVID-19.
冠状病毒 SARS-CoV-2 的爆发和大流行对全球公共卫生和经济造成了重大威胁。全球人民必须采取行动，开发安全有效的预防和治疗方法，这是极其紧迫的。纳米抗体来源于单链骆驼抗体，在各种挑战病毒中显示出抗病毒特性。在本研究中，开发了具有高亲和力的多价纳米抗体，以阻断 SARS-CoV-2 刺突与 ACE2 蛋白的相互作用。
从一个天然 VHH 文库中筛选出了四个针对刺突蛋白及其 RBD 结构域的特异性纳米抗体。其中，Nb91-hFc 和 Nb3-hFc 通过中和体外刺突假型病毒显示出抗病毒活性。随后，构建了多价纳米抗体以提高中和能力。结果，杂二聚体纳米抗体 Nb91-Nb3-hFc 表现出最强的 RBD 结合亲和力和中和 SARS-CoV-2 假病毒的能力，IC 值约为 1.54 nM。
本研究表明，天然 VHH 文库可作为快速获取和开发抗病毒纳米抗体的潜在资源。杂二聚体纳米抗体 Nb91-Nb3-hFc 可能可作为治疗 COVID-19 的潜在治疗剂。
