A novel nanobody with good druggability to prevent and treat MERS-CoV infection

摘要 由中东呼吸综合征冠状病毒(MERS-CORNAV)引起的中东呼吸综合征(MERS)持续流行 CoV)已对全球公共卫生构成威胁，呼吁发展创新有效的 干预策略。我们以前的研究已经证明，细胞中的受体结合域(RBD) MERS冠状病毒尖峰蛋白(S)，介导病毒与受体二肽基肽酶4(DPP4)的结合， 包含一个关键的中和结构域(CND)，作为疫苗开发的重要靶点 和中和抗体。几种以RBD为靶点的中和单抗 已有中和活性和/或对MERS冠状病毒感染的保护作用的报道。尽管他们 这些常规抗体具有卓越的安全性和较强的特异性，具有体积大(如免疫球蛋白为160 kDa)和 复杂的结构。这些特点导致不稳定，限制了快速、大规模的生产。 与常规抗体不同，骆驼重链抗体(VHH)的可变区，或 纳米体(Nb)，具有分子尺寸小(~15 kDa)、热稳定性强、产率高等特点 药效性好，特别适合作为一种抗病毒药物快速大规模生产 负担得起的价格，以满足疫情爆发期间的医疗需求。我们之前已经开发出了几种有效的 并鉴定了3株RBD靶向的中和NBs。基座 根据我们的经验和初步数据，我们假设一种新颖、稳定和有效的RBD特异性 可以开发中和NB来对抗MERS。这项提议的具体目标是：1)产生 人源化MERS冠状病毒RBD特异性延长半衰期中和NBS；2)MERS冠状病毒特性研究 3)评价RBD特异性人源化的体内外效果。 NBS抗MERS冠状病毒感染。拟议研究的长期目标是开发一种新的 用于预防和治疗MERS冠状病毒感染的具有良好药效性的纳米体。类似的方法 可用于开发针对其他I类包膜病毒的预防和治疗药物 流行病/大流行的可能性。

Abstract The continuous epidemic of Middle East respiratory syndrome (MERS) caused by MERS-coronavirus (MERS- CoV) has posed a threat to global public health, calling for the development of innovative and effective intervention strategies. Our previous studies have demonstrated that the receptor-binding domain (RBD) in the MERS-CoV spike (S) protein, which mediates virus binding to the receptor dipeptidyl peptidase 4 (DPP4), contains a critical neutralizing domain (CND), serving as an important target for the development of vaccines and neutralizing antibodies. A number of RBD-targeting neutralizing monoclonal antibodies (mAbs) with potent neutralizing activity and/or protection against MERS-CoV infection have been reported. In spite of their superior safety and strong specificity, these conventional antibodies have large size (e.g., 160 kDa for IgG) and complicated structures. These characteristics result in instability and limit rapid, large-scale production. Different from conventional antibodies, variable domains of camelid heavy chain-only antibody (VHH), or nanobody (Nb), has small molecular size (~15 kDa), strong thermal stability, high production yield and other good druggabilities, making it particularly suitable for rapid and large-scale production as an antiviral drug with affordable price to meet healthcare needs during an outbreak. We have previously developed several effective RBD-specific mouse and human neutralizing mAbs and identified three RBD-targeting neutralizing Nbs. Based on our experience and preliminary data, we hypothesize that a novel, stable, and effective RBD-specific neutralizing Nb can be developed to combat MERS. The specific aims of this proposal are: 1) to generate humanized MERS-CoV RBD-specific neutralizing Nbs with extended half-lives; 2) to characterize MERS-CoV RBD-specific humanized Nbs; and 3) to evaluate the in vitro and in vivo efficacy of RBD-specific humanized Nbs against MERS-CoV infection. The long-term goal of the proposed study is to develop a novel nanobody with good druggability for the prevention and treatment of MERS-CoV infection. Similar approaches can be applied to develop prophylactic and therapeutic agents against other class I enveloped viruses with epidemic/pandemic potential.