Camelid-derived and synthetic single-domain antibodies (sdAbs) are emerging as potent weapons against the novel coronavirus, SARS-CoV-2. sdAbs are small, compact, thermostable immunoglobulin elements capable of binding targets with subnanomolar affinities. By leveraging the power of phage- and yeast surface-display technologies, rare sdAbs can be isolated from highly diverse and complex antibody libraries. Once in hand, sdAbs can be engineered to improve binding affinity, avidity, target specificities, and biodistribution. In this Opinion piece we highlight a series of sophisticated studies describing the identification of ultrapotent sdAbs directed against the receptor-binding domain (RBD) of the SARS-CoV-2 Spike protein. We discuss the possible applications of these antibodies in the global fight against COVID-19.

源自骆驼的合成单域抗体 (sdAb) 正在成为对抗新型冠状病毒 SARS-CoV-2 的有力武器。sdAb 是小型、紧凑、热稳定的免疫球蛋白元件，能够以亚纳摩尔亲和力结合靶标。通过利用噬菌体和酵母表面展示技术的力量，可以从高度多样化和复杂的抗体库中分离出稀有的 sdAb。一旦到达手中，sdAb 就可以被改造以提高结合亲和力、亲合力、靶标特异性和生物分布。在这篇评论文章中，我们重点介绍了一系列复杂的研究，描述了针对 SARS-CoV-2 刺突蛋白受体结合域 (RBD) 的超强 sdAb 的鉴定。我们讨论这些抗体在全球抗击 COVID-19 的斗争中的可能应用。