Ossianix, Inc, Stevenage Bioscience Catalyst, Stevenage, UK.
Ossianix, Inc, Philadelphia, Pennsylvania, USA.
FASEB J. 2021 Nov;35(11):e21970. doi: 10.1096/fj.202100986RR.
Single domain shark variable domain of new antigen receptor (VNAR) antibodies can offer a viable alternative to conventional Ig-based monoclonal antibodies in treating COVID-19 disease during the current pandemic. Here we report the identification of neutralizing single domain VNAR antibodies selected against the severe acute respiratory syndrome coronavirus 2 spike protein derived from the Wuhan variant using phage display. We identified 56 unique binding clones that exhibited high affinity and specificity to the spike protein. Of those, 10 showed an ability to block both the spike protein receptor binding domain from the Wuhan variant and the N501Y mutant from interacting with recombinant angiotensin-converting enzyme 2 (ACE2) receptor in vitro. In addition, three antibody clones retained in vitro blocking activity when the E484K spike protein mutant was used. The inhibitory property of the VNAR antibodies was further confirmed for all 10 antibody clones using ACE2 expressing cells with spike protein from the Wuhan variant. The viral neutralizing potential of the VNAR clones was also confirmed for the 10 antibodies tested using live Wuhan variant virus in in vitro cell infectivity assays. Single domain VNAR antibodies, due to their low complexity, small size, unique epitope recognition, and formatting flexibility, should be a useful adjunct to existing antibody approaches to treat COVID-19.
单域鲨鱼可变域新型抗原受体（VNAR）抗体可以为治疗当前大流行期间的 COVID-19 疾病提供一种可行的替代传统 Ig 基单克隆抗体的方法。在这里，我们报告了使用噬菌体展示技术针对源自武汉变异株的严重急性呼吸综合征冠状病毒 2 刺突蛋白选择的中和性单域 VNAR 抗体的鉴定。我们鉴定了 56 个独特的结合克隆，这些克隆对刺突蛋白表现出高亲和力和特异性。其中，有 10 个克隆显示出既能阻断武汉变异株刺突蛋白受体结合域，又能阻断 N501Y 突变体与重组血管紧张素转化酶 2（ACE2）受体相互作用的能力。此外，当使用 E484K 刺突蛋白突变体时，三种抗体克隆在体外仍保留阻断活性。使用来自武汉变异株的刺突蛋白表达 ACE2 的细胞进一步证实了 VNAR 抗体的抑制特性。使用来自武汉变异株的活病毒在体外细胞感染实验中也证实了 10 种测试抗体的病毒中和潜力。由于单域 VNAR 抗体具有低复杂性、小尺寸、独特的表位识别和格式灵活性，因此应该成为治疗 COVID-19 的现有抗体方法的有用辅助手段。
