Laboratory of Molecular Medicine, Department of Clinical Immunology, University Hospital of Copenhagen, Copenhagen, Denmark.
Laboratory of Molecular Medicine, Department of Clinical Immunology, University Hospital of Copenhagen, Copenhagen, Denmark; Institute of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.
J Biol Chem. 2021 Jan-Jun;296:100536. doi: 10.1016/j.jbc.2021.100536. Epub 2021 Mar 11.
Transmission of Severe Acute Respiratory Syndrome Coronavirus 2 from humans to animals has been reported for many domesticated species, including farmed minks. The identification of novel spike gene mutations appearing in minks has raised major concerns about potential immune evasion and challenges for the global vaccine strategy. One genetic variant, known as "cluster five," arose among farmed minks in Denmark and resulted in a complete shutdown of the world's largest mink production. However, the functional properties of this new variant are not established. Here we present functional data on the cluster-five variant, which contains a mutation resulting in a Y453F residue change in the receptor-binding domain (RBD) of the spike protein. Using an ELISA-based angiotensin-converting enzyme-2/RBD inhibition assay, we show that the Y453F variant does not decrease established humoral immunity from previously infected individuals or affect the neutralizing antibody response in a vaccine mouse model based on the original Wuhan strain RBD or spike as antigens. However, biolayer interferometry analysis demonstrates that it binds the human angiotensin-converting enzyme-2 receptor with a 4-fold higher affinity than the original strain, suggesting an enhanced transmission capacity and a possible challenge for viral control. These results also indicate that the rise in the frequency of the cluster-five variant in mink farms might be a result of the fitness advantage conferred by the receptor adaptation rather than evading immune responses.
已报道多种家养动物可传播严重急性呼吸综合征冠状病毒 2，包括养殖水貂。新型刺突基因突变出现在水貂中，引起了对潜在免疫逃避和全球疫苗策略挑战的极大关注。一种名为“cluster five”的遗传变异株出现在丹麦的养殖水貂中，导致世界上最大的水貂养殖场全部关闭。然而，这种新变体的功能特性尚未确定。在此，我们提供了关于 cluster five 变体的功能数据，该变体在刺突蛋白的受体结合域（RBD）中包含一个导致 Y453F 残基变化的突变。我们使用基于 ELISA 的血管紧张素转换酶-2/RBD 抑制测定法，表明 Y453F 变体不会降低先前感染个体的既定体液免疫，也不会影响基于原始武汉株 RBD 或刺突作为抗原的疫苗小鼠模型中的中和抗体反应。然而，生物层干涉分析表明，它与人血管紧张素转换酶-2 受体的结合亲和力比原始株高 4 倍，表明其传播能力增强，可能对病毒控制构成挑战。这些结果还表明，水貂养殖场中 cluster five 变体频率的上升可能是由于受体适应带来的适应性优势所致，而不是逃避免疫反应。
