■自SARS-CoV-2爆发以来,疫苗已证明其抵抗病毒感染的有效性,降低严重性,降低感染者的死亡率。然而,由于SARS-CoV-2的快速和持续突变,许多可用疫苗的保护能力受到挑战.因此,迫切需要能够引发针对各种SARS-CoV-2变体的有效广泛中和抗体的疫苗。
■在这项研究中,我们通过向原型刺突蛋白的Fc融合受体结合域(RBD)引入一系列屏蔽聚糖,开发了一种新型的SARS-CoV-2亚单位候选疫苗.该方法旨在掩盖非中和表位并将免疫应答集中在关键的中和表位上。
■通过质谱分析确认所有修饰的位点是高度糖基化的。聚糖屏蔽的RBD(gsRBD)与人ACE2受体的结合亲和力与野生型RBD(wtRBD)相当。当与弗氏佐剂或铝佐剂联合使用时,用gsRBD免疫小鼠表明,聚糖屏蔽的引入不会损害RBD的抗体诱导能力。重要的是,与wtRBD相比,gsRBD显着增强了针对SARS-CoV-2假病毒的中和抗体的产生。值得注意的是,它对β表现出显著的保护活性(B.1.351),Delta(B.1.617.2),和Omicron(B.1.1.529),大约3倍,7折,比wtRBD高17倍,分别。
■我们的数据证明了这种多表位掩蔽策略是生产高活性疫苗的有效方法。
Since the outbreak of SARS-CoV-2, vaccines have demonstrated their effectiveness in resisting virus infection, reducing severity, and lowering the mortality rate in infected individuals. However, due to the rapid and ongoing mutations of SARS-CoV-2, the protective ability of many available vaccines has been challenged. Therefore, there is an urgent need for vaccines capable of eliciting potent broadly neutralizing antibodies against various SARS-CoV-2 variants.
In this study, we developed a novel subunit vaccine candidate for SARS-CoV-2 by introducing a series of shielding glycans to the Fc-fused receptor-binding domain (RBD) of the prototypic spike protein. This approach aims to mask non-neutralizing epitopes and focus the immune response on crucial neutralizing epitopes.
All modified sites were confirmed to be highly glycosylated through mass spectrometry analysis. The binding affinity of the
glycan-shielded RBD (gsRBD) to the human ACE2 receptor was comparable to that of the wildtype RBD (wtRBD). Immunizing mice with gsRBD when combined with either Freund\'s adjuvant or aluminum adjuvant demonstrated that the introduction of the
glycan shield did not compromise the antibody-inducing ability of RBD. Importantly, the gsRBD significantly enhanced the generation of neutralizing antibodies against SARS-CoV-2 pseudoviruses compared to the wtRBD. Notably, it exhibited remarkable protective activity against Beta (B.1.351), Delta (B.1.617.2), and Omicron (B.1.1.529), approximately 3-fold, 7- fold, and 17-fold higher than wtRBD, respectively.
Our data proved this multiple-epitope masking strategy as an effective approach for highly active vaccine production.