Seephetdee Chotiwat, Buasri Nattawut, Bhukhai Kanit, Srisanga Kitima, Manopwisedjaroen Suwimon, Lertjintanakit Sarat, Phueakphud Nut, Pakiranay Chatbenja, Kangwanrangsan Niwat, Srichatrapimuk Sirawat, Kirdlarp Suppachok, Sungkanuparph Somnuek, Chutipongtanate Somchai, Thitithanyanont Arunee, Hongeng Suradej, Wongtrakoongate Patompon
Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand.
Department of Physiology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand.
Vaccines (Basel). 2021 May 12;9(5):498. doi: 10.3390/vaccines9050498.
Updated and revised versions of COVID-19 vaccines are vital due to genetic variations of the SARS-CoV-2 spike antigen. Furthermore, vaccines that are safe, cost-effective, and logistic-friendly are critically needed for global equity, especially for middle- to low-income countries. Recombinant protein-based subunit vaccines against SARS-CoV-2 have been reported using the receptor-binding domain (RBD) and the prefusion spike trimers (S-2P). Recently, a new version of prefusion spike trimers, named HexaPro, has been shown to possess two RBD in the "up" conformation, due to its physical property, as opposed to just one exposed RBD found in S-2P. Importantly, this HexaPro spike antigen is more stable than S-2P, raising its feasibility for global logistics and supply chain. Here, we report that the spike protein HexaPro offers a promising candidate for the SARS-CoV-2 vaccine. Mice immunized by the recombinant HexaPro adjuvanted with aluminum hydroxide using a prime-boost regimen produced high-titer neutralizing antibodies for up to 56 days after initial immunization against live SARS-CoV-2 infection. Also, the level of neutralization activity is comparable to that of convalescence sera. Our results indicate that the HexaPro subunit vaccine confers neutralization activity in sera collected from mice receiving the prime-boost regimen.
由于新冠病毒刺突抗原的基因变异，新冠疫苗的更新和修订版本至关重要。此外，为实现全球公平，尤其是对中低收入国家而言，迫切需要安全、具有成本效益且便于物流的疫苗。已经报道了基于重组蛋白的针对新冠病毒的亚单位疫苗，使用受体结合域（RBD）和预融合刺突三聚体（S-2P）。最近，一种名为HexaPro的预融合刺突三聚体新版本已被证明由于其物理特性，在“向上”构象中拥有两个RBD，而在S-2P中仅发现一个暴露的RBD。重要的是，这种HexaPro刺突抗原比S-2P更稳定，提高了其在全球物流和供应链中的可行性。在此，我们报告刺突蛋白HexaPro为新冠病毒疫苗提供了一个有前景的候选物。用氢氧化铝佐剂重组HexaPro通过初免-加强免疫方案免疫的小鼠，在初次免疫后长达56天内针对活新冠病毒感染产生了高滴度中和抗体。此外，中和活性水平与康复期血清相当。我们的结果表明，HexaPro亚单位疫苗在接受初免-加强免疫方案的小鼠收集的血清中赋予中和活性。
