2019年冠状病毒病(COVID-19)大流行仍在继续。严重急性呼吸系统综合症冠状病毒2(SARS-CoV-2)变种(VOCs)在全球范围内流行,使其对现有的疫苗和抗病毒药物具有抗性。因此,评估基于变异的广谱疫苗以优化免疫反应并提供广泛的保护性非常重要。在这项研究中,我们在使用CHO细胞的GMP级车间中基于Beta变体表达了刺突三聚体蛋白(S-TM)。用S-TM蛋白联合氢氧化铝(Al)和CpG寡核苷酸(CpG)佐剂免疫小鼠两次以评价其安全性和功效。用S-TM+Al+CpG免疫的BALB/c诱导针对武汉-Hu-1株的高中和抗体滴度(野生型,WT),Beta和Delta变体,甚至是Omicron变体。此外,与S-TM+Al组相比,S-TM+Al+CpG组有效诱导小鼠更强的Th1偏倚细胞免疫应答。此外,第二次免疫后,H11-K18hACE2小鼠受到很好的保护,免受SARS-CoV-2Beta毒株的攻击,100%的存活率。肺部病毒载量和病理病变显著降低,在小鼠脑组织中未检测到病毒。我们的候选疫苗对目前的SARS-CoV-2挥发性有机化合物是实用和有效的,这将支持其潜在的序贯免疫和初次免疫的进一步临床开发。重要性严重急性呼吸综合征冠状病毒2(SARS-CoV-2)的适应性突变的不断出现继续挑战现有疫苗和药物的使用和开发。目前正在评估能够诱导针对SARS-CoV-2变体的更高和更广泛的保护性免疫应答的基于变体的疫苗的价值。本文表明,基于Beta变体的重组预融合刺突蛋白具有高度免疫原性,可以在小鼠中诱导更强的Th1偏向性细胞免疫应答,并且可以有效地抵抗SARS-CoV-2Beta变体的攻击。重要的是,这种基于Beta的SARS-CoV-2疫苗还可以提供强大的体液免疫反应,具有针对野生型和不同关注变体(VOCs)的有效广泛的中和能力:Delta,和OmicronBA.1变体。迄今为止,这里描述的疫苗已经以中试规模生产(200L),和发展,填充过程,毒理学安全性评估也已经完成,这提供了对新出现的SARS-CoV-2变体和疫苗开发的及时反应。
The coronavirus disease 2019 (COVID-19) pandemic is still ongoing. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOCs) are circulating worldwide, making it resistant to existing vaccines and antiviral drugs. Therefore, the evaluation of variant-based expanded spectrum vaccines to optimize the immune response and provide broad protectiveness is very important. In this study, we expressed spike trimer protein (S-TM) based on the Beta variant in a GMP-grade workshop using CHO cells. Mice were immunized twice with S-TM protein combined with aluminum hydroxide (Al) and CpG Oligonucleotides (CpG) adjuvant to evaluate its safety and efficacy. BALB/c immunized with S-TM + Al + CpG induced high neutralizing antibody titers against the Wuhan-Hu-1 strain (wild-type, WT), the Beta and Delta variants, and even the Omicron variant. In addition, compared with the S-TM + Al group, the S-TM + Al + CpG group effectively induced a stronger Th1-biased cell immune response in mice. Furthermore, after the second immunization, H11-K18 hACE2 mice were well protected from challenge with the SARS-CoV-2 Beta strain, with a 100% survival rate. The virus load and pathological lesions in the lungs were significantly reduced, and no virus was detected in mouse brain tissue. Our vaccine candidate is practical and effective for current SARS-CoV-2 VOCs, which will support its further clinical development for potential sequential immune and primary immunization. IMPORTANCE Continuous emergence of adaptive mutations of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to challenge the use and development of existing vaccines and drugs. The value of variant-based vaccines that are capable of inducing a higher and broader protection immune response against SARS-CoV-2 variants is currently being evaluated. This article shows that a recombinant prefusion spike protein based on a Beta variant was highly immunogenic and could induced a stronger Th1-biased cell immune response in mice and was effectively protective against challenge with the SARS-CoV-2 Beta variant. Importantly, this Beta-based SARS-CoV-2 vaccine could also offer a robust humoral immune response with effectively broad neutralization ability against the wild type and different variants of concern (VOCs): the Beta, Delta, and Omicron BA.1 variants. To date, the vaccine described here has been produced in a pilot scale (200L), and the development, filling process, and toxicological safety evaluation have also been completed, which provides a timely response to the emerging SARS-CoV-2 variants and vaccine development.