Department of Health Development and Medicine, Osaka University Graduate School of Medicine, Japan.
Department of Health Development and Medicine, Osaka University Graduate School of Medicine, Japan; Anges Inc, Japan.
Curr Res Transl Med. 2022 Sep;70(4):103348. doi: 10.1016/j.retram.2022.103348. Epub 2022 Apr 20.
To fight against the worldwide COVID-19 pandemic, the development of an effective and safe vaccine against SARS-CoV-2 is required. As potential pandemic vaccines, DNA/RNA vaccines, viral vector vaccines and protein-based vaccines have been rapidly developed to prevent pandemic spread worldwide. In this study, we designed plasmid DNA vaccine targeting the SARS-CoV-2 Spike glycoprotein (S protein) as pandemic vaccine, and the humoral, cellular, and functional immune responses were characterized to support proceeding to initial human clinical trials. After intramuscular injection of DNA vaccine encoding S protein with alum adjuvant (three times at 2-week intervals), the humoral immunoreaction, as assessed by anti-S protein or anti-receptor-binding domain (RBD) antibody titers, and the cellular immunoreaction, as assessed by antigen-induced IFNγ expression, were up-regulated. In IgG subclass analysis, IgG2b was induced as the main subclass. Based on these analyses, DNA vaccine with alum adjuvant preferentially induced Th1-type T cell polarization. We confirmed the neutralizing action of DNA vaccine-induced antibodies by a binding assay of RBD recombinant protein with angiotensin-converting enzyme 2 (ACE2), a receptor of SARS-CoV-2, and neutralization assays using pseudo-virus, and live SARS-CoV-2. Further B cell epitope mapping analysis using a peptide array showed that most vaccine-induced antibodies recognized the S2 and RBD subunits. Finally, DNA vaccine protected hamsters from SARS-CoV-2 infection. In conclusion, DNA vaccine targeting the spike glycoprotein of SARS-CoV-2 might be an effective and safe approach to combat the COVID-19 pandemic.
为了抗击全球 COVID-19 大流行，需要开发针对 SARS-CoV-2 的有效和安全疫苗。作为潜在的大流行疫苗，DNA/RNA 疫苗、病毒载体疫苗和基于蛋白质的疫苗已被迅速开发，以防止全球大流行传播。在这项研究中，我们设计了针对 SARS-CoV-2 刺突糖蛋白（S 蛋白）的质粒 DNA 疫苗作为大流行疫苗，并对体液、细胞和功能免疫反应进行了表征，以支持进行初步的人体临床试验。在肌肉内注射带有铝佐剂的编码 S 蛋白的 DNA 疫苗（间隔 2 周 3 次）后，通过抗 S 蛋白或抗受体结合域（RBD）抗体滴度评估的体液免疫反应和通过抗原诱导的 IFNγ 表达评估的细胞免疫反应得到上调。在 IgG 亚类分析中，诱导 IgG2b 作为主要亚类。基于这些分析，带有铝佐剂的 DNA 疫苗优先诱导 Th1 型 T 细胞极化。我们通过 RBD 重组蛋白与 SARS-CoV-2 受体血管紧张素转换酶 2（ACE2）的结合测定和使用假病毒和活 SARS-CoV-2 的中和测定来证实 DNA 疫苗诱导的抗体的中和作用。进一步使用肽阵列进行 B 细胞表位映射分析表明，大多数疫苗诱导的抗体识别 S2 和 RBD 亚单位。最后，DNA 疫苗保护仓鼠免受 SARS-CoV-2 感染。总之，针对 SARS-CoV-2 刺突糖蛋白的 DNA 疫苗可能是应对 COVID-19 大流行的有效和安全方法。
