A protein vaccine with Alum/c-GAMP/poly(I:C) rapidly boosts robust immunity against SARS-CoV-2 and variants of concern
Ruyan Zhang, Xuguang Yin, Shihao Zhou, Haiwei Zhang, Jie Lu, Chen-Bin He, Jian Wang, Yu Wen, Yuting Li, Yanling Liu, Ran-Ran Feng, Dong Ding, Huawei Wei, Rui Gong, Guang‐Fu Yang, Jun Guo
Abstract
Adjuvants are important components in vaccines to increase the immunogenicity of proteins and induce optimal immunity. In this study, we designed a novel ternary adjuvant system Alum + c-GAMP + poly(I:C) with STING agonist 3,3'-c-GAMP (c-GAMP) and TLR3 agonist poly(I:C) co-adsorbed on the conventional adjuvant aluminum gel (Alum), and further constructed an S1 protein vaccine. Two doses of vaccination with the ternary adjuvant vaccine were sufficient to induce a balanced Th1/Th2 immune response and robust humoral and cellular immunity. Additionally, the ternary adjuvant group had effective neutralizing activity against live virus SARS-CoV-2 and pseudovirus of all variants of concern (alpha, beta, gamma, delta and omicron). These results indicate that the ternary adjuvants have a significant synergistic effect and can rapidly trigger potent immune responses; the combination of the ternary adjuvant system with S1 protein is a promising COVID-19 vaccine candidate.