The structures of immunogens that elicit the most potent neutralization antibodies to prevent COVID-19 infection are still under investigation. In this study, we tested the efficacy of a recombinant trimeric Spike protein containing polyI:C (PIKA) adjuvant in mice immunized by a 0–7–14 day schedule. The results showed that a Spike protein-specific antibody was induced at Day 21 with titer of above 50,000 on average, as measured by direct binding. The neutralizing titer was above 1000 on average, as determined by a pseudo-virus using monoclonal antibodies (40592-MM57 and 40591-MM43) with IC50 at 1 μg/mL as standards. The protein/peptide array-identified receptor-binding domain (RBD) was considered as immunodominant. No linear epitopes were found in the RBD, although several linear epitopes were found in the C-terminal domain right after the RBD and heptad repeat regions. Our study supports the efficacy of a recombinant trimeric Spike protein vaccine candidate for COVID-19 that is safe and ready for storage and distribution in developing countries.
【저자키워드】 COVID-19, Vaccine, Neutralizing antibodies, adjuvant, 【초록키워드】 Structure, Efficacy, spike, antibody, monoclonal antibody, IC50, Protein, COVID-19 infection, mice, RBD, immunogen, vaccine candidate, distribution, Neutralization antibody, binding, Neutralizing titer, C-terminal domain, Safe, Support, domain, average, immunodominant, heptad repeat, regions, linear epitope, Prevent, immunized, pseudo-virus, trimeric, tested, Day, elicit, the RBD, 【제목키워드】 spike, potent, recombinant, induced, candidate, Containing,