S–6P exhibits better immunogenicity than S–2P at lower doses of COVID-19 mRNA vaccines

Objective

The objective of this study was to determine whether a new combination of immunogens could be more effective than the S–2P design in terms of eliciting an immune response. The study aimed to use a unified formulation standard to make a comparison between the new immunogen combination than the S–2P design.

Methods

The study analyzed the published immunogen mutation strategies of known COVID-19 vaccines and also Spike protein variants in the RCSB database to identify the most promising immunogen combination. By choosing different Spike protein variants, we prepared well characterized mRNA preparations and administered them to BALB/C mice using a commercial lipid for encapsulation.

Results

The study found that our mRNA preparations stimulated strong humoral and cellular immunity, with a neutralizing antibody titer of >1*10⁴ at 28 days and a Th1-biased cellular immune response. Furthermore, our results indicate that the S–6P-GSAS variant elicits superior immunogenicity at lower doses compared to the S–2P variant.

Conclusion

Our study suggests that the S–6P-GSAS variant may elicit a stronger immune response at lower doses compared to the S–2P design, indicating its potential as a promising immunogen candidate for COVID-19 vaccines. Further research is needed to explore the efficacy of this novel combination in addressing the challenges posed by emerging Spike protein variants.