Synergistic effect of nucleoside modification and ionizable lipid composition on translation and immune responses to mRNA vaccines.

Lipid nanoparticle (LNP) components can impact the safety and immunogenicity of mRNA vaccines. Here we examine the mechanisms contributing to the performance of mRNA-LNP vaccines by exploring the impact of nucleoside modifications and LNP components on translational efficiency, innate immune activation, and immunogenicity. Our data reveals several molecular and immunological parameters affected by nucleoside modification including a synergistic effect of the mRNA and ionizable lipid composition on the immune activation triggered by the mRNA-LNP formulation. Our results indicate changes in the LNP composition, independent from whether the mRNA is modified or unmodified, caused differential expression of genes associated with innate and antiviral immunity. We believe these findings offer valuable insights into mRNA vaccine function and offer strategies for enhancing vaccine efficacy and reducing the reactogenicity of next generation mRNA vaccines.