Prototype LNP-mRNA vaccine candidates [SC_RNAseq]

We developed prototype LNP-mRNA vaccine candidates against SARS-CoV-2 Delta, SARS-CoV and MERS-CoV, and test how multiplexing LNP-mRNAs can induce effective immune responses in animal models. Triplex and Duplex LNP-mRNA vaccination induced antigen-specific antibody responses against SARS-CoV-2, SARS-CoV and MERS-CoV. Single cell RNA-seq profiled the global systemic immune repertoires and respective transcriptome signatures of vaccinated animals, revealing systemic increase in activated B cells, and differential gene expression across major adaptive immune cells. Sequential vaccination showed potent antibody responses against all three species, significantly stronger than simultaneous vaccination in mixture. These data demonstrated feasibility, antibody responses and single cell immune profiles of multi-species coronavirus vaccination. The direct comparison between simultaneous and sequential vaccination offers insights on optimization of vaccination schedules to provide broad and potent antibody immunity against three major pathogenic coronavirus species. PBMCs were isolated and processed from immunized mice and analyzed by scRNA-seq.