Staggered immunization with mRNA vaccines encoding SARS-CoV-2 polymerase or spike antigens broadens the T cell epitope repertoire

The infrequently altered SARS-CoV-2 protein RNA dependent RNA polymerase (RdRp) is a promising target for T cell-targeting mRNA vaccines. We used single cell RNA sequencing (scRNA-seq) to define the transcriptional profile and TCR repertoire of CD8+ cells in mice immunized with a mRNA vaccine encoding SARS-CoV-2. CD8+ splenocytes were isolated from mice immun ized with a RdRp-encoding mRNA vaccine and analyzed using scRNAseq and scVDJ-seq.