Figure 1.

Design and production of sa-mRNA S and sa-mRNA S-N vaccines

(A) Full-length SARS-CoV-2 prefusion S and full-length N protein sequences based on the SARS-CoV-2/human/USA/WA-CDC-WA1/2020 virus (original virus) were inserted into Alphavirus-based sa-mRNA with both S and N downstream of two distinct subgenomic promoters. sa-mRNA S or sa-mRNA S-N transfected baby hamster kidney (BHK) cells were analyzed by flow cytometry for S+ or S+N+ expressing cells (B) and western blotting for expression of S and N proteins (C). (D) Flow cytometry was also used to analyze relative level of S protein expression in S+ expressing cells.