Porcine epidemic diarrhea (PED) is a highly contagious disease that causes high mortality in suckling piglets. Although several licensed inactivated and live attenuated vaccines were widely used, the infection rate remains high due to unsatisfactory protective efficacy. In this study, mRNA vaccine candidates against PED were prepared, and their immunogenicity was evaluated in mice and pregnant sows. The mRNA PED vaccine based on heterodimer of viral receptor binding region (RBD) showed good immunogenicity. It elicited robust humoral and cellular immune responses in mice, and the neutralizing antibody titer reached 1:300 after a single vaccination. Furthermore, it induced neutralizing antibody level similar to that of the inactivated vaccine in pregnant sows. This study developed a new design of PED vaccine based on the mRNA-RBD strategy and demonstrated the potential for clinical application.
Keywords: cellular immune response; humoral immune response; mRNA vaccine; porcine epidemic diarrhea; receptor-binding region.