PEDV-spike-protein-expressing mRNA vaccine protects piglets against PEDV challenge

Abstract

Porcine epidemic diarrhea virus (PEDV), a swine enteropathogenic coronavirus, causes severe diarrhea in neonatal piglets, which is associated with a high mortality rate. Thus, developing effective and safe vaccines remains a top priority for controlling PEDV infection. Here, we designed two lipid nanoparticle (LNP)encapsulated mRNA (mRNALNP) vaccines encoding either the fulllength PEDV spike (S) protein or a multiepitope chimeric spike (Sm) protein. We found that the S mRNALNP vaccine was superior to the Sm mRNALNP vaccine at inducing antibody and cellular immune responses in mice. Evaluation of the immunogenicity and efficacy of the S mRNA vaccine in piglets confirmed that it induced robust PEDVspecific humoral and cellular immune responses in vivo. Importantly, the S mRNALNP vaccine not only protected actively immunized piglets against PEDV but also equipped neonatal piglets with effective passive antiPEDV immunity in the form of colostrumderived antibodies after the immunization of sows. Our findings suggest that the PEDVS mRNALNP vaccine is a promising candidate for combating PEDV infection. IMPORTANCE Porcine epidemic diarrhea virus (PEDV) continues to harm the global swine industry. It is important to develop a highly effective vaccine to control PEDV infection. Here, we report a PEDV spike (S) mRNA vaccine that primes a potent antibody response and antigenspecific Tcell responses in immunized piglets. Active and passive immunization can protect piglets against PED following the virus challenge. This study highlights the efficiency of the PEDVS mRNA vaccine and represents a viable approach for developing an efficient PEDV vaccine.