Virus-like particle-derived vaccine induces broad neutralising antibodies against porcine epidemic diarrhea virus (PEDV)

Although vaccines against porcine epidemic diarrhea viruses (PEDVs) are available, PED outbreaks still occur in many countries due to the emergence of new variants. Therefore, more work is required to develop efficient and broadly protective vaccines. To this end, we present here a new vaccine candidate, AP205-S1, which could effectively elicit systemic and mucosal antibody responses in mice and pigs. The vaccine was generated by coupling the S1 protein of PEDV-KB2013-130 with AP205-VLP via SpyCatcher/SpyTag bonding. AP205-S1 demonstrated an intact and homogenous viral particle structure and packed ssRNA. Upon administration in mice, AP205-S1 induced high amounts of S1-specific IgG antibodies in sera as well as in gastrointestinal tracts, especially after the booster. Importantly, these antibodies were able to neutralize PEDV KB2013-130 in vitro, indicating that the vaccine protects against PEDV infection. Of note, AP205-S1-elicited antibodies exhibited cross-neutralizing potencies against AH-2018 strains, belonging to the G-I group. Last but not least, S1-specific IgG antibodies were stimulated in pigs after AP205-S1 immunization, which could recognize and block PEDV from infecting Vero cells in vitro. The viral loads in AP205-S1-immunized pigs were strikingly reduced compared to AP205-SpyCatcher-immunized pigs. In conclusion, AP205-S1 exhibited excellent immunogenicity in mice and pigs and posed protection against PEDV infection in pigs.