Porcine Deltacoronavirus-like Particles Produced by a Single Recombinant Baculovirus Elicit Virus-Specific Immune Responses in Mice

Abstract

Porcine deltacoronavirus (PDCoV) causes diarrhea and vomiting in neonatal piglets worldwide and has the potential for cross-species transmission. Therefore, virus-like particles (VLPs) are promising vaccine candidates because of their safety and strong immunogenicity. To the best of our knowledge, the present study reported for the first time the generation of PDCoV VLPs using a baculovirus expression vector system, and electron micrograph analyses revealed that PDCoV VLPs appeared as spherical particles with a diameter similar to that of the native virions. Furthermore, PDCoV VLPs effectively induced mice to produce PDCoV-specific IgG and neutralizing antibodies. In addition, VLPs could stimulate mouse splenocytes to produce high levels of cytokines IL-4 and IFN-γ. Moreover, the combination of PDCoV VLPs and Freund’s adjuvant could improve the level of the immune response. Together, these data showed that PDCoV VLPs could effectively elicit humoral and cellular immunity in mice, laying a solid foundation for developing VLP-based vaccines to prevent PDCoV infections.

Prevention and Control of Swine Enteric Coronaviruses in China: A Review of Vaccine Development and Application

“…So, they have no risk of reversion to virulence and can elicit similar levels of robust humoral and cellular immune responses as LAVs [ 130 , 131 , 132 ]. VLP-based vaccines composed of the S, M, and E proteins against PEDV or PDCoV have been developed using a baculovirus expression vector system [ 133 , 134 ]. The immunogenicity of VLPs was evaluated in mice.…”

“…The immunogenicity of VLPs was evaluated in mice. Both VLPs could induce high levels of specific IgG and VN antibodies in serum and cytokines in splenocytes [ 133 , 134 ]. In addition, Guo et al engineered a chimeric VLP vaccine candidate using the phage Qbeta coat protein presenting the universal epitope of coronavirus (conservative residues -WDYPKCDRA- located in nsp12), including PEDV and PDCoV [ 135 ].…”