Immunogenicity of Subunit Vaccine of E2 Protein Against Atypical Porcine Pestivirus in Pigs

An atypical porcine pestivirus (APPV) causes congenital tremor (CT) type A-II in piglets and has caused considerable financial losses to the pig industry worldwide. This study aimed to develop an effective vaccine candidate against APPV. In this study, we constructed a prokaryotic expressing APPV E2 protein by Escherichia coli and evaluated the immunogenicity of the APPV E2 subunit vaccine with three different adjuvants in piglets by E2-enzyme-linked immunosorbent assay antibody and the protection against APPV challenge in pigs. E2 protein was successfully expressed by the Escherichia coli prokaryotic expression system firstly, and was confirmed by western blot assay. The E2-enzyme-linked immunosorbent assay antibody detection method was established. Vaccined piglets mounted virus-specific IgG responses. The E2 protein emulsified with ISA 201VG and Gel 02 adjuvant induced significantly higher levels of antibodies than those emulsified with IMS 1313VG adjuvant. The vaccine with ISA 201VG adjuvant had highest antibody levels and can protect against APPV infection. The results demonstrated that Escherichia coli-expressed E2 is mounting an immune response in pigs, E2 subunit vaccine maybe a potential vaccine candidate for the prevention of APPV infection, ISA 201VG and Gel 02 adjuvant can be used as candidate adjuvants for vaccines. This study provides a basis for the further research of APPV vaccine.