ABSTRACT
In present study, in order to develop a new and effective porcine epidemic diarrhea virus (PEDV)vaccine, three B cell epitopes and the truncated S1 gene of PEDV spike protein were combined and inserted into the immunodominant region of the HBcAg. Then the constructed recombinant plasmid HBcAg-PE was transformed to E. coli BL21 (DE3) for expression. After purification and identification by Western-blot, the expressed recombinant proteins HBPE were injected into BALB/c mice as vaccine antigen with different doses through intramuscular injection and its immune effect were preliminary evaluated. The results showed that the recombinant proteins HBPE was expressed as precipitation form and it could reacted specifically with PEDV-positive serum after purification and renaturation. Besides, the RH could induce anti-PEDV specific antibodies and the related Thl and Th2 cytokines in mice. The above results indicate that the recombinant compound epitope antigen of PEDV was successfully constructed. and its immunogenicity as a new vaccine candidate was evaluated in the mice in this study. The results of this study provided a new idea for the development of PEDV genetic engineering vaccine in the future.
ABSTRACT
Although porcine deltacoronavirus (PDCoV) is a significant pandemic threat in the swine population and has caused significant economic losses, information regarding the immune response in conventionally weaned pigs infected with PDCoV is scarce. Hence, the immune response in conventionally weaned pigs infected with PDCoV was assessed after challenge and rechallenge. After the first challenge, obvious diarrhea and viral shedding developed successively in all pigs in the four inoculation dose groups from 3 to 14 days postinfection (dpi), and all pigs recovered (no clinical symptoms or viral shedding) by 21 dpi. All pigs in the four groups exhibited significantly increased PDCoV-specific IgG, IgA and virus-neutralizing (VN) antibody (Ab) titers and IFN-γ levels in the serum after the first challenge. All pigs were completely protected against rechallenge at 21 dpi. The serum levels of PDCoV-specific IgG, IgA, and VN Abs increased further after rechallenge. Notably, the IFN-γ level declined continuously after 7 dpi. In addition, the levels of PDCoV-specific IgG, IgA and VN Abs in saliva increased significantly after rechallenge and correlated well with the serum Ab titers. Furthermore, the appearance of clinical symptoms of PDCoV infection in conventionally weaned pigs was delayed with reduced inoculation doses. In summary, the data presented here offer important reference information for future PDCoV animal infection and vaccine-induced immunoprotection experiments.