Construction Of Bivalent Nucleic Acid Vaccines Against IBV And IBDV And Immune Adjuvant Effect Of Chicken IL-8 On The Vaccines In Chicken

In this study, IBV S1, IBDV VP2 were subcloned into eukaryotic expression vector, respectively followed by fused expression in the same vector to construct three recombinant plasmids named r pVAX-IBV S1 pVAX-IBDV VP2 and pVAX-IBV S1-linker-IBDV VP2. Transient transfection of these three fusion plasmids in vitro showed that the genes could be expressed in BHK cells and could be recognized by specific anti-IBV monoclonal antibody and anti-IBDV polyclonal antibody. The results provided the useful materials for subsequent immunization in vivo.The experimental chicken were divided into 8 groups, the S1 group inoculated with the pVSX-IBV S1, VP2 group inoculated with the pVAX-IBDV VP2, the SV group inoculated with the pVAX-IBV S1-linker-IBDV VP2, the SV18 group inoculated with the pVAX-IBV S1-linker-IBDV VP2 and pVAX-ChIL-18, the 18 group inoculated with the pVAX-ChIL-18, the YM group inoculate with the IBV and IBDV vaccines, the PBS group inoculated with PBS, the pVAX group inoculated with empty pcDNA3.1 vetor. Lymphocyte proliferative assay, enzyme linkered immunosorbent assay, neutralization antibody and flow cytometric technique were used to detect the immune response of different groups at different days post-immunization. Finally chickens in different treatment groups were challenged with IBV and IBDV to compare the difference of the protection rate of the plasmids.The results showed that the bivalent DNA vaccine has a protective effect against the two viruses. In addition, ChIL-18 used as an adjuvant enhanced the immune effect of the bivalent DNA vaccine.