Prokaryotic expression and analysis of a recombinant fusion protein of epi-tope of VP2 gene of isolated strains of infectious pancreatic necrosis virus

Abstract

Infectious pancreatic necrosis virus(IPNV) is a major viral pathogen of salmonid fish and causes serious economic losses to salmonid aquaculture.We amplified a 616 bp epitope of the VP2 gene from recent IPNV-ZYX isolated from farmed rainbow trout(Oncorhynchus mykiss) of China,and cloned into pCold TF vector(designated as pCold TF-VP2 COE).The expression of recombinant plasmid pCold TF-VP2 COE in E.coli BL21(DE3) was induced and detected by SDS-PAGE analysis.The predicted molecular weight for recombinant VP2 COE protein was approximately 78 ku and this was confirmed in this study.The fusion protein was purified with ProBondTMresin from the suspension centrifuged and the antisera against VP2 COE protein were produced.The prepared antisera reacted specifically with IPNV(ATCC VR-1318)antigen by indirect ELISA.The antisera against VP2 COE protein had OD values at least twice that obtained for the negative control serum at a dilution of 1:12 800.IFA showed specific reaction of the antisera against VP2 COE protein with liver samples of rainbow trout naturally infected with IPNV in Heilongjiang province.The results showed that the expressed VP2 COE protein was immunogenical and antigenical which was the same as the natural IPNV VP2 protein.All this work established a foundation for further study on vaccine and rapid diagnosis of IPNV.