Recombinant expression and polyclonal antibody preparation of the nucleoprotein, phosphoprotein and matrix protein of spring viremia of carp virus

Spring viremia of carp virus (SVCV) is an OIE listed highly pathogenic agent of several economically important Cyprinidae fish species. Currently, there is no effective vaccine or drug available for this virus, and prevention of SVC mostly relies on prompt diagnosis. Previously, detection methods based on the G gene or the G glycoprotein have been developed. However, the highly genetic diversity of the G gene seriously limits the reliability of those methods. To develop a rapid immunological detection method for SVCV, the N, P and M genes of SVCV were cloned into a pRSET-A prokaryotic expression vector. Recombinant proteins were then induced with 1 mmol/L IPTG at 37 °C. Next, recombinant proteins were purified and used to immunize New Zealand rabbits. Titers and specificities of antibodies were verified by indirect ELISA and Western blot. Our results indicated the obtained antibodies were highly specific to SVCV and the titers could reach at least as high as 204 800. Besides, indirect ELISA assays based on prepared antibodies showed there was no cross reaction with other aquatic viruses. Our results will be useful for the rapid immunological detection of SVCV and provide a new insight into the vaccine development of SVCV.