Soluble Expression And Identification Of Antigen Domain Of Classical Swine Fever Virus E2 Protein

Classical swine fever(CSF)is one of the most important infectious diseases that endanger the health of pigs.It has acute,hot and highly contacted characteristics,causing huge economic losses to the pig industry in the world.Classical swine fever virus(CSFV)can form four structural proteins and eight non-structural proteins under the action of lytic enzymes.The envelope glycoprotein E2 protein is an immunodominant protein that can induce the body to produce neutralizing antibodies and protect animals from swine fever.An in-depth study of E2 protein revealed that regions A,B,C,and D are the major antigenic regions in the E2 gene.Therefore,The expression and purification of E2 major antigenic regions containing A,B,C,and D regions have important research significance and application value for the research and detection of swine fever disease.In this study,we used prokaryotic expression system to express the gene(531 bp)in the main antigen region containing A,B,C,and D regions of E2 protein.Connect E2 antigen gene with PET-28a-SUMO expression vector.SUMO was used as the solute tag to increase the solubility of the protein,and Set the induction temperature at 37°C,28°C,16°C and IPTG concentrations 0.1,0.3,0.5,0.7,1 mmol/L for optimization.The results showed that the target protein SUMO-E2 is expressed in a soluble form at a low temperature of 16°C,and the soluble protein expression is highest at an IPTG concentration of 0.7 mmol/L.After nickel secondary column chromatography,the target protein was obtained at a concentration of 0.7 mg/mL.Western-blot analysis of soluble E2 protein has good reactogenicity and mouse immunoassay proved that E2 protein has good immunogenicity.Western-blot analysis and ELISA test proved that soluble E2 protein has good reactogenicity,and can be used as antigen for detection of swine fever antibody.The acquisition of E2 protein lays the foundation for the establishment of classical swine fever serological detection method.