| Classical swine fever is a highly contagious febrile infectious disease caused by classical swine fever virus,and it is one of the main infectious diseases affecting the pig industry.Vaccination is the main method of preventing and controlling of this disease.Monitoring of CSFV antibody level in pigs reflects the immune protection level of swine.In this study,serological detection of classical swine fever antibody level of swine fever in some areas of Jiangxi Province from 2018 to 2018 was carried out in order to understand the immune protection level of classical swine fever in different stages.Classical swine fever virus E2 protein is a structural protein of classical swine fever virus and the main protective antigen of classical swine fever virus.At present,commercial classical swine fever E2 protein subunit vaccine has been used in the immune prevention and control of classical swine fever.In this study,a recombinant swinepox virus expressing classical swine fever E2 protein was constructed,and classical swine fever E2 protein was successfully expressed,which laid the foundation for the research and development of classical swine fever subunit vaccine.1.Investigation on Antibody level of Classical Swine Fever in Jiangxi Province.A total of 16424 pig sera,which collected from porcine farms in Jiangxi Province from 2016 to 2018,were tested for classical swine fever antibody(including10238 breeding pigs,1107 lactating piglets,2745 nursery pigs and 2289 fattening pigs)by using the classical swine fever antibody detection kit made by IDEXX Company.As shown with results,the positive rates of classical swine fever antibodies from 2016 to 2018 were 82.53%,83.21% and 82.88% respectively.The positive rates of classical swine fever antibodies in spring,summer,autumn and winter were 83.19%,81.41%,83.53% and 83.27%,respectively,and the difference of antibody positive rate between different seasons is not obvious.The positive rate of classical swine fever antibody varied greatly in different stages: the positive rate of breeding pigs was90.16%,that of suckling piglets was 73.23%,that of nursing pigs was 59.20%,and that of fattening pigs was 82.96%.The level of antibody to swine fever in nursery pigs is the lowest,which may be caused by the attenuation of maternal antibodies at the stage of suckling piglets,irrational immunization procedures or the body has not had enough time to produce a good immune response.The positive rates of classical swine fever antibodies in Nanchang,Jiujiang,Ganzhou,Yichun,Shangrao,Ji’an,Fuzhou,Jingdezhen,Pingxiang,Xinyu and Yingtan were 86.23%,82.94%,87.55%,82.35%,79.23%,82.87%,82.49%,87.70%,75.29%,86.21% and 79.42%,respectively.2.Construction of Recombinant Swine pox virus expressing Classical Swine Fever E2 protein.The full-length E2 gene was synthesized from the genome of classical swine fever virus Jiangxi isolate CSFV-JXNC01-2015(KX064281.1).The E2 gene was amplifified by PCR with primers(3’ terminal tagged protein 6 × his).(Based on In-fusion Clone method,the E2 gene was incorporated into the p SWE101 transfer vector.Using this system,a recombinant virus p SWE101-P28-E2-His was produced.)SWPV-JX20 G of swinepox virus isolated from Jiangxi was the parent virus,and the TK gene was the insertion site of the foreign gene.Vaccinia virus promoter P28 starts the foreign gene.After transfection and 5 rounds of recombinant virus purification,the pure recombinant swinepox virus r SWPV-P28-E2-His had been obtained.The recombinant virus was proliferated and verified by SDS-PAGE.The results showed that the recombinant virus successfully expressed the soluble E2 protein. |
PDF Full Text Request