Analysis Of The PRRSV Specific Immune Responsiveness And The Changes Of Lymphocyte Subpopulatiorts In Swines After CSF Vaccination

Porcine reproductive and respiratory syndrome virus (PRRSV) was found in thelate of the1980s and spread rapidly all over the world。The virus is one of the mostimportant virus pathogens in pig industry now. PRRSV has two genetypes; they areEuropean genetype (Ⅰtype) and American genetype (Ⅱ type). It is the Americantype that is prevalent in most regions in China. Classical Swine fever is an acute,febrile and contagious disease which is caused by classical fever virus (CSFV). Themost effective way to prevent and control those two fatal diseases is immunizationtherapy. However, as the immunization program is different, we don’t know if there isan influence between the immune responses in the immuned pigs and neither theinfluence level. Our research is aimd to find the influence between CSF immune andPRRS immune in routine immunization program and provide the theory evidence toimprove the immune level and achieve a better immunization effect.In our study, we tested the specific pathogen and antibody in the peripheral bloodof523-week-old piglets from a herd in Changchun city. Firstly, we used ELISAtechnology to choose the samples which’s CSFV antibody and PRRSV antibody werenegative. Secondly, we used PCR technology to test if those samples had CSFV orPRRSV and kept the blood samples which did not have the CSFV, neither the PRRSV.Thirdly, we picked out the samples which had PRV or PCV-2. Finally,22specificpathogen-and antibody-free piglets were comfirmed and15of them were chose to beused in our study which’s growth state were similar to each other.In our experimental process, the piglets were vaccinated the Swine feverthermo-stable vaccine, live (rabbit origin).14days later, they were accepted thehighly pathogenic porcine reproductive and respiratory syndrome vaccine (strainTJM-F92). The peripheral blood was collected at the14thand28thday after HP-PRRSV immunization. The antibody level and the lymphocyte subpopulationswere tested by ELISA technology and flow cytometry respectively in order to find theinfluence of immune response of Swine fever thermo-stable vaccine to HP-PRRSVTJM-F92vaccine. The result indicates that at the14thday after HP-PRRSV TJM-F92immunization, the piglet that produced effective CSFV-antibody is73.33%of thewhole piglets and the ones that produced PRRSV-antibody is6.67%. Compired to theeffective-CSFV-antibody-free group, in the group with effective CSFV-antibody thenumber of CD3+and CD8+were reduced obviously, the number of CD4+and theratio of CD4+/CD8+were increased, which meant that the totall number of Tlymphocyte was decreased, most of the lymphocyte were divisive to CD4+, thenumber of memory lymphocyte was fewer and the vaccine emerged a higher level ofimmunization response. At the28thday after HP-PRRSV TJM-F92immunization, thetwo antibodys effective level was up to73.4%. In the CSFV-high antibody group, thenumber of CD3+was rised again but the number of CD4+and the ratio ofCD4+/CD8+was decreased, which was lesser than that in the group of CSFV-lowantibody. The result showed that the immune level was higher when the piglet got abetter immunization of CSF vaccine and the piglets responded to the HP-PRRSVvaccine rapidly to get an immune reaction and their lymphocyte differentiated in ashort time. At the14thday and28thday after HP-PRRSV TJM-F92, compared toCSFV-low antibody group, the number of CD4+, CD4+CD8+, CD4-CD8-and theratio of CD4+/CD8+were more in the CSFV-high antibody group but the numberof CD3+and CD8+were lower. In PRRSV-high antibody group, the number ofCD4-CD8-was higher than that in PRRSV-low antibody group.In a word, the response result to Swine fever thermo-stable vaccine doesinfluence the immune response to HP-PRRSV TJM-F92vaccine and a high level ofCSF immune response can raise the quality of HP-PRRSV immune response.