The Research And Evaluation Of National Reference Standard Of Highly Pathogenic Porcine Reproductive And Respiratory Syndrome Living Vaccine(Strain JXA1-R)

A large breakout of highly pathogenic porcine reproductive and respiratory syndrome has caused severe economic losses to the swine industry in2006. China animal disease prevention and control center successfully developed the first living highly pathogenic porcine reproductive and respiratory syndrome virus vaccine (strain JXA1-R) after years.At present, the Ministry of Agriculture approved the production of porcine reproductive and respiratory syndrome vaccine in many enterprises, but currently due to the lack of standard references on the market, it is difficult to evaluate and control its quality. So National Reference used to control the quality of the vaccine are needed to be developed as soon as possible.This study primarily finished the establishment of the preparation and selection methods of national reference standard of highly pathogenic porcine reproductive and respiratory syndrome vaccine (JXA1-R strain). After comparison, selecting a patch with high potency and good uniformity. After manufacturing, its characteristics were measured.In order to measure the potency of vaccine precisely, the probes and primers were designed and synthesized according to the conserved genes of PRRSV and then reaction parameters were optimized to develop a real-time fluorescent quantitative PCR method for evaluation of highly pathogenic porcine reproductive and respiratory syndrome living vaccine (JXA1-R strain) reference standard. The method is used before and after virus cell culturing, after is10times before. Statistical correlation analysis indicates that there is good correlation between this new method and traditional method(TCID50). Last, collaborative study is carried out to demonstrate that the candidate national reference standard for PRRSV(JXAI-R) is suitable for its potency by TCID50.Then the raw data from every participant company are analyzed by statistical analysis, and the uncertainty of assay is introduced into the assignment of national reference standard PRRSV(JXA1-R) to get more precise result with an fiducial range.