The Research And Evaluation Of Reference Standard Of Porcine Circovirus Type 2 Inactivated Vaccine

Porcine Circovirus Type 2(PCV2) is the main pathogen of post-weaning multisystemic wasting syndrome(PMWS), which has caused severe economic losses to the swine industry. To prevent and control the contagion of PCV2, the Ministry of Agriculture approved 5 strains of PCV2 inactivated vaccine, which are produced by 16 factories respectively. However, none of the vaccines share the same method of potency test, and some of them still has to use swine to evaluate its potency, while the negative pig is hard to find and the experiment is time and energy wasting. All of these problems increase the difficulty to the supervision of the quality control of the PCV2 vaccine. And due to the lack of the normative reference standard,which is necessary in the mice immunity test to estimate PCV2 inactivated vaccine(strain SH), a reference standard of PCV2 inactivated vaccine is needed to be developed as soon as possible.Primarily, this study selected a patch of PCV2 inactivated vaccine(strain SH) with good quality and uniformity as the candidate material. After manufacturing, its characteristics were measured.Meanwhile, the swine challenge assay was carried out to ensure that the vaccine is effective and qualified to be a reference standard in the alternative method. Then, in order to establish an alternative method in vitro, which is more objective and accurate, a real-time fluorescent quantitative PCR method was developed and optimized, and the statistical correlation analysis demonstrated that there was a good correlation between this new method and the mice immunity test. Besides, because of the various potency test method among the vaccines with different strains, an applicability test was tried with the mice immunity method, but the result indicated that a further trial is necessary. Last, a collaborative study was carried out to demonstrate that the reference standard for PCV2 inactivated vaccine was suitable for its intended use. The raw data from 4 participant labs were analyzed by statistical analysis,and the uncertainty of assay was introduced into the assignment of the reference standard to get more precise result with an fiducial range.