| Porcine epidemic diarrhea (PED) is an infectious disease that caused by the porcine epidemic diarrhea virus (PEDV), the main symptoms of this disease is diarrhea and vomiting, it can infect porcine of all ages, mortality rates remain high. This disease has become a major problem in the pig industry since it was found in the 1970s, and it has brought huge losses to Europe and Asia pig industry in short time. Therefore, the development of PEDV vaccine becomes particularly important, and the study of the characteristics of production seed virus is the basis for vaccine research.In this study, we cultured the PEDV-SC-P strain in Vero cells. According to the standard Chinese Veterinary Pharmacopoeia 2010 edition and The Veterinary Biological Products Quality Standards of the People’s Republic of China 2001 edition, we were did pure test for production cells and the PEDV-SC-P strain’s proliferation characteristics, genetic stability, physicochemical properties, purity, safety, immunogenicity, specificity and strain’s optimal preservation conditions were tested in order to assess its development prospects and value as a vaccine seed virus. Cells and Viruses purely check results show that there was no presence of bacterium, mildew, mycoplasma and exogenous viruses in the PEDV culture with Vero cells and PEDV strain; Proliferation characteristics and genetic stability studies show that, PEDV in Vero cells serially passaged 40 times, stable cytopathic effect (CPE) appeared in every times, proliferation of virus in the cytoplasm, virus content peaked in the 36 hours after inoculation, and the virus have stable virulence and high genetic stability; Physical and chemical properties studies show that PEDV strain sensitive for chloroform and ether, and 5-BUDR without its DNA replication inhibition what, in line enveloped RNA virus signatures; PEDV strain have well stability in the environment of PH3-7, and its thermal stability is not high, sensitive for above 55℃; Multiple generations times of PEDV test results indicate that, each generation times viral content are greater than or equal 106PFU/mL, can be specificity combined with standard positive serum; Vaccination to piglets, no adverse reactions and safety; Vaccinated pigs can withstand PEDV-Ea virulent strain, morbidity and mortality were better than the control group, PEDV-SC-P strain with good immunogenicity. The storage conditions and time of virus strain studies show that the lyophilized basic seed in the environment of below -20℃ stored for 18 months is still in line with the virus content standards; The production seed in the liquid state,-20℃ to save 9 months still meet the requirements of viral content,-70℃ can be stored for at least 18 months. The results of this study showed that the detection of PEDV-SC-P strain for vaccine production are in line with the conditions, PEDV-SC-P strain have the value with vaccine development. This study provides data support and theoretical basis for PEDV-SC-P strain’s vaccine development, laid a solid foundation for the next step in vaccine research work. |
