Preparation And Immune Effect Evaluation Of Inactivated Vaccine For Japanese Encephalitis Virus On Swine

Japanese encephalitis?JE?,caused by Japanese encephalitis virus,is the zoonosis and its main medium is culex?Cx.?.The sow easily get latent infection,especially when the farrowing sow get infected,it will bring about a series of reproductive disorders such as high fever,abortion,stillbirth,mummy fetus,etc.At the same time,it can lead to infertility and boar orchitis,causing huge economic losses to pig industry modernization.The JE patient will develop symptom of high fever,consciousness disorders,convulsions,tetanic spasm and meningeal irritation symptoms,threatening human health.Therefore,the control of JE can not only improve the efficiency of swine industry and reduce the loss,but also can provide a powerful guarantee for human health and sustainable development.To obtain high titer viruses and more effective vaccine of JEV/GD from swine,this study optimize the conditions of JEV multiplication on Vero cells and virus inactivation.The results showed that the most suitable serum concentration on Vero cells was 10%NCS;the optimal maintaining serum concentration in liquid was 2%NCS;the best inoculation dose was 1%;the best cell inoculation density was 60%⁸0%;the best inoculation method was asynchronous inoculation;the best time for harvesting virus was 90h;the best conditions for inactivation was 0.1%formalin with inactivating for 24h.By optimizing the condition,the virus TCID₅₀ reached 10^7.9/mL.In strict accordance with C hina Biological Products,the safety and great promising oil emulsion inactivated JEV/GD vaccine and attenuated vaccine by the use of high-titer virus solution was prepared,which would contribute to the further industrial production of JE vaccine.In order to evaluate the immune efficacy of JEV/GD oil emulsion inactivated vaccine,an artificial infection model of GD strain was established.The results showed that the body temperature was slightly increased after artificial infect ion of piglets,and there were some neurological symptoms,poor appetite and testicular enlargement.The attack of the pathological changes can be used for piglets immune attack protection test,indicating that the model has been basically established.RT-PCR was used to detect the serum samples of0 d?7 d?9 d?11 d?13 d?15 d?21 d?28 d after virus attacking,but failed to find the JEV virus.The efficacy of JEV/GD oil emulsion inactivated vaccine showed that high antigen content generated antibody earlier,JEV antibody can be detected after 14 d and became positive after 21 d,strengthening the immune antibody level of JEV would greatly improve after 21 d.The results also showed that the JEV antibody level was low after primary immunity,but the level of JEV antibody was greatly improved after the second immunization.It can be known,the research on the preparation of porcine JEV/GD strains of oil emulsion inactivated vaccine has good immunogenicity characteristics,high safety,long duration of antibody and the huge market prospects.