| Swine Japanese encephalitis and porcine circovirus disease are seriousinfectious diseases against the pig industry, and Japanese encephalitis seriously harmto human health. There is no effective drug treatment for the two diseases, vaccinationis an effective mean to prevent and control the two diseases. In order to prevent thedouble diseases effectively, we studied the proliferation dynamic of LS strain ofJapanese encephalitis virus in Vero cell, the immunogenicity of LS strain of Japaneseencephalitis virus, we also preparated the swine Japanese encephalitis-porcinecircovirus disease combined oil emulsion inactivated vaccine with LS strain ofJapanese encephalitis virus and HNYY strain of porcine circovirus type2which wereisolated and identified by our laboratory. The specific results are as follows:1. Studies of the physical and chemical characteristics of LS strain of Japaneseencephalitis virus and the proliferation dynamic of LS strain of Japanese encephalitisvirus in Vero cellThe proliferation law of LS strain of Japanese encephalitis was studied in Verocell, the physical and chemical characteristics was studied too. The strain wasinoculated in Vero cell which grew into a single layer in25cm2cell culture flasks withinoculation amount of106.2TCID50.Collected the cell supernatants and suspensionsevery8h after inoculation, and the virus titers was measured later. The virus titers ofthe cell supernatants and suspensions peaked at56h after inoculation, respectively for106.0TCID50/0.1mL and106.5TCID50/0.1mL;The study of the physical and chemicalcharacteristics show that the strain is sensitive to ether, trypsin, hot (56℃),acid(pH5.0),not sensitive to repeated freezing and thawing. This is consistent with theliterature.2. Studies of the immunogenicity of LS strain of Japanese encephalitisThe LS strain of Japanese encephalitis virus was inoculated to Vero cell forproliferation, then the harvested virus was inactivated by formaldehyde and wassubjected with mineral oil adjuvant, oil emulsion inactivated vaccine preparated.Immunogenicity studies of the vaccine were taken in mice and pigs. The results showthat the vaccine induced an average of1:64latex agglutination test (LAT) antibodies titers against Japanese encephalitis virus in mice, induced an average of1:200hemagglutination inhibition (HI) antibody titers against Japanese encephalitis virusin pigs. The antibody titers of the vaccine are higher than commercially available pigJapanese encephalitis inactivated vaccine. The strain has a good immunogenicity.3. Studies of swine Japanese encephalitis-porcine circovirus disease combinedinactivated vaccineThe solutions with high virus titers were harvested by proliferating Japaneseencephalitis virus (LS strain) in Vero cell and proliferating porcine circovirus type2(HNYY strain) in PK-15cell. Then the solutions concentrated, inactivated byformaldehyde, mixed with an equal amount, added oil adjuvant. At last, the swineJapanese encephalitis-porcine circovirus disease combined oil emulsion inactivatedvaccine was preparated. The vaccine was tested by physical properties testing, sterilitytesting, security testing and immunogenicity test. Results show that the form of thetrial combined vaccine is stable, the combined vaccine is safe to mice, and inducedtwo antibodies against Japanese encephalitis virus and porcine circovirus type2inmice after vaccination. The vaccine induced an average of1:37.33latex agglutinationtest (LAT) Japanese encephalitis virus and an average of1:3200ELISA antibodiestiters against porcine circovirus type2in mice. The two antibodies of the combinedvaccine are not lower than the corresponding single vaccines. So there are not mutualinterference between the two antigens, the two antigens did not mutually affectimmune response each other in the animals. |
