Preliminary Study On Thermotolerant Form Of Classical Swine Fever (CSF) Vaccine

Classical swine fever(CSF)which caused by classical swine fever virus is an acute,febrile,highly contagious and mortality disease of swine.It is one of the substaintial disease to prevent in hog industry.Classical swine fever vaccine is one of the most useful method to prevent CSF.Freeze-drying technology is considered as an effective vaccine manufacturing measures at home and aboard currently,by adding thermo-tolerance,CSF live vaccine can be stored at 2?8? for 2 years.However,It contains a high proportion of gelatin and protein,they always cause the adverse reaction of fervent allergy and fever in the immune process,affecting the vaccine's safety and efficiency.In addition,lyophillized vaccine is strict with environment temperature,the process of preservation,transportation and usage must rely on high array cold chain system,bring much inconvenience to preservation,transportation and usage of vaccines.Vacuum foam drying vaccine usually have a better thermotolerance,can effectively decrease the dependence of cold chain.This study is intended to improve the lyophilized vaccine of CSF and develop its vacuum foam drying vaccine.The optimized of formulation and drying process and aging test was used to screened no protein no gelatin lyoprotectant formulation which solved the problem of safety which caused by the protein and gelatin,and foam drying agents which protect CSFV were explored,laid the foundation for study of CSF vaccine stored at room temperature.1 Lyophilization research of CSF live vaccineThe main components of freeze drying protective agent are sucrose,lactose,and EDTA,by single factor variable experiment,form of the fomula,dry form of the vaccine,the redidual moisture content as indicators to screened the thermotolerant agent of CSF freeze drying vaccine.S3-T1 formula which contain gelatin and protein and D4 formula without gelatin and foreign protein were screened,D4 is the first thermotolerant formula without gelatin and foreign protein of CSF freeze dried vaccine,which can effectively avoid the incidental immune response caused by gelatin and protein in the process of using.In view of the lyophilized product layer,shrinking,by controlle the shelf temperature of sublimation stage and adjust primary drying time,dry form of the vaccine,redidual moisture and 37? 10d degrees of virus as the standard,Then make three batches of product use the best formula D4 and S3-T1and the best freeze drying process.S3-T1 can protect CSF vaccine at 37? for 16 days which titer decreased less than 1.0,D4 can protect CSF vaccine at 37? for 11 days which titer decreased less than 0.7,both of them are meet the requirements.2 Vacuum foam drying research of CSF live vaccineThe main components of VFD protective agent are trehalose and glycerol and so on,by single factor variable experiment,and the recipe form,dry form of the vaccine,the redidual moisture content as indicator to screened the VFD thermotolerant agent of CSF vaccine.T28C series was selected as CSF vaccine VFD basis thermotolerant formula,then adjust its composition and process potimization,by rabbits temperature experiments to check out its thermotolerant potency,T28C-16 and T28C-38 formulas were selected finally.To adjust and optimize the primary and secondary drying process after determine the formulation.Adjust the maintaining time between 300200Pa which is the important stage of expanding foam,discover 10min is best.The time of secondary drying was selected from 40,42 and 44 hours,the result shows that the residual moisture of product with 40 hours was higher than 4%,which is disqualification,product which dried with 42 and 44 hours were both qualified,considering the cost,42 hours is best in secondary process.Three batches of product were made after determine the best formula and best VFD process,by aging test,T28C-16 can protect CSF vaccine at 37? for 15 days which titer decreased less than 1.0,T28C-38 can protect CSF vaccine at 37? for 20 days which titer decreased less than 1.0.Disturbance test showed that the simple formula can not cause the rabbits'thermal reaction,so the formula is not influence the thermal reaction of rabbits.