The Study On The Production Of Combined Newcastle Disease(ND)and Avian Influenza(AI)Inactivated Vaccine(Strain LaSota+Strain HP)

In order to inquire the key points of the quality control in the Combined Newcastle Disease(ND)and Avian Influenza(AI)Inactivated Vaccine(Strain LaSota+Strain HP)production process and provide scientific basis,virus reproduction,antigen ultrafiltration,inactivation,emulsification,were studied in this paper.1.Virus reproduction:10 day-old chick embryos were inoculated with New castle Disease virus(NDV)LaSota strain and Avian influenza virus(AIV)H9 subtype HP strain respectively and harvested at different time points.Then,virus titer of different harvest time points were detected.As a result,the highest level of virus titer of NDV reached 109.7EID50/ml at 84h-96h.The highest level of AIV antigen reached 109.7EID50/ml at 66h-78h,and the virus titer remained at 109.7EID50/ml till 96 h.The result showed that the optimal harvest time point for NDV was 96h,which should not be conserved at-15℃ for more than 3 months,and the optimal harvest time point for AIV was 96h,which should not be saved at-15℃ for more than 2 months.2.Antigen ultrafiltration:Different times of concentration gradients were used to concentrate the NDV and AIV.Then,the comparison of viral load,hemagglutination titer and immunity were studied.According to the experimental data and actual production,the optimal concentration gradient for NDV and AIV were both 2 times.3.The concentration of formaldehyde and the inactivation time:The influence of different formaldehyde concentration and inactivation time on inactivating the NDV and AIV were studied in order to obtain the most appropriate inactivation condition.The result showed that the optimal inactivation condition for NDV was with 0.1%formaldehyde and inactivated for 16h.The optimal inactivation condition for AIV was 0.1%formaldehyde and inactivated for 18 h.4.Emulsification:The effect of different time points and speed for emulsification were also studied in this chapter.The result suggested that the best condition for emulsification was 3000r/min for 45minutes to 75 minutes.According to the immunity tests by using the samples which were emulsified through different ratio of water-phase antigen and oil phase.The result suggested that the optimal ratio of water-phase antigen and oil phase were 1:3.