Clinical Immune Response Study Of Pseudorabies Vaccine And The Initial Establishment Of GB Antibody Level Evaluation Method

Since the rebound outbreak of the disease PRV in 2011, which is still one of the major infectious diseases that affecting pig farms production. It is the main measures to control this disease in our country to carry out ELISA serological detection and teffective immunization of the gene deleted vaccine. So studying on gB antibody response regμlarit of immuned pigs, establishing an objective evaluation ELISA method for detecting gB antibody,which can guide a reasonable vaccine and help control the disease.We mainly using the IDEXX-gB/gE antibody detection kit to test on 7 lactating sows and their 21 suckling piglets、46 nursery pigs before and after vaccination.Finally,we excluded the wild virus infection of nursery pigs and infered the wild virus infection pressure of this farm is small,the gB maternal antibody can be persisted to 95-111 days,the optimum first immune time can be delayed from 75 to 95 days, and then carryig out the second immunization at a reasonable time.it will receive a better mmune effect.Besides,when we proceed the first immunization at the optimal S/N interval which is more than 0.5, the positive conversion of gB antibody is better.These conclusions can provide a better guidance for PRV gene deleted vaccine immune, it also make important significance for PRV prevention in the actual production. In addition, it is found that the gB antibody level differences between individual can be distinguished clearly when we detected the dilutied 8 sows gB antibody serum which S/N value below 0.1,and the 8 serums just have been dilutied by 100,200 and 400 times.So it proves that IDEXX-PRV-gB kit has few applicability for the detection of sow serum.In addition.we expressed PRV conservative glycoprotein gB at 86aa-480aa and 540aa-734aa fragment according to the corresponding gene sequence by using the prokaryotic expression system of Escherichia coli.The expressed gB-M and gB-N are both inclusion protein, after urea solubilized and purified，we did Western-blot experiment, and found that these two proteins both have good reactivity with PRV standard positive serum.Through the initial serum detecting experiment, we pick out gB-M protein as the antigen protein to establish the method. Then we preliminary established the gB-M antigen ELISA detection method.Throμgh the assay of testing 226 clinical positive and negtive serum that detected by IDEXX-PRV-gB kit. we just found the method and IDEXX-PRV-gB kit have the coincidence rate、sensitivity and specificity are 80.1%、91.9%、72.9% respectively. Among them, the coincidence rate of the 64 sows positive sera was 95.3%, but the coincidence rate of piglets positive sera was only 53.9%.Compared with the IDEXX-PRV-gB kit in the detection of serum in sows, we found that this method can clearly distinguish the difference of gB antibody level among individuals. The author thinks that the glycosylation modification of gB protein expressed by the prokaryotic expression system is not sufficient, and its sensitivity is not high.