Immune Reseach On Genetic Engineering Subunit Vaccine Of Cow Mastitis

For the benefit of practical production, we applied the genetic engineering subunit vaccine of Staphylococcus aureus to immune the cow, then observed how it can influence the incidence of mastitis and milk productivity. We have established ELISA method to detect peculiar antibody and established regressive equation and regressive curve base on the serum OD value and serum titers according statistics. We also reasearched the increase and decline regulation of peculiar antibody after the immunity.Mastitis is an usual and common disease of cow. Subclinical mastitis is the most usual clinical case. Because of it have no obvious clinical symptom, we usually apply some special methods to examine it. There are many methods to examine this disease. We have examined 173 cows through the usual mehtod such as SMT method, NaOH method, H2O2 mehtod and BTB method, through general analysis, there are 89 cows suffered subclinical mastitis, the positive rate is 51.45%. There were 181 positive breast districts and the positive rate was 26.66%. We also isolated 225 strains of bacteria from the positive breast districts, the rate is 82.54%. The bacteria mainly include Staphylococcus aureus, Streptococcus dysgalacitiae and Streptococcus agalactiae, the positive rate was 40.44%, 19.11% and 18.22% respectively. There also were other bacteria such as E.coli, Streptococcus uberis and Staphylococcus epidermidis etc. Base on the need of test, we chose 60 cow from test cow according to different conditions. Then we allocated them into 2 large groups, namely the test group and control group. A group include cow which suffered subclinical mastitis; B group included 10 healthy 10 post partum; C group included 10 healthy cow that beginning to propagate. The control group included 10 same period, same house and same kind condition cows comparing with test group. We gave the test cow subcutaneous injection with lml vaccine at buttocks. We immunized the cow 3 times and the interval was 15 days. We immediately sampled 10 ml blood after the every injection and 1, 2, 3, 4, 5 months after the final injection. Then we isolated serum from blood and Frozen it at - 20 C for carrying out peculiar antibody detection. At the 4th month after the third immunity, we carried out statistical analysis of the incidence of subclinical mastitis, the daily milk production and so on. The result indicated that the incidence of subclinical mastitis of test group was obviously lower than that of controlgroup. The effective rate was 55.6%, 66.7% and 50.0% respectively. The milk production was obviously increased. The increasing rate was 12.84%, 10.29% and 9.10% respectively. From the clinical standpoint, we made concluded that the genetic engineering subunit vaccine have practical value.Base on the conventional ELISA method, we have established ELISA detection method to detect the serum peculiar antibody of vaccine. We also optimized the reaction condition and established standard peculiar ELISA detection program. Then we applied this method to supervise the increasing and declining regulation of peculiar antibody and offered basis theory for clinical application of this vaccine. At the time of second immunity, the average peculiar serum antibody titers increased quickly and the average OD value was 1.08. The peculiar antibody titers reached the highest level and the OD value was 1.80 at 1 month after the third immunity. The peculiar antibody titers still maintained high level at 5 month after the third immunity. There was no discrepancy among the immune groups. For the better of estimating the peculiar antibody titers through the OD value, we diluted serum 1:100 times and compared the OD value with corresponding serum antibody titers, then analyzed the relation by statistics. We found that the there are certain linear relation between them. Then we worked out the regressive equation and drew out the regressive curve. The regressive equation is y = - 1.621 + 0.244 log2x( y: the OD value of the serum which was diluted times; x: the reciprocal of serum antibody titer...