金黄色葡萄球菌性奶牛乳房炎多价疫苗的研制和免疫效果评价

为研制用于预防金黄色葡萄球菌性奶牛乳房炎的免疫疫苗,使用4株血清型为外膜多糖336型(336PS)、荚膜多糖5型(CP5)和荚膜多糖8型(CP8)强毒力金黄色葡萄球菌试制出金黄色葡萄球菌多价疫苗,并通过抗体水平监测、攻毒保护试验以及两个牧场的田间试验对免疫效果进行了评价。抗体水平监测显示,首免后30 d即可产生较高的抗体水平,二次免疫后有效抗体水平可持续到产后210 d;人工攻毒保护试验显示,疫苗对金黄色葡萄球菌引起的临床型乳房炎的保护率为89%;田间试验结果表明,该疫苗对奶牛临床型乳房炎的保护率在75.2%～83.3%之间,对隐性乳房炎的保护率在49.9%～52.2%之间,免疫组日产奶量较对照组平均提高1.26 kg以上。上述结果表明,所试制的疫苗可以显著降低泌乳牛金黄色葡萄球菌引起的临床型和隐性乳房炎发病率并提高产奶量。

Development and Immune Efficacy of Polyvalent Staphylococcus Aureus Vaccine against Bovine Mastitis

To develop a Staphylococcus aureus vaccine for bovine mastitis prevention, the polyvalent vaccine was prepared with 4 serotype virulent strains consisting of type 5 capsular polysaccharide （CP5）, type 8 capsular polysaceharide（ CP8 ） and type 336 polysaccharides （336PS）. Its immune efficacy against Staphylococcus aureus mastitis was evaluated by antibody level, challenge trial and 2 farms＇ field trial. The results showed that the vaccine could elicit a higher antibody level at 30 days after first immunization, and the antibody level could last 210 days postpartum after second immunization. Protection rate was 89% for clinical mastitis challenged with Staphylococcus aureus. Similarly, the protection rate of field trial was 75.2% -83.3% for clinical mastitis and 49.9% -52.2% for subclinical mastitis. The milk yield increased more than 1.26 kg in vaccinated group compared with control. In sum, this vaccine could reduce the incidence of clinical and subclinical mastitis induced by Staphylococcus aureus, and increase daily milk production of vaccinated dairy cow significantly.