牛乳腺炎无乳链球菌表面免疫相关蛋白及磷酸甘油酸激酶对奶牛的免疫保护作用

Immune protection of surface immunogenic protein of dairy cow mastitis Streptococcus agalactiae and phosphoglycerate kinase to dairy cow

目的分析牛乳腺炎无乳链球菌表面免疫相关蛋白(surface immunogenic protein,SIP)及磷酸甘油酸激酶(phosphoglycerate kinase,PGK)对奶牛的免疫保护作用。方法制备SIP、PGK、SIP+PGK 3种亚单位抗原乳化免疫制剂,并设无乳链球菌全菌体裂解疫苗免疫组。均经科尔沁奶牛乳房基部乳上淋巴结附近皮下免疫,于初免后第0、14、42、56、70、84天,经颈静脉采血,分离血清,采用间接ELISA法检测各组血清抗体滴度;初免后第43天,利用无乳链球菌临床分离株进行乳头感染试验,同时设未免疫对照组。结果 SIP抗原、PGK抗原及全菌体裂解疫苗组初免后第56天抗体滴度均达到峰值,分别为1∶6 600、1∶6 400和1∶4 100;而SIP+PGK抗原组在初免疫后第70天达到峰值,为1∶9 600;SIP+PGK混合抗原的免疫保护率达83.3%,与SIP抗原、PGK抗原及全菌体裂解疫苗组(免疫保护率分别为33.3%、41.6%和58.3%)相比,差异有统计学意义(P<0.05)。结论牛乳腺炎无乳链球菌SIP+PGK混合抗原的免疫保护率优于两种抗原的单独免疫效果,可免疫奶牛预防无乳链球菌性乳腺炎。

Objective To analyze the immune protection of surface immunogenic protein （SIP） of dairy cow mastitis Streptococcus agalactiae and phosphoglyeerate kinase （PGK） to diary cow. Methods Three kinds of emulsified subunit antigens, SIP, PGK and SIP ＋ PGK were prepared and immunized s. c. to the base of breast, near to lymphonodi supramammarici for 3 times on days 0, 14 and 28 respectively, using S. agalactiae whole cell cleavage vaccine as parallel control. Venous blood samples were collected on days 0, 14, 42, 56, 70 and 84 after the first immunization, from which sera were separated and determined for antibody titer by indirect ELISA. The nipples of dairy cows on day 43 after the first immunization were infected with the clinical isolate of S. agalactiae, using those unimmunized as blank control. Results The serum antibody titers of diary cows in SIP, PGK and S. agalactiae whole cell cleavage vaccine groups reached peak values on day 56 after the first immunization, which were 1 ： 6 600, 1 ： 6 400 and 1 ： 4 100 respectively. However, the antibody titer in SIP ＋ PGK group reached a peak value of 1 ： 9 600 on day 70 after the first immunization. The protective rate in SIP ＋ PGK group was 83.3%, which was significantly higher than those in SIP （33.3%）, PGK （41.6%） and S. agalactiae whole cell cleavage vaccine （58. 3%） groups （P 〈 0. 05）. Conclusion The immune protective rate of SIP ＋ PGK mixed antigen was superior to those of SIP or PGK alone, which was suitable for the prophylaxis of dairy cow mastitis.