猪瘟母源抗体衰减及保护水平分析

Classical Swine Fever Maternal Antibodies Decreasing Patternand Threshold of the Protective Level Research

关键词:  猪瘟  母源抗体  中和抗体

Key words:  CSF, maternal  antibodies, neutralization  titer

摘要:

为了分析仔猪体内猪瘟母源抗体的衰减规律,推测母源抗体临界保护水平,制定科学的免疫程序,本研究测定了断奶时母猪和仔猪抗体水平；监测仔猪母源抗体变化至81日龄；分两个日龄组进行了攻毒实验,分别为81日龄12头仔猪(来自5头母猪),35日龄仔猪25头(来自5头母猪),并用RT-nPCR进行了跟踪检测,对部分耐过猪用兔体中和法测定了中和效价。结果表明,母猪抗体水平不均衡,会导致仔猪群体母源抗体水平不均衡；仔猪群体ELISA抗体到60日龄时仍然有67%(12/18)的个体抗体阻断率在50%以上；81日龄攻毒时有3头(3/12)耐过,35日龄攻毒时,能全部耐过(25/25),但有2头(2/25)在攻毒27天后仍然呈PCR阳性,此时中和抗体水平从<1:4到1:16不等,推测35日龄是母源抗体保护的临界线。

Abstract:

In order to analyse classical swine fever maternal antibodies decreasing pattern and threshold of the protective Level, antibody of sow and piglets were detected at weaning day, maternal antibodies of piglets were monitored until 81 days after birtth, moreover, 12 81-days piglets from 5 sows and 25 35-days piglets from another 5 sows were challenged by SM strain. and furthermore were monintored with RT nPCR, the antibody level of 7 piglets were detected with rabbit neutralization test. The results shows that, antibody of sow is correlative to that of piglets, antibody uniformity of sow lead to the uniformity of piglets, blocking rates is more than 50% in 72%(13/18) piglets at 60 days post birth. However, after challenging, 3(3/12) 81-days piglets could survived,but in 35 days piglets, all piglets(25/25) could survived, but RT-nPCR detection was positive from 2 piglet(2/25). the neutralization antibody titers were from < 1:4 to 1:16. the results indicated that 35 days maybe the threshold of preotective level.