猪口蹄疫O型、A型二价3B蛋白表位缺失灭活疫苗不同首免日龄对免疫效果影响测定

Determination of the Effect of Different First Immunization Ages of Pig Foot-and-Mouth Disease Type O and Type A Bivalent Inactivated Vaccines with 3B Protein Epitope Deletion

为评价猪口蹄疫O型、A型二价3B蛋白表位缺失灭活疫苗不同首免时间对免疫效果的影响,选择二组不同日龄试验猪只进行免疫接种,接种疫苗当天采集试验猪血样测定母源抗体水平,并分别在首免和二免后不同间隔时间采集血样,分别用口蹄疫液相阻断ELISA和非结构蛋白抗体ELISA方法检测猪O型、A型口蹄疫抗体和非结构蛋白抗体水平。结果显示:40日龄首免的猪只,一免后31 d,A型和O型口蹄疫抗体阳性率分别为94.12%和100%,二免后60 d,分别为31.58%和36.84%;70日龄首免的猪只,一免后30 d,A型和O型口蹄疫抗体阳性率均为100%,二免后54 d,均为97.96%。表位缺失疫苗免疫后,两个试验猪群口蹄疫非结构蛋白抗体均为阴性。结果表明:70日龄首免的猪群,其口蹄疫O型和A型抗体阳性率较同期40日龄首免的猪群高,说明母源抗体水平低的仔猪对该疫苗的免疫应答水平更高。

In order to evaluate the effect of different first immunization times on the immune effect of swine foot-and-mouth disease type O and type A bivalent 3B protein epitope deletion inactivated vaccines.We selected two groups of test pigs of different ages for immunization.The blood samples of the test pigs were collected on the day of vaccination to determine the level of maternal antibody,and blood samples were collected at different intervals after the first immunization and the second immunization respectively.Then FMD liquid-phase blocking ELISA and non-structural protein antibody ELISA were used to detect the levels of swine O-type,A-type FMD antibody and non-structural protein antibody respectively.The test results showed that 31 days after the first immunization of the 40-day-old pigs,the positive rates of A and O FMD antibodies were 94.12%and 100%,respectively,and 31.58%and 36.84%after the second immunization 60 days;30 days after the immunization of the pigs,the positive rates of FMD antibody of type A and type O were both 100%,and 54 days after the secondary immunization,both were 97.96%.We saw that after immunization with the epitope-deleted vaccine,both test herds were negative for FMD non-structural protein antibodies.The results showed that the positive rate of FMD type O and A antibodies in pigs immunized for the first time at the age of 70 days was higher than that of pigs immunized for the first time at the age of 40 days in the same period,indicating that piglets with low maternal antibody levels had a higher level of immune response to the vaccine.