猪流行性腹泻病毒变异株疫苗免疫剂量和血清中和效价研究

Vaccine immunization dosage and serum neutralization titers of the variant of porcine epidemic diarrhea virus

为了研究猪流行性腹泻病毒变异毒株灭活疫苗的免疫剂量及免疫后抗体的中和效价,选择初产母猪于产前42 d首次免疫,后海穴注射,间隔21日以相同剂量和方法加强免疫,免疫剂量分别为0.5 mL、1.0 mL、2.0 mL和4.0 mL,采集母猪血清和仔猪血清,采用变异强毒株、经典毒株CV777进行血清中和试验分析免疫抗体效价,ELISA抗体检测试剂盒检测血清IgG抗体效价。结果表明,2 mL、4.0 mL免疫剂量组血清抗体与变异毒株中和效价均≥1∶128,与CV777中和效价≤1∶64,二免后母猪血清IgG抗体S/P值均>2.0,仔猪断奶时母猪血清抗体S/P≥1.4,0.5 mL、1.0 mL免疫组抗体中和效价、S/P值均较低。确定2 mL为最佳免疫剂量,加强免疫后血清抗体中和效价≥1∶128,对母猪损伤小,经济效益高。

To study the immunization dosage of the inactivated vaccine against the variant of porcine epidemic diarrhea virus(PEDV)and the neutralizing titers of plasma samples from immunized sows,premiparous sows were selected to be immunized by injection the at Houhai point on 42 th day before delivery,and 22 days later,the pigs received enhanced immunization with the same dose of the inactivated vaccine.The immunization doses applied were 0.5 mL,1.0 mL,2.0 mL and 4.0 mL respectively.Serum samples were collected from the sows at different time points.The immunological serum titers were analyzed by neutralization test using the variant strain and the classical strain CV777,and the IgG antibody titers were detected by the ELISA antibody detection kit.The results showed that the neutralization titers of antibody in serum reacted with the variant strain in the 2.0 mL and 4.0 mL dose immunization groups were≥1∶128,and the titers of serum antibody reacted with CV777 strain were≤1∶64.The mean S/P values of the antibody SP of the IgG were>2.0.When piglets were weaned,the S/P values of the antibody in serum were≥1.4.The neutralization titers and the S/P values of the 0.5 mL or 1.0 mL immunized groups were rather low.The present study indicated that 2 mL was the optimal immunization dose and that the neutralization titers of serum after enhanced immunization were≥1∶128,which would pose less damage to sows and high economic benefit.