猪圆环病毒2型感染对猪繁殖与呼吸综合征灭活疫苗体液免疫的影响

本试验采用ELISA方法对单独接种猪繁殖与呼吸综合征病毒(PRRSV)变异株灭活苗组(HP组,n=3)和PCV2感染且出现病毒血症后接种PRRSV变异株灭活苗组(PCV2/HP组,n=3)不同时相血清中的PRRSV抗体进行检测;并对HP和PCV2/HP组血清中PCV2特异的抗体和核酸分别进行ELISA和荧光定量PCR检测。结果表明,在首免后70 d HP组血清平均抗体效价极显著高于PCV2/HP组(P<0.01);首免后56、63和77 d HP组平均抗体效价明显高于PCV2/HP组。其中在首免后56和63 d HP组抗体阳性率均达67%(2/3),PCV2/HP组在相应时相抗体阳性率为0;在首免后70和77 d HP组抗体阳性率均达100%(3/3),PCV2/HP组在相应时相抗体阳性率仅为0和33%(1/3)。结果提示PCV2感染可在一定程度上抑制PRRSV变异株(JXA1)特异性的抗体反应。

Effects on Humoral Immune Response to Porcine Reproductive and Respiratory Syndrome Inactivated Vaccine after Experimental Infection of Porcine Circovirus Type 2

The levels of the antibody response against PRRSV mutant strain(JXA1) inactivited vaccine were measured by ELISA at different time for pigs vaccinated with JXA1 inactivited vaccine(HP group, n=3), pigs inoculated with porcine circovirus type 2 (PCV2) and with JXA1 inactivited vaccine two weeks later (when PCV2 viremia was detected by PCR, PCV2/HP group, n=3), respectively.And distribution of genome or antibodies specific to PCV2 of HP group and PCV2/HP group were detected by ELISA or Real-time fluorescent PCR, respectively.The results showed that experimental infection of PCV2 was successful.In pigs inoculated with both PCV2 and JXA1 inactivited vaccine, the antibody response to JXA1 inactivited vaccine was significantly lower than that of animals treated with JXA1 inactivited vaccine vaccination alone at 70 days postvaccination(DPV).The average titers of antibodies against PRRSV in animals of HP group were obviously higher than those of the PCV2/HP group at 56,63 and 77 DPV, respectively.The positive rates of antibodies against PRRSV in pigs of HP group were 67% at 56 and 63 DPV, but those of PCV2/HP group were both 0. The positive rates of antibodies against PRRSV in pigs of HP group were 100% at 70 and 77 DPV, but those of PCV2/HP group were 0 and 33%, respectively.The results suggested that the infection of PCV2 could suppress the antibody response to JXA1 inactivited vaccine.