猪圆环病毒2型感染对猪瘟疫苗体液免疫应答的影响

Effects on humoral immune response to classical swine fever vaccine after experimental infection of porcine circovirus type 2

采用ELISA方法对单独接种猪瘟疫苗组(CSFV组,n=3)、PCV2感染且出现病毒血症后接种猪瘟疫苗组(PCV2/CSFV组,n=3)及PCV2感染同时接种猪瘟疫苗组(CSFV/PCV2组,n=3)不同时相血清中的猪瘟抗体进行检测;并对PCV2感染对照组(PCV2组)及PCV2/CSFV和CSFV/PCV2组血清中PCV2特异的抗体和核酸分别进行ELISA和PCR检测。结果表明,在接种后52 d CSFV组血清中抗体的阻断值显著高于CSFV/PCV2组(P<0.05);接种后42 d和52 d CSFV组平均抗体效价明显高于PCV2/CSFV和CSFV/PCV2组,其中在52 d CSFV组抗体阳性率达100%(3/3)而PCV2/CSFV和CSFV/PCV2在相应时相抗体阳性率仅为67%(2/3)。结果提示PCV2感染可在一定程度上抑制猪瘟疫苗特异性的抗体反应。

The levels of the antibody response against classic swine fever （CSF） vaccine were measured by blocking ELISA at different time for pigs vaccinated with CSF vaccine （CSFV group, n = 3）, pigs inoculated with porcine circovirus type 2 （PCV2） and with CSF vaccine two weeks later （when PCV2 viremia was detected by PCR,PCV2/ CSFV group,n= 3） ,or inoculated with both CSF vaccine and PCV2 at the same time （CSFV/PCV2 group, n = 3）, respectively. And distribution of genome or antibodies specific to PCV2 of the PCV2 infection group,PCV2/CSFV group and CSFV/PCV2 group were also detected by indirect ELISA or PCR, respectively. The results showed that experimental infection of PCV2 was successful. In pigs inoculated with both PCV2 and CSF vaccine, the antibody response to CSF vaccine was significantly lower than that of animals treated with CSF vaccine vaccination alone at 52 days postinoculation （DPI）. The average titers of antibodies against CSFV in animals of CSFV group were obviously higher than those of the PCV2/CSFV or CSFV/PCV2 group at 49 and 52DPI,respeetively. The positive rate of antibodies against CSFV in pigs of CSFV group was 100% in comparison with that of animals inoculated with PCV2 and the vaccine （only 67%）. The results suggested that the infection of PCV2 could suppress the antibody response to classical swine fever vaccine.