猪圆环病毒2型(PCV2)主要有三种基因型,即PCV2a,PCV2b和PCV2d,其中PCV2b和PCV2d是目前最常见的。这些不同基因型之间存在抗原差异。探讨PCV2抗原差异对疫苗免疫保护作用的影响。在猪身上进行了交叉免疫保护试验。三个基因型菌株,PCV2a-CL,PCV2b-MDJ和PCV2d-LNHC,灭活和乳化以制备灭活疫苗来免疫猪,然后用循环菌株PCV2b-BY和PCV2d-LNHC攻击。免疫过氧化物酶单层测定(IPMA)和微量中和测定用于检测针对PCV2的三种不同基因型的抗体。结果表明,3种基因型疫苗诱导猪产生针对相同和不同基因型PCV2的抗体,但针对相同基因型的IPMA和中和抗体水平高于针对不同基因型的IPMA和中和抗体水平。定量聚合酶链反应(qPCR),病毒滴定和免疫组织化学用于检测PCV2基因组DNA,活病毒和抗原,分别,在实验猪的腹股沟淋巴结中。在挑战PCV2b-BY菌株后,与未免疫组相比,用三种基因型疫苗免疫的猪腹股沟淋巴结中的病毒DNA载量减少了99%以上.在用PCV2d-LNHC菌株攻击后,用PCV2a免疫的猪腹股沟淋巴结中的病毒DNA载量,PCV2b和PCV2d基因型疫苗减少了93.8%,99.8%和98.3%,分别,与未免疫对照相比。此外,在用任何基因型疫苗免疫的猪的腹股沟淋巴结中均未检测到活的PCV2病毒或抗原(0/18),但两者均在未免疫对照组的实验猪的淋巴结中检测到(6/6)。这些发现表明,尽管三种基因型菌株的抗原差异导致抗体水平的显着差异,它们似乎对不同基因型之间的交叉保护作用不大。
There are three main genotypes of porcine circovirus type 2 (PCV2), namely PCV2a, PCV2b and PCV2d, of which PCV2b and PCV2d are currently the most common. There are antigenic differences between these different genotypes. To explore the effect of PCV2 antigen differences on the immune protection provided by vaccines, a cross-immune protection test was carried out in pigs. Three genotype strains, PCV2a-CL, PCV2b-MDJ and PCV2d-LNHC, were inactivated and emulsified to prepare inactivated vaccines to immunize pigs, who were then challenged with the circulating strains PCV2b-BY and PCV2d-LNHC. Immunoperoxidase monolayer assays (IPMAs) and micro-neutralization assays were used to detect antibodies against the three different genotypes of PCV2. The results showed that the three genotype vaccines induced pigs to produce antibodies against the same and different genotypes of PCV2, but the levels of IPMA and neutralizing antibodies against the same genotype were higher than those against different genotypes. Quantitative Polymerase Chain Reaction (qPCR), virus titration and immunohistochemistry were used to detect PCV2 genomic DNA, live virus and antigen, respectively, in inguinal lymph nodes of experimental pigs. Following challenge with the PCV2b-BY strain, the viral DNA load in the inguinal lymph nodes of pigs immunized with the three genotype vaccines was reduced by more than 99 % compared to the unimmunized group. Following challenge with the PCV2d-LNHC strain, the viral DNA loads in the inguinal lymph nodes of pigs immunized with PCV2a, PCV2b and PCV2d genotype vaccines were reduced by 93.8 %, 99.8 % and 98.3 %, respectively, compared to unimmunized controls. In addition, neither live PCV2 virus nor antigen were detected in the inguinal lymph nodes of pigs immunized with any of the genotype vaccines (0/18), but both were detected in the lymph nodes of experimental pigs in the unimmunized control group (6/6). These findings suggest that, although the antigenic differences of the three genotype strains induce significant differences in antibody levels, they seem to have little effect on cross-protection between different genotypes.