Porcine reproductive and respiratory syndrome (PRRS), caused by the PRRS virus (PRRSV), remains a major economic threat to swine production throughout the world. The aim of this study was to investigate the humoral and cell-mediated immune responses to PRRSV in 10 PRRSV vaccinated and 10 non-vaccinated young pigs obtained from a PRRSV-seropositive herd under field conditions. On day 35 days of post-vaccination (dpv), two PRRSV seropositive mixed-litter pigs were added to each group to co-mingle the animals. Serum and whole blood samples were collected from all pigs on the first day of vaccination, as well as on the 21, 35, 49, and 63 dpv. The PRRSV-specific humoral and cell-mediated immune response was determined by ELISA and flow cytometry analysis. The PRRSV ELISA sample to positive (S/P) ratio was found to be positive at the threshold level until the age of 84 days in both non-vaccinated and vaccinated groups, whereas the IFN-γ positive staining cytotoxic (CD8+) cells were rapidly expressed in the early periods of vaccination and co-mingling, but were not found to be specific to PRRSV. This result might have been due to an unspecific response to stress antigens. Further studies should be conducted to obtain more immune response data over long-term observation periods and to study the effect of PRRSV endemic strain vaccinations in endemically-infected herds.

中文翻译：

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从PRRSV流行地区的PRRSV阳性暴露状态群获得的幼猪对猪繁殖与呼吸综合征病毒的免疫应答。

由PRRS病毒（PRRSV）引起的猪生殖和呼吸综合症（PRRS）仍然是全世界猪生产的主要经济威胁。这项研究的目的是调查在野外条件下从PRRSV血清阳性的牛群中接种的10头PRRSV疫苗接种和10头未接种的小猪的体液和细胞介导的对PRRSV的免疫反应。疫苗接种后第35天（dpv），将每只PRRSV血清反应阳性混合型产仔猪添加到每组中，将它们混合在一起。在接种的第一天以及21、35、49和63 dpv时，从所有猪中采集血清和全血样品。PRRSV特异的体液和细胞介导的免疫反应通过ELISA和流式细胞仪分析确定。在未接种组和已接种组中，发现PRRSV ELISA样品的阳性（S / P）比在阈值水平均为阳性，直到84天龄，而IFN-γ阳性染色的细胞毒性（CD8 +）细胞迅速在疫苗接种和混合早期阶段表达，但未发现特定于PRRSV。该结果可能是由于对应激抗原的非特异性反应所致。应该进行进一步的研究，以在长期观察期内获得更多的免疫反应数据，并研究PRRSV地方毒株疫苗接种在地方感染牛群中的作用。但未发现特定于PRRSV。该结果可能是由于对应激抗原的非特异性反应所致。应该进行进一步的研究，以在长期观察期内获得更多的免疫反应数据，并研究PRRSV地方毒株疫苗接种在地方感染牛群中的作用。但未发现特定于PRRSV。该结果可能是由于对应激抗原的非特异性反应所致。应该进行进一步的研究，以在长期观察期内获得更多的免疫反应数据，并研究PRRSV地方毒株疫苗接种在地方感染牛群中的作用。