Porcine reproductive and respiratory syndrome (PRRS), a serious disease of swine caused by the PRRS virus (PRRSV), had a severe economic impact worldwide. As commonly used PRRS vaccines, the attenuated or inactivated vaccines, provide unsatisfactory immune protection, a new PRRS vaccine is urgently needed. In this study, a part of the PRRSV ORF6 gene (from 253 to 519 bp) encoding the hydrophilic domain of PRRSV M protein was integrated into two Listeria strains via homologous recombination to generate two PRRS vaccine candidates, namely LI-M’ and LM-ΔactAplcB-M’. Both candidate vaccines showed similar growth rate as their parent strains in culture media, but presented different bacterial loads in target organs. As the integrated heterogenous gene was not expressed, LM-ΔactAplcB-M’ was excluded from the immunological test. In a mouse model, LI-M’ provoked both CD4+ and CD8+ T cell-mediated immunity. In addition, LI-M’ boosting dramatically enhanced CD8+ T cell-mediated immunity without affecting the response intensity of CD4+ T cell-mediated immunity. All of these data suggest that LI-M’ is a promising PRRS vaccine candidate.
J Mol Microbiol Biotechnol

中文翻译：

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用表达猪繁殖与呼吸综合征病毒截断的M蛋白的伊斯特氏菌对小鼠进行疫苗接种可诱导抗原特异性CD4 +和CD8 + T细胞介导的免疫。

猪繁殖与呼吸综合症（PRRS）是由PRRS病毒（PRRSV）引起的一种严重的猪病，对全世界产生了严重的经济影响。作为减毒或灭活的常用PRRS疫苗，免疫保护效果不理想，因此迫切需要一种新的PRRS疫苗。在这项研究中，部分PRRSV ORF6基因（从253到519 bp）编码PRRSV M蛋白的亲水域，通过同源重组整合到两个李斯特菌菌株中，生成了两个PRRS候选疫苗，即LI-M'和LM- Δ actAplcB-M'。两种候选疫苗在培养基中均显示出与其亲本菌株相似的生长速率，但在靶器官中呈现出不同的细菌负荷。由于未表达整合的异源基因，因此将LM- ΔactAplcB -M'从免疫学测试中排除。在小鼠模型中，LI-M'引起CD4 +和CD8 + T细胞介导的免疫。此外，LI-M'增强作用大大增强了CD8 + T细胞介导的免疫，而不会影响CD4 + T细胞介导的免疫的反应强度。所有这些数据表明LI-M'是有前途的PRRS疫苗候选者。
微生物微生物学杂志