Department of Microbiology, Third Military Medical University, Chongqing 400038, China.
Microb Pathog. 2013 Oct;63:8-15. doi: 10.1016/j.micpath.2013.05.011. Epub 2013 Jun 5.
Streptococcus suis (S. suis) serotype 2 usually cause infection in swine. Recently, two large-scale outbreaks in China with severe streptococcal toxic shock syndrome (STSS) and high mortality raised worldwide concern to human S. suis infection. To reveal the molecular pathogenesis of S. suis 2 during human infection, in-vivo induced antigen technology (IVIAT) was applied to identify the in-vivo induced genes (ivi genes) of S. suis 05ZYH33. The ivi genes are specifically expressed or up-regulated in-vivo and always associated with the in-vivo survival and pathogenicity of pathogens. In present study, convalescent sera from S. suis 05ZYH33 infected patients were pooled and fully adsorbed with in-vitro grown S. suis 05ZYH33 and Escherichia coli BL21 (DE3). Genomic expression library of 05ZYH33 was repeatedly screened with colony immunoblot assay using adsorbed sera. Finally, 19 genes were assessed as ivi genes of 05ZYH33. Fifteen of 19 genes encode proteins with biological functions in substance transport and metabolism, cell structure biogenesis, cell cycle control, replication, translation and other functions. The 4 remaining genes encode proteins with unknown functions. Of the 19 ivi genes, five (SSU05_0247, 0437, 1577, 1664 and 2144) encode proteins with no immunoreactivity to control sera from healthy individuals never exposed to 05ZYH33. The successful identification of ivi genes not only sheds light on understanding the pathogenesis of S. suis 05ZYH33 during its human infection, but also provides potential targets for the developments of new vaccines, therapeutic drugs and diagnostic reagents against human S. suis infection.
猪链球菌 2 型通常引起猪感染。最近，中国发生了两起大规模的链球菌中毒性休克综合征（STSS）暴发，死亡率高，引起了全球对人类猪链球菌感染的关注。为了揭示人类感染猪链球菌 2 型的分子发病机制，应用体内诱导抗原技术（IVIAT）鉴定了猪链球菌 05ZYH33 的体内诱导基因（ivi 基因）。ivi 基因在体内特异性表达或上调，与病原体在体内的存活和致病性始终相关。在本研究中，收集了猪链球菌 05ZYH33 感染患者的恢复期血清，并与体外生长的猪链球菌 05ZYH33 和大肠杆菌 BL21（DE3）充分吸附。使用吸附后的血清，通过菌落免疫印迹法对 05ZYH33 的基因组表达文库进行了反复筛选。最终，鉴定出 19 个基因作为 05ZYH33 的 ivi 基因。19 个基因中的 15 个编码具有物质转运和代谢、细胞结构发生、细胞周期控制、复制、翻译等功能的蛋白质。其余 4 个基因编码具有未知功能的蛋白质。在 19 个 ivi 基因中，有 5 个（SSU05_0247、0437、1577、1664 和 2144）编码的蛋白质与从未接触过 05ZYH33 的健康个体对照血清无免疫反应。成功鉴定出 ivi 基因不仅有助于了解人类感染猪链球菌 05ZYH33 的发病机制，而且为开发针对人类猪链球菌感染的新型疫苗、治疗药物和诊断试剂提供了潜在靶点。
