Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, MS 39762, USA.
Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, MS 39762, USA.
Fish Shellfish Immunol. 2017 Jul;66:480-486. doi: 10.1016/j.fsi.2017.05.043. Epub 2017 May 19.
A virulent clonal population of Aeromonas hydrophila (VAh) is recognized as the etiological agent in outbreaks of motile aeromonas septicemia (MAS) in catfish aquaculture in the southeastern United States since 2009. Genomic subtraction revealed three outer membrane proteins present in VAh strain ML09-119 but not in low virulence reference A. hydrophila strains: major outer membrane protein OmpA1, TonB-dependent receptor (Tdr), and transferrin-binding protein A (TbpA). Here, the genes encoding ompA1, tdr, and tbpA were cloned from A. hydrophila ML09-119 and expressed in Escherichia coli. The purified recombinant OmpA1, Tdr, and TbpA proteins had estimated molecular weights of 37.26, 78.55, and 41.67 kDa, respectively. Catfish fingerlings vaccinated with OmpA1, Tdr, and TbpA emulsified with non-mineral oil adjuvant were protected against subsequent VAh strain ML09-119 infection with 98.59%, 95.59%, and 47.89% relative percent survival (RPS), respectively. Furthermore, the mean liver, spleen, and anterior kidney bacterial concentrations were significantly lower in catfish vaccinated with the OmpA1 and Tdr than the sham-vaccinated control group. ELISA demonstrated that catfish immunized with OmpA1, Tdr, and TbpA produce significant antibody response by 21 days post-immunization. Therefore, OmpA1 and Tdr proteins could be used as potential candidates for vaccine development against virulent A. hydrophila infection. However, TbpA protein failed to provide strong protection.
一种毒力克隆的嗜水气单胞菌（VAh）种群被认为是自 2009 年以来美国东南部鲶鱼养殖中运动性气单胞菌败血症（MAS）暴发的病原体。基因组消减显示，VAh 株 ML09-119 中存在三种外膜蛋白，但在低毒力参考嗜水气单胞菌菌株中不存在：主要外膜蛋白 OmpA1、TonB 依赖性受体（Tdr）和转铁蛋白结合蛋白 A（TbpA）。在此，从嗜水气单胞菌 ML09-119 中克隆了编码 ompA1、tdr 和 tbpA 的基因，并在大肠杆菌中表达。纯化的重组 OmpA1、Tdr 和 TbpA 蛋白的估计分子量分别为 37.26、78.55 和 41.67 kDa。用 OmpA1、Tdr 和 TbpA 与非矿物油佐剂乳化的鲶鱼苗进行疫苗接种，对随后的 VAh 株 ML09-119 感染的相对保护率（RPS）分别为 98.59%、95.59%和 47.89%。此外，用 OmpA1 和 Tdr 疫苗接种的鲶鱼的肝、脾和前肾的细菌浓度明显低于假疫苗接种对照组。ELISA 表明，用 OmpA1、Tdr 和 TbpA 免疫的鲶鱼在免疫后 21 天产生了显著的抗体反应。因此，OmpA1 和 Tdr 蛋白可作为针对毒力嗜水气单胞菌感染的疫苗开发的潜在候选物。然而，TbpA 蛋白未能提供强有力的保护。
