Han Yanhui, Zhao Bin, Zhang Min, Hong Yang, Han Hongxiao, Cao Xiaodan, Lu Ke, Lin Jiaojiao, Fu Zhiqiang
Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology, Ministry of Agriculture of China, Shanghai, 200241, People's Republic of China.
College of Animal Science and Technology, Henan Institute of Science and Technology, Xinxiang, Henan, 453003, People's Republic of China.
Parasitol Res. 2017 Apr;116(4):1361-1372. doi: 10.1007/s00436-017-5415-0. Epub 2017 Mar 11.
Thioredoxin peroxidases (TPxs) play an important role in maintaining redox homeostasis and in protecting organisms from the accumulation of toxic reactive oxygen species (ROS). In this study, we isolated the thioredoxin peroxidase-3 gene of Schistosoma japonicum, SjTPx-3. The open reading frame (ORF) of SjTPx-3 was 663 bp encoding 220 amino acids with a molecular weight of 24.99 kDa and an isoelectric point of 6.20. Quantitative real-time reverse transcription-polymerase chain reaction indicated that SjTPx-3 was expressed in all different stages of the parasites, with highest expression in 35-day-old worms. The ORF of SjTPx-3 was subcloned into pET-32a (+) vectors and expressed in Escherichia coli. Recombinant SjTPx-3 (rSjTPx-3) was expressed as a soluble protein with good antigenicity, as demonstrated by western blotting. Immunohistochemical analysis revealed that SjTPx-3 was mainly localized on the tegument of the parasites. Mice vaccinated with rSjTPx-3 had a 37.02% (P < 0.05) reduction in worm burden and 56.52% (P < 0.05) reduction in liver egg production compared with control, unvaccinated mice. Enzyme-linked immunosorbent assay analysis demonstrated that rSjTPx-3 could induce high levels of anti-rSjTPx-3-specific IgG, IgG1, and IgG2a antibodies. Characteristic Th1 and Th2 immune response cytokines were detected by flow cytometry and were increased by rSjTPx-3. Taken together, these results suggest that SjTPx-3 is an antioxidant enzyme responsible for protecting S. japonicum from oxidative stress. rSjTPx-3 may represent a potential vaccine candidate and/or new drug target for patients with schistosomiasis.
硫氧还蛋白过氧化物酶（TPxs）在维持氧化还原稳态以及保护生物体免受有毒活性氧（ROS）积累的影响方面发挥着重要作用。在本研究中，我们分离出了日本血吸虫的硫氧还蛋白过氧化物酶-3基因，即SjTPx-3。SjTPx-3的开放阅读框（ORF）为663 bp，编码220个氨基酸，分子量为24.99 kDa，等电点为6.20。定量实时逆转录-聚合酶链反应表明，SjTPx-3在寄生虫的所有不同发育阶段均有表达，在35日龄虫体中表达量最高。将SjTPx-3的ORF亚克隆到pET-32a(+)载体中，并在大肠杆菌中表达。重组SjTPx-3（rSjTPx-3）以可溶性蛋白形式表达，具有良好的抗原性，蛋白质免疫印迹法证明了这一点。免疫组织化学分析显示，SjTPx-3主要定位于寄生虫的体表。与未接种疫苗的对照小鼠相比，接种rSjTPx-3的小鼠虫体负荷降低了37.02%（P<0.05），肝脏虫卵产量降低了56.52%（P<0.05）。酶联免疫吸附测定分析表明，rSjTPx-3可诱导高水平的抗rSjTPx-3特异性IgG、IgG1和IgG2a抗体。通过流式细胞术检测到了特征性的Th1和Th2免疫反应细胞因子，且rSjTPx-3使其增加。综上所述，这些结果表明SjTPx-3是一种抗氧化酶，负责保护日本血吸虫免受氧化应激。rSjTPx-3可能是血吸虫病患者潜在的疫苗候选物和/或新的药物靶点。
