Guo Jiaying, Li Fangjie, Wang Lingna, Deng Han, He Lan, Zhao Junlong
College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, China.
Key Laboratory of the Provincial Education, Department of Heilongjiang for Common Animal Disease, Prevention and Treatment, College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, China.
Parasitol Res. 2025 Mar 6;124(3):28. doi: 10.1007/s00436-025-08472-6.
Babesia gibsoni is the infectious agent of canine babesiosis, a vector-borne infection that poses a global threat to the canine health. As B. gibsoni is an erythrocytic intracellular parasite, the completion of its genome and transcriptome sequencing and analysis facilitates the elucidation of the mechanism of B. gibsoni residue in the erythrocyte. The main function of red blood cells (RBCs) is oxygen delivery; thus, B. gibsoni may be exposed to high levels of oxidative stress. To date, no report is available on the mechanism by which B. gibsoni survives oxidative stress inside the RBCs. In this study, the thioredoxin peroxidase, an important type of peroxidoxin, was identified from B. gibsoni, with 255 amino acids and a molecular weight of 27.7 kDa. There are two conserved "VCP" domains at the N- and C-termini, respectively, indicating that this gene was a 2-Cys peroxiredoxin belonging to the PTZ00137 superfamily. It was named BgTPx-2 and was detected to be located in the B. gibsoni-infected erythrocytes through an indirect immunofluorescence assay using the polyclonal antibody against the recombinant TPx-2. Additionally, its antioxidant activity was analyzed by mixed-function oxidation assay, and BgTPx-2 could protect the pBluescript SK ( +) plasmid from oxidative damage, suggesting an antioxidant function of BgTPx-2. Moreover, the immunogenicity of BgTPx-2 was tested by Western blotting and ELISA using the serum of beagle dogs infected with B. gibsoni, and the positive serum exhibited a detectable and significant antibody response against BgTPx-2 on day 4 and day 9 post-infection, respectively.
吉氏巴贝斯虫是犬巴贝斯虫病的病原体，这是一种通过媒介传播的感染病，对犬类健康构成全球威胁。由于吉氏巴贝斯虫是一种红细胞内寄生的寄生虫，其基因组和转录组测序及分析的完成有助于阐明吉氏巴贝斯虫在红细胞内残留的机制。红细胞（RBC）的主要功能是输送氧气；因此，吉氏巴贝斯虫可能会面临高水平的氧化应激。迄今为止，尚无关于吉氏巴贝斯虫在红细胞内抵抗氧化应激机制的报道。在本研究中，从吉氏巴贝斯虫中鉴定出一种重要的过氧化物酶——硫氧还蛋白过氧化物酶，其含有255个氨基酸，分子量为27.7 kDa。在N端和C端分别有两个保守的“VCP”结构域，表明该基因是属于PTZ00137超家族的2-半胱氨酸过氧化物酶。它被命名为BgTPx-2，并通过使用针对重组TPx-2的多克隆抗体进行间接免疫荧光测定，检测到其位于吉氏巴贝斯虫感染的红细胞中。此外，通过混合功能氧化测定分析了其抗氧化活性，BgTPx-2可以保护pBluescript SK（+）质粒免受氧化损伤，表明BgTPx-2具有抗氧化功能。此外，使用感染吉氏巴贝斯虫的比格犬血清通过蛋白质印迹法和酶联免疫吸附测定法测试了BgTPx-2的免疫原性，阳性血清在感染后第4天和第9天分别对BgTPx-2表现出可检测到的显著抗体反应。
