Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA 99164-7040, USA.
The National Institutes of Health, National Institute of Allergy and Infectious Diseases, DEA, Rockville, MD 20852, USA.
Int J Parasitol. 2019 Feb;49(2):127-137. doi: 10.1016/j.ijpara.2018.05.015. Epub 2018 Oct 25.
The factors involved in gain or loss of virulence in Babesia bovis are unknown. Spherical body protein 2 truncated copy 11 (sbp2t11) transcripts in B. bovis were recently reported to be a marker of attenuation for B. bovis strains. Increased cytoadhesion of B. bovis-infected red blood cells (iRBC) to vascular endothelial cells is associated with severe disease outcomes and an indicator of parasite virulence. Here, we created a stable B. bovis transfected line over-expressing sbp2t11 to determine whether up-regulation of sbp2t11 is associated with changes in cytoadhesion. This line was designated sbp2t11up and five B. bovis clonal lines were derived from the sbp2t11up line by limiting dilution for characterisation. We compared the ability of iRBCs from the sbp2t11up line and its five derivative clonal lines to adhere to bovine brain endothelial cells, using an in vitro cytoadhesion assay. The same lines were selected for in vitro cytoadhesion and the levels of sbp2t11 transcripts in each selected line were quantified. Our results demonstrate that up-regulation of sbp2t11 is accompanied by a statistically significant reduction in cytoadhesion. Confirmed up-regulation of sbp2t11 in B. bovis concomitant with the reduction of iRBC in vitro cytoadhesion to bovine brain endothelial cell is consistent with our previous finding that up-regulation of sbp2t11 is an attenuation marker in B. bovis and suggests the involvement of sbp2t11 transcription in B. bovis virulence.
牛巴贝斯虫毒力增减的相关因素尚不清楚。最近有报道称，牛巴贝斯虫的球体蛋白 2 截断拷贝 11（sbp2t11）转录本是牛巴贝斯虫株减毒的标志。牛巴贝斯虫感染的红细胞（iRBC）与血管内皮细胞的细胞黏附增加与严重的疾病结果相关，是寄生虫毒力的一个指标。在此，我们构建了一个稳定表达 sbp2t11 的牛巴贝斯虫转染系，以确定 sbp2t11 的上调是否与细胞黏附的变化相关。该系被命名为 sbp2t11up，通过有限稀释从 sbp2t11up 系中衍生出五个牛巴贝斯虫克隆系，用于特征分析。我们比较了 sbp2t11up 系及其五个衍生的克隆系的 iRBC 与牛脑内皮细胞黏附的能力，使用体外细胞黏附试验。选择相同的系进行体外细胞黏附，定量分析每个选定系中 sbp2t11 转录本的水平。我们的结果表明，sbp2t11 的上调伴随着细胞黏附的统计学显著降低。牛巴贝斯虫中 sbp2t11 的上调与体外 iRBC 对牛脑内皮细胞黏附的减少相伴随，这与我们之前的发现一致，即 sbp2t11 的上调是牛巴贝斯虫的减毒标志，并表明 sbp2t11 转录参与了牛巴贝斯虫的毒力。
