Terkawi M Alaa, Jia Honglin, Gabriel Aboge, Goo Youn-Kyoung, Nishikawa Yoshifumi, Yokoyama Naoaki, Igarashi Ikuo, Fujisaki Kozo, Xuan Xuenan
National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido, 080-8555, Japan.
Parasitol Res. 2007 Dec;102(1):35-40. doi: 10.1007/s00436-007-0718-1. Epub 2007 Sep 6.
Babesia gibsoni ribosomal phosphoprotein P0 (BgP0) was previously identified as a cross-protective antigen against Babesia microti infection in mice. Interestingly, the same protein showed considerable antigenicity when tested with serum samples collected from Babesia-infected animals. Moreover, the polyclonal antibody raised against the recombinant BgP0 (rBgP0) recognized the P0 homologues from other Babesia species either by immunoblotting or by immunoscreening. The P0 genes from Babesia caballi, Babesia equi, and Babesia bigemina were then cloned and sequenced. The phylogenic analyses based on the amino acid sequences indicated that BgP0 has high identities with B. caballi P0 (88.1%), B. bigemina P0 (85.6%), Babesia bovis P0 (81.4%), and B. equi P0 (64.9%). Western blot analyses revealed that the corresponding native proteins ranged between 31 and 34 kDa, consistent with predicated molecular weight of Babesia P0. Furthermore, the immunogenic property of anti-rBgP0 IgG was evaluated against a B. bovis in vitro culture. The growth of B. bovis parasites was restricted by anti-rBgP0 IgG in a concentration-dependent manner, and significant reductions in parasitemia were observed only at 1 mg/ml in the culture. Taken together, these data suggest that P0 is a conserved protective antigen among Babesia species and might be a potentially universal vaccine candidate for babesiosis.
吉氏巴贝斯虫核糖体磷蛋白P0（BgP0）先前被鉴定为一种针对小鼠微小巴贝斯虫感染的交叉保护性抗原。有趣的是，当用从感染巴贝斯虫的动物收集的血清样本进行检测时，相同的蛋白质显示出相当强的抗原性。此外，针对重组BgP0（rBgP0）产生的多克隆抗体通过免疫印迹或免疫筛选识别来自其他巴贝斯虫物种的P0同源物。然后克隆并测序了来自驽巴贝斯虫、马巴贝斯虫和双芽巴贝斯虫的P0基因。基于氨基酸序列的系统发育分析表明，BgP0与驽巴贝斯虫P0（88.1%）、双芽巴贝斯虫P0（85.6%）、牛巴贝斯虫P0（81.4%）和马巴贝斯虫P0（64.9%）具有高度同源性。蛋白质印迹分析显示相应的天然蛋白分子量在31至34 kDa之间，与预测的巴贝斯虫P0分子量一致。此外，评估了抗rBgP0 IgG对牛巴贝斯虫体外培养物的免疫原性。抗rBgP0 IgG以浓度依赖性方式限制了牛巴贝斯虫寄生虫的生长，并且仅在培养物中1 mg/ml时观察到显著的虫血症降低。综上所述，这些数据表明P0是巴贝斯虫物种间保守的保护性抗原，可能是巴贝斯虫病潜在的通用疫苗候选物。
