Terkawi M Alaa, Jia Honglin, Zhou Jinlin, Lee Eung-goo, Igarashi Ikuo, Fujisaki Kozo, Nishikawa Yoshifumi, Xuan Xuenan
National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan.
Vaccine. 2007 Mar 1;25(11):2027-35. doi: 10.1016/j.vaccine.2006.11.041. Epub 2006 Dec 8.
Babesia gibsoni ribosomal phosphoprotein P0 (BgP0) was identified as an immunodominant cross-reactive antigen with B. microti. The BgP0 gene is a single copy with a predicted open reading frame of 942 bp and 314 amino acids. The BgP0 was expressed as a glutathione S-transferase fusion protein in Escherichia coli. The serum raised in mice with the recombinant BgP0 showed a specific band with a 34-kDa molecular mass in the extracts of B. gibsoni and B. microti merozoites. Furthermore, the intraperitoneal (i.p.) immunization of rBgP0 and Freund's adjuvant induced strong humoral response consisting of mixed immunoglobulins IgG1 and IgG2a in BALB/c mice. Following the challenge with B. microti, these mice delayed the onset of parasites and significantly reduced the peripheral parasitemia. On the other hand, passive-transfer of purified anti-BgP0 IgG into SCID mice showed partial protection against B. microti challenge infection. It was only effective in restricting the initial parasitemia but not later during its progress. Taken together, the immunological response elicited by rBgP0 protected the mice against B. microti challenge infection. These data suggest that BgP0 is a potentially universal vaccine candidate for both B. gibsoni and B. microti infections.
吉氏巴贝斯虫核糖体磷蛋白P0（BgP0）被鉴定为与微小巴贝斯虫具有免疫显性交叉反应的抗原。BgP0基因是单拷贝基因，预测的开放阅读框为942 bp，编码314个氨基酸。BgP0在大肠杆菌中表达为谷胱甘肽S-转移酶融合蛋白。用重组BgP0免疫小鼠产生的血清在吉氏巴贝斯虫和微小巴贝斯虫裂殖子提取物中显示出一条分子量为34 kDa的特异性条带。此外，用rBgP0和弗氏佐剂进行腹腔（i.p.）免疫在BALB/c小鼠中诱导了由混合免疫球蛋白IgG1和IgG2a组成的强烈体液反应。在用微小巴贝斯虫攻击后，这些小鼠延迟了寄生虫的出现并显著降低了外周血寄生虫血症。另一方面，将纯化的抗BgP0 IgG被动转移到SCID小鼠中显示出对微小巴贝斯虫攻击感染的部分保护作用。它仅在限制初始寄生虫血症方面有效，而在其进展后期无效。综上所述，rBgP0引发的免疫反应保护小鼠免受微小巴贝斯虫攻击感染。这些数据表明BgP0是吉氏巴贝斯虫和微小巴贝斯虫感染的潜在通用疫苗候选物。
