Okamura Masashi, Yokoyama Naoaki, Takabatake Noriyuki, Okubo Kazuhiro, Ikehara Yuzuru, Igarashi Ikuo
National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan.
Exp Parasitol. 2007 May;116(1):91-4. doi: 10.1016/j.exppara.2006.11.006. Epub 2007 Jan 4.
In the present study, the subcellular localization of the host red blood cell (RBC) membrane components, the alpha2-3-linked sialic acid (SA) residues and the lipid bilayer, was observed during the asexual growth of Babesia bovis using two erythrocyte probes, the SA-specific lectin (MALII) and the lipophilic fluorescent (PKH2) probes, respectively. In confocal laser scanning microscopy with MALII, the SA residues on the surface of parasitized RBCs appeared to accumulate into the intracellular parasites as the parasites matured as well as to remain on the surface of extracellular parasites. Furthermore, when PKH2-labeled RBCs were infected with B. bovis, PKH2 signals were also observed around both the intracellular and the extracellular parasites, similarly to the results of MALII. These results indicated that the components derived from the host erythrocyte membrane are incorporated into the intracellular parasites during their asexual growth within the parasitized RBC, suggesting the possible formation of a parasitophorous vacuole-based network or a parasite surface coat.
在本研究中，分别使用两种红细胞探针，即SA特异性凝集素（MALII）和亲脂性荧光（PKH2）探针，在牛巴贝斯虫无性生长期间观察宿主红细胞（RBC）膜成分、α2-3连接的唾液酸（SA）残基和脂质双层的亚细胞定位。在使用MALII的共聚焦激光扫描显微镜下，随着寄生虫的成熟，被寄生红细胞表面的SA残基似乎会积累到细胞内寄生虫中，同时也会保留在细胞外寄生虫的表面。此外，当用PKH2标记的红细胞感染牛巴贝斯虫时，在细胞内和细胞外寄生虫周围也观察到了PKH2信号，这与MALII的结果相似。这些结果表明，在被寄生红细胞内无性生长期间，源自宿主红细胞膜的成分被整合到细胞内寄生虫中，提示可能形成基于寄生泡的网络或寄生虫表面被膜。
