Castillo M G, Yoshino T P
Department of Pathobiological Sciences, University of Wisconsin School of Veterinary Medicine, 2115 Observatory Drive, Madison, Wisconsin 53706, USA.
Parasitology. 2002 Dec;125(Pt 6):513-25.
Due to shared characteristics with snail haemocytes, the Biomphalaria glabrata embryonic (Bge) cell line has been used as a model in vitro system for the study of snail-trematode interactions. In this study, Bge cells were used to characterize the adherence of snail host cells to schistosome primary sporocysts, and to test the effect of carbohydrates as inhibitors of this behaviour. Bge cells bound to the surface of >90% of Schistosoma mansoni sporocysts and, based on a semi-quantitative cell adhesion scale of 1-4, exhibited a cell adhesion index (CAI) of 2.45. This cellular adhesion was significantly inhibited in the presence of selected carbohydrate-containing substances. Fucoidan was the most potent inhibitor, reducing Bge cell-binding prevalence to approximately 50% and the CAI to 1.6. Other inhibitory compounds included mannose-6-phosphate, heparin, dextran sulfate, and various forms of the polysaccharide carrageenan. Fluoresceinated-fucoidan was found to attach to Bge cells confirming their ability to associate with sugar moieties. These results were further supported by the specific binding of surface biotinylated Bge cell proteins to sporocyst tegumental glycoproteins ranging from 40 to 120 kDa. N-linked tegumental carbohydrates appeared to represent ligands for Bge cell proteins since N-glycosidase treatment of blotted tegumental glycoproteins completely abolished biotinylated Bge protein binding. We hypothesize that the involvement of lectins as potential host cellular receptors in snail cell-sporocyst interactions, and suggest that negatively charged (mainly sulfated) carbohydrate moieties may represent the schistosome surface ligand(s).
由于与蜗牛血细胞具有共同特征，光滑双脐螺胚胎（Bge）细胞系已被用作体外模型系统，用于研究蜗牛与吸虫的相互作用。在本研究中，Bge细胞用于表征蜗牛宿主细胞对血吸虫初级子孢蚴的黏附，并测试碳水化合物作为这种行为抑制剂的效果。Bge细胞与超过90%的曼氏血吸虫子孢蚴表面结合，基于1 - 4的半定量细胞黏附量表，表现出2.45的细胞黏附指数（CAI）。在存在选定的含碳水化合物物质的情况下，这种细胞黏附受到显著抑制。岩藻依聚糖是最有效的抑制剂，将Bge细胞结合发生率降低至约50%，CAI降低至1.6。其他抑制性化合物包括6 - 磷酸甘露糖、肝素、硫酸葡聚糖以及各种形式的多糖角叉菜胶。发现荧光标记的岩藻依聚糖附着于Bge细胞，证实了它们与糖部分结合的能力。表面生物素化的Bge细胞蛋白与40至120 kDa的子孢蚴体表糖蛋白的特异性结合进一步支持了这些结果。N - 连接的体表碳水化合物似乎代表Bge细胞蛋白的配体，因为对印迹的体表糖蛋白进行N - 糖苷酶处理完全消除了生物素化的Bge蛋白结合。我们假设凝集素作为潜在的宿主细胞受体参与蜗牛细胞 - 子孢蚴相互作用，并表明带负电荷（主要是硫酸化）的碳水化合物部分可能代表血吸虫表面配体。
