Adhesion Molecule of Borrelia burgdorferi ; Its Function and Application

检测了伯氏疏螺旋体与存在于各种类型细胞中的鞘糖脂的结合活性。B.burgdorferi特异性结合半乳糖神经酰胺（GalCer）和葡萄糖神经酰胺（GicCer），但不结合其他鞘糖脂。B.burgdorferi与多种鞘糖脂结合的特异性表明，该种结合受体为神经酰胺单己糖苷。使用化学修饰的GalCer显示了半乳糖神经酰胺中的糖和N-酰基部分用于Borre 1 ia结合的必要性。低代毒力菌株与薄层板上的GalCer结合活性和与CHO-K1细胞的体外结合活性均比高代无毒力菌株高3倍。结合不受用单特异性抗外表面蛋白C（OspC）血清预处理疏螺旋体的影响。这些结果表明疏螺旋体与表达鞘糖脂的细胞表面的结合在哺乳动物宿主的感染中起重要作用，但OspC与结合无关。以生物素标记的GalCer为探针进行的印迹分析表明，37 kDa和67 kDa两种蛋白参与了伯氏B菌与半乳糖神经酰胺的结合。37 kDa和67 kDa蛋白分别被确定为甘油醛-3-磷酸脱氢酶（GAPDH）和热休克蛋白62的同源物。将大肠杆菌表达的重组GAPDH与TLC板上的GalCer结合。本研究结果表明GAPDH是伯氏疏螺旋体的粘附因子之一。

The binding activities of Borrelia burgdorferi to glycosphingolipid which are present in various types of cells were examined. B.burgdorferi bound specifically to galactosylceramide (GalCer) and glucosylceramide (GicCer), but not to other glycosphingolipids. The binding specificity of B.burgdorferi to various glycosphingolipid suggested that the binding receptor in the species is ceramide monohexoside. The necessity of the sugar and N-acyl moieties in galactosylceramide for the binding of Borre1ia was shown using chemically modified GalCer. The binding activities of the low-passage virulent strains to GalCer on TLC plates and to CHO-K1 cells in vitro were threefold higher than those of high-passage avirulent strains. Binding was no affected by pretreatment of Borrelia with monospecific anti-outer surface protein C (OspC) serum. These results indicated that the binding of Borrelia to glycosphingolipid expressed cell surface play an essential role in infection of mammalian hosts, but that OspC is not associated with binding. Two proteins, 37kDa and 67kDa, were involved in binding of B.burgdorferi to galactosylceramide as shown by blotting assay using biotinylated GalCer as a probe. 37kDa and 67kDa proteins reactive were determined as glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and homologue of heat shock protein 62, respectively. Recombinant GAPDH expressed by E.coli were bound with GalCer on TLC plate. The finding obtained in this study indicated that GAPDH is one of adhesion factor of B.burgdorferi.