Lazarovici P, Yavin E
Biochim Biophys Acta. 1985 Jan 25;812(2):523-31. doi: 10.1016/0005-2736(85)90327-x.
Human erythrocytes in suspension acquire gangliosides containing di- and trisialosyl residues added to the maintenance medium. This is reflected in the increased cell-associated sialic acid content and ability to bind 125I-labeled tetanus toxin. A salt-sensitive and a salt-insensitive ganglioside-mediated toxin-cell surface association is detected which is reduced after sialidase treatment of ganglioside-supplemented cells. The salt-insensitive ganglioside-cell association is saturable after 2 h incubation in 0.3 M mannitol buffer and has an optimum at pH 5. The association process is higher at 37 degrees C than at 4 degrees C, depends on cell density, and is considerably higher in metabolically active cells compared to lysed cells. Pretreatment of cells with trypsin decreases the salt-resistant toxin association with ganglioside-supplemented cells. In contrast, glutaraldehyde-fixed cells treated with trypsin and supplemented with gangliosides bind more toxin which is insensitive to salt. Ganglioside-mediated tetanus toxin binding to the intact erythrocyte membrane can be utilized as a model system for studying the role of glycolipids in membrane function.
悬浮状态下的人红细胞会摄取添加到维持培养基中的含有二唾液酸和三唾液酸残基的神经节苷脂。这表现为细胞相关唾液酸含量增加以及结合125I标记破伤风毒素的能力增强。检测到一种盐敏感和一种盐不敏感的神经节苷脂介导的毒素 - 细胞表面结合，在对补充了神经节苷脂的细胞进行唾液酸酶处理后这种结合会减少。在0.3M甘露醇缓冲液中孵育2小时后，盐不敏感的神经节苷脂 - 细胞结合是可饱和的，且在pH5时有最佳值。结合过程在37℃时比在4℃时更高，取决于细胞密度，并且与裂解细胞相比，在代谢活跃的细胞中要高得多。用胰蛋白酶预处理细胞会降低补充了神经节苷脂的细胞与盐抗性毒素的结合。相反，用胰蛋白酶处理并用神经节苷脂补充的戊二醛固定细胞结合更多对盐不敏感的毒素。神经节苷脂介导的破伤风毒素与完整红细胞膜的结合可作为研究糖脂在膜功能中作用的模型系统。
