Sandvig K, Brown J E
Infect Immun. 1987 Feb;55(2):298-303. doi: 10.1128/iai.55.2.298-303.1987.
The ionic requirements for entry of Shiga toxin into cells were examined by measuring inhibition of protein synthesis after short-term incubations with toxin. The sensitivity of Vero cells and HeLa cells to Shiga toxin was strongly dependent on the divalent cation present. Vero cells were most sensitive in the presence of CaCl2 and SrCl2, whereas HeLa cells were equally sensitive in the presence of MgCl2, SrCl2, and CaCl2. Both cell lines were protected by BaCl2, CoCl2, and MnCl2. Inhibitors of Ca2+ transport, like verapamil, D600, and Co2+ as well as the calcium-ionophores A23187 and ionomycin, protected both cell lines. HEp-2 cells were protected against Shiga toxin by a high concentration of potassium in the medium as well as by potassium depletion of the cells. Substitution of chloride in the medium with slowly permeable anions, like SO42- and SCN-, protected the cells against Shiga toxin. High concentrations of the ionophore nigericin that increase pH of acidic intracellular vesicles did not protect Vero cells against Shiga toxin. Shiga Toxin X-114 at pH values below 4.5. This binding was shifted to higher pH values after pretreatment of the toxin with dithiothreitol. The results indicate that Ca2+ transport through physiologically occurring Ca2+ channels is required for entry of Shiga toxin into cells. Furthermore, the sensitivity of cells of Shiga toxin is strongly dependent on the anions present.
通过测量毒素短期孵育后蛋白质合成的抑制情况，研究了志贺毒素进入细胞的离子需求。Vero细胞和HeLa细胞对志贺毒素的敏感性强烈依赖于存在的二价阳离子。在CaCl2和SrCl2存在时Vero细胞最敏感，而HeLa细胞在MgCl2、SrCl2和CaCl2存在时同样敏感。两种细胞系都受到BaCl2、CoCl2和MnCl2的保护。Ca2+转运抑制剂，如维拉帕米、D600和Co2+以及钙离子载体A23187和离子霉素，对两种细胞系都有保护作用。HEp - 2细胞在培养基中高浓度钾存在时以及细胞钾耗竭时受到志贺毒素的保护。用缓慢渗透的阴离子如SO42-和SCN-替代培养基中的氯离子可保护细胞免受志贺毒素侵害。高浓度的尼日利亚菌素可提高酸性细胞内小泡的pH值，但不能保护Vero细胞免受志贺毒素侵害。志贺毒素X - 114在pH值低于4.5时结合。用二硫苏糖醇预处理毒素后，这种结合转移到更高的pH值。结果表明，志贺毒素进入细胞需要通过生理存在的Ca2+通道进行Ca2+转运。此外，细胞对志贺毒素的敏感性强烈依赖于存在的阴离子。
