F199E substitution reduced toxicity of Clostridium perfringens epsilon toxin by depriving the receptor binding capability
F199E substitution reduced toxicity of Clostridium perfringens epsilon toxin by depriving the receptor binding capability
复制标题
F199E 取代通过剥夺受体结合能力降低产气荚膜梭菌ε毒素的毒性
DOI：
10.1080/21645515.2017.1303022
复制
发表时间：
2017-01-01
影响因子：
4.8
通讯作者：
Wang, Jinglin
中科院分区：
文献类型：
--
作者：
Kang, Jingjing;Gao, Jie;Wang, Jinglin
肠毒素（ETX）是由产气荚膜梭菌B型和D型菌株产生的一种强毒素，可引起人畜疾病。突变体rETXF199E先前被证明是一种良好的疫苗候选物。然而，有关机制仍然不明。为了阐明F199E取代如何降低ETX毒性，我们进行了一系列实验。结果表明，rETXF199E的细胞结合和成孔能力几乎被消除。我们推测F199E取代通过剥夺ETX的受体结合能力来降低毒性，这有助于ETX的结构域I负责细胞结合的假设。此外，我们的数据表明，ETX可以引起细胞内Ca2+库的Ca2+释放，这可能是导致细胞死亡的替代途径的基础。此外，根据扫描电子显微镜，观察到ETX诱导的MDCK细胞皱缩，其中凹陷和波峰首先出现在凝聚的MDCK细胞表面上。这些数据还证明了rETXF199 E作为人类候选疫苗的安全性和潜力。总之，这项工作的发现可能有助于更好地理解ETX的致病机制和开发针对ETX引起的疾病的疫苗，使用突变蛋白。
ABSTRACT Epsilon toxin (ETX), a potent toxin, is produced by types B and D strains of Clostridium perfringens, which could cause severe diseases in humans and domestic animals. Mutant rETXF199E was previously demonstrated to be a good vaccine candidate. However, the mechanism concerned remains unknown. To clarify how F199E substitution reduced ETX toxicity, we performed a series of experiments. The results showed that the cell-binding and pore-forming ability of rETXF199E was almost abolished. We speculated that F199E substitution reduced toxicity by depriving the receptor binding capability of ETX, which contributed to the hypothesis that domain I of ETX is responsible for cell binding. In addition, our data suggested that ETX could cause Ca2+ release from intracellular Ca2+ stores, which may underlie an alternate pathway leading to cell death. Furthermore, ETX induced crenation of the MDCK cells was observed, with sags and crests first appearing on the surface of condensed MDCK cells, according to scanning electron microscopy. The data also demonstrated the safety and potentiality of rETXF199E as a vaccine candidate for humans. In summary, findings of this work potentially contribute to a better understanding of the pathogenic mechanism of ETX and the development of vaccine against diseases caused by ETX, using mutant proteins.