福氏2a志贺氏菌2457T HtpG蛋白诱导小鼠炎性反应

目的]构建福氏2a志贺氏菌2457T株的htpG缺失突变株和回复株,对HtpG蛋白的功能进行初步研究.方法]采用X-Red重组系统对htpG基因进行缺失突变,构建了福氏2a志贺氏菌2457T株的htpG缺失突变株,并利用低拷贝质粒构建了htpG突变株的回复株.在此基础上,对野生株、突变株和回复株的生长曲线、生化反应、豚鼠角膜试验进行了比较分析,并考察了野生株、突变株和回复株腹腔注射引起小鼠炎症反应的强弱.结果]HtpG蛋白功能与福氏志贺氏菌的基本生化代谢无关,也不影响细菌穿透上皮细胞的能力,但腹腔注射后能够引起小鼠强烈的炎症反应.结论]HtpG蛋白功能可能与细菌的免疫致病性相关.

HtpG protein of Shigella flexneri 2a strain 2457T evokes inflammatory response in mice

Objective] To analyze the function of htpG of S. flexneri 2a 2457T, we constructed an htpG deletion mutant and a recovery mutant. Methods] g-Red recombination system was used to construct an htpG deletion mutant of S. flexneri 2a 2457T. In addition, a recover mutant was obtained by introducing a low-copy plasmid containing one copy of htpG gene into the deletion mutant. Then, the growth curves of wild-type strain, deletion mutant and recover mutant were measured. Some of biochemical tests were also investigated. Furthermore, the Sereny tests were performed to evaluate the virulence of these strains. Results] No significant difference were observed among three strains. However, the titers of some inflammatory factors evoked by wild-type strain, deletion mutant and recovery mutant in intraperitoneal injected mice were quite different. Conclusion] These results suggest that the HtpG protein of Shigella flexneri 2a strain 2457T might be involved in the immunopathogenesis.