弗氏志贺氏菌O抗原多糖致病性研究

Study on Pathogenesis of O-polysaccharide from Shigella Flexneri

志贺氏菌外膜的脂多糖(LPS)在致病和诱导免疫保护中都起重要作用。为探讨脂多糖分子外侧O抗原多糖(O-PS)的特异性致病作用,应用酶解-凝胶层析法提取和纯化弗氏志贺氏菌5型M90 T的O抗原多糖,进行了体内外实验。结果显示:M90T O抗原多糖单独对HeLa细胞具有毒性作用,对兔回肠袢粘膜有致炎和血性渗出作用。提示O抗原多糖可能是造成腹泻的特异性因素之一,不同于脂多糖的内毒素反应。

Lipopolysaccharides(LPS)of the outer membrane of Shigella flexneri play important roles in triggering the pathogenic effects and inducing immune protection. To investigate the specific pathogenesis of O-po-lysaccharide(O-PS) which is on the outside of LPS,the O-PS was isolated and purified from Shigella flexneri 5 M90T by enzymatic hydrolysis and gel chromatography. In vitro and in vivo experiments with the purified O-PS from the strain revealed that the O-PS alone was toxic to He La cells and caused mucosal inflammation and hemorrhagic exudation in ileal loop of rabbit, suggesting that O-PS might be one of the factors causing diarrhea and its mechanism was different from endotoxin reactions of LPS.