狄氏副拟杆菌胞外多糖粗提物的免疫调节活性

Immunomodulatory activity of crude exopolysaccharide from Parabacteroides distasonis

通过水提醇沉、Sevag试剂除蛋白、AB-8大孔吸附树脂脱色得到狄氏副拟杆菌Parabacteroides distasonis胞外多糖粗提物(PEP),并以巨噬细胞RAW 264.7为模型,采用MTT、Griess、DCFH、中性红实验和实时荧光定量PCR,对PEP的体外免疫调节活性进行探究。结果表明PEP为首次从狄氏副拟杆菌中提取到的胞外多糖,PEP是由甘露糖、鼠李糖、葡萄糖、半乳糖及岩藻糖按照19.35∶8.70∶5.24∶8.17∶1.00的比例组成的杂多糖,并且PEP显示以浓度依赖的方式促进巨噬细胞的增殖,增加巨噬细胞对NO、活性氧的释放,增强巨噬细胞的吞噬能力,并在基因水平上提高巨噬细胞中细胞因子(IL-1β、IL-6、TNF-α)的表达量,表明PEP具有良好的免疫调节能力,为PEP未来发展成为潜在的免疫刺激剂提供了一定的参考价值。

Crude exopolysaccharide(PEP)from Parabacteroides distasonis was obtained by extraction in water,precipitation in ethanol,deproteinization using Sevag reagent and decolorization by AB-8 macroporous adsorption resin.Using RAW 264.7 macrophage as a model,the immunomodulatory xactivity of PEP was investigated by MTT assay,Griess assay,DCFH assay,neutral red experiment and real-time fluorescence quantitative PCR.The PEP was the exopolysaccharide extracted from Parabacteroides distasonis for the first time,and PEP was a heteropolysaccharide composed of mannose,rhamnose,glucose,galactose and fucose in a ratio of 19.35∶8.70∶5.24∶8.17∶1.00.Functional investigation showed that PEP could promote the proliferation of macrophages,increase the release of nitric oxide and reactive oxygen species by macrophages,enhance the phagocytosis ability of macrophages,and promote the production of cytokines(IL-1β,IL-6,TNF-α)by macrophages at the gene level in a concentration-dependent manner.The results suggested that PEP possessed good immunomodulatory ability,providing a certain reference value for the development of PEP as a potential immune stimulant in the future.