Elucidation of immunostimulatory effect of capsular polysaccharides produced by lactic acid bacteria using pseudo-bacterial cell model.

我们用链霉亲和素包裹的荧光小球与从乳球菌细胞中提纯的生物素化的胶囊多糖(CPS)偶联，构建了一个假细菌细胞模型。将CPS标记的微球加入巨噬细胞样细胞系J774.1，并对吞噬CPS标记微球的细胞进行流式细胞术分析。提纯了乳酸乳球菌C59胞外蛋白特异性的Ru红结合因子，经鉴定为RNAs，其中核糖体RNAs为主要成分。扫描电子显微镜下，C59细胞表面可见颗粒状结构，但未见RNA被洗脱的病变。CPS缺失的C59同源菌株C63的表面没有观察到颗粒状结构。下一代测序结果表明，C59和C63具有相同的EPS基因簇。

We have constructed a pseudo-bacterial cell model using streptavidin coated fluorescent beads in conjugation with biotinylated capsular polysaccharides (CPS) purified from Lactococcus cells. The CPS-labeled beads were added to macrophage-like cell line J774.1 and cells that engulfed CPS-labeled beads were analyzed by flow cytometry. Ruthenium red-binding factor specific to the CPS of Lactococcus lactis C59 was purified and found to be RNAs, in which ribosome RNAs were the main components. By scanning electron microscopy, there were particle-like structures on the cell surface of C59 but no lesions from which RNAs were eluted. Particle-like structures were not observed on the surface of strain C63, a CPS-deficient C59 congenic strain. The result of next-generation sequencing showed that C59 and C63 possessed the identical eps gene cluster.