Olmsted S B, Dunny G M, Erlandsen S L, Wells C L
Department of Laboratory Medicine, University of Minnesota, Minneapolis 55455.
J Infect Dis. 1994 Dec;170(6):1549-56. doi: 10.1093/infdis/170.6.1549.
Aggregation substance, a plasmid-encoded Enterococcus faecalis surface protein, plays a role in mediating the formation of mating aggregates, resulting in plasmid transfer. The role of aggregation substance in the internalization of E. faecalis by cultured intestinal epithelial cells, namely HT-29 cells, was analyzed. It was associated with a significant increase in endocytosis of E. faecalis by HT-29 cells: Numbers of internalized enterococci were fewer than of an invasive strain of Listeria monocytogenes, similar to Salmonella typhimurium and another L. monocytogenes strain, and greater than relatively noninvasive strains of E. faecalis, Proteus mirabilis, and Escherichia coli. Electron microscopy confirmed aggregation substance on the surface of strains interacting with the enterocyte microvillous surface, and intracellular enterococci were localized within membrane-bound vacuoles in the enterocyte cytoplasm. Thus, aggregation substance may facilitate E. faecalis internalization by host epithelial cells.
聚集物质是一种由质粒编码的粪肠球菌表面蛋白，在介导交配聚集体的形成从而导致质粒转移过程中发挥作用。分析了聚集物质在培养的肠上皮细胞（即HT-29细胞）内化粪肠球菌过程中的作用。它与HT-29细胞对粪肠球菌的内吞作用显著增加有关：内化的肠球菌数量少于侵袭性单核细胞增生李斯特菌菌株，与鼠伤寒沙门氏菌和另一株单核细胞增生李斯特菌相似，且多于相对非侵袭性的粪肠球菌、奇异变形杆菌和大肠杆菌菌株。电子显微镜证实与肠上皮细胞微绒毛表面相互作用的菌株表面存在聚集物质，并且细胞内的肠球菌定位于肠上皮细胞质中膜结合的液泡内。因此，聚集物质可能促进宿主上皮细胞对粪肠球菌的内化。
