Pezzicoli Alfredo, Santi Isabella, Lauer Peter, Rosini Roberto, Rinaudo Daniela, Grandi Guido, Telford John L, Soriani Marco
Novartis Vaccines and Diagnostics, Siena, Italy.
J Infect Dis. 2008 Sep 15;198(6):890-8. doi: 10.1086/591182.
We have recently shown that group B Streptococcus (GBS) crosses the epithelial barrier by a paracellular route. Here, we show that, although deletion of the pilus backbone protein did not affect GBS adhesiveness, it reduced the pathogen's capacity to transcytose through differentiated human epithelial cells. In addition, contrary to our expectation, a strain with a mutant pilus ancillary protein and reduced adhesiveness translocated through the epithelial monolayer in a fashion identical to that of the isogenic wild-type strain. To monitor the localization of pili during GBS paracytosis, we performed 3-dimensional confocal experiments. By this approach, we observed that pili located in the intercellular space ahead of translocating bacteria. These results were also confirmed by a novel in vitro model of GBS infection in which bacteria bind to epithelial surfaces against the action of gravitation. These findings suggest a dual role for pilus components during the critical steps leading to GBS dissemination in the host.
我们最近发现B族链球菌（GBS）通过细胞旁途径穿过上皮屏障。在此，我们表明，尽管菌毛主干蛋白的缺失不影响GBS的黏附性，但它降低了病原体通过分化的人上皮细胞进行转胞吞作用的能力。此外，与我们的预期相反，一株菌毛辅助蛋白发生突变且黏附性降低的菌株以与同基因野生型菌株相同的方式穿过上皮单层。为了监测GBS细胞旁运输过程中菌毛的定位，我们进行了三维共聚焦实验。通过这种方法，我们观察到菌毛位于正在转运的细菌前方的细胞间隙中。这些结果也通过一种新型的GBS感染体外模型得到了证实，在该模型中细菌在重力作用下仍能黏附于上皮表面。这些发现表明菌毛成分在导致GBS在宿主体内传播的关键步骤中具有双重作用。
