Invasion of epithelial cells by Actinobacillus actinomycetemcomitans: A dynamic, multistep process
Invasion of epithelial cells by Actinobacillus actinomycetemcomitans: A dynamic, multistep process
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DOI：
10.1128/iai.64.8.2988-2997.1996
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发表时间：
1996-08-01
影响因子：
3.1
通讯作者：
FivesTaylor, PM
中科院分区：
文献类型：
--
作者：
Meyer, DH;Lippmann, JE;FivesTaylor, PM
对牙周病病原体--伴生放线放线杆菌的侵袭过程进行了显微镜观察和活细胞定量检测，并对KB和MDCK细胞进行了检测。显微镜观察发现，伴随放线菌入侵过程的相关事件发生得很快。扫描电子显微镜显示，在感染后30分钟内，放线菌伴生的放线菌伴随着KB细胞表面的凹坑，其他放线菌则通过唇状边缘的孔道进入KB细胞。透射电子显微镜和免疫荧光显微镜都表明，到这个时候，一些细菌实际上已经进入、复制和离开宿主细胞。扫描电子显微镜显示，感染的KB细胞呈纤维状突起，内含细菌构象的突起。一些突起在KB细胞之间形成细胞间连接。免疫荧光显微镜显示有伴生放线菌的突起。内化放线菌伴生放线菌从一个MDCK上皮细胞单层扩散到另一个上皮细胞单层是用我们实验室发展的一种夹心法证明的。伴放线放线菌通过极化的MDCK细胞的转胞作用也被证实。这项研究表明，伴生放线杆菌进入上皮细胞后不久，它们会经历快速增殖，随后可能会在有时延伸到相邻上皮细胞之间的突起中发现。这些突起被认为是伴随放线菌在细胞间传播的媒介。伴随放线菌细菌的内吞作用也可能发生细胞间的传播，这些细菌通过不连接上皮细胞的基本突起释放到培养液中。伴生放线菌侵袭过程是如此动态的这一发现，为了解这种牙周病原体与哺乳动物细胞的相互作用提供了重要的新线索。
The invasion process of Actinobacillus actinomycetemcomitans, a periodontopathogen, was studied with microscopy and viable quantitative assays using both KB and Madin-Darby canine kidney (MDCK) epithelial cells. Microscopy revealed that the events associated with the A. actinomycetemcomitans invasion process occurred rapidly. Scanning electron micrographs revealed A. actinomycetemcomitans associated with craters on the KB cell surface and others entering the KB cells through apertures with lip-like rims within 30 min of infection. Both transmission electron and immunofluorescence micrographs demonstrated that by this time some bacteria had, in fact, already entered, replicated, and exited host cells. Scanning electron micrographs revealed that infected KB cells exhibited fibrillar protrusions which contained bulges with the conformation of bacteria. Some protrusions formed intercellular connections between KB cells. Immunofluorescence micrographs revealed protrusions which harbored A. actinomycetemcomitans. The spread of internalized A. actinomycetemcomitans from one MDCK epithelial cell monolayer to another was demonstrated using a sandwich assay developed in our laboratory. Transcytosis of A. actinomycetemcomitans through polarized MDCK cells was also demonstrated. This study indicates that soon after entry of A. actinomycetemcomitans bacteria into epithelial cells, they undergo rapid multiplication and may subsequently be found in protrusions which sometimes extend between neighboring epithelial cells. The protrusions are are thought to mediate the cell-to-cell spread of A. actinomycetemcomitans. Cell-to-cell spread may also occur by the endocytosis of A. actinomycetemcomitans bacteria which have been released into the medium via rudimentary protrusions which do not interconnect epithelial cells. The finding that the A. actinomycetemcomitans invasion process is so dynamic sheds significant new light on the interaction of this periodontopathogen with mammalian cells.