Tart R C, van de Rijn I
Wake Forest University Medical Center, Winston-Salem, North Carolina 27157-1064.
Infect Immun. 1993 Dec;61(12):4994-5000. doi: 10.1128/iai.61.12.4994-5000.1993.
Bacterial attachment to host tissue is considered to be a crucial primary step in pathogen infection. Previous studies have shown that Streptococcus defectivus adheres specifically to cell-secreted extracellular matrix (ECM). Though generally not exposed in vivo, this host tissue is exposed at endothelial cell junctions and sites of tissue injury. In this report, we identify a ca. 200-kDa surface protein of S. defectivus involved in ECM adherence. Nitrous acid-derived mutant strains that were unable to bind ECM and which failed to adsorb adhesin-specific antibody from polyclonal inhibitory sera were isolated. A surface protein (ca. 200 kDa) was absent from ECM-nonadherent mutants, indicating its involvement in ECM attachment. Additionally, affinity-purified antibody to the ca. 200-kDa protein inhibited whole-cell S. defectivus ECM attachment, whereas antibody to the same region of the nonadherent mutant cell wall-associated protein profile did not. Furthermore, solubilized cell wall-associated protein extracts of parent but not mutant strains bound ECM, confirming the significance of this protein in ECM adherence. Therefore, we propose that the ca. 200-kDa protein is the major S. defectivus surface component that mediates the ECM attachment of these organisms.
细菌附着于宿主组织被认为是病原体感染的关键起始步骤。先前的研究表明，缺陷链球菌能特异性地附着于细胞分泌的细胞外基质（ECM）。尽管这种宿主组织在体内通常不会暴露，但在内皮细胞连接处和组织损伤部位会暴露。在本报告中，我们鉴定出一种参与ECM附着的缺陷链球菌约200 kDa的表面蛋白。分离出了不能结合ECM且无法从多克隆抑制血清中吸附粘附素特异性抗体的亚硝酸衍生突变菌株。ECM非粘附突变体中不存在一种表面蛋白（约200 kDa），表明其参与了ECM附着。此外，针对约200 kDa蛋白的亲和纯化抗体抑制了缺陷链球菌全细胞对ECM的附着，而针对非粘附突变体细胞壁相关蛋白谱相同区域的抗体则没有。此外，亲本菌株而非突变菌株的可溶性细胞壁相关蛋白提取物能结合ECM，证实了该蛋白在ECM附着中的重要性。因此，我们认为约200 kDa的蛋白是介导这些生物体ECM附着的主要缺陷链球菌表面成分。
