A novel fibronectin-binding protein of Streptococcus suis serotype 2 contributes to epithelial cell invasion and in vivo dissemination
A novel fibronectin-binding protein of Streptococcus suis serotype 2 contributes to epithelial cell invasion and in vivo dissemination
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DOI：
10.1016/j.vetmic.2012.09.004
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发表时间：
2013-02-22
影响因子：
3.3
通讯作者：
Zhou, Rui
中科院分区：
文献类型：
--
作者：
Li, Wei;Wan, Yun;Zhou, Rui
猪链球菌2型（Streptococcussuisserotype 2，SS 2）是一种重要的人畜共患病原菌。在这项研究中，一种新的体内诱导蛋白Ssa，由功能未知的基因SSU05_1311编码，被确定为表面锚定的纤连蛋白结合蛋白。重组Ssa及其截短的N端结构域（残基33-153）蛋白均能与人纤连蛋白高亲和力结合。SS 2中ssa的同基因敲除导致细菌与固定化纤连蛋白的结合减少。与野生型菌株相比，SS 2 Δ ssa突变体显示人咽上皮（HEp-2）细胞的粘附和侵袭减少。在大肠杆菌中，Ssa纤连蛋白结合结构域的异源表面展示增强了细菌对HEp-2细胞的附着和进入。从鼻内感染的Balb/c小鼠的血液和脑中回收的SS 2 Δ ssa突变体比野生型菌株少。但野生型和突变型在调理条件下对巨噬细胞（RAW264.7）的吞噬作用和对小鼠PMNs的杀菌作用无显著差异。我们的数据表明，Ssa是SS 2在体内穿过粘膜上皮传播的重要毒力因子。(C)2012爱思唯尔有限公司版权所有。
Streptococcus suis serotype 2 (SS2) is an important pathogen with zoonotic potential. In this study, a novel in vivo induced protein Ssa, encoded by the functionally unknown gene SSU05_1311, was identified as a surface anchored fibronectin-binding protein. The recombinant Ssa as well as its truncated proteins harboring the N-terminal domain (residues 33-153) could bind to human fibronectin with high-affinity. Isogenic knockout of ssa in SS2 led to decrease of bacterial binding to immobilized fibronectin. SS2 Delta ssa mutant showed reduced adherence and invasion of human pharyngeal epithelial (HEp-2) cells compared to the wild type strain. Heterologous surface display of Ssa fibronectin-binding domain in Escherichia coli enhanced the bacterial attachment and entry to HEp-2 cells. Less SS2 Delta ssa mutants than the wild type strain were recovered from the blood and brains of the Balb/c mice infected intranasally. But there was no significant difference between the wild type and the mutant on phagocytosis by macrophages (RAW264.7) and bacterial killing by murine PMNs under opsonizing condition. Our data suggest that Ssa is an important virulence factor for SS2 crossing the mucosal epithelia to disseminate in vivo. (C) 2012 Elsevier B.V. All rights reserved.