Scavenger receptor gp340 aggregates group A streptococci by binding pili
Scavenger receptor gp340 aggregates group A streptococci by binding pili
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DOI：
10.1111/j.1365-2958.2008.06220.x
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发表时间：
2008-06-01
影响因子：
3.6
通讯作者：
Grandi, Guido
中科院分区：
文献类型：
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作者：
Edwards, Andrew M.;Manetti, Andrea G. O.;Grandi, Guido
A群链球菌（GAS）是引起细菌性咽炎的最常见原因。气体在咽部定植的第一个障碍是唾液。除了形成物理屏障外，唾液还含有先天和获得性免疫的成分。先前的研究表明，唾液诱导细菌聚集，这可能是一种清除机制。由于一些口腔链球菌在唾液中的聚集是由长蛋白附属物介导的，我们假设GAS的菌毛可能有类似的行为。野生型GAS M1菌株SF370在唾液中聚集，而菌毛缺陷突变体则没有聚集。同样，在乳酸乳球菌表面异源表达多种GAS菌毛可诱导唾液聚集，而对照菌株则不受影响。进一步研究发现，聚集菌结合唾液成分gp340。纯化的gp340聚集了野生型GAS和表达GAS菌毛的L. lactis，而不是对照菌株。在gp340的结合和聚集中，GAS缺陷突变体被废除。此外，gp340介导的聚集减少了细菌对人上皮细胞的粘附，表明其在宿主防御中起作用。
Group A streptococci (GAS) are the most frequent cause of bacterial pharyngitis. The first obstacle to GAS colonization of the pharynx is saliva. As well as forming a physical barrier, saliva contains components of innate and acquired immunity. Previous work has shown that saliva induces bacterial aggregation, which may serve as a clearance mechanism. As the aggregation of some oral streptococci in saliva is mediated by long proteinaceous appendages, we hypothesized that pili of GAS might behave similarly. Wild-type GAS M1 strain SF370 aggregated in saliva, while pilus-defective mutants did not. Similarly, heterologous expression of diverse GAS pili on the surface of Lactococcus lactis induced aggregation in saliva, while control strains were unaffected. Further studies revealed that aggregating bacteria bound salivary component gp340. Purified gp340 aggregated wild-type GAS and L. lactis expressing GAS pili, but not control strains. GAS pilus-defective mutants were abrogated in gp340 binding and aggregation. Furthermore, gp340-mediated aggregation reduced bacterial adhesion to human epithelial cells, suggesting a role in host defence.