Effect of Group A Streptococcal Cysteine Protease on Invasion of Epithelial Cells

Pei Jane Tsai, Chih Feng Kuo, Kuei Yuan Lin, Yee Shin Lin, Huan Yao Lei, Fen Fen Chen, Jen Ren Wang, Jiunn Jong Wu

研究成果: Article同行評審

77 引文 斯高帕斯(Scopus)


Cysteine protease of group A streptococci (GAS) is considered an important virulence factor. However, its role in invasiveness of GAS has not been investigated. We demonstrated in this study that two strains of protease-producing GAS had the ability to invade A-549 human respiratory epithelial cells. Isogenic protease mutants were constructed by using integrational plasmids to disrupt the speB gene and confirmed by Southern hybridization and Western immunoblot analyses. No extracellular protease activity was produced by the mutants. The mutants had growth rates similar to those of the wild-type strains and produced normal levels of other extracellular proteins. When invading A-549 cells, the mutants had a two- to threefold decrease in activity compared to that of the wild-type strains. The invasion activity increased when the A-549 cells were incubated with purified cysteine protease and the mutant. However, blockage of the cysteine protease with a specific cysteine protease inhibitor, E-64, decreased the invasion activity of GAS. Intracellular growth of GAS was not found in A-549 cells. The presence or absence of protease activity did not affect the adhesive ability of GAS. These results suggested that streptococcal cysteine protease can enhance the invasion ability of GAS in human respiratory epithelial cells.

頁(從 - 到)1460-1466
期刊Infection and Immunity
出版狀態Published - 1998 4月

All Science Journal Classification (ASJC) codes

  • 寄生物學
  • 微生物學
  • 免疫學
  • 傳染性疾病


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