A surface‐exposed neuraminidase affects complement resistance and virulence of the oral spirochaete Treponema denticola. Issue 5 (1st August 2013)

• Record Type: Journal Article
• Authors: Kurniyati, Kurni; Zhang, Weiyan; Zhang, Kai; Li, Chunhao
• Is Part Of: Molecular microbiology. Volume 89:Issue 5(2013)
• Page Start: 842
• Page End: 856
• Publication Date: 2013-08-01
• Subjects: Molecular microbiology -- Periodicals; 572.829
• DOI: 10.1111/mmi.12311
• Languages: English
• ISSNs: 0950-382X

Abstract

Summary: Neuraminidases (sialidases) catalyse the removal of terminal sialic acid from glycoconjugates. Bacterial pathogens often utilize neuraminidases to scavenge host sialic acid, which can be utilized either as a nutrient or as a decorating molecule to disguise themselves from host immune attacks. Herein, a putative neuraminidase (TDE0471) was identified in Treponema denticola, an oral spirochaete associated with human periodontitis. TDE0471 is a cell surface‐exposed exo‐neuraminidase that removes sialic acid from human serum proteins; it is required for T. denticola to grow in a medium that mimics gingival crevice fluid, suggesting that the spirochaete may use sialic acid as a nutrient in vivo . TDE0471 protects T. denticola from serum killing by preventing the deposition of membrane attack complexes on the bacterial cell surface. Animal studies revealed that a TDE0471‐deficient mutant is less virulent than its parental wild‐type strain in BALB/C mice. However, it causes a level of tissue damage similar to the wild type in complement‐deficient B6.129S4‐ C3 tm1 Crr /J mice albeit the damage caused by both bacterial strains is more severe in these transgenic mice. Based on these results, we propose that T. denticola has evolved a strategy to scavenge host sialic acid using its neuraminidase, which allows the spirochaete to acquire nutrients and evade complement killing.