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A surface‐exposed neuraminidase affects complement resistance and virulence of the oral spirochaete T reponema denticola
Author(s) -
Kurniyati Kurni,
Zhang Weiyan,
Zhang Kai,
Li Chunhao
Publication year - 2013
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.12311
Subject(s) - biology , neuraminidase , microbiology and biotechnology , sialic acid , virulence , spirochaete , glycoconjugate , virulence factor , virology , biochemistry , bacteria , gene , genetics , virus
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 ( TDE 0471) was identified in T reponema denticola , an oral spirochaete associated with human periodontitis. TDE 0471 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 . TDE 0471 protects T . denticola from serum killing by preventing the deposition of membrane attack complexes on the bacterial cell surface. Animal studies revealed that a TDE 0471‐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 B 6.129 S 4‐ C 3 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.