[Capsular saliva acid of Streptococcus suis 2 influences virulence and host inflammatory responses].
OBJECTIVE
We clarified the pathogenic influence of the absence of Streptococcus suis type 2 capsular saliva acid on BLAB/c mice.


METHODS
The virulence of the experimental strains were compared; the distribution of strains in vivo was determined by quantitative plating. Histopathological analysis was used to qualitatively compare the different pathogenicity of wild strain and knockout strains. ELISA was used to test the levels of cytokine in whole blood cells for the stimulation of strains.


RESULTS
The virulence of mutant strains was significantly reduced, and when the genes were restored, toxicity levels were recovered to that of the wild type strain. The distribution in blood and in the brain between wild strain and knock out strains has significant difference, and Streptococcus suis type 2 strains can cause different degrees of brain damage. During the in vitro test, the mutant strains can stimulate the whole blood cells to secrete higher levels of MCP-1 and IL-6.


CONCLUSIONS
Capsular saliva acid affects bacterial virulence and host cell inflammation response. As an important virulence factor of Streptococcus suis type 2, it can damage the blood brain barrier and cause meningitis.
Institute of Military Medical Sciences, Nanjing Command, Nanjing 210002, China.
Jie
J
Shi
Dan
D
Hu
Jing
J
Zhu
Xianyun
X
Zhang
Tianqing
T
Hou
Jingjing
J
Guo
Xiuzhen
X
Pan
Xianfu
X
Li
Changjun
C
Wang
D000818:Animals; D016667:Bacterial Capsules / Q000502:physiology*; D007249:Inflammation / Q000209:etiology*; D008297:Male; D016920:Meningitis, Bacterial / Q000209:etiology; D051379:Mice; D008807:Mice, Inbred BALB C; D017011:Streptococcus suis / Q000145:classification / Q000254:growth & development / Q000472:pathogenicity*; D014774:Virulence