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Streptococcus suis serotype 2 interactions with human brain microvascular endothelial cells.
N Charland1, V Nizet, C E Rubens
1Groupe de Recherche sur les Maladies Infectieuses du Porc, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada J2S 7C6.
Infection and Immunity
|January 20, 2000
Summary
Streptococcus suis serotype 2 does not invade brain cells but adheres to them. Cytotoxicity, caused by suilysin, may facilitate Streptococcus suis entry into the central nervous system.
Area of Science:
- Microbiology
- Pathogenesis
- Zoonotic Diseases
Background:
- Streptococcus suis serotype 2 causes swine infections and zoonotic diseases like meningitis.
- Bacterial pathogenesis, particularly Streptococcus suis entry into the central nervous system, is not well understood.
- Group B streptococci (GBS) invade and damage brain microvascular endothelial cells (BMEC), a step in neonatal meningitis.
Purpose of the Study:
- To investigate the interactions between Streptococcus suis serotype 2 and human endothelial cells.
- To compare Streptococcus suis serotype 2 interactions with BMEC and human umbilical vein endothelial cells (HUVEc) against those of GBS.
- To elucidate the mechanisms by which Streptococcus suis may cross the blood-brain barrier.
Main Methods:
- Invasion assays using BMEC and HUVEc.
- Adherence assays with Streptococcus suis and GBS (wild-type and acapsular mutants).
- Lactate dehydrogenase (LDH) release assays to measure cytotoxicity.
- Inhibition studies using cholesterol and antisuilysin antibodies.
Main Results:
- Streptococcus suis serotype 2 did not invade BMEC or HUVEc, unlike GBS.
- Streptococcus suis adhered specifically to BMEC, while GBS adhered to both cell types.
- Capsule presence did not affect adherence for either bacterial species.
- Some Streptococcus suis strains exhibited significant cytotoxicity towards BMEC, mediated by suilysin.
- Cytotoxicity was inhibited by cholesterol and antisuilysin antibodies.
Conclusions:
- Streptococcus suis serotype 2 may utilize adherence and suilysin-induced BMEC injury, rather than direct invasion, to reach the central nervous system.
- Suilysin is a key factor in Streptococcus suis-induced endothelial cell damage.
- Understanding these interactions is crucial for developing strategies against Streptococcus suis meningitis.