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Published on: July 1, 2018
Adherence of Streptococcus suis to porcine endothelial cells
L Benga1, P Friedl, P Valentin-Weigand
1Institut für Mikrobiologie, Zentrum für Infektionsmedizin, Stiftung Tierärztliche Hochschule, Hannover, Germany.
Abstract:
Streptococcus suis can cause invasive diseases in pigs and humans, such as meningitis or arthritis. Adherence to and invasion of endothelial cells might represent important steps in survival and spread of S. suis within the host. We tested in vitro adherence and invasion of S. suis strains using a porcine brain microvascular and aortal endothelial cell line. Four S. suis strains were tested with and without prior treatment with porcine serum containing anti-S. suis antibodies. Strains included a capsular serotype 2 strain and its non-encapsulated isogenic mutant strain, as well as two non-typeable (NT) strains, which expressed no capsule under our experimental conditions. Strains adhered to both cell lines to different extents depending on encapsulation and pre-treatment with porcine immune serum. The serotype 2 strain showed almost no adherence, whereas the non-encapsulated mutant strain adhered strongly. Similarly, both NT strains adhered substantially better than the serotype 2 strain. Pre-treatment of bacteria with porcine serum increased adherence of the encapsulated serotype 2 strain and decreased adherence of the non-encapsulated strains. None of the strains was able to efficiently invade either of the two cell lines, except for one NT strain, which showed a very low extend of invasion. Our results suggest that S. suis can adhere to but not invade porcine endothelial cells, and that this interaction may involve different bacterial surface structures, such as capsular polysaccharides and/or binding sites for serum components.
Insights
Streptococcus suis adheres to porcine endothelial cells, with capsule presence influencing bacterial interaction. Encapsulation affects adherence, but invasion is generally limited, suggesting surface structures are key for S. suis host interaction.
Area of Science:
- Veterinary Microbiology
- Bacterial Pathogenesis
- Cell Biology
Background:
- Streptococcus suis is a significant zoonotic pathogen causing severe diseases in pigs and humans.
- Endothelial cell interactions are crucial for bacterial dissemination and host survival.
- Understanding Streptococcus suis adherence and invasion mechanisms is vital for disease control.
Purpose of the Study:
- To investigate the in vitro adherence and invasion capabilities of Streptococcus suis strains to porcine endothelial cells.
- To determine the role of bacterial encapsulation and serum opsonization in these interactions.
Main Methods:
- Utilized porcine brain microvascular and aortal endothelial cell lines for in vitro assays.
- Tested four Streptococcus suis strains: a capsular serotype 2 strain, its non-encapsulated mutant, and two non-typeable strains.
- Assessed bacterial adherence and invasion with and without prior treatment with porcine immune serum.
Main Results:
- Bacterial adherence varied significantly based on encapsulation; the non-encapsulated mutant and non-typeable strains showed stronger adherence than the serotype 2 strain.
- Pre-treatment with porcine serum enhanced adherence of the encapsulated strain but decreased adherence of non-encapsulated strains.
- Efficient invasion of endothelial cells by Streptococcus suis was not observed, with only one non-typeable strain showing minimal invasion.
Conclusions:
- Streptococcus suis demonstrates adherence to porcine endothelial cells, a process influenced by capsular polysaccharides and serum components.
- The lack of efficient invasion suggests adherence is a more critical step for S. suis pathogenesis in this context.
- Bacterial surface structures and host immune factors play complex roles in modulating Streptococcus suis-endothelial cell interactions.
