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Positive- and Negative-Control Pathways by Blood Components for Intermedilysin Production in Streptococcus
Toshifumi Tomoyasu1,2, Takahiro Yamasaki3, Shinya Chiba3
1Department of Bioscience and Bioindustry, Graduate School of Bioscience and Bioindustry, Tokushima University Graduate School, Tokushima, Japan.
Infection and Immunity
|June 14, 2017
Summary
Bacterial growth in fetal bovine serum upregulates Streptococcus intermedius virulence factors like intermedilysin (ILY). Human plasma, however, contains factors that inhibit these virulence factors, impacting bacterial pathogenicity.
Area of Science:
- Microbiology
- Bacterial Pathogenesis
- Molecular Biology
Background:
- Streptococcus intermedius is an opportunistic pathogen.
- Intermedilysin (ILY) is a key virulence factor.
- MsgA and NanA are glycosidases involved in glycan degradation.
Purpose of the Study:
- To investigate the effect of culture conditions on S. intermedius virulence.
- To determine the role of MsgA and NanA in ILY regulation.
- To explore the influence of human plasma on S. intermedius pathogenicity.
Main Methods:
- Culturing S. intermedius in fetal bovine serum (FBS) and human plasma.
- Measuring hemolytic activity and glycosidase activity.
- Analyzing gene expression in wild-type and mutant strains.
- Assessing cytotoxicity and neutralization by human plasma.
Main Results:
- FBS culture enhanced ILY, MsgA, and NanA activity.
- Released monosaccharides (galactose, N-acetylneuraminic acid) from FBS stimulated gene expression.
- Human plasma inhibited FBS-induced virulence factor expression and activity.
- Human plasma immunoglobulins neutralized ILY, MsgA, and NanA, reducing cytotoxicity.
Conclusions:
- Blood components differentially regulate S. intermedius virulence.
- FBS contains factors that upregulate virulence, while human plasma contains inhibitory factors.
- These interactions influence the pathogenicity of S. intermedius.
