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Positive- and Negative-Control Pathways by Blood Components for Intermedilysin Production in Streptococcus intermedius
- Source :
- Infection and Immunity. 85
- Publication Year :
- 2017
- Publisher :
- American Society for Microbiology, 2017.
-
Abstract
- Streptococcus intermedius is an opportunistic bacterial pathogen secreting a human-specific cytolysin called intermedilysin (ILY) as a major pathogenic factor. This bacterium can degrade glycans into monosaccharides using two glycosidases, multisubstrate glycosidase A (MsgA) and neuraminidase (NanA). Here, we detected a stronger hemolytic activity mediated by ILY when S. intermedius PC574 was cultured in fetal bovine serum (FBS) than when it was grown in the standard culture medium. FBS-cultured cells also showed higher MsgA and NanA activity, although overproduction of ILY in FBS was undetectable in mutants nanA -null and msgA -null. Addition of purified MsgA and NanA to the FBS resulted in a release of 2.8 mM galactose and 4.3 mM N -acetylneuraminic acid; these sugar concentrations were sufficient to upregulate the expression of ILY, MsgA, and NanA. Conversely, when strain PC574 was cultured in human plasma, no similar increase in hemolytic activity was observed. Moreover, addition of human plasma to the culture in FBS appeared to inhibit the stimulatory effect of FBS on ILY, MsgA, and NanA, although there were individual differences among the plasma samples. We confirmed that human plasma contains immunoglobulins that can neutralize ILY, MsgA, and NanA activities. In addition, human plasma had a neutralizing effect on cytotoxicity of S. intermedius toward HepG2 cells in FBS, and a higher concentration of human plasma was necessary to reduce the cytotoxicity of an ILY-high-producing strain than an ILY-low-producing strain. Overall, our data show that blood contains factors that stimulate and inhibit ILY expression and activity, which may affect pathogenicity of S. intermedius .
- Subjects :
- 0301 basic medicine
Erythrocytes
Virulence Factors
030106 microbiology
Immunology
Streptococcus intermedius
Microbiology
03 medical and health sciences
chemistry.chemical_compound
Bacteriocins
Humans
Pathogen
biology
virus diseases
Bacterial Infections
Hep G2 Cells
biology.organism_classification
respiratory tract diseases
030104 developmental biology
Infectious Diseases
chemistry
Galactose
Hepatocytes
biology.protein
Parasitology
Cytolysin
Antibody
Neuraminidase
Fetal bovine serum
Bacteria
Subjects
Details
- ISSN :
- 10985522 and 00199567
- Volume :
- 85
- Database :
- OpenAIRE
- Journal :
- Infection and Immunity
- Accession number :
- edsair.doi.dedup.....137b2d20215073288abeb4ddda07cd77