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Effect on polymorphonuclear cell function of a human-specific cytotoxin, intermedilysin, expressed by Streptococcus
M G Macey1, R A Whiley, L Miller
1Department of Haematology, Barts and the London NHS Trust, United Kingdom. macey.marion@royalhos-tr.nthames.nhs.uk
Infection and Immunity
|September 13, 2001
Summary
Intermedilysin (ILY) from Streptococcus intermedius impacts polymorphonuclear cell (PMN) function. While decreasing intact PMNs, ILY enhances PMN calcium, CD11b expression, and phagocytosis, potentially influencing deep-seated abscesses.
Area of Science:
- Microbiology
- Immunology
- Cell Biology
Background:
- Streptococcus intermedius is a commensal oral bacterium and an opportunistic pathogen.
- Intermedilysin (ILY) is a cytolysin produced by S. intermedius, specific for human cells.
- Polymorphonuclear cells (PMNs) are crucial for innate immunity.
Purpose of the Study:
- To investigate the effects of purified intermedilysin (ILY) on polymorphonuclear cell (PMN) function.
- To understand the role of ILY in the context of bacterial infections and host immune response.
Main Methods:
- Purified intermedilysin (ILY) was used to treat human PMNs.
- Assays included measurement of intact PMNs, intracellular calcium, CD11b expression, metabolic burst, and phagocytosis of Staphylococcus aureus.
- Comparison was made between active and heat-inactivated ILY.
Main Results:
- Active ILY significantly reduced the number of intact PMNs at 40 ng/microl after 60 minutes.
- Active ILY did not exhibit chemotaxis but increased intracellular calcium levels in PMNs.
- Active ILY enhanced PMN metabolic burst and phagocytosis of Staphylococcus aureus.
Conclusions:
- Intermedilysin (ILY) modulates PMN function, impacting both cell viability and activity.
- These findings suggest a complex role for ILY in S. intermedius infections, potentially contributing to abscess formation.
- ILY's effects on PMNs warrant further investigation for understanding its pathogenicity.