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Purification of a monocytosis-producing activity from Listeria monocytogenes
Abstract:
The monocytosis-producing activity (MPA) from Listeria monocytogenes is shown to be associated with the cell envelope. Both MPA and immunosuppressive activity were readily extracted with aqueous solvents and separated as two independent activities by gel filtration and ion-exchange chromatography. As little as 10 microng of the resulting MPA-containing fraction caused a ninefold elevation in the level of circulating monocytes. The molecular weight of the fraction was approximately 22,000, and it contained phosphorus and carbohydrate.
Insights
Monocytosis-producing activity (MPA) from Listeria monocytogenes elevates circulating monocytes. This bacterial cell envelope component was isolated and characterized, showing significant immune-modulating effects.
Area of Science:
- Microbiology
- Immunology
Background:
- Listeria monocytogenes is a known pathogen.
- Bacterial cell envelopes contain various bioactive molecules.
Purpose of the Study:
- To isolate and characterize the monocytosis-producing activity (MPA) from Listeria monocytogenes.
- To investigate the biological activity of MPA.
Main Methods:
- Extraction of MPA using aqueous solvents.
- Separation of MPA by gel filtration and ion-exchange chromatography.
- Administration of MPA to assess its effect on monocyte levels.
Main Results:
- MPA is associated with the cell envelope of Listeria monocytogenes.
- MPA and immunosuppressive activity are distinct.
- A fraction containing MPA caused a ninefold increase in circulating monocytes at 10 micrograms.
- The active fraction had a molecular weight of approximately 22,000 Da and contained phosphorus and carbohydrate.
Conclusions:
- Listeria monocytogenes produces a potent monocytosis-inducing factor.
- MPA is a distinct molecular entity with significant immunomodulatory potential.
- Further characterization of MPA could reveal novel insights into immune regulation.