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Relationship between non-specific activity of macrophages and immune responses to Listeria monocytogenes
Abstract:
Delayed footpad reactions and acquired cellular resistance to Listeria monocytogenes were studied in mice whose mononuclear phagocyte system (MPS) had been blocked or stimulated. Colloidal carbon was used for the blockade of MPS and Corynebacterium parvum used for the stimulation. Strong delayed footpad reactions. On the other hand, the i.v. injection of 3 X 10(1) listeria induced an appreciable level mice, while in MPS-stimulated mice, i.v. injection with even 4 X 10(3) listeria could not induce such strong delayed footpad reaction. On the other hand, the i.v. injection of 3 X 10(1) listeria induced an appreciable level of delayed footpad reaction only in MPS-blocked mice. Acquired cellular resistance was depressed by MPS stimulation, whereas it was augmented by MPS blockade. These results suggested that non-specific activity of MPS modulates subsequent immune responses after inoculation of listeria.
Insights
Modulating the mononuclear phagocyte system (MPS) impacts immune responses to Listeria monocytogenes. MPS blockade enhances cellular resistance and footpad reactions, while stimulation depresses them.
Area of Science:
- Immunology
- Microbiology
Background:
- The mononuclear phagocyte system (MPS) plays a crucial role in innate and adaptive immunity.
- Understanding how MPS activity influences host defense against bacterial infections is vital.
Purpose of the Study:
- To investigate the effect of modulating mononuclear phagocyte system (MPS) activity on immune responses to Listeria monocytogenes.
- To determine how MPS blockade or stimulation impacts delayed footpad reactions and acquired cellular resistance.
Main Methods:
- Mice underwent blockade of the MPS using colloidal carbon or stimulation with Corynebacterium parvum.
- Delayed footpad reactions and acquired cellular resistance were assessed after Listeria monocytogenes inoculation.
Main Results:
- MPS blockade significantly enhanced delayed footpad reactions and acquired cellular resistance to Listeria monocytogenes.
- MPS stimulation led to depressed acquired cellular resistance and reduced delayed footpad reactions.
- Higher doses of Listeria monocytogenes were required to elicit a response in MPS-stimulated mice compared to MPS-blocked mice.
Conclusions:
- Non-specific activity of the mononuclear phagocyte system (MPS) significantly modulates subsequent immune responses to Listeria monocytogenes.
- Modulating MPS activity offers a potential strategy for influencing host defense against bacterial pathogens.