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Suppression of interferon gamma production in mice treated with carrageenan
Abstract:
Effects of carrageenan (CAR) treatment on the response of interferon (IFN) production in vivo and in vitro after stimulation with an IFN-gamma inducer, staphylococcal enterotoxin A (SEA), was investigated. The IFN-gamma production in mice stimulated with SEA was impaired after i.v. administration of a 20 mg/kg dose of CAR. Spleen cells (SC) from CAR-treated mice had decreased ability to produce IFN in vitro after stimulation with the same inducer. SC obtained from mice during the suppressive state inhibited IFN-gamma production when they were co-cultured with mononuclear cells prepared from spleens of untreated control mice. This suppressor cell activity could be removed from SC by an adherence technique to plastic surface. The SC with suppressor activity were not inactivated by treatments with monoclonal anti-Thy-1.2 antibody, anti-asialo GM1 antisera and anti-mouse immunoglobulin antisera followed by complement. The suppressive activity was detected in cell-free culture fluids of macrophage fractions containing suppressor cell activity. These results suggest that the decrease in IFN-gamma production in mice pretreated with CAR may associate with the presence of suppressor cells characterized to the monocyte/macrophage lineage.
Insights
Carrageenan treatment impairs interferon-gamma production in mice. This impairment is linked to the emergence of suppressor cells, likely of monocyte/macrophage origin, affecting immune responses.
Area of Science:
- Immunology
- Pharmacology
Background:
- Interferon-gamma (IFN-γ) is crucial for immune responses.
- Carrageenan (CAR) is known to modulate immune functions.
Purpose of the Study:
- To investigate the effect of carrageenan on IFN-γ production.
- To identify the cellular mechanisms underlying carrageenan-induced immune suppression.
Main Methods:
- Mice were treated with carrageenan and stimulated with staphylococcal enterotoxin A (SEA).
- Interferon-gamma production was measured in vivo and in vitro using spleen cells.
- Suppressor cell activity was assessed through co-culture experiments and cell characterization.
Main Results:
- Carrageenan treatment significantly reduced IFN-γ production in mice stimulated with SEA.
- Spleen cells from carrageenan-treated mice showed diminished IFN-γ production capacity in vitro.
- Suppressor cells, identified within the monocyte/macrophage lineage, were found to inhibit IFN-γ production.
Conclusions:
- Carrageenan administration suppresses IFN-γ production in mice.
- The observed suppression is mediated by the induction of monocyte/macrophage-derived suppressor cells.
- These findings highlight a novel immunomodulatory role of carrageenan.