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Molecular mechanisms of toxicant-induced immunosuppression: role of second messengers
M P Holsapple1, J G Karras, J A Ledbetter
1Toxicology Research Laboratory, Dow Chemical Company, Midland, Michigan 48674, USA.
Abstract:
Changes in immunocompetence following chemical exposure have been established for a wide variety of unrelated agents. For the vast majority of immunotoxic compounds thus far identified, disruption of normal immune function is clearly mediated through direct interactions between the agent, or its metabolite, and immunocompetent cells. Regardless of whether this interaction occurs at the level of the cell membrane or at intracellular sites, basic regulatory processes mediated by second messengers are often altered. These alterations can ultimately result in immunologic dysfunction, which is most often manifested as immunosuppression. The specific disruptions in intracellular signaling produced by a number of immunotoxic compounds have now been identified, leading to a basic understanding of their molecular mechanism of action. Equally important, through the application of these agents as biological probes, new insights have been gained pertaining to which intracellular processes control which cellular functions within various populations of immunocompetent cells.
Insights
Chemicals can impair immune function by directly affecting immune cells, altering cell signaling pathways, and causing immunosuppression. Understanding these molecular mechanisms provides insights into immune cell regulation.
Area of Science:
- Immunotoxicology
- Molecular Immunology
- Cellular Signaling
Background:
- Chemical exposures are known to alter immune competence.
- Immunotoxic compounds often interact directly with immune cells, disrupting normal function.
- These interactions can affect cell membranes or intracellular sites, altering regulatory processes.
Purpose of the Study:
- To elucidate the molecular mechanisms by which immunotoxic compounds affect immune cells.
- To understand how alterations in intracellular signaling lead to immunologic dysfunction.
- To utilize immunotoxic agents as probes to gain insights into immune cell regulation.
Main Methods:
- Review of existing literature on immunotoxicology and chemical exposure.
- Analysis of studies detailing direct interactions between chemicals and immunocompetent cells.
- Examination of research on second messenger systems and intracellular signaling pathways.
Main Results:
- Immunotoxic compounds disrupt immune function primarily through direct interaction with immunocompetent cells.
- Alterations in intracellular signaling pathways, mediated by second messengers, are a common mechanism.
- This disruption often manifests as immunosuppression.
- Specific molecular disruptions have been identified for various immunotoxic compounds.
Conclusions:
- Direct interaction with immune cells and subsequent alteration of intracellular signaling are key mechanisms of chemical-induced immunotoxicity.
- Understanding these molecular pathways is crucial for comprehending immune cell regulation.
- Immunotoxic compounds serve as valuable tools for dissecting immune cell functions.