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An increase in basal glucocorticoid concentration with age induces suppressor macrophages with high-density Fc gamma
T Kizaki1, T Ookawara, S Oh-Ishi
1Department of Hygiene, National Defense Medical College, Saitama, Japan.
Immunology
|June 26, 1998
Summary
Aging impairs immune function, with older mice showing increased suppressor cells in their peritoneum. Elevated corticosterone (a glucocorticoid) drives this, potentially causing age-related immunosuppression.
Area of Science:
- Immunology
- Neuroendocrinology
- Gerontology
Background:
- Immune and neuroendocrine functions decline with age.
- Age-related immunosuppression mechanisms require elucidation.
Purpose of the Study:
- Investigate peritoneal cell functions and phenotypes in aged mice.
- Examine the role of glucocorticoids (GC) in age-related immunomodulation.
Main Methods:
- Flow cytometry to analyze peritoneal exudate cells (PECs).
- Assessed spleen cell proliferation responses.
- Measured serum corticosterone and GC receptor mRNA expression.
- Used GC antagonist RU 38,486 (mifepristone).
Main Results:
- Old mice PECs significantly suppressed T-cell proliferation.
- Increased proportion of Fc gamma RII/IIIbright cells in old mice PECs.
- Fc gamma RII/IIIbright cells exhibited potent immunosuppressive activity.
- Elevated basal corticosterone and GC receptor mRNA in old mice.
- GC antagonist normalized Fc gamma RII/IIIbright cell proportion.
Conclusions:
- Increased basal corticosterone in aged mice induces Fc gamma RII/IIIbright suppressor cells.
- This mechanism likely contributes to age-related immunosuppression.