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Interleukin 2 receptor expression by T cells in human aging.
F M Orson1, C K Saadeh, D E Lewis
1Department of Internal Medicine, Baylor College of Medicine, Houston, Texas.
Cellular Immunology
|December 1, 1989
Summary
Older adults show reduced T cell responses due to fewer cells expressing interleukin-2 receptors (IL-2R). However, their T cells release high amounts of soluble IL-2R, impacting immune function in aging.
Area of Science:
- Immunology
- Gerontology
- Cell Biology
Background:
- Cell-mediated immunity and T cell proliferation decline with age.
- Interleukin-2 receptors (IL-2R) are crucial for T cell responses.
- Understanding age-related changes in IL-2R is vital for immune health in the elderly.
Purpose of the Study:
- To compare IL-2R expression and soluble IL-2R alpha chain release in young versus aged individuals.
- To investigate the functional impact of altered IL-2R in aging T cells.
Main Methods:
- Mononuclear cells from healthy aged and young donors were stimulated with PHA.
- Quantities and affinities of cell surface IL-2R were measured.
- Soluble IL-2R alpha chain (sIL-2Rα) release was quantified.
Main Results:
- Aged individuals had fewer PHA-stimulated cells expressing the IL-2R alpha chain (CD25+).
- Despite lower CD25+ expression, aged cells released significantly higher amounts of sIL-2Rα.
- Surface IL-2R affinities and numbers per CD25+ cell were comparable between age groups.
- Exogenous IL-2 or sIL-2Rα did not alter T cell proliferation in either group.
Conclusions:
- Healthy aging is associated with diminished induction of cell surface IL-2R on T cells.
- Aged individuals exhibit dysregulated sIL-2Rα release, potentially contributing to immune alterations.
- The findings suggest a complex interplay between cell surface and soluble IL-2R in the aging immune system.