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Memory CD8 T lymphocytes express inhibitory MHC-specific Ly49 receptors.
M C Coles1, C W McMahon, H Takizawa
1Department of Molecular Biology, Cancer Research Laboratory, University of California at Berkeley, Berkely, USA.
European Journal of Immunology
|December 22, 1999
Summary
A subset of aged memory CD8(+) T cells express Ly49 inhibitory receptors, impacting their immune function. This Ly49 expression appears to dampen T cell receptor-mediated activation, potentially preventing autoimmunity.
Area of Science:
- Immunology
- Cell Biology
- T cell biology
Background:
- Natural killer (NK) cells use Ly49 receptors to identify targets via major histocompatibility complex class I molecules.
- Ly49 receptors are found on NK cells and CD1-restricted NK1 T cells in mice.
Purpose of the Study:
- To characterize a population of memory cytotoxic (CD8(+)) T lymphocytes that express inhibitory Ly49 receptors.
- To investigate the functional consequences of Ly49 expression on these T cells.
Main Methods:
- Characterization of T cell populations in aging mice.
- Analysis of mutant mouse strains lacking key immune components (TAP, MHC class I, MHC class II).
- Assessment of T cell receptor-mediated activation and Ly49-mediated inhibition.
Main Results:
- A significant population of memory CD8(+) T cells express Ly49 receptors, increasing with age.
- Development of these Ly49-expressing cells requires TAP, MHC class I, and MHC class II molecules.
- Ly49 expression inhibits T cell receptor-mediated activation of CD8(+) T cells through interaction with MHC class I molecules.
Conclusions:
- Memory CD8(+) T cells can acquire Ly49 expression, particularly in aging individuals.
- Ly49 expression on memory CD8(+) T cells may serve to dampen immune responses or prevent self-reactivity (autoreactivity).