Abstract
The accumulation of CD28(-) T cells, particularly within the CD8 subset, is one of the most prominent changes during T-cell homeostasis and function associated with aging in humans. CD28, a major co-stimulatory receptor, is responsible for the optimal antigen-mediated T-cell activation, proliferation and survival of T cells. CD28(-) T cells exhibit reduced antigen receptor diversity, defective antigen-induced proliferation and a shorter replicative lifespan while showing enhanced cytotoxicity and regulatory functions. Gene expression analyses reveal profound changes of CD28(-) T cells in comparison to their CD28(+) counterparts and corroborate their functional differences. Here we review recent advances in our understanding of CD28(-) T cells and their role in the age-associated decline of immune function.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, N.I.H., Intramural
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Research Support, Non-U.S. Gov't
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Review
MeSH terms
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Aging / immunology*
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Animals
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CD28 Antigens / genetics
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CD28 Antigens / immunology*
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CD4-Positive T-Lymphocytes / immunology*
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CD4-Positive T-Lymphocytes / metabolism
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CD8-Positive T-Lymphocytes / immunology*
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CD8-Positive T-Lymphocytes / metabolism
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Cell Adhesion Molecules / immunology
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Cell Adhesion Molecules / metabolism
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Cytokines / immunology
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Cytokines / metabolism
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Humans
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Interferons / immunology
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Interferons / metabolism
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Receptors, Cytokine / immunology
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Receptors, Cytokine / metabolism
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Receptors, Natural Killer Cell / immunology
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Receptors, Natural Killer Cell / metabolism
Substances
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CD28 Antigens
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Cell Adhesion Molecules
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Cytokines
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Receptors, Cytokine
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Receptors, Natural Killer Cell
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Interferons