Abstract
Naïve and memory CD4 and CD8 T cells constitute a highly dynamic system with constant homeostatic and antigen-driven proliferation, influx, and loss of T cells. Thymic activity dwindles with age and essentially ceases in the later decades of life, severely constraining the generation of new T cells. Homeostatic control mechanisms are very effective at maintaining a large and diverse subset of naïve CD4 T cells through the 7th decade of life, but eventually and abruptly fail at about the age of 75 years. In contrast, the CD8 T cell compartment is more unstable, with progressive diminution of naïve T cells and increasing loss of diversity during mid adulthood. Vaccination strategies need to aim at developing a broad repertoire of memory T cells before the critical time period when the naïve CD4 T-cell repertoire collapses. Research efforts need to aim at understanding T-cell homeostatic control mechanisms to ultimately expand the time period of repertoire stability.
Original language | English |
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Pages (from-to) | 400-406 |
Number of pages | 7 |
Journal | Experimental Gerontology |
Volume | 42 |
Issue number | 5 SPEC. ISS. |
DOIs | |
State | Published - May 2007 |
Keywords
- Aging
- Immunosenescence
- T-cell homeostasis
- T-cell receptor
- T-cell repertoire
- Thymus