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Aging Leads to Disturbed Homeostasis of Memory Phenotype CD8+ Cells
- Source :
- The Journal of Experimental Medicine; February 2002, Vol. 195 Issue: 3 p283-293, 11p
- Publication Year :
- 2002
-
Abstract
- Examining the rate of in vivo T cell turnover (proliferation) in aged mice revealed a marked reduction in turnover at the level of memory-phenotype CD44hi CD8+ cells relative to young mice. Based on adoptive transfer experiments, the reduced turnover of aged CD44hi CD8+ cells reflected an inhibitory influence of the aged host environment. Aged CD44hi CD8+ cells also showed poor in vivo responses to IL-15 and IL-15–inducing agents, but responded well to IL-15 in vitro. Two mechanisms could account for the reduced turnover of aged CD44hi CD8+ cells in vivo. First, aging was associated with a prominent and selective increase in Bcl-2 expression in CD44hi CD8+ cells. Hence, the reduced turnover of aged CD44hi CD8+ cells may in part reflect the antiproliferative effect of enhanced Bcl-2 expression. Second, the impaired in vivo response of aged CD44hi CD8+ cells to IL-15 correlated with increased serum levels of type I interferons (IFN-I) and was largely reversed by injection of anti–IFN-I antibody. Hence the selective reduction in the turnover of aged CD44hi CD8+ cells in vivo may reflect the combined inhibitory effects of enhanced Bcl-2 expression and high IFN-I levels.
Details
- Language :
- English
- ISSN :
- 00221007 and 15409538
- Volume :
- 195
- Issue :
- 3
- Database :
- Supplemental Index
- Journal :
- The Journal of Experimental Medicine
- Publication Type :
- Periodical
- Accession number :
- ejs57368304
- Full Text :
- https://doi.org/10.1084/jem.20011267