IL-15 Activates Telomerase and Minimizes Telomere Loss and May Preserve the Replicative Life Span of Memory CD8 super(+) T Cells In Vitro

• Published in: The Journal of immunology (1950) Vol. 174; no. 7; pp. 4019 - 4024
• Main Authors: Li, Yu, Zhi, Wang, Wareski, Przemyslaw, Weng, Nan-Ping
• Format: Journal Article
• Language: English
• Published: 01-04-2005
• ISSN: 0022-1767

The preservation of the replicative life span of memory CD8 super(+) T cells is vital for long-term immune protection. Although IL-15 plays a key role in the homeostasis of memory CD8 super(+) T cells, it is unknown whether IL-15 regulates the replicative life span of memory CD8 super(+) T cells. In this study, we report an analysis of telomerase expression and telomere length in human memory phenotype CD8 super(+) T cells maintained by IL-15 in vitro. We demonstrate that IL- 15 is capable of activating telomerase in memory CD8 super(+) T cells via Jak3 and PI3K signaling pathways. Furthermore, IL-15 induces a sustained level of telomerase activity over long periods of time, and in turn minimizes telomere loss in memory CD8 super(+) T cells after substantial cell divisions. These findings suggest that IL-15 activates stable telomerase expression and compensates telomere loss in memory phenotype CD8 super(+) T cells, and that telomerase may play an important role in memory CD8 super(+) T cell homeostasis.