Article

Differential effects of STAT5 and PI3K/AKT signaling on effector and memory CD8 T-cell survival

Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA.
Proceedings of the National Academy of Sciences (Impact Factor: 9.81). 09/2010; 107(38):16601-6. DOI: 10.1073/pnas.1003457107
Source: PubMed

ABSTRACT During viral infection, effector CD8 T cells contract to form a population of protective memory cells that is maintained by IL-7 and IL-15. The mechanisms that control effector cell death during infection are poorly understood. We investigated how short- and long-lived antiviral CD8 T cells differentially used the survival and cell growth pathways PI3K/AKT and JAK/STAT5. In response to IL-15, long-lived memory precursor cells activated AKT significantly better than short-lived effector cells. However, constitutive AKT activation did not enhance memory CD8 T-cell survival but rather repressed IL-7 and IL-15 receptor expression, STAT5 phosphorylation, and BCL2 expression. Conversely, constitutive STAT5 activation profoundly enhanced effector and memory CD8 T-cell survival and augmented homeostatic proliferation, AKT activation, and BCL2 expression. Taken together, these data illustrate that effector and memory cell viability depends on properly balanced PI3K/AKT signaling and the maintenance of STAT5 signaling.

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