Interleukin 4 (IL-4) or IL-7 prevents the death of resting T cells: stat6 is probably not required for the effect of IL-4

A Vella, TK Teague, J Ihle, J Kappler… - The Journal of …, 1997 - rupress.org
A Vella, TK Teague, J Ihle, J Kappler, P Marrack
The Journal of experimental medicine, 1997rupress.org
Although much is known about the activation, proliferation, and function of CD4+ T cells, little
is known about how they survive as resting T cells in animals. Resting T cells have a half-life
in animals of more than a week; however, when they are removed from animals and placed
in tissue culture their half-life falls to∼ 24 h. In this paper, we show that the survival of resting
T cells in vitro is promoted by two cytokines, interleukins 4 and 7 (IL-4, IL-7). They may do
this in part by maintaining levels of survival-promoting proteins such as Bcl-2 in the cells …
Although much is known about the activation, proliferation, and function of CD4+ T cells, little is known about how they survive as resting T cells in animals. Resting T cells have a half-life in animals of more than a week; however, when they are removed from animals and placed in tissue culture their half-life falls to ∼24 h. In this paper, we show that the survival of resting T cells in vitro is promoted by two cytokines, interleukins 4 and 7 (IL-4, IL-7). They may do this in part by maintaining levels of survival-promoting proteins such as Bcl-2 in the cells, because the levels of Bcl-2 and Bcl-Xl in resting T cells fall rapidly after the cells are isolated from animals, and are maintained by culture in IL-4. Because the IL-4 receptor is known to signal through the JAK1 and JAK3/Stat6 pathway, we tested whether Stat6 was required for IL-4– dependent T cell survival. Surprisingly, we found that IL-4 rescued T cells from apoptosis in what appeared to be a Stat6-independent manner. These results demonstrate that the survival of resting T cells is an active process that can be affected by signals delivered by cytokines and also suggest that the IL-4 receptor on resting T cells may use a novel signaling pathway to facilitate T cell viability.
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