Emergence of NK Cell Hyporesponsiveness after Two IL-15 Stimulation Cycles.IL-15 is a cytokine playing a crucial role in the function of immune cells, including NK and CD8 T cells.  In this study, we demonstrated that in vivo, in mice, IL-15-prestimulated NK cells were no longer able to respond to a second cycle of IL-15 stimulation.  Moreover, NK cells from immunodeficient mice could respond to two cycles of IL-15 stimulation, whereas an adoptive transfer of CD44+CD8+ cells impaired their responsiveness to the second cycle.  Conversely, in immunocompetent mice, NK cell responsiveness to a second IL-15 stimulation was restored by the depletion of CD8+ cells.  These biological findings refine our understanding of the complex mode of action of NK cells in vivo, and they should be taken into consideration for IL-15-based therapy.
IL-15
Emergence of NK Cell Hyporesponsiveness after Two IL-15 Stimulation Cycles.IL-15 is a cytokine playing a crucial role in the function of immune cells, including NK and CD8 T cells.  In this study, we demonstrated that in vivo, in mice, IL-15-prestimulated NK cells were no longer able to respond to a second cycle of IL-15 stimulation.  Moreover, NK cells from immunodeficient mice could respond to two cycles of IL-15 stimulation, whereas an adoptive transfer of CD44+CD8+ cells impaired their responsiveness to the second cycle.  Conversely, in immunocompetent mice, NK cell responsiveness to a second IL-15 stimulation was restored by the depletion of CD8+ cells.  These biological findings refine our understanding of the complex mode of action of NK cells in vivo, and they should be taken into consideration for IL-15-based therapy.
IL-15
Emergence of NK Cell Hyporesponsiveness after Two IL-15 Stimulation Cycles.IL-15 is a cytokine playing a crucial role in the function of immune cells, including NK and CD8 T cells.  In this study, we demonstrated that in vivo, in mice, IL-15-prestimulated NK cells were no longer able to respond to a second cycle of IL-15 stimulation.  Moreover, NK cells from immunodeficient mice could respond to two cycles of IL-15 stimulation, whereas an adoptive transfer of CD44+CD8+ cells impaired their responsiveness to the second cycle.  Conversely, in immunocompetent mice, NK cell responsiveness to a second IL-15 stimulation was restored by the depletion of CD8+ cells.  These biological findings refine our understanding of the complex mode of action of NK cells in vivo, and they should be taken into consideration for IL-15-based therapy.
IL-15
This was illustrated by defects in cell maturation, proliferation, and activation, seemingly linked to the environment surrounding NK cells but not related to the presence of CD4 regulatory T cells, TGF-β, or IL-10.  Moreover, NK cells from immunodeficient mice could respond to two cycles of IL-15 stimulation, whereas an adoptive transfer of CD44+CD8+ cells impaired their responsiveness to the second cycle. 
CD4
This was illustrated by defects in cell maturation, proliferation, and activation, seemingly linked to the environment surrounding NK cells but not related to the presence of CD4 regulatory T cells, TGF-β, or IL-10. 
TGF-β
This was illustrated by defects in cell maturation, proliferation, and activation, seemingly linked to the environment surrounding NK cells but not related to the presence of CD4 regulatory T cells, TGF-β, or IL-10. 
IL-10
Moreover, NK cells from immunodeficient mice could respond to two cycles of IL-15 stimulation, whereas an adoptive transfer of CD44+CD8+ cells impaired their responsiveness to the second cycle. 
CD44+CD8+
Moreover, NK cells from immunodeficient mice could respond to two cycles of IL-15 stimulation, whereas an adoptive transfer of CD44+CD8+ cells impaired their responsiveness to the second cycle.  Conversely, in immunocompetent mice, NK cell responsiveness to a second IL-15 stimulation was restored by the depletion of CD8+ cells. 
CD8+