The NF-κB regulator Bcl-3 and the BH3-only proteins Bim and Puma control the death of activated T cells

A Bauer, A Villunger, V Labi… - Proceedings of the …, 2006 - National Acad Sciences
A Bauer, A Villunger, V Labi, SF Fischer, A Strasser, H Wagner, RM Schmid, G Häcker
Proceedings of the National Academy of Sciences, 2006National Acad Sciences
Apoptosis of activated T cells is critical for the termination of immune responses. Here we
show that adjuvant-stimulated dendritic cells secrete cytokines that prime activated T cells
for survival and analyze the roles of the NF-κB regulator Bcl-3 and the proapoptotic Bcl-2
family members Bim and Puma. Bcl-3 overexpression increased survival, and activated bcl-
3−/− T cells died abnormally rapidly. Cytokines from adjuvant-stimulated dendritic cells
induced Bcl-3, but survival through cytokine priming was Bcl-3-independent. Apoptosis …
Apoptosis of activated T cells is critical for the termination of immune responses. Here we show that adjuvant-stimulated dendritic cells secrete cytokines that prime activated T cells for survival and analyze the roles of the NF-κB regulator Bcl-3 and the proapoptotic Bcl-2 family members Bim and Puma. Bcl-3 overexpression increased survival, and activated bcl-3−/− T cells died abnormally rapidly. Cytokines from adjuvant-stimulated dendritic cells induced Bcl-3, but survival through cytokine priming was Bcl-3-independent. Apoptosis inhibition by Bcl-3 involved blockade of Bim activation, because Bim was overactivated in Bcl-3-deficient cells, and Bcl-3 failed to increase survival of bim−/− T cells. However, adjuvants increased survival also in Bim-deficient T cells. This Bim-independent death pathway is at least in part regulated by Puma, as shown by analysis of puma−/− and noxa−/− T cells. IL-1, IL-7, and IL-15 primed T cells for survival even in the absence of Bim or Puma. Our data define interrelations and a Bim-independent pathway to activated T cell death.
National Acad Sciences