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. Author manuscript; available in PMC: 2014 Nov 15.
Published in final edited form as: Semin Immunol. 2013 Nov 5;25(4):313–320. doi: 10.1016/j.smim.2013.10.010

Figure 1.

Figure 1

Signal integration determines T cell fate. Activated T cells integrate signals triggered by recognition of MHC-antigen (Ag) complexes by the TCR, together with those induced by the engagement of CD28 by B7 ligands and by binding of IL-2 to the IL-2 receptor. Those signals translate into the activation of a series of signaling pathways, including increased calcium entry and activation of PKCθ, Ras/MAPKs, PI3K/AKT and mTOR, which allow the T cell to upregulate its metabolism and induce the transcription factors (e.g. NFAT, Fos/Jun or NFκB) required to maintain an activation-induced program of gene expression. When TCR engagement occurs in the absence of costimulation and/or the presence of inhibitory signals (e.g. effects of Tregs on DCs and effector T cells or engagement of coinhibitory receptors such as CTLA-4, PD-1 or A2aR) and unbalance activation of those signaling pathways leads to the induction of an alternative program of gene expression that will result in anergy.