Nave CD8 T cells require both IL-7 signaling and TCR signaling through the interaction with self peptides and MHC complex for T cell homeostasis. However nobody knows why these cells require two signals or why IL-7 signaling is not enough, since IL-7 signaling by itself can provide strong survival signals. Because IL-7 signaling can down-regulate IL-7R expression, we hypothesizes that down-regulation of IL-7R causes a problem for nave CD8 T cell homeostasis and survival. To address this question, we used T cells expressing transgenic IL-7R under the control of the human CD2 promoter which is not down-regulated by IL-7 stimulation. We found that IL-7R Tg nave CD8 T cells can proliferate dramatically in vitro in response to IL-7. This suggests that the maintenance of IL-7Ra expression is important for the proliferation by IL-7. HY TCR Tg female T cells cannot undergo homeostatic proliferation because their TCR affinity to self ligand is too low. We found that their IL-7R expression is very low and can be up-regulated by stronger TCR signaling. Interestingly, introducing an IL-7Ra Tg to HY T cells rescued their homeostatic proliferation. Consequently, we have discovered a new mechanism of T cell homeostasis in which homeostatic TCR signaling mediates the maintenance of IL-7R expression.

National Institute of Health (NIH)
National Cancer Institute (NCI)
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National Cancer Institute Division of Basic Sciences
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Takada, Kensuke; Van Laethem, Francois; Xing, Yan et al. (2015) TCR affinity for thymoproteasome-dependent positively selecting peptides conditions antigen responsiveness in CD8(+) T cells. Nat Immunol 16:1069-76
Pobezinsky, Leonid A; Etzensperger, Ruth; Jeurling, Susanna et al. (2015) Let-7 microRNAs target the lineage-specific transcription factor PLZF to regulate terminal NKT cell differentiation and effector function. Nat Immunol 16:517-24
Tai, Xuguang; Singer, Alfred (2014) Basis of Treg development in the thymus. Cell Cycle 13:501-2
Van Laethem, François; Tikhonova, Anastasia N; Pobezinsky, Leonid A et al. (2013) Lck availability during thymic selection determines the recognition specificity of the T cell repertoire. Cell 154:1326-41
Tai, Xuguang; Erman, Batu; Alag, Amala et al. (2013) Foxp3 Transcription Factor Is Proapoptotic and Lethal to Developing Regulatory T Cells unless Counterbalanced by Cytokine Survival Signals. Immunity :
Pobezinsky, Leonid A; Angelov, Georgi S; Tai, Xuguang et al. (2012) Clonal deletion and the fate of autoreactive thymocytes that survive negative selection. Nat Immunol 13:569-78
McCaughtry, Tom M; Etzensperger, Ruth; Alag, Amala et al. (2012) Conditional deletion of cytokine receptor chains reveals that IL-7 and IL-15 specify CD8 cytotoxic lineage fate in the thymus. J Exp Med 209:2263-76
Tai, Xuguang; Van Laethem, Francois; Pobezinsky, Leonid et al. (2012) Basis of CTLA-4 function in regulatory and conventional CD4(+) T cells. Blood 119:5155-63
Adoro, Stanley; Park, Jung-Hyun; Singer, Alfred (2012) Coreceptor gene "imprinting:" a genetic solution to a developmental dilemma in T cells. Cell Cycle 11:833-4
Tikhonova, Anastasia N; Van Laethem, François; Hanada, Ken-ichi et al. (2012) αβ T cell receptors that do not undergo major histocompatibility complex-specific thymic selection possess antibody-like recognition specificities. Immunity 36:79-91

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