1. RasGRP1 regulates antigen-induced developmental programming by naive CD8 T cells.
- Author
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Priatel JJ, Chen X, Huang YH, Chow MT, Zenewicz LA, Coughlin JJ, Shen H, Stone JC, Tan R, and Teh HS
- Subjects
- Animals, Cell Differentiation immunology, Cell Proliferation, Guanine Nucleotide Exchange Factors deficiency, Guanine Nucleotide Exchange Factors immunology, Interleukin-2 pharmacology, Lymphocyte Activation immunology, Mice, Mice, Knockout, Signal Transduction immunology, Transgenes, Antigens immunology, CD8-Positive T-Lymphocytes immunology, Guanine Nucleotide Exchange Factors physiology
- Abstract
Ag encounter by naive CD8 T cells initiates a developmental program consisting of cellular proliferation, changes in gene expression, and the formation of effector and memory T cells. The strength and duration of TCR signaling are known to be important parameters regulating the differentiation of naive CD8 T cells, although the molecular signals arbitrating these processes remain poorly defined. The Ras-guanyl nucleotide exchange factor RasGRP1 has been shown to transduce TCR-mediated signals critically required for the maturation of developing thymocytes. To elucidate the role of RasGRP1 in CD8 T cell differentiation, in vitro and in vivo experiments were performed with 2C TCR transgenic CD8 T cells lacking RasGRP1. In this study, we report that RasGRP1 regulates the threshold of T cell activation and Ag-induced expansion, at least in part, through the regulation of IL-2 production. Moreover, RasGRP1(-/-) 2C CD8 T cells exhibit an anergic phenotype in response to cognate Ag stimulation that is partially reversible upon the addition of exogenous IL-2. By contrast, the capacity of IL-2/IL-2R interactions to mediate Ras activation and CD8 T cell expansion and differentiation appears to be largely RasGRP1-independent. Collectively, our results demonstrate that RasGRP1 plays a selective role in T cell signaling, controlling the initiation and duration of CD8 T cell immune responses.
- Published
- 2010
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