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Phenotypic and Functional Analysis of Activated Regulatory T Cells Isolated from Chronic Lymphocytic Choriomeningitis Virus-infected Mice
Published on: June 22, 2016
c-FLICE inhibitory protein expression inhibits T-cell activation
1Graduate Institute of Immunology, National Taiwan University, Taipei, Taiwan, ROC.
Abstract:
Cellular FLICE-inhibitory protein (c-FLIP) inhibits death receptor-mediated apoptosis by specific interaction with FADD and procaspase-8, and may thus interfere with activation events mediated by FADD and caspase-8. Recent studies, however, suggest that c-FLIP also transmits activation signals. The role of c-FLIP on T-cell activation was examined here using several transgenic mice with variable c-FLIP expression. In all c-FLIP-transgenic mice, Fas-mediated apoptosis and in vitro activation-induced T-cell death were suppressed, and T-cell proliferation and IL-2 production were inhibited. c-FLIP transgene also promoted in vivo thymocyte death. Higher c-FLIP transgene expression was correlated with a more profound suppression of T-cell activation and a prominent disturbance in mature thymocyte development. There was no evidence of increased activation and proliferation in all c-FLIP-transgenic T cells examined. Instead, suppression of T-cell activation in c-FLIP-transgenic T cells could be a combinatory effect of FADD/caspase-8-dependent signals and c-FLIP-specific activities.
Insights
Cellular FLICE-inhibitory protein (c-FLIP) suppresses T-cell activation and proliferation. Variable c-FLIP expression in transgenic mice inhibited IL-2 production and disrupted thymocyte development, suggesting complex roles in T-cell signaling.
Area of Science:
- Immunology
- Molecular Biology
- Cell Biology
Background:
- Cellular FLICE-inhibitory protein (c-FLIP) is known to inhibit apoptosis via death receptor pathways.
- Emerging evidence suggests c-FLIP may also play a role in signal transduction and cellular activation.
- The precise function of c-FLIP in T-cell activation remains incompletely understood.
Purpose of the Study:
- To investigate the role of c-FLIP in T-cell activation using transgenic mouse models.
- To determine how varying levels of c-FLIP expression impact T-cell responses.
- To elucidate the mechanisms by which c-FLIP influences T-cell proliferation, cytokine production, and development.
Main Methods:
- Generation and analysis of transgenic mice with differential c-FLIP expression.
- Assessment of Fas-mediated apoptosis and activation-induced T-cell death in vitro.
- Measurement of T-cell proliferation and IL-2 production.
- Evaluation of thymocyte development and T-cell populations in vivo.
Main Results:
- Transgenic mice exhibited suppressed Fas-mediated apoptosis and activation-induced T-cell death.
- T-cell proliferation and IL-2 production were significantly inhibited in c-FLIP-transgenic mice.
- Elevated c-FLIP expression correlated with more pronounced suppression of T-cell activation and thymocyte development.
- No evidence of enhanced T-cell activation or proliferation was observed; instead, thymocyte death was promoted in vivo.
Conclusions:
- c-FLIP plays a significant inhibitory role in T-cell activation, proliferation, and IL-2 production.
- The suppression of T-cell activation by c-FLIP appears to be a combined effect of FADD/caspase-8-dependent signaling and c-FLIP-specific functions.
- c-FLIP dysregulation profoundly impacts T-cell development and function, highlighting its critical role in immune regulation.
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