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T cell unresponsiveness correlates with quantitative TCR levels in a transgenic model
R J Homer1, C Mamalaki, D Kioussis
1Section of Immunobiology, Yale University School of Medicine, New Haven, CT 06510.
International Immunology
|December 1, 1993
Summary
T-cell receptor (TCR) density critically influences immune tolerance. High TCR density leads to T-cell deletion, while low density prevents activation, establishing a quantitative threshold for tolerance induction.
Area of Science:
- Immunology
- Molecular Biology
- Transgenic Models
Background:
- Immune tolerance is crucial for preventing autoimmunity.
- T-cell receptor (TCR) signaling plays a key role in T-cell development and activation.
- The quantitative aspects of TCR signaling in tolerance remain incompletely understood.
Purpose of the Study:
- To investigate the role of T-cell receptor (TCR) density in immune tolerance induction.
- To determine if TCR expression levels influence negative selection and T-cell activation.
Main Methods:
- Generation of two transgenic mouse lines with varying V beta 11 T-cell receptor (TCR) expression levels.
- Breeding these mice with I-E expressing mice.
- Analysis of T-cell deletion and in vitro activation based on TCR density.
Main Results:
- T cells expressing high levels of V beta 11 TCR were deleted via negative selection.
- T cells expressing less than 10% of normal TCR density were not deleted and showed no in vitro activation.
- A direct correlation was observed between TCR density and in vitro T-cell activation across both mouse strains.
Conclusions:
- TCR density is a critical quantitative factor in immune tolerance.
- A definable signal threshold exists for TCR-mediated tolerance induction.
- These findings highlight the importance of TCR signal strength in maintaining self-tolerance.