Related Experiment Videos
T cells down-modulate peptide-MHC complexes on APCs in vivo
Ross M Kedl1, Brian C Schaefer, John W Kappler
1Department of Immunology, National Jewish Medical and Research Center, University of Colorado Health Sciences Center, Denver, CO 80206, USA. rmkedl@mmm.com
Nature Immunology
|December 4, 2001
Summary
High-affinity T cells win out over low-affinity cells during an immune response by outcompeting them for antigen. This competition mechanism favors high-affinity T cells, enhancing secondary T cell responses.
Area of Science:
- Immunology
- Cellular immunology
- T cell biology
Background:
- T cell competition is a known phenomenon in immune responses.
- This competition may influence the maturation of secondary T cell responses.
Purpose of the Study:
- To investigate the role of T cell competition in affinity maturation.
- To determine how T cell affinity affects competition dynamics during an immune response in vivo.
Main Methods:
- Studying T cell competition in response to antigenic challenge in vivo.
- Analyzing competition efficiency between T cells with different specificities (peptide-MHC).
- Assessing the impact of high-affinity T cells on antigen presentation.
Main Results:
- High-affinity T cells outcompeted lower-affinity T cells during antigenic challenge.
- Competition was more efficient between T cells recognizing the same peptide-MHC.
- High-affinity T cells induced antigen loss from antigen-presenting cells, reducing ligand availability.
Conclusions:
- T cell competition, particularly among cells with the same specificity, drives affinity maturation.
- High-affinity T cells gain a competitive advantage by reducing antigen ligand concentration.
- This mechanism explains how secondary T cell responses become more refined over time.