Related Experiment Videos
Rare, structurally homologous self-peptides promote thymocyte positive selection
Fabio R Santori1, William C Kieper, Stuart M Brown
1Michael Heidelberger Division of Immunology, Department of Pathology and Kaplan Cancer Center, New York University School of Medicine, 550 First Avenue, NY 10016, USA.
Immunity
|August 28, 2002
Summary
Researchers identified rare self-peptides that positively select T cells by recognizing specific self-peptide/MHC complexes. These selecting peptides, derived from F-actin capping protein and beta-catenin, can be found using homology-based search strategies.
Area of Science:
- Immunology
- Molecular Biology
- T cell biology
Background:
- Positive selection of T cells requires recognition of self-peptide/MHC complexes.
- The identity and characteristics of these self-ligands remain debated.
- Understanding self-ligands is crucial for T cell receptor (TCR) specificity.
Purpose of the Study:
- To identify naturally occurring self-peptides that induce positive selection of T cells with a specific TCR (OT-I).
- To investigate the relationship between self-peptide structure and T cell selection.
- To develop strategies for identifying selecting self-peptides.
Main Methods:
- Employed two complementary strategies: bioassay-based and bioinformatics-based approaches.
- Identified self-peptides derived from F-actin capping protein and beta-catenin.
- Analyzed charge conservation at key TCR contact residues for identified and other self-peptides.
Main Results:
- Both bioassay and bioinformatics methods converged on the same self-peptides.
- Identified self-peptides exhibited charge conservation at two critical TCR contact residues.
- Biological activity of other self-peptides and peptide libraries correlated with TCR contact residue conservation.
Conclusions:
- Selecting self-peptides are rare and possess conserved features at TCR contact sites.
- Homology-based search strategies are effective for identifying these crucial self-peptides.
- Findings provide insights into the mechanisms of T cell positive selection and self-tolerance.