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Pseudopeptide ligands for MHC II-restricted T cells
J Cotton1, M Hervé, S Pouvelle
1Département d'Ingénierie et d'Etudes des Protéines, CEA-Saclay, Gif-sur-Yvette, France.
International Immunology
|April 9, 1998
Summary
Modifying peptide bonds can create stable peptidomimetics that bind MHC II molecules and stimulate T cells, offering new therapeutic strategies for controlling immune responses.
Area of Science:
- Immunology
- Peptide Chemistry
- Drug Discovery
Background:
- Therapeutic peptides face limitations due to proteolytic degradation.
- Modifying peptide backbones is a strategy to enhance stability.
- MHC II-restricted peptides involve backbone interactions, complicating peptidomimetic design.
Purpose of the Study:
- To investigate the impact of single amide bond modifications on peptide binding to MHC II molecules.
- To assess the effect of these modifications on T cell stimulation.
- To explore the potential of peptidomimetics for controlling T cell responses.
Main Methods:
- Synthesized twenty pseudopeptide analogs of a snake neurotoxin-derived peptide.
- Replaced central amide bonds with reduced (psi[CH2-NH]) or N-methylated (psi[CO-NMe]) bonds.
- Assessed MHC II (I-Ed) binding capacity and T cell stimulation activity.
Main Results:
- Several pseudopeptides showed reduced or no MHC II binding and T cell stimulation.
- One-third of analogs retained significant I-Ed binding activity.
- One-fifth of analogs demonstrated T cell stimulation, with two showing native-like activity.
- Peptide binding affinity did not always correlate with T cell stimulation efficacy.
Conclusions:
- Single amide bond modifications can yield peptidomimetics with retained or enhanced biological activity.
- Main chain modifications influence both MHC II binding and T cell recognition.
- Peptidomimetic approaches can generate novel MHC II ligands for modulating T cell responses.