Cutting Edge: Trimolecular Interaction of TCR with MHC Class II and Bacterial Superantigen Shows a Similar Affinity to MHC:Peptide Ligands
| Autor: | Stella Redpath, S. Munir Alam, Christina M. Lin, Anne M. O’Rourke, Nicholas R. J. Gascoigne |
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| Rok vydání: | 1999 |
| Předmět: | |
| Zdroj: | The Journal of Immunology. 163:6-10 |
| ISSN: | 1550-6606 0022-1767 |
| Popis: | Bacterial superantigens such as Staphylococcus aureus enterotoxin A (SEA) are very potent stimulators of T cells. They bind to the Vβ region of the TCR and to MHC class II, stimulating T cells at nanomolar concentrations. Using surface plasmon resonance measurements, we find that binding between the individual components of the complex (TCR-class II, TCR-SEA, SEA-class II) is very weak, but that the stability of the trimolecular complex is considerably enhanced, reaching an affinity similar to that found for TCR interactions with MHC:peptide ligand. Thus, the potency of SEA in stimulation of T cells is not due to particularly strong affinities between the proteins, but to a cooperative effect of interactions in the TCR-SEA-MHC class II trimolecular complex that brings the kinetics into a similar range to binding of conventional Ags. This range may be the optimum for T cell activation. |
| Databáze: | OpenAIRE |
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