Cutting edge: trimolecular interaction of TCR with MHC class II and bacterial superantigen shows a similar affinity to MHC:peptide ligands.

Journal Article (Journal Article)

Bacterial superantigens such as Staphylococcus aureus enterotoxin A (SEA) are very potent stimulators of T cells. They bind to the Vbeta 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.

Full Text

Duke Authors

Cited Authors

  • Redpath, S; Alam, SM; Lin, CM; O'Rourke, AM; Gascoigne, NR

Published Date

  • July 1, 1999

Published In

Volume / Issue

  • 163 / 1

Start / End Page

  • 6 - 10

PubMed ID

  • 10384091

International Standard Serial Number (ISSN)

  • 0022-1767


  • eng

Conference Location

  • United States