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High affinity T cell receptors from yeast display libraries block T cell activation by superantigens

M C Kieke1, E Sundberg, E V Shusta

  • 1Department of Biochemistry, University of Illinois, Urbana, IL, 61801, USA.

Journal of Molecular Biology
|April 9, 2001
PubMed

Insights

Researchers engineered T cell receptor (TCR) mutants to block superantigen activity. These engineered TCRs potently inhibited staphylococcal enterotoxin C3 (SEC3)-mediated T cell responses, offering potential therapeutic strategies.

Area of Science:

  • Immunology
  • Molecular Biology
  • Biochemistry

Background:

  • T cell receptor (TCR) activation by superantigens like bacterial enterotoxins can cause hyperimmune reactions.
  • Enterotoxins bind MHC class II and TCR beta-chain, leading to widespread T cell stimulation.
  • Understanding TCR-enterotoxin interactions is crucial for developing antagonists.

Purpose of the Study:

  • To elucidate molecular interactions between TCRs and staphylococcal enterotoxin C3 (SEC3).
  • To engineer soluble TCR mutants with enhanced affinity for SEC3.
  • To generate potential antagonists for SEC3-induced hyperimmune responses.

Main Methods:

  • Engineered single-chain TCR mutants (Vbeta-linker-Valpha) displayed on yeast cells.
  • Utilized flow cytometry with fluorescently labeled SEC3 for mutant selection.
  • Characterized mutations at the TCR:SEC3 interface and measured binding affinity.

Main Results:

  • Identified mutations primarily in Vbeta residues at the TCR:SEC3 interface.
  • Engineered Vbeta domain exhibited a 1000-fold increase in affinity for SEC3 (K(D)=7 nM).
  • Soluble Vbeta mutant potently inhibited SEC3-mediated T cell activity.

Conclusions:

  • Remodeled SEC3-binding surface on engineered TCR mutants enhances affinity.
  • Soluble Vbeta mutants demonstrate potential as antagonists for enterotoxin-induced T cell activation.
  • These engineered proteins may serve as therapeutic agents against hyperimmune reactions.

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