Signal extinction and T cell repolarization in T helper cell-antigen-presenting cell conjugates

Eur J Immunol. 1996 Sep;26(9):2012-6. doi: 10.1002/eji.1830260907.


We have previously demonstrated that in T cell-antigen-presenting cell (APC) conjugates many T cell receptors (TCR) are serially triggered by a few peptide-MHC complexes, resulting in sustained signaling. Here, we investigate the mechanisms that determine the duration and extent of signaling. We show that in the course of the T helper cell-APC interaction, down-regulation of triggered TCR leads to extinction of signaling. However, T cells that have been activated by a previous encounter with peptide-pulsed APC and have extinguished signaling can swiftly repolarize towards APC displaying higher antigen concentrations and dedicate their help to these cells. These results demonstrate that TCR down-regulation allows T cells to calibrate their response and dedicate their help to APC offering the highest stimulus.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Antigen-Presenting Cells / physiology*
  • Calcium / metabolism
  • Cell Polarity
  • Humans
  • Lymphocyte Activation
  • Molecular Sequence Data
  • Receptors, Antigen, T-Cell / physiology
  • T-Lymphocytes / physiology*
  • T-Lymphocytes, Helper-Inducer / physiology*


  • Receptors, Antigen, T-Cell
  • Calcium