Signals involved in thymocyte positive and negative selection

Semin Immunol. 1999 Aug;11(4):263-72. doi: 10.1006/smim.1999.0182.


Extensive research has focused upon understanding how thymocytes distinguish between interactions that lead to positive or negative selection. Various intracellular pathways that are activated after TCR engagement are outlined in this review, and their contribution to thymocyte selection is discussed. Although thymocyte fate is generally governed by a quantitative/avidity model, this largely reflects the interactions that occur at the cell surface. Therefore, we outline possible models of how different intercellular interactions are translated into intracellular signals that diverge and lead to thymocyte survival or death.

Publication types

  • Review

MeSH terms

  • Animals
  • Cell Death
  • Cell Differentiation / immunology*
  • Cell Survival
  • Humans
  • Receptors, Antigen, T-Cell, alpha-beta / physiology
  • Signal Transduction / immunology*
  • T-Lymphocytes / cytology*
  • T-Lymphocytes / immunology


  • Receptors, Antigen, T-Cell, alpha-beta