The peptide ligands mediating positive selection in the thymus control T cell survival and homeostatic proliferation in the periphery

Immunity. 1999 Aug;11(2):173-81. doi: 10.1016/s1074-7613(00)80092-8.


Positive selection to self-MHC/peptide complexes has long been viewed as a device for skewing the T cell repertoire toward recognition of foreign peptides presented by self-MHC molecules. Here, we provide evidence for an alternative possibility, namely, that the self-peptides controlling positive selection in the thymus serve to maintain the longevity of mature T cells in the periphery. Surprisingly, when total T cell numbers are reduced, these self-ligands become overtly stimulatory and cause naive T cells to proliferate and undergo homeostatic expansion.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Cell Survival
  • Histocompatibility Antigens Class II / physiology
  • Homeostasis*
  • Lymphocyte Activation*
  • Mice
  • Mice, Transgenic
  • Peptides / physiology*
  • Receptors, Antigen, T-Cell / physiology
  • T-Lymphocytes / physiology*
  • Thymus Gland / physiology*


  • Histocompatibility Antigens Class II
  • Peptides
  • Receptors, Antigen, T-Cell