Homeostatic proliferation and survival of naïve and memory T cells

Eur J Immunol. 2009 Aug;39(8):2088-94. doi: 10.1002/eji.200939444.


The immune system relies on homeostatic mechanisms in order to adapt to the changing requirements encountered during steady-state existence and activation by antigen. For T cells, this involves maintenance of a diverse repertoire of naïve cells, rapid elimination of effector cells after pathogen clearance, and long-term survival of memory cells. The reduction of T-cell counts by either cytotoxic drugs, irradiation, or certain viruses is known to lead to lymphopenia-induced proliferation and restoration of normal T-cell levels. Such expansion is governed by the interaction of TCR with self-peptide/MHC (p/MHC) molecules plus contact with cytokines, especially IL-7. These same ligands, i.e. p/MHC molecules and IL-7, maintain naïve T lymphocytes as resting cells under steady-state T-cell-sufficient conditions. Unlike naïve cells, typical "central" memory T cells rely on a combination of IL-7 and IL-15 for their survival in interphase and for occasional cell division without requiring signals from p/MHC molecules. Other memory T-cell subsets are less quiescent and include naturally occurring activated memory-phenotype cells, memory cells generated during chronic viral infections, and effector memory cells. These subsets of activated memory cells differ from central memory T cells in their requirements for homeostatic proliferation and survival. Thus, the factors controlling T-cell homeostasis can be seen to vary considerably from one subset to another as described in detail in this review.

Publication types

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

MeSH terms

  • Animals
  • Cell Proliferation*
  • Cell Survival / immunology
  • Homeostasis / immunology*
  • Humans
  • Immunologic Memory / immunology*
  • Lymphocyte Activation / immunology
  • Models, Immunological
  • Receptors, Antigen, T-Cell / immunology
  • T-Lymphocytes / cytology
  • T-Lymphocytes / immunology*


  • Receptors, Antigen, T-Cell