1. ¹Immunology and Inflammation Program, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
2. ²Division of Immunology and Allergy, University Hospital of Lausanne, CHUV, Lausanne, Switzerland
3. ³Department of Immunology, The Scripps Research Institute, La Jolla, CA, USA

Correspondence: Professor J Sprent, Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, New South Wales, 2010, Australia. E-mail: j.sprent@garvan.org.au

Received 7 February 2008; Accepted 18 February 2008; Published online 25 March 2008.

Abstract

The pool of mature T cells comprises a heterogeneous mixture of naive and memory CD4⁺ and CD8⁺ cells. These cells are long lived at a population level but differ markedly in their relative rates of turnover and survival. Here, we review how contact with exogenous stimuli, notably self MHC ligands and various _c cytokines, plays a decisive role in controlling normal T cell homeostasis.