Homeostasis of memory T cells.
The pool of memory T cells is regulated by homeostatic mechanisms to persist for prolonged periods at a relatively steady overall size. Recent work has shown that two members of the common gamma chain (gammac) family of cytokines, interleukin-7 (IL-7) and IL-15, govern homeostasis of memory T cells. These two cytokines work in conjunction to support memory T-cell survival and intermittent background proliferation. Normal animals contain significant numbers of spontaneously arising memory-phenotype (MP) cells, though whether these cells are representative of true antigen-specific memory T cells is unclear. Nevertheless, it appears that the two types of memory cells do not display identical homeostatic requirements. For antigen-specific memory CD8+ T cells, IL-7 is primarily important for survival while IL-15 is crucial for their background proliferation. For memory CD4+ T cells, IL-7 has an important role, whereas the influence of IL-15 is still unclear.
Surh
Charles D
CD
The Scripps Research Institute, La Jolla, CA 92037, USA. csurh@scripps.edu
Boyman
Onur
O
Purton
Jared F
JF
Sprent
Jonathan
J
D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D006706:Homeostasis / Q000276:immunology; D006801:Humans; D007156:Immunologic Memory / Q000276:immunology*; D007372:Interferons / Q000276:immunology; D019409:Interleukin-15 / Q000276:immunology; D015851:Interleukin-7 / Q000276:immunology; D051379:Mice; D015375:Receptors, Interleukin-2 / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
D019409:Interleukin-15; D015851:Interleukin-7; D015375:Receptors, Interleukin-2; D007372:Interferons