title: Interleukin 15 controls both proliferation and survival of a subset of memory-phenotype CD8(+) T cells.
abstract: Previous work has shown that memory-phenotype CD44(hi) CD8(+) cells are controlled by a cytokine, interleukin (IL)-15. However, the dependency of CD44(hi) CD8(+) cells on IL-15 is partial rather than complete. Here, evidence is presented that CD44(hi) CD8(+) cells comprise a mixed population of IL-15-dependent and IL-15-independent cells. The major subset of CD122(hi) CD44(hi) CD8(+) cells is heavily dependent on IL-15 by three different parameters, namely (1) "bystander" proliferation induced via IFN-induced stimulation of the innate immune system, (2) normal "background" proliferation, and (3) T cell survival; IL-15 dependency is most extreme for the Ly49(+) subset of CD122(hi) CD44(hi) CD8(+) cells. In contrast to CD122(hi) cells, the CD122(lo) subset of CD44(hi) CD8(+) cells is IL-15 independent; likewise, being CD122(lo), CD44(hi) CD4(+) cells are IL-15 independent. Thus, subsets of memory-phenotype T cells differ radically in their sensitivity to IL-15.
authors.affiliation: Department of Immunology, The Scripps Research Institute, La Jolla, CA 92037, USA.
authors.forename: Adam D
authors.initials: AD
authors.lastname: Judge
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Zhang
authors.forename: Hideki
authors.initials: H
authors.lastname: Fujii
authors.forename: Charles D
authors.initials: CD
authors.lastname: Surh
authors.forename: Jonathan
authors.initials: J
authors.lastname: Sprent
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D002455:Cell Division / Q000187:drug effects / Q000276:immunology*; D002469:Cell Separation / Q000379:methods; D002470:Cell Survival / Q000187:drug effects / Q000276:immunology*; D005434:Flow Cytometry; D018960:Hyaluronan Receptors / Q000032:analysis; D007156:Immunologic Memory; D019409:Interleukin-15 / Q000494:pharmacology*; D007376:Interleukin-2 / Q000172:deficiency / Q000235:genetics / Q000276:immunology; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D018345:Mice, Knockout; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000276:immunology*
chemical_list: D018960:Hyaluronan Receptors; D019409:Interleukin-15; D007376:Interleukin-2