title: IL-15-high-responder developing NK cells bearing Ly49 receptors in IL-15-/- mice.
abstract: In mice lacking IL-15, NK cell development is arrested at immature stages, providing an opportunity to investigate the earliest developing NK cells that would respond to IL-15. We show in this study that immature NK cells were present in the spleen as well as bone marrow (BM) and contained IL-15-high-responder cells. Thus, mature NK cells were generated more efficiently from IL-15(-/-) than from control donor cells in radiation BM chimeras, and the rate of IL-15-induced cell division in vitro was higher in NK cells in the spleen and BM from IL-15(-/-) mice than in those from wild-type mice. Phenotypically, NK cells developed in IL-15(-/-) mice up to the minor but discrete CD11b(-)CD27(+)DX5(hi)CD51(dull)CD127(dull)CD122(hi) stage, which contained the majority of Ly49G2(+) and D(+) NK cells both in the spleen and BM. Even among wild-type splenic NK cells, IL-15-induced proliferation was most prominent in CD11b(-)DX5(hi) cells. Notably, IL-15-mediated preferential expansion (but not conversion from Ly49(-) cells) of Ly49(+) NK cells was observed in vitro only for NK cells in the spleen. These observations indicated the uneven distribution of NK cells of different developing stages with variable IL-15 responsiveness in these lymphoid organs. Immature NK cells in the spleen may contribute, as auxiliaries to those in BM, to the mature NK cell compartment through IL-15-driven extramarrow expansion under steady-state or inflammatory conditions.
authors.affiliation: Department of Immunology and Infectious Diseases, Shinshu University Graduate School of Medicine, Matsumoto 390-8621, Japan.
authors.forename: Katsumi
authors.initials: K
authors.lastname: Yoshizawa
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Nakajima
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Notake
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Miyagawa
authors.forename: Shigeaki
authors.initials: S
authors.lastname: Hida
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Taki
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D002454:Cell Differentiation / Q000235:genetics / Q000276:immunology*; D002478:Cells, Cultured; D007249:Inflammation / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D019409:Interleukin-15 / Q000096:biosynthesis* / Q000172:deficiency / Q000235:genetics; D007694:Killer Cells, Natural / Q000166:cytology / Q000276:immunology* / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D055650:NK Cell Lectin-Like Receptor Subfamily A / Q000096:biosynthesis / Q000172:deficiency / Q000378:metabolism*; D013154:Spleen / Q000166:cytology / Q000254:growth & development / Q000276:immunology
chemical_list: D019409:Interleukin-15; D055650:NK Cell Lectin-Like Receptor Subfamily A