title: Requirement for membrane lymphotoxin in natural killer cell development.
abstract: Development of natural killer (NK) cells is thought to depend on interactions between NK progenitors and the bone marrow (BM) microenvironment; however, little is known about the molecular signals involved. Here we show that lymphotoxin (LT) provides an important signal for the development of both NK cells and NK/T cells. LTalpha-/- mice show marked reduction in splenic and BM NK and NK/T cell numbers and dramatically impaired NK and NK/T cell function. Mice deficient in either tumor necrosis factor receptor (TNFR)-I or TNFR-II have normal numbers of NK and NK/T cells, implying that neither of the TNFRs nor soluble LTalpha3 is required for development of these cell types. Reciprocal BM transfers between LTalpha-/- and wild-type mice suggest that close interactions between membrane LT-expressing NK cell precursors and LT-responsive radioresistant stromal cells are necessary for NK cell development. When LT-deficient BM cells are incubated with IL-15, NK cells are formed. In addition, LT-deficient BM cells produce IL-15 after activation. Thus, membrane LT appears to deliver a signal for NK cell development that is either independent of IL-15 or upstream in the IL-15 pathway. These results reveal a novel function for membrane LT in NK and NK/T cell development. They also support a cellular and molecular mechanism by which NK cell precursors themselves deliver essential signals, through the membrane ligand, that induce the microenvironment to promote further NK cell and NK/T cell development.
authors.affiliation: Departments of Internal Medicine and Pathology, Howard Hughes Medical Institute, and Center for Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA.
authors.forename: K
authors.initials: K
authors.lastname: Iizuka
authors.forename: D D
authors.initials: DD
authors.lastname: Chaplin
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
authors.forename: Q
authors.initials: Q
authors.lastname: Wu
authors.forename: L E
authors.initials: LE
authors.lastname: Pegg
authors.forename: W M
authors.initials: WM
authors.lastname: Yokoyama
authors.forename: Y X
authors.initials: YX
authors.lastname: Fu
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D001854:Bone Marrow Cells / Q000166:cytology / Q000276:immunology; D016026:Bone Marrow Transplantation / Q000276:immunology*; D003602:Cytotoxicity, Immunologic; D005720:Gamma Rays; D006084:Graft Rejection / Q000276:immunology; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D007165:Immunosuppression Therapy; D019409:Interleukin-15 / Q000235:genetics / Q000494:pharmacology / Q000502:physiology; D007694:Killer Cells, Natural / Q000276:immunology*; D017710:Lymphocyte Transfusion; D008233:Lymphotoxin-alpha / Q000235:genetics / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D018345:Mice, Knockout; D018124:Receptors, Tumor Necrosis Factor / Q000172:deficiency / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D047888:Receptors, Tumor Necrosis Factor, Type I; D047889:Receptors, Tumor Necrosis Factor, Type II; D013154:Spleen / Q000276:immunology
chemical_list: D015703:Antigens, CD; D019409:Interleukin-15; D008233:Lymphotoxin-alpha; D018124:Receptors, Tumor Necrosis Factor; D047888:Receptors, Tumor Necrosis Factor, Type I; D047889:Receptors, Tumor Necrosis Factor, Type II