title: Homeostasis of V alpha 14i NKT cells.
abstract: CD1d-reactive natural killer T (NKT) cells with an invariant V alpha 14 rearrangement (V alpha 14i) are a distinct subset of T lymphocytes that likely have important immune-regulatory functions. Little is known regarding the factors responsible for their peripheral survival. Using alpha-galactosylceramide-containing CD1d tetramers to detect V alpha 14i NKT cells, we show here that the expansion of V alpha 14i NKT cells in lymphopenic mice was not dependent on CD1d expression and was unaffected by the presence of host NKT cells. Additionally, we found that IL-15 was important in the expansion and/or survival of V alpha 14i NKT cells, with IL-7 playing a lesser role. These results demonstrate that the homeostatic requirements for CD1d-restricted NKT cells, which are CD4(+) or CD4(-)CD8(-), resemble those of CD8(+) memory T cells. We propose that this expansion and/or survival in the periphery of V alpha 14i NKT cells is affected by competition for IL-15, and that IL-15-requiring cells-such as NK cells and CD8(+) memory cells-may define the V alpha 14i NKT cell niche.
authors.affiliation: Division of Developmental Immunology, La Jolla Institute for Allergy and Immunology, 10355 Science Center Drive, San Diego, CA 92121, USA.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Matsuda
authors.forename: Laurent
authors.initials: L
authors.lastname: Gapin
authors.forename: Stéphane
authors.initials: S
authors.lastname: Sidobre
authors.forename: William C
authors.initials: WC
authors.lastname: Kieper
authors.forename: Joyce T
authors.initials: JT
authors.lastname: Tan
authors.forename: Rhodri
authors.initials: R
authors.lastname: Ceredig
authors.forename: Charles D
authors.initials: CD
authors.lastname: Surh
authors.forename: Mitchell
authors.initials: M
authors.lastname: Kronenberg
mesh_terms: D000818:Animals; D018949:Antigens, CD1 / Q000276:immunology*; D055610:Antigens, CD1d; D000944:Antigens, Differentiation, B-Lymphocyte / Q000276:immunology*; D002455:Cell Division; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D006706:Homeostasis; D019409:Interleukin-15 / Q000276:immunology*; D015851:Interleukin-7 / Q000276:immunology; D007694:Killer Cells, Natural / Q000276:immunology*; D008231:Lymphopenia / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*
chemical_list: D018949:Antigens, CD1; D055610:Antigens, CD1d; D000944:Antigens, Differentiation, B-Lymphocyte; D000949:Histocompatibility Antigens Class II; D019409:Interleukin-15; D015851:Interleukin-7; C045084:invariant chain