title: Interleukin-18 regulates T helper 1 or 2 immune responses of human cord blood CD4+ V alpha 24+V beta 11+ natural killer T cells.
abstract: Natural killer T (NKT) cells, exhibiting both T-cell and NK-cell markers, are known to regulate immune responses by secreting T-helper (Th) 1 and Th2 cytokines. We analyzed NKT cells in cord blood (CB) for phenotypical and functional characteristics and regulatory mechanisms that control Th1 and Th2 determination. Human CB V alpha 24+V beta 11+ NKT cells were predominantly the CD4+ single positive (SP) phenotype (approximately 96%), in contrast to adult peripheral blood V alpha 24+V beta 11+ NKT cells which are composed of a dominant population of the CD4-CD8-double negative (DN) phenotype and a minor population of the CD4+ SP phenotype. The CB CD4+ V alpha 24+ NKT cells, following stimulation with the primary culture, gained the capacity to secrete interferon (IFN)-gamma, a Th1 cytokine, and interleukin (IL)-13, a Th2 cytokine. The combination of IL-18 and IL-12 induced IFN-gamma production in CB CD4+ V alpha 24+ NKT cells, while IL-18 in combination with IL-2 induced IL-13 production in these cells. Thus, IL-18 regulates the determination of the Th1 or Th2 immune response by human CD4+ V alpha 24+ NKT cells through different cytokine combinations.
authors.affiliation: Laboratory of Cell Transplantation, Institute for Advanced Medical Sciences, Hyogo College of Medicine, Hyogo 663-8501, Japan.
authors.forename: Yuka
authors.initials: Y
authors.lastname: Fujibayashi
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Fujimori
authors.forename: Ikuyo
authors.initials: I
authors.lastname: Kasumoto
authors.forename: Shunro
authors.initials: S
authors.lastname: Kai
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hara
authors.forename: Haruki
authors.initials: H
authors.lastname: Okamura
authors.forename: Hiroko
authors.initials: H
authors.lastname: Tsutsui
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Ogawa
authors.forename: Kenji
authors.initials: K
authors.lastname: Nakanishi
mesh_terms: D015704:CD4 Antigens / Q000378:metabolism*; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism; D005312:Fetal Blood / Q000166:cytology* / Q000276:immunology; D006801:Humans; D020382:Interleukin-18 / Q000494:pharmacology*; D007694:Killer Cells, Natural / Q000166:cytology / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism*; D008213:Lymphocyte Activation / Q000187:drug effects*; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000378:metabolism*; D018417:Th1 Cells / Q000187:drug effects* / Q000276:immunology; D018418:Th2 Cells / Q000187:drug effects* / Q000276:immunology
chemical_list: D015704:CD4 Antigens; D016207:Cytokines; D020382:Interleukin-18; D016693:Receptors, Antigen, T-Cell, alpha-beta