title: Selective expansion and partial activation of human NK cells and NK receptor-positive T cells by IL-2 and IL-15.
abstract: IL-2 and IL-15 are lymphocyte growth factors produced by different cell types with overlapping functions in immune responses. Both cytokines costimulate lymphocyte proliferation and activation, while IL-15 additionally promotes the development and survival of NK cells, NKT cells, and intraepithelial lymphocytes. We have investigated the effects of IL-2 and IL-15 on proliferation, cytotoxicity, and cytokine secretion by human PBMC subpopulations in vitro. Both cytokines selectively induced the proliferation of NK cells and CD56(+) T cells, but not CD56(-) lymphocytes. All NK and CD56(+) T cell subpopulations tested (CD4(+), CD8(+), CD4(-)CD8(-), alphabetaTCR(+), gammadeltaTCR(+), CD16(+), CD161(+), CD158a(+), CD158b(+), KIR3DL1(+), and CD94(+)) expanded in response to both cytokines, whereas all CD56(-) cell subpopulations did not. Therefore, previously reported IL-15-induced gammadelta and CD8(+) T cell expansions reflect proliferations of NK and CD56(+) T cells that most frequently express these phenotypes. IL-15 also expanded CD8alpha(+)beta(-) and Valpha24Vbeta11 TCR(+) T cells. Both cytokines stimulated cytotoxicity by NK and CD56(+) T cells against K562 targets, but not the production of IFN-gamma, TNF-alpha, IL-2, or IL-4. However, they augmented cytokine production in response to phorbol ester stimulation or CD3 cross-linking by inducing the proliferation of NK cells and CD56(+) T cells that produce these cytokines at greater frequencies than other T cells. These results indicate that IL-2 and IL-15 act at different stages of the immune response by expanding and partially activating NK receptor-positive lymphocytes, but, on their own, do not influence the Th1/Th2 balance of adaptive immune responses.
authors.affiliation: Department of Immunology, St. James's Hospital, Dublin, Ireland.
authors.forename: J
authors.initials: J
authors.lastname: Dunne
authors.forename: S
authors.initials: S
authors.lastname: Lynch
authors.forename: C
authors.initials: C
authors.lastname: O'Farrelly
authors.forename: S
authors.initials: S
authors.lastname: Todryk
authors.forename: J E
authors.initials: JE
authors.lastname: Hegarty
authors.forename: C
authors.initials: C
authors.lastname: Feighery
authors.forename: D G
authors.initials: DG
authors.lastname: Doherty
mesh_terms: D019002:CD56 Antigen / Q000032:analysis; D002455:Cell Division / Q000187:drug effects; D015329:Gene Rearrangement, T-Lymphocyte; D006801:Humans; D016130:Immunophenotyping; D007371:Interferon-gamma / Q000096:biosynthesis / Q000235:genetics; D019409:Interleukin-15 / Q000494:pharmacology*; D007376:Interleukin-2 / Q000096:biosynthesis / Q000235:genetics / Q000494:pharmacology*; D015847:Interleukin-4 / Q000096:biosynthesis / Q000235:genetics; D020014:K562 Cells; D007694:Killer Cells, Natural / Q000187:drug effects* / Q000276:immunology; D008213:Lymphocyte Activation / Q000187:drug effects*; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000276:immunology; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000276:immunology; D018040:Receptors, Neurokinin-1 / Q000378:metabolism*; D011994:Recombinant Proteins / Q000494:pharmacology; D016176:T-Lymphocyte Subsets / Q000187:drug effects* / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis / Q000235:genetics
chemical_list: D019002:CD56 Antigen; D019409:Interleukin-15; D007376:Interleukin-2; D016693:Receptors, Antigen, T-Cell, alpha-beta; D016692:Receptors, Antigen, T-Cell, gamma-delta; D018040:Receptors, Neurokinin-1; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D015847:Interleukin-4; D007371:Interferon-gamma