title: IL-12 induces monocyte IL-18 binding protein expression via IFN-gamma.
abstract: IL-18 is a Th1 cytokine that synergizes with IL-12 and IL-2 in the stimulation of lymphocyte IFN-gamma production. IL-18 binding protein (IL-18BP) is a recently discovered inhibitor of IL-18 that is distinct from the IL-1 and IL-18 receptor families. In this report we show that IL-18BPa, the IL-18BP isoform with the highest affinity for IL-18, was strongly induced by IL-12 in human PBMC. Other Th1 cytokines, including IFN-gamma, IL-2, IL-15, and IL-18, were also capable of augmenting IL-18BPa expression. In contrast, IL-1alpha, IL-1beta, TNF-alpha, IFN-gamma-inducible protein-10, and Th2 cytokines such as IL-4 and IL-10 did not induce IL-18BPa. Although monocytes were found to be the primary source of IL-18BPa, the induction of IL-18BPa by IL-12 was mediated through IFN-gamma derived predominantly from NK cells. IL-18BPa production was observed in cancer patients receiving recombinant human IL-12 and correlated with the magnitude of IFN-gamma production. The IFN-gamma/IL-18BPa negative feedback loop identified in this study may be capable of broadly controlling immune activation by cytokines that synergize with IL-18 to induce IFN-gamma and probably plays a key role in the modulation of both innate and adaptive immunity.
authors.affiliation: Department of Medicine, Division of Hematology/Oncology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA.
authors.forename: Korina G
authors.initials: KG
authors.lastname: Veenstra
authors.forename: Zdenka L
authors.initials: ZL
authors.lastname: Jonak
authors.forename: Stephen
authors.initials: S
authors.lastname: Trulli
authors.forename: Jared A
authors.initials: JA
authors.lastname: Gollob
mesh_terms: D000906:Antibodies / Q000494:pharmacology; D002478:Cells, Cultured; D016207:Cytokines / Q000494:pharmacology; D006023:Glycoproteins / Q000096:biosynthesis* / Q000235:genetics; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D007371:Interferon-gamma / Q000037:antagonists & inhibitors / Q000276:immunology / Q000502:physiology*; D018664:Interleukin-12 / Q000494:pharmacology* / Q000627:therapeutic use; D007694:Killer Cells, Natural / Q000276:immunology; D007700:Kinetics; D009000:Monocytes / Q000187:drug effects / Q000276:immunology*; D009369:Neoplasms / Q000188:drug therapy / Q000276:immunology; D012333:RNA, Messenger / Q000096:biosynthesis; D018417:Th1 Cells / Q000276:immunology; D015533:Transcriptional Activation
chemical_list: D000906:Antibodies; D016207:Cytokines; D006023:Glycoproteins; D036341:Intercellular Signaling Peptides and Proteins; D012333:RNA, Messenger; C118370:interleukin-18 binding protein; D018664:Interleukin-12; D007371:Interferon-gamma