scholarly journals Coactivating Signals for the Hepatic Lymphocyte Gamma Interferon Response to Francisella tularensis

2006 ◽  
Vol 75 (3) ◽  
pp. 1335-1342 ◽  
Author(s):  
Jason R. Wickstrum ◽  
Kee-Jong Hong ◽  
Sirosh Bokhari ◽  
Natalie Reed ◽  
Nicholas McWilliams ◽  
...  
Keyword(s):  
Francisella Tularensis ◽  
Neutralizing Antibodies ◽  
Synergistic Effects ◽  
Gamma Interferon ◽  
Interferon Response ◽  
Interleukin 12 ◽  
Secondary Site ◽  
Ifn Γ

ABSTRACT The facultative intracellular bacterium Francisella tularensis is capable of causing systemic infections in various hosts, including mice and humans. The liver is a major secondary site of F. tularensis infection, but hepatic immune responses to the pathogen remain poorly defined. Immune protection against the pathogen is thought to depend on the cytokine gamma interferon (IFN-γ), but the cellular basis for this response has not been characterized. Here we report that natural killer cells from the livers of naïve uninfected mice produced IFN-γ when challenged with live bacteria in vitro and that the responses were greatly increased by coactivation of the cells with either recombinant interleukin-12 (IL-12) or IL-18. Moreover, the two cytokines had strong synergistic effects on IFN-γ induction. Neutralizing antibodies to either IL-12 or IL-18 inhibited IFN-γ production in vitro, and mice deficient in the p35 subunit of IL-12 failed to show IFN-γ responses to bacterial challenge either in vitro or in vivo. Clinical isolates of highly virulent type A Francisella tularensis subsp. tularensis organisms were comparable to the live attenuated vaccine strain of Francisella tularensis subsp. holarctica in their ability to induce IL-12 and IFN-γ expression. These findings demonstrate that cells capable of mounting IFN-γ responses to F. tularensis are resident within the livers of uninfected mice and depend on coactivation by IL-12 and IL-18 for optimum responses.

scholarly journals Toll-Like Receptor 2 Controls the Gamma Interferon Response to Francisella tularensis by Mouse Liver Lymphocytes

2007 ◽  
Vol 75 (11) ◽  
pp. 5338-5345 ◽  
Author(s):  
Kee-Jong Hong ◽  
Jason R. Wickstrum ◽  
Hung-Wen Yeh ◽  
Michael J. Parmely
Keyword(s):  
Francisella Tularensis ◽  
Cell Types ◽  
Gamma Interferon ◽  
Interferon Response ◽  
Interleukin 12 ◽  
Toll Like Receptor ◽  
Wild Type ◽  
Ifn Γ ◽  
Deficient Mice

ABSTRACT The production of gamma interferon (IFN-γ) is a key step in the protective innate immune response to Francisella tularensis. Natural killer cells and T cells in the liver are important sources of this cytokine during primary F. tularensis infections, and interleukin-12 (IL-12) appears to be an essential coactivating cytokine for hepatic IFN-γ expression. The present study was undertaken to determine whether or not macrophages (Mφ) or dendritic cells (DC) provide coactivating signals for the liver IFN-γ response in vitro, whether IL-12 mediates these effects, and whether Toll-like receptor (TLR) signaling is essential to induce this costimulatory activity. Both bone marrow-derived Mφ and DC significantly augmented the IFN-γ response of F. tularensis-challenged liver lymphocytes in vitro. While both cell types produced IL-12p40 in response to F. tularensis challenge, only DC secreted large quantities of IL-12p70. DC from both IL-12p35-deficient and TLR2-deficient mice failed to produce IL-12p70 and did not costimulate liver lymphocytes for IFN-γ production in response to viable F. tularensis organisms. Conversely, liver lymphocytes from TLR2-deficient mice cocultured with wild-type accessory cells produced IFN-γ at levels comparable to those for wild-type hepatic lymphocytes. These findings indicate that TLR2 controls hepatic lymphocyte IFN-γ responses to F. tularensis by regulating DC IL-12 production. While Mφ also coinduced hepatic IFN-γ production in response to F. tularensis, they did so in a fashion less dependent on TLR2.

scholarly journals In Vivo Clearance of an Intracellular Bacterium, Francisella tularensis LVS, Is Dependent on the p40 Subunit of Interleukin-12 (IL-12) but Not on IL-12 p70

2002 ◽  
Vol 70 (4) ◽  
pp. 1936-1948 ◽  
Author(s):  
Karen L. Elkins ◽  
Allison Cooper ◽  
Susan M. Colombini ◽  
Siobhán C. Cowley ◽  
Tara L. Kieffer
Keyword(s):  
T Cells ◽  
Francisella Tularensis ◽  
Intracellular Bacterium ◽  
Interleukin 12 ◽  
Intracellular Growth ◽  
Lethal Challenge ◽  
Immune Lymphocytes ◽  
Ifn Γ

ABSTRACT To determine the role of interleukin-12 (IL-12) in primary and secondary immunity to a model intracellular bacterium, we have comprehensively evaluated infection with Francisella tularensis LVS in three murine models of IL-12 deficiency. Mice lacking the p40 protein of IL-12 (p40 knockout [KO] mice) and mice treated in vivo with neutralizing anti-IL-12 antibodies survived large doses of primary and secondary LVS infection but never cleared bacteria and exhibited a chronic infection. In dramatic contrast, mice lacking the p35 protein (p35 KO mice) of heterodimeric IL-12 readily survived large doses of primary sublethal LVS infection as well as maximal secondary lethal challenge, with only a slight delay in clearance of bacteria. LVS-immune wild-type (WT) lymphocytes produced large amounts of gamma interferon (IFN-γ), but p35 KO and p40 KO lymphocytes produced much less; nonetheless, similar amounts of NO were found in all cultures containing immune lymphocytes, and all immune lymphocytes were equally capable of controlling intracellular growth of LVS in vitro. Purified CD4+ and CD8+ T cells from both WT and p40 KO mice controlled intracellular growth, even though T cells from WT mice produced much more IFN-γ than those from p40 KO mice, and p40 KO T cells did not adopt a Th2 phenotype. Thus, while IL-12 p70 stimulation of IFN-γ production may be important for bacteriostasis, IL-12 p70 is not necessary for appropriate development of LVS-immune T cells that are capable of controlling intracellular bacterial growth and for clearance of primary or secondary LVS infection. Instead, an additional mechanism dependent on the IL-12 p40 protein, either alone or in another complex such as the newly discovered heterodimer IL-23, appears to be responsible for actual clearance of this intracellular bacterium.

scholarly journals Gamma Interferon Is Dispensable for Neopterin Production In Vivo

2005 ◽  
Vol 12 (12) ◽  
pp. 1437-1441 ◽  
Author(s):  
R. Sghiri ◽  
J. Feinberg ◽  
F. Thabet ◽  
K. Dellagi ◽  
J. Boukadida ◽  
...  
Keyword(s):  
Human Monocyte ◽  
Gamma Interferon ◽  
Interleukin 12 ◽  
Enzyme Linked Immunosorbent Assay ◽  
Deleterious Mutations ◽  
Serum Neopterin ◽  
Ifn Γ ◽  
Dependent Pathway

ABSTRACT Previous studies have indicated that neopterin is synthesized in vitro by human monocyte-derived macrophages and dendritic cells upon stimulation with gamma interferon (IFN-γ). Neopterin production under specific conditions in vitro has also been obtained upon stimulation with IFN-α and/or IFN-β. However, it is unknown if any IFN-γ-independent neopterin synthesis is possible in vivo. In the present study we investigated the serum neopterin concentrations in patients affected by the syndrome of Mendelian susceptibility to mycobacterial disease (MSMD). Indeed, this syndrome is characterized by deeply impaired or absent IFN-γ production or function due to severe mutations in molecules involved in IFN-γ/interleukin-12 (IL-12)/IL-23-dependent pathway. Serum neopterin levels were measured by an enzyme-linked immunosorbent assay in 27 patients with MSMD. We found that serum neopterin levels are elevated in the complete absence of IFN-γ activity due either to a complete deficiency of its receptor or to deleterious mutations of IL-12 or its receptor. These data clearly indicate that, as reported from in vitro studies, other stimuli are able to induce neopterin synthesis in vivo. Consequently, neopterin cannot be used as means of diagnosis of MSMD due to IFN-γ-, IL-12-, and IL-23-dependent pathway defects.

scholarly journals Protective Role for Macrophages in Respiratory Francisella tularensis Infection

2017 ◽  
Vol 85 (6) ◽  
Author(s):  
Donald J. Steiner ◽  
Yoichi Furuya ◽  
Michael B. Jordan ◽  
Dennis W. Metzger
Keyword(s):  
Francisella Tularensis ◽  
Protective Role ◽  
Interleukin 12 ◽  
Wild Type ◽  
Content Type ◽  
Highly Sensitive ◽  
Neutrophil Depletion ◽  
Ifn Γ

ABSTRACT Francisella tularensis causes lethal pneumonia following infection of the lungs by targeting macrophages for intracellular replication; however, macrophages stimulated with interferon gamma (IFN-γ) can resist infection in vitro. We therefore hypothesized that the protective effect of IFN-γ against F. tularensis in vivo requires macrophages receptive to stimulation. We found that the lethality of pulmonary F. tularensis LVS infection was exacerbated under conditions of alveolar macrophage depletion and in mice with a macrophage-specific defect in IFN-γ signaling (termed mice with macrophages insensitive to IFN-γ [MIIG mice]). We previously found that treatment with exogenous interleukin 12 (IL-12) protects against F. tularensis infection; this protection was lost in MIIG mice. MIIG mice also exhibited reduced neutrophil recruitment to the lungs following infection. Systemic neutrophil depletion was found to render wild-type mice highly sensitive to respiratory F. tularensis infection, and depletion beginning at 3 days postinfection led to more pronounced sensitivity than depletion beginning prior to infection. Furthermore, IL-12-mediated protection required NADPH oxidase activity. These results indicate that lung macrophages serve a critical protective role in respiratory F. tularensis LVS infection. Macrophages require IFN-γ signaling to mediate protection, which ultimately results in recruitment of neutrophils to further aid in survival from infection.

scholarly journals Beryllium, an Adjuvant That Promotes Gamma Interferon Production

2000 ◽  
Vol 68 (7) ◽  
pp. 4032-4039 ◽  
Author(s):  
Julia Y. Lee ◽  
Olga Atochina ◽  
Benjamin King ◽  
Leslie Taylor ◽  
Merle Elloso ◽  
...  
Keyword(s):  
Lymph Node ◽  
Gamma Interferon ◽  
Effective Control ◽  
Interleukin 12 ◽  
Spleen Cells ◽  
Th2 Response ◽  
Th1 Response ◽  
Ifn Γ

ABSTRACT Beryllium is associated with a human pulmonary granulomatosis characterized by an accumulation of CD4+ T cells in the lungs and a heightened specific lymphocyte proliferative response to beryllium (Be) with gamma interferon (IFN-γ) release (i.e., a T helper 1 [Th1] response). While an animal model of Be sensitization is not currently available, Be has exhibited adjuvant effects in animals. The effects of Be on BALB/c mice immunized with soluble leishmanial antigens (SLA) were investigated to determine if Be had adjuvant activity for IFN-γ production, an indicator of the Th1 response. In this strain of Leishmania-susceptible BALB/c mice, a Th2 response is normally observed after in vivo SLA sensitization and in vitro restimulation with SLA. If interleukin-12 (IL-12) is given during in vivo sensitization with SLA, markedly increased IFN-γ production and decreased IL-4 production are detected. We show here that when beryllium sulfate (BeSO4) was added during in vivo sensitization of BALB/c mice with SLA and IL-12, significantly increased IFN-γ production and decreased IL-4 production from lymph node and spleen cells were detected upon in vitro SLA restimulation. No specific responses were observed to Be alone. Lymph node and spleen cells from all mice proliferated strongly and comparably upon in vitro restimulation with SLA and with SLA plus Be; no differences were noted among groups of mice that received different immunization regimens. In vivo, when Be was added to SLA and IL-12 for sensitization of BALB/c mice, more effective control ofLeishmania infection was achieved. This finding has implications for understanding not only the development of granulomatous reactions but also the potential for developing Be as a vaccine adjuvant.

scholarly journals Resistance to Acute Babesiosis Is Associated with Interleukin-12- and Gamma Interferon-Mediated Responses and Requires Macrophages and Natural Killer Cells

2003 ◽  
Vol 71 (4) ◽  
pp. 2002-2008 ◽  
Author(s):  
Irma Aguilar-Delfin ◽  
Peter J. Wettstein ◽  
David H. Persing
Keyword(s):  
Nk Cells ◽  
Gamma Interferon ◽  
Interleukin 12 ◽  
No Production ◽  
Cytokine Responses ◽  
Early Production ◽  
Ifn Γ ◽  
Crucial Part

ABSTRACT We examined the role of the cytokines gamma interferon (IFN-γ) and interleukin-12 (IL-12) in the model of acute babesiosis with the WA1 Babesia. Mice genetically deficient in IFN-γ-mediated responses (IFNGR2KO mice) and IL-12-mediated responses (Stat4KO mice) were infected with the WA1 Babesia, and observations were made on the course of infection and cytokine responses. Levels of IFN-γ and IL-12 in serum increased 24 h after parasite inoculation. The augmented susceptibility observed in IFNGR2KO and Stat-4KO mice suggests that the early IL-12- and IFN-γ-mediated responses are involved in protection against acute babesiosis. Resistance appears to correlate with an increase in nitric oxide (NO) production. In order to assess the contribution of different cell subsets to resistance against the parasite, we also studied mice lacking B cells, CD4+ T cells, NK cells, and macrophages. Mice genetically deficient in B lymphocytes or CD4+ T lymphocytes were able to mount protective responses comparable to those of immunosufficient mice. In contrast, in vivo depletion of macrophages or NK cells resulted in elevated susceptibility to the infection. Our observations suggest that a crucial part of the response that protects from the pathogenic Babesia WA1 is mediated by macrophages and NK cells, probably through early production of IL-12 and IFN-γ, and induction of macrophage-derived effector molecules like NO.

scholarly journals Development of a Human Gamma Interferon Enzyme Immunoassay and Comparison with Tuberculin Skin Testing for Detection ofMycobacterium tuberculosis Infection

1998 ◽  
Vol 5 (4) ◽  
pp. 531-536 ◽  
Author(s):  
Nuket Desem ◽  
Stephen L. Jones
Keyword(s):  
Enzyme Immunoassay ◽  
Skin Test ◽  
Skin Testing ◽  
Gamma Interferon ◽  
Tuberculin Skin Testing ◽  
In Vitro Test ◽  
Detection Range ◽  
Ifn Γ

ABSTRACT A sensitive two-step simultaneous enzyme immunoassay (EIA) for human gamma interferon (IFN-γ) has been developed and used as an in vitro test for human tuberculosis (TB) in comparison with tuberculin skin testing. The EIA was shown to be highly sensitive, detecting less than 0.5 IU of recombinant human IFN-γ per ml within a linear detection range of 0.5 to 150 IU/ml. The assay was highly reproducible and specific for native IFN-γ. In addition, the assay detected chimpanzee, orangutan, gibbon, and squirrel monkey IFN-γs. Cross-reactions with other human cytokines or with IFN-γs derived from mice, cattle, or Old World monkeys were not evident. The assay was used to detect TB infection by incubating whole blood overnight with human, avian, and bovine tuberculin purified protein derivatives (PPDs), as well as positive (mitogen)- and negative-control preparations. The levels of IFN-γ in plasma supernatants were then determined. Blood from 10 tuberculin skin test-positive individuals responded predominantly to the human tuberculin PPD antigen and to a lesser extent to bovine and avian PPD antigens. By contrast, blood from 10 skin test-negative individuals showed minimal responses or no response to any of the tuberculin PPDs. Detectable levels of IFN-γ were present in all blood samples stimulated with mitogen. In vivo tuberculin reactivity was correlated with IFN-γ responsiveness in vitro. These results support the further study of the blood culture–IFN-γ EIA system as an alternative to skin testing for the detection of human TB infection.

Contribution of Natural Killer Cells to Inhibition of Angiogenesis by Interleukin-12

Blood ◽  
1999 ◽  
Vol 93 (5) ◽  
pp. 1612-1621 ◽  
Author(s):  
Lei Yao ◽  
Cecilia Sgadari ◽  
Keizo Furuke ◽  
Eda T. Bloom ◽  
Julie Teruya-Feldstein ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Nk Cells ◽  
Natural Killer ◽  
Cell Function ◽  
Nk Cell ◽  
Primary Cultures ◽  
Interleukin 12 ◽  
Ifn Γ

Abstract Interleukin-12 (IL-12) inhibits angiogenesis in vivo by inducing interferon-γ (IFN-γ) and other downstream mediators. Here, we report that neutralization of natural killer (NK) cell function with antibodies to either asialo GM1 or NK 1.1 reversed IL-12 inhibition of basic fibroblast growth factor (bFGF)-induced angiogenesis in athymic mice. By immunohistochemistry, those sites where bFGF-induced neovascularization was inhibited by IL-12 displayed accumulation of NK cells and the presence of IP-10–positive cells. Based on expression of the cytolytic mediators perforin and granzyme B, the NK cells were locally activated. Experimental Burkitt lymphomas treated locally with IL-12 displayed tumor tissue necrosis, vascular damage, and NK-cell infiltration surrounding small vessels. After activation in vitro with IL-12, NK cells from nude mice became strongly cytotoxic for primary cultures of syngeneic aortic endothelial cells. Cytotoxicity was neutralized by antibodies to IFN-γ. These results document that NK cells are required mediators of angiogenesis inhibition by IL-12, and provide evidence that NK-cell cytotoxicity of endothelial cells is a potential mechanism by which IL-12 can suppress neovascularization.

Natural-killer cells and dendritic cells: “l'union fait la force”

Blood ◽  
2005 ◽  
Vol 106 (7) ◽  
pp. 2252-2258 ◽  
Author(s):  
Thierry Walzer ◽  
Marc Dalod ◽  
Scott H. Robbins ◽  
Laurence Zitvogel ◽  
Eric Vivier
Keyword(s):  
Dendritic Cells ◽  
Nk Cells ◽  
Natural Killer ◽  
Cell Activation ◽  
Nk Cell ◽  
Interleukin 12 ◽  
Cell Contact ◽  
Ifn Γ

AbstractSeveral recent publications have focused on the newly described interactions between natural-killer (NK) cells and dendritic cells (DCs). Activated NK cells induce DC maturation either directly or in synergy with suboptimal levels of microbial signals. Immature DCs appear susceptible to autologous NK-cell-mediated cytolysis while mature DCs are protected. NK-cell-induced DC activation is dependent on both tumor necrosis factor-α (TNF-α)/interferon-γ (IFN-γ) secretion and a cell-cell contact involving NKp30. In vitro, interleukin-12 (IL-12)/IL-18, IL-15, and IFN-α/β production by activated DCs enhance, in turn, NK-cell IFN-γ production, proliferation, and cytotoxic potential, respectively. In vivo, NK-cell/DC interactions may occur in lymphoid organs as well as in nonlymphoid tissues, and their consequences are multiple. By inducing DC activation, NK-cell activation induced by tumor cells can indirectly promote antitumoral T-cell responses. Reciprocally, DCs activated through Toll-like receptors (TLRs) induce potent NK-cell activation in antiviral responses. Thus, DCs and NK cells are equipped with complementary sets of receptors that allow the recognition of various pathogenic agents, emphasizing the role of NK-cell/DC crosstalk in the coordination of innate and adaptive immune responses.

dSLIM Immunomodulators Induce Anti-Tumor Responses Both In Vitro and In Vivo.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1727-1727
Author(s):  
Manuel Schmidt ◽  
Javier de Cristobal ◽  
Astrid Sander ◽  
Bernadette Brzezicha ◽  
Sven A. König Merediz ◽  
...  
Keyword(s):  
Tumor Cell ◽  
Tumor Cells ◽  
Neutralizing Antibodies ◽  
De Novo ◽  
Tumor Cell Line ◽  
Control Group ◽  
Γδt Cells ◽  
Ifn Γ

Abstract Cytosine-guanine (CpG) motifs containing oligonucleotides (ODN) are commonly used for immunomodulatory purpose in cancer therapy and for the treatment of allergic diseases since they resemble bacterial DNA and serve as “danger signals”. These CpG-ODNs promote predominately a TH1-response with secretion of IL-12 and IFN-γ, In addition their broad potential includes activation of B-cell proliferation, monocyte stimulation and secretion of IgM and IL-6, and stimulation of plasmacytoid DC to produce IFN-α/-β and thus γδT-cells and NK-cells to express CD69 and secrete IFN-γ. Usually phosphorothioate (PS) modifications are to enhance the stability, but these are leading to several side-effects, like severe organ enlargements, morphological changes and immunosuppression in mice. We designed immunomodulatory molecules based on short covalently-closed dumbbell-like structures (dSLIM) to stabilize the DNA without the otherwise necessary PS-modification. To evaluate the anti-tumor effect of the dSLIM molecules we developed an in vitro anti-tumor assay. This assay uses supernatant from dSLIM-activated human PBMCs for incubation with tumor cells in vitro. We observed increased apoptosis and necrosis of the HT-29 tumor cell line after incubation with supernatant from dSLIM-treated PBMC which was significantly higher than the effect of supernatant from non-treated PBMC. In addition, supernatant from dSLIM-treated PBMC increased the expression of HLA-ABC on the tumor cells, a pre-requisite for tumor cell recognition by the immune system. These effects were confirmed with human HEK293 and murine Renca cell lines. Analyzing the effect with neutralizing antibodies to various apoptosis-related cytokines, we observed a crucial role of IFN-γ but not IFN-α or TNFα. To investigate the anti-tumor effects of dSLIM in vivo, we employed a SKH1 murine model which is prone to spontaneous development of papillomas. Using chemicals for initiation and weekly promotion of de novo papilloma development we compared groups of weekly s.c. or i.p. dSLIM injections, respectively, with the PBS control group. The number of papilloma developing mice was significantly lower in the dSLIM groups and the total number of papillomas on all mice was reduced by approximately 50%. In conclusion, we showed that dSLIM immunomodulators exhibit potent anti-tumor effects in vitro and in vivo.

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