Search results for "interferon"
showing 10 items of 963 documents
Killed Candida albicans yeasts and hyphae inhibit gamma interferon release by murine natural killer cells.
2006
ABSTRACT Killed yeasts and hyphae of Candida albicans inhibit gamma interferon secretion by highly purified murine NK cells in response to the Toll-like receptor ligands lipopolysaccharide and zymosan. This effect, which is also observed in the presence of NK-activating cytokines (interleukin-2 [IL-2], IL-12, and IL-15), may represent a novel mechanism of immune evasion that contributes to the virulence of C. albicans .
The macrophage-activating tetrapeptide tuftsin induces nitric oxide synthesis and stimulates murine macrophages to kill Leishmania parasites in vitro.
1994
The macrophage-activating tetrapeptide tuftsin was able to activate, in a dose-dependent manner, murine macrophages to express nitric oxide (NO) synthase and to produce NO. Tuftsin required lipopolysaccharides for the optimal induction of NO production and synergized with gamma interferon in the induction of NO synthesis. Tuftsin-dependent NO production was sensitive to inhibition by dexamethasone and the NO synthase specific inhibitor LGN-monomethylarginine (L-NMMA). Murine peritoneal macrophages activated by tuftsin were able to kill the amastigotes of the intracellular protozoan parasite Leishmania major in vitro.
Skin-derived macrophages from Leishmania major-susceptible mice exhibit interleukin-12- and interferon-gamma-independent nitric oxide production and …
2002
Co-administration of CpG-containing immunostimulatory oligodeoxynucleotides and parasite antigen protects susceptible BALB/c mice from otherwise progressive infection with Leishmania major. Although the protective effect of CpG-containing immunostimulatory oligodeoxynucleotides is clearly dependent on endogenous interleukin-12 and interferon-gamma production, the source of these Th1-promoting cytokines in infected mice is unknown. In contrast to macrophages from Leishmania-resistant C57BL/6 mice, macrophages from susceptible BALB/c mice are hyporesponsive to stimulation with lipopolysaccharide and interferon-gamma. While studying interactions of various antigen-presenting cells with Leishma…
Intravitreal injection of bevacizumab induces inflammatory alterations in a uveitis experimental model.
2010
PurposeBevacizumab is currently used as an intravitreal agent in the treatment of inflammatory-associated eye diseases. The aim of the current study is to explore the effects of the intravitreal injection of bevacizumab on aqueous humour cytokines and chemokines in an experimental uveitis model.MethodsEndotoxin-induced uveitis was induced in rats by footpad injections. Bevacizumab was administered by intravitreal injection (75 μg in 3–μL samples) and different chemokine and cytokine proteins were quantified in aqueous humor.ResultsIntravitreal administration of bevacizumab led to a several-fold increase of RANTES, MCP-1, and IFN-γ concentrations in aqueous humor of endotoxin-treated rats.Co…
Tolerance and M2 (alternative) macrophage polarization are related processes orchestrated by p50 nuclear factor κB
2009
Cells of the monocyte-macrophage lineage play a central role in the orchestration and resolution of inflammation. Plasticity is a hallmark of mononuclear phagocytes, and in response to environmental signals these cells undergo different forms of polarized activation, the extremes of which are called classic or M1 and alternative or M2. NF-kappaB is a key regulator of inflammation and resolution, and its activation is subject to multiple levels of regulation, including inhibitory, which finely tune macrophage functions. Here we identify the p50 subunit of NF-kappaB as a key regulator of M2-driven inflammatory reactions in vitro and in vivo. p50 NF-kappaB inhibits NF-kappaB-driven, M1-polariz…
Colocalization but differential regulation of neuronal NO synthase and nicotinic acetylcholine receptor in C2C12 myotubes.
2003
In mammalian skeletal muscle, neuronal-type nitric oxide synthase (nNOS) is found to be enriched at neuromuscular endplates. Here we demonstrate the colocalization of the nicotinic acetylcholine receptor (nAChR, stained with α-bungarotoxin) and nNOS (stained with a specific antibody) in murine C2C12myotubes. However, coimmunoprecipitation experiments demonstrated no evidence for a direct protein-protein association between the nAChR and nNOS in C2C12myotubes. An antibody to the α1-subunit of the nAChR did not coprecipitate nNOS, and an nNOS-specific antibody did not precipitate the α1-subunit of the nAChR. Treatment of mice with bacterial LPS downregulated the expression of nNOS in skeletal…
Resistance of natural killer T cell-deficient mice to systemic Shwartzman reaction.
2000
The generalized Shwartzman reaction in mice which had been primed and challenged with lipopolysaccharide (LPS) depends on interleukin (IL)-12-induced interferon (IFN)-gamma production at the priming stage. We examined the involvement in the priming mechanism of the unique population of Valpha14 natural killer T (NKT) cells because they promptly produce IFN-gamma after IL-12 stimulation. We report here that LPS- or IL-12-primed NKT cell genetically deficient mice were found to be resistant to LPS-elicited mortality. This outcome can be attributed to the reduction of IFN-gamma production, because injection of recombinant mouse IFN-gamma, but not injection of IL-12, effectively primed the NKT …
Release of IL-12 by dendritic cells activated by TLR ligation is dependent on MyD88 signaling, whereas TRIF signaling is indispensable for TLR synerg…
2010
Abstract Synergistic activation of dendritic cells by combinations of TLR ligands requires both MyD88- and TRIF-dependent signaling. Recently, it has been shown that certain combinations of TLR ligands act in synergy to induce the release of IL-12 by DCs. In this study, we sought to define the critical parameters underlying TLR synergy. Our data show that TLR ligands act synergistically if MyD88- and TRIF-dependent ligands are combined. TLR4 uses both of these adaptor molecules, thus activation via TLR4 proved to be a synergistic event on its own. TLR synergy did not affect all aspects of DC activation but enhanced primarily the release of certain cytokines, particularly IL-12, whereas the …
Identification and characterization of a novel Ets-2-related nuclear complex implicated in the activation of the human interleukin-12 p40 gene promot…
1997
Interleukin-12 (IL-12) is a proinflammatory cytokine produced by antigen-presenting cells in response to many microbial infections. IL-12 plays an important role in the generation of T helper type-1 cells, which favor cell-mediated immune response. IL-12 is composed of two different subunits, p40 and p35, whose expression can be regulated concomitantly or differentially. Monocytic cells, the major producers of IL-12, can be primed by interferon-gamma (IFN-gamma) to produce optimal amounts of IL-12 in response to LPS stimulation as a consequence of bacterial infection. The priming effect is exerted primarily at the transcriptional level on the p40 promoter in conjunction with the effects of …
Corynebacterium parvum (Propionibacterium acnes): an inducer of tumor necrosis factor-alpha in human peripheral blood mononuclear cells and monocytes…
1990
The present study investigates the potential capacity of the immunostimulant Corynebacterium parvum (C.p.) to induce tumor necrosis factor-alpha (TNF-alpha) in human peripheral blood mononuclear cells (PBMC) and blood monocytes (BMo) in vitro. Both at the mRNA and protein level, stimulation of PBMC and BMo upon C.p. induces TNF-alpha. Compared to the hitherto used TNF-alpha inducers in vitro such as Sendai virus, phytohemagglutinin or lipopolysaccharide the C.p. stimulus displayed a threefold stronger induction of TNF-alpha production (p less than 0.001). Using C.p. as an inducer it was possible to demonstrate that TNF-alpha production is regulated by prostaglandin E2; preincubation of the …