scholarly journals Immunoglobulin A1 Protease, an Exoenzyme of Pathogenic Neisseriae, Is a Potent Inducer of Proinflammatory Cytokines

1999 ◽  
Vol 190 (8) ◽  
pp. 1049-1058 ◽  
Author(s):  
Dirk R. Lorenzen ◽  
Frank Düx ◽  
Uwe Wölk ◽  
Anastasios Tsirpouchtsidis ◽  
Gaby Haas ◽  
...  

A characteristic of human pathogenic Neisseriae is the production and secretion of an immunoglobulin (Ig)A1-specific serine protease (IgA1 protease) that cleaves preferentially human IgA1 and other target proteins. Here we show a novel function for native IgA1 protease, i.e., the induction of proinflammatory cytokines such as tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, and IL-8 from peripheral blood mononuclear cells. The capacity of IgA1 protease to elicit such cytokine responses in monocytes was enhanced in the presence of T lymphocytes. IgA1 protease did not induce the regulatory cytokine IL-10, which was, however, found in response to lipopolysaccharide and phytohemagglutinin. The immunomodulatory effects caused by IgA1 protease require a native form of the enzyme, and denaturation abolished cytokine induction. However, the proteolytic activity is not required for the cytokine induction by IgA1 protease. Our results indicate that IgA1 protease exhibits important immunostimulatory properties and may contribute substantially to the pathogenesis of neisserial infections by inducing large amounts of TNF-α and other proinflammatory cytokines. In particular, IgA1 protease may represent a key virulence determinant of bacterial meningitis.

2002 ◽  
Vol 11 (5) ◽  
pp. 325-328 ◽  
Author(s):  
E. Jablonska

Background: It has recently been shown that soluble interleukin-6 receptor (sIL-6R) alone or complexed with interleukin (IL)-6, besides their regulatory role in a wide variety of both normal and abnormal biologic reactions mediated by IL-6, could be an effective stimulator of the cell function.Aims: The key question of the present study is whether the sIL-6Rα or sIL-6R with IL-6 released by polymorphonuclear leukocytes (PMN) can influence cytokine secretion such as tumor necrosis factor-α (TNF-α) by peripheral blood mononuclear cells (PBMC), which together with PMN develop the inflammatory and immune response of a host.Methods: Cells were isolated from heparinized whole blood of healthy persons. The PMN were cultured for 1 h at 37°C in 5% CO2. After incubation, the culture supernatant of PMN was removed and was added to PBMC. The PBMC were cultured for 1 h at 37°C in the same conditions. In the culture supernatants and lysates of PMN, we examined the concentrations of sIL-6R by enzyme-linked immunosorbent assay (ELISA). TNF-α was measured at both protein and mRNA levels. Protein levels were determined by ELISA. To examine TNF-α mRNA expression, we isolated mRNA from PBMC after culture, using TRIZOL Reagent. The quantity of mRNA TNF-α was determined by the Quantikine mRNA assay.Results and conclusion: The results obtained revealed that sIL-6R with IL-6 secreted by PMN may play a regulatory role in the immune response by modulating the TNF-α expression and its production by PBMC. This may have a significant influence on an early phase of the inflammation and other reactions mediated by TNF-α.


2006 ◽  
Vol 13 (3) ◽  
pp. 319-328 ◽  
Author(s):  
Madhavan P. Nair ◽  
Supriya Mahajan ◽  
Jessica L. Reynolds ◽  
Ravikumar Aalinkeel ◽  
Harikrishnan Nair ◽  
...  

ABSTRACT The flavonoids comprise a large class of low-molecular-weight plant metabolites ubiquitously distributed in food plants. These dietary antioxidants exert significant antitumor, antiallergic, and anti-inflammatory effects. The molecular mechanisms of their biological effects remain to be clearly understood. We investigated the anti-inflammatory potentials of a safe, common dietary flavonoid component, quercetin, for its ability to modulate the production and gene expression of the proinflammatory cytokine tumor necrosis factor alpha (TNF-α) by human peripheral blood mononuclear cells (PBMC). Our results showed that quercetin significantly inhibited TNF-α production and gene expression in a dose-dependent manner. Our results provide direct evidence of the anti-inflammatory effects of quercetin by PBMC, which are mediated by the inhibition of the proinflammatory cytokine TNF-α via modulation of NF-κβ1 and Iκβ.


1998 ◽  
Vol 42 (8) ◽  
pp. 1911-1916 ◽  
Author(s):  
Anja Lührmann ◽  
Jürgen Thölke ◽  
Ingrid Behn ◽  
Jens Schumann ◽  
Gisa Tiegs ◽  
...  

ABSTRACT We show that the coumeromycin antibiotic novobiocin, a potent inhibitor of ADP ribosylation, prevents lipopolysaccharide (LPS)-induced tumor necrosis factor alpha (TNF-α), interleukin-1 (IL-1), IL-6, and IL-10 secretion in human peripheral blood mononuclear cells. It shares these cytokine-suppressing properties with other inhibitors of ADP ribosylation. We found that novobiocin prevents TNF-α production by inhibiting translation of the TNF-α mRNA. Elevated TNF-α levels in mice treated withd-galactosamine (GalN)-LPS or GalN-TNF were not reduced by novobiocin; however, the drug exhibited hepatoprotective properties. Novobiocin causes downregulation of the surface molecules on monocytes, among which CD14 was the most affected. The diminished expression of surface molecules was not observed on T and B lymphocytes. Similar to other inhibitors of ADP ribosylation, novobiocin prevents LPS-induced phosphate labelling of γ-actins.


2003 ◽  
Vol 47 (12) ◽  
pp. 3704-3707 ◽  
Author(s):  
Jung-Hyun Choi ◽  
Min-Jin Song ◽  
Seung-Han Kim ◽  
Su-Mi Choi ◽  
Dong-Gun Lee ◽  
...  

ABSTRACT The effects of moxifloxacin, a new methoxyfluoroquinolone, on the production of proinflammatory cytokines from human peripheral blood mononuclear cells (PBMCs) were evaluated. Moxifloxacin inhibited the production of tumor necrosis factor alpha (TNF-α) and/or interleukin-6 (IL-6) by PBMCs stimulated with lipopolysaccharide (LPS), lipoteichoic acid (LTA), and heat-killed bacteria in a concentration-dependent manner without cytotoxic effects. The addition of moxifloxacin reduced the population of cells positive for CD-14 and TNF-α and for CD-14 and IL-6 among the LPS- or LTA-stimulated PBMCs. By Western blot analysis, moxifloxacin pretreatment reduced the degradation of IκBα in LPS-stimulated PBMCs. In conclusion, moxifloxacin could interfere with NF-κB activation by inhibiting the degradation of IκBα and reduce the levels of production of proinflammatory cytokines.


Biomolecules ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1777
Author(s):  
Beata Kaleta ◽  
Aleksander Roszczyk ◽  
Michał Zych ◽  
Monika Kniotek ◽  
Radosław Zagożdżon ◽  
...  

A common edible mushroom Lentinula edodes, is an important source of numerous biologically active substances, including polysaccharides, with immunomodulatory and antitumor properties. In the present work, the biological activity of the crude, homogenous (Se)-enriched fraction (named Se-Le-30), which has been isolated from L. edodes mycelium by a modified Chihara method towards human peripheral blood mononuclear cells (PBMCs) and peripheral granulocytes, was investigated. The Se-Le-30 fraction, an analog of lentinan, significantly inhibited the proliferation of human PBMCs stimulated with anti-CD3 antibodies or allostimulated, and down-regulated the production of tumor necrosis factor (TNF)-α by CD3+ T cells. Moreover, it was found that Se-Le-30 significantly reduced the cytotoxic activity of human natural killer (NK) cells. The results suggested the selective immunosuppressive activity of this fraction, which is non-typical for mushroom derived polysaccharides.


1992 ◽  
Vol 70 (5) ◽  
pp. 719-722 ◽  
Author(s):  
Michael J. Rieder ◽  
Monica Mask ◽  
Ingrid A. Bird

Hypersensitivity reactions are the most common adverse events associated with therapy with the sulphonamide antibiotics. These reactions have been shown to occur among individuals with pharmacogenetically determined differences in the capacity of their cells to detoxify reactive products of oxidative metabolism of the sulphonamides. These reactions appear to be propagated by an inflammatory response by the immune system. To investigate the role of the cytokine tumour necrosis factor (TNF-α) in these reactions, we studied the production of TNF-α by peripheral blood mononuclear cells (PBMCs) that had been incubated with sulfamethoxazole and murine microsomes in the presence and absence of a microsomal-activating system and TNF-α production by PBMCs in the presence and absence of the hydroxylamine derivative of sulfamethoxazole. The PBMCs showed a time-related increase in the production of TNF-α. There was no increase in TNF-α production seen during incubation with sulphonamide reactive metabolites; rather, there was a decrease in TNF-α elaboration that was most marked when PBMCs were incubated with the hydroxylamine of sulfamethoxazole. There is no evidence from these in vitro studies that TNF-α is involved as a mediator of the inflammatory response in sulphonamide hypersensitivity adverse drug reactions.Key words: sulphonamide, tumour necrosis factor, adverse drug reaction, hydroxylamine.


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