scholarly journals Lipooligosaccharide and Polysaccharide Capsule: Virulence Factors of Neisseria meningitidis That Determine Meningococcal Interaction with Human Dendritic Cells

2002 ◽  
Vol 70 (5) ◽  
pp. 2454-2462 ◽  
Author(s):  
Alexandra Unkmeir ◽  
Ulrike Kämmerer ◽  
Anne Stade ◽  
Claudia Hübner ◽  
Sabine Haller ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Neisseria Meningitidis ◽  
Wild Type ◽  
Proinflammatory Response ◽  
Necrosis Factor Alpha ◽  
Cytokine Induction ◽  
Cytokines And Chemokines ◽  
Factor Alpha ◽  
Human Dendritic Cells ◽  
Necrosis Factor

ABSTRACT In this work we analyzed the roles of meningococcal lipooligosaccharide (LOS) and capsule expression in the interaction of Neisseria meningitidis with human dendritic cells (DC). Infection of DC with serogroup B wild-type meningococci induced a strong burst of the proinflammatory cytokines and chemokines tumor necrosis factor alpha, interleukin-6 (IL-6), and IL-8. In contrast, a serogroup B mutant strain lacking LOS expression barely led to cytokine induction, demonstrating that meningococcal LOS is the main mediator of the proinflammatory response in human DC. Sialylation of meningococcal LOS did not influence cytokine secretion by DC. However, we found the phagocytosis of N. meningitidis by human DC to be inhibited by LOS sialylation. In addition, the expression of the meningococcal serogroup A, B, and C capsules dramatically reduced DC adherence of N. meningitidis and phagocytosis to some extent. Hence, LOS sialylation and capsule expression are independent mechanisms protecting N. meningitidis from the phagocytic activity of human DC.

scholarly journals Interaction of Neisseria meningitidis with Human Dendritic Cells

2001 ◽  
Vol 69 (11) ◽  
pp. 6912-6922 ◽  
Author(s):  
Annette Kolb-Mäurer ◽  
Alexandra Unkmeir ◽  
Ulrike Kämmerer ◽  
Claudia Hübner ◽  
Thomas Leimbach ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Neisseria Meningitidis ◽  
Proinflammatory Cytokines ◽  
Interleukin 1 ◽  
Necrosis Factor Alpha ◽  
Tnf Α ◽  
Cytokine Levels ◽  
Factor Alpha ◽  
Human Dendritic Cells ◽  
Necrosis Factor

ABSTRACT Infection with Neisseria meningitidis serogroup B is responsible for fatal septicemia and meningococcal meningitis. The severity of disease directly correlates with the production of the proinflammatory cytokines tumor necrosis factor alpha (TNF-α), interleukin-1 (IL-1), IL-6, and IL-8. However, the source of these cytokines has not been clearly defined yet. Since bacterial infection involves the activation of dendritic cells (DCs), we analyzed the interaction of N. meningitidis with monocyte-derived DCs. Using N. meningitidis serogroup B wild-type and unencapsulated bacteria, we found that capsule expression significantly impaired neisserial adherence to DCs. In addition, phagocytic killing of the bacteria in the phagosome is reduced by at least 10- to 100-fold. However, all strains induced strong secretion of proinflammatory cytokines TNF-α, IL-6, and IL-8 by DCs (at least 1,000-fold at 20 h postinfection [p.i.]), with significantly increased cytokine levels being measurable by as early as 6 h p.i. Levels of IL-1β, in contrast, were increased only 200- to 400-fold at 20 h p.i. with barely measurable induction at 6 h p.i. Moreover, comparable amounts of cytokines were induced by bacterium-free supernatants of Neisseria cultures containing neisserial lipooligosaccharide as the main factor. Our data suggest that activated DCs may be a significant source of high levels of proinflammatory cytokines in neisserial infection and thereby may contribute to the pathology of meningococcal disease.

scholarly journals Differential Role of Lipooligosaccharide of Neisseria meningitidis in Virulence and Inflammatory Response during Respiratory Infection in Mice

2006 ◽  
Vol 74 (10) ◽  
pp. 5506-5512 ◽  
Author(s):  
Maria Leticia Zarantonelli ◽  
Michel Huerre ◽  
Muhamed-Kheir Taha ◽  
Jean-Michel Alonso
Keyword(s):  
Inflammatory Response ◽  
Neisseria Meningitidis ◽  
Lipid A ◽  
Meningococcal Infection ◽  
Proinflammatory Response ◽  
Necrosis Factor Alpha ◽  
Factor Alpha ◽  
Respiratory Challenge ◽  
Necrosis Factor

ABSTRACT Meningococcal lipooligosaccharide (LOS) induces a strong proinflammatory response in humans during meningococcal infection. We analyzed the role of LOS in the inflammatory response and virulence during the early infectious process in a mouse model of meningococcal respiratory challenge. An lpxA mutant strain (serogroup B) devoid of LOS (strain Z0204) could not persist in the lungs and did not invade the blood. The persistence in the lungs and invasion of the bloodstream by a rfaD mutant expressing truncated LOS with only lipid A and 3-deoxy-d-manno-2-octulosonic acid molecules (strain Z0401) was intermediate between those of the wild-type and Z0204 strains. Both LOS mutants induced acute pneumonia with the presence of infiltrating polymorphonuclear leukocytes in lungs. Although tumor necrosis factor alpha production was reduced in mice infected with the mutant of devoid LOS, both LOS mutants induced production of other proinflammatory cytokines, such as interleukin-1β (IL-1β), IL-6, and the murine IL-8 homolog KC. Together, these results suggest that meningococcal LOS plays a role during the early infectious and invasive process, and they further confirm that other, nonlipopolysaccharide components of Neisseria meningitidis may significantly contribute to the inflammatory reaction of the host.

scholarly journals Tumour necrosis factor-alpha but not lipopolysaccharide enhances preference of murine dendritic cells for Th2 differentiation

Immunology ◽  
2003 ◽  
Vol 108 (1) ◽  
pp. 42-49 ◽  
Author(s):  
Kazuhiro Kikuchi ◽  
Yoshiki Yanagawa ◽  
Toshimasa Aranami ◽  
Chikako Iwabuchi ◽  
Kazuya Iwabuchi ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Tumour Necrosis Factor ◽  
Tumour Necrosis ◽  
Tumour Necrosis Factor Alpha ◽  
Necrosis Factor Alpha ◽  
Factor Alpha ◽  
Th2 Differentiation ◽  
Necrosis Factor

Interferon-Gamma and Tumor Necrosis Factor-Alpha Promote the Binding of Dendritic Cells to Fibronectin

Pathobiology ◽  
1994 ◽  
Vol 62 (3) ◽  
pp. 120-126 ◽  
Author(s):  
Thomas Chang-Yao Tsao ◽  
Weijia Xia ◽  
Gary M. Rodberg ◽  
Clare E. Pinto ◽  
Richard L. Kradin
Keyword(s):  
Dendritic Cells ◽  
Tumor Necrosis Factor ◽  
Tumor Necrosis Factor Alpha ◽  
Interferon Gamma ◽  
Tumor Necrosis ◽  
Necrosis Factor Alpha ◽  
Factor Alpha ◽  
Necrosis Factor

scholarly journals Tumor Necrosis Factor Alpha-Induced Apoptosis Requires p73 and c-ABL Activation Downstream of RB Degradation

2004 ◽  
Vol 24 (10) ◽  
pp. 4438-4447 ◽  
Author(s):  
B. Nelson Chau ◽  
Tung-Ti Chen ◽  
Yisong Y. Wan ◽  
James DeGregori ◽  
Jean Y. J. Wang
Keyword(s):  
Tumor Necrosis Factor ◽  
Tumor Necrosis Factor Alpha ◽  
Tumor Necrosis ◽  
Wild Type ◽  
Necrosis Factor Alpha ◽  
Abl Tyrosine Kinase ◽  
Tnf Α ◽  
Factor Alpha ◽  
Induced Apoptosis ◽  
Necrosis Factor

ABSTRACT The retinoblastoma protein (RB) suppresses cell proliferation and apoptosis. We have previously shown that RB degradation is required for tumor necrosis factor alpha (TNF-α) to induce apoptosis. We show here the identification of two apoptotic effectors, i.e., c-ABL tyrosine kinase and p73, which are activated by TNF-α following RB degradation. In cells expressing a degradation-resistant RB protein (RB-MI), TNF-α does not activate c-ABL. RB-MI also inhibits TNF-α-mediated activation of p73. Genetic deletion and pharmacological inhibition of c-ABL or p73 diminish the apoptotic response to TNF-α in human cell lines and mouse fibroblasts. Thymocytes isolated from RbMI/MI , Abl −/−, or p73 −/− mice are resistant to TNF-α-induced apoptosis compared to their wild-type counterparts. This is in contrast to p53 −/− thymocytes, which exhibit a wild-type level of apoptosis in response to TNF-α. Thus, c-ABL and p73 contribute to apoptosis induced by TNF-α, in addition to their role in promoting DNA damage-associated cell death.

scholarly journals Keratins Modulate c-Flip/Extracellular Signal-Regulated Kinase 1 and 2 Antiapoptotic Signaling in Simple Epithelial Cells

2004 ◽  
Vol 24 (16) ◽  
pp. 7072-7081 ◽  
Author(s):  
Stéphane Gilbert ◽  
Anne Loranger ◽  
Normand Marceau
Keyword(s):  
Tumor Necrosis Factor ◽  
Tumor Necrosis Factor Alpha ◽  
Tumor Necrosis ◽  
Null Mouse ◽  
Wild Type ◽  
Necrosis Factor Alpha ◽  
Extracellular Signal Regulated Kinase ◽  
Extracellular Signal ◽  
Factor Alpha ◽  
Necrosis Factor

ABSTRACT Among the large family of intermediate filament proteins, the keratin 8 and 18 (K8/K18) pair constitutes a hallmark for all simple epithelial cells, such as hepatocytes and mammary cells. Functional studies with different cell models have suggested that K8/K18 are involved in simple epithelial cell resistance to several forms of stress that may lead to cell death. We have reported recently that K8/K18-deprived hepatocytes from K8-null mice are more sensitive to Fas-mediated apoptosis. Here we show that upon Fas, tumor necrosis factor alpha receptor, or tumor necrosis factor alpha-related apoptosis-inducing ligand receptor stimulation, an inhibition of extracellular signal-regulated kinase 1 and 2 (ERK1/2) activation sensitizes wild-type but not K8-null mouse hepatocytes to apoptosis and that a much weaker ERK1/2 activation occurs in K8-null hepatocytes. In turn, this impaired ERK1/2 activation in K8-null hepatocytes is associated with a drastic reduction in c-Flip protein, an event that also holds in a K8-null mouse mammary cell line. c-Flip, along with Raf-1, is part of a K8/K18-immunoisolated complex from wild-type hepatocytes, and Fas stimulation leads to further c-Flip and Raf-1 recruitment in the complex. This points to a new regulatory role of simple epithelium keratins in the c-Flip/ERK1/2 antiapoptotic signaling pathway.

scholarly journals Maturation of Human Dendritic Cells by Cell Wall Skeleton of Mycobacterium bovis Bacillus Calmette-Guérin: Involvement of Toll-Like Receptors

2000 ◽  
Vol 68 (12) ◽  
pp. 6883-6890 ◽  
Author(s):  
Shoutaro Tsuji ◽  
Misako Matsumoto ◽  
Osamu Takeuchi ◽  
Shizuo Akira ◽  
Ichiro Azuma ◽  
...  
Keyword(s):  
Cell Wall ◽  
Dendritic Cells ◽  
Mycobacterium Bovis ◽  
Surface Expression ◽  
Necrosis Factor Alpha ◽  
Mycolic Acids ◽  
Tnf Α ◽  
Toll Like Receptor 2 ◽  
Factor Alpha ◽  
Human Dendritic Cells

ABSTRACT The constituents of mycobacteria are an effective immune adjuvant, as observed with complete Freund's adjuvant. In this study, we demonstrated that the cell wall skeleton of Mycobacterium bovis bacillus Calmette-Guérin (BCG-CWS), a purified noninfectious material consisting of peptidoglycan, arabinogalactan, and mycolic acids, induces maturation of human dendritic cells (DC). Surface expression of CD40, CD80, CD83, and CD86 was increased by BCG-CWS on human immature DC, and the effect was similar to those of interleukin-1β (IL-1β), tumor necrosis factor alpha (TNF-α), heat-killed BCG, and viable BCG. BCG-CWS induced the secretion of TNF-α, IL-6, and IL-12 p40. CD83 expression was increased by a soluble factor secreted from BCG-CWS-treated DC and was completely inhibited by monoclonal antibodies against TNF-α. BCG-CWS-treated DC stimulated extensive allogeneic mixed lymphocyte reactions. The level of TNF-α secreted through BCG-CWS was partially suppressed in murine macrophages with no Toll-like receptor 2 (TLR 2) or TLR4 and was completely lost in TLR2 and TLR4 double-deficient macrophages. These results suggest that the BCG-CWS induces TNF-α secretion from DC via TLR2 and TLR4 and that the secreted TNF-α induces the maturation of DC per se.

scholarly journals Transient Neutralization of Tumor Necrosis Factor Alpha Can Produce a Chronic Fungal Infection in an Immunocompetent Host: Potential Role of Immature Dendritic Cells

2005 ◽  
Vol 73 (1) ◽  
pp. 39-49 ◽  
Author(s):  
Amy C. Herring ◽  
Nicole R. Falkowski ◽  
Gwo-Hsiao Chen ◽  
Rod A. McDonald ◽  
Galen B. Toews ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Fungal Infection ◽  
Immune Deviation ◽  
Immunocompetent Host ◽  
Necrosis Factor Alpha ◽  
Immature Dendritic Cells ◽  
Tnf Α ◽  
Factor Alpha ◽  
Ifn Γ ◽  
Necrosis Factor

ABSTRACT The mechanisms underlying induction of immune dysregulation and chronic fungal infection by a transient tumor necrosis factor alpha (TNF-α) deficiency remain to be defined. The objective of our studies was to determine the potential contribution of neutropenia and immature dendritic cells to the immune deviation. Administration of an anti-TNF-α monoclonal antibody at day 0 neutralized TNF-α only during the first week of a pulmonary Cryptococcus neoformans infection. Transient neutralization of TNF-α resulted in transient depression of interleukin-12 (IL-12), monocyte chemotactic protein 1 (MCP-1), and gamma interferon (IFN-γ) production but permanently impaired long-term clearance of the infection from the lungs even after the levels of these cytokines increased and a vigorous inflammatory response developed. Early neutrophil recruitment was defective in the absence of TNF-α. However, as demonstrated by neutrophil depletion studies, this did not account for the decrease in IL-12 and IFN-γ levels and did not play a role in establishing chronic pulmonary cryptococcal infection. Transient TNF-α neutralization also produced a deficiency in CD11c+ MHC II+ cells and IL-12 in the lymph nodes, potentially implicating a defect in mature dendritic cell trafficking. Transfer of cryptococcal antigen-pulsed immature dendritic cells into naïve mice prior to intratracheal challenge resulted in the development of a nonprotective immune response to C. neoformans that was similar to that observed in anti-TNF-α-treated mice (increased IL-4, IL-5, and IL-10 levels, pulmonary eosinophilia, and decreased clearance). Thus, stimulation of an antifungal response by immature dendritic cells can result in an immune deviation similar to that produced by transient TNF-α deficiency, identifying a new mechanism by which a chronic fungal infection can occur in an immunocompetent host.

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