scholarly journals The Presence of CD14 Overcomes Evasion of Innate Immune Responses by Virulent Francisella tularensis in Human Dendritic Cells In Vitro and Pulmonary Cells In Vivo

2009 ◽  
Vol 78 (1) ◽  
pp. 154-167 ◽  
Author(s):  
Jennifer C. Chase ◽  
Catharine M. Bosio
Keyword(s):  
Dendritic Cells ◽  
Francisella Tularensis ◽  
Cytokine Production ◽  
Necrosis Factor Alpha ◽  
Pulmonary Cells ◽  
Factor Alpha ◽  
Bacterial Replication ◽  
Human Dendritic Cells

ABSTRACT Francisella tularensis is a Gram-negative bacterium that causes acute, lethal disease following inhalation. We have previously shown that viable F. tularensis fails to stimulate secretion of proinflammatory cytokines following infection of human dendritic cells (hDC) in vitro and pulmonary cells in vivo. Here we demonstrate that the presence of the CD14 receptor is critical for detection of virulent F. tularensis strain SchuS4 by dendritic cells, monocytes, and pulmonary cells. Addition of soluble CD14 (sCD14) to hDC restored cytokine production following infection with strain SchuS4. In contrast, addition of anti-CD14 to monocyte cultures inhibited the ability of these cells to respond to strain SchuS4. Addition of CD14 or blocking CD14 following SchuS4 infection in dendritic cells and monocytes, respectively, was not due to alterations in phagocytosis or replication of the bacterium in these cells. Administration of sCD14 in vivo also restored cytokine production following infection with strain SchuS4, as assessed by increased concentrations of tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), IL-12p70, and IL-6 in the lungs of mice receiving sCD14 compared to mock-treated controls. In contrast to homogenous cultures of monocytes or dendritic cells infected in vitro, mice treated with sCD14 in vivo also exhibited controlled bacterial replication and dissemination compared to mock-treated controls. Interestingly, animals that lacked CD14 were not more susceptible or resistant to pulmonary infection with SchuS4. Together, these data support the hypothesis that the absence or low abundance of CD14 on hDC and in the lung contributes to evasion of innate immunity by virulent F. tularensis. However, CD14 is not required for development of inflammation during the last 24 to 48 h of SchuS4 infection. Thus, the presence of this receptor may aid in control of virulent F. tularensis infections at early, but not late, stages of infection.

scholarly journals Fimbriated Porphyromonas gingivalis Is More Efficient than Fimbria-Deficient P. gingivalis in Entering Human Dendritic Cells In Vitro and Induces an Inflammatory Th1 Effector Response

2004 ◽  
Vol 72 (3) ◽  
pp. 1725-1732 ◽  
Author(s):  
Ravi Jotwani ◽  
Christopher W. Cutler
Keyword(s):  
Dendritic Cells ◽  
Porphyromonas Gingivalis ◽  
Cell Metabolism ◽  
Necrosis Factor Alpha ◽  
Immature Dendritic Cells ◽  
Factor Alpha ◽  
Ifn Γ ◽  
Gingival Mucosa ◽  
Human Dendritic Cells

ABSTRACT Porphyromonas gingivalis is a fimbriated mucosal pathogen implicated in chronic periodontitis (CP). The fimbriae are required for invasion of the gingival mucosa and for induction of CP in animal models of periodontitis. CP is associated with infection of immature dendritic cells (DCs) by P. gingivalis in situ and with increased numbers of dermal DCs (DDCs) and mature DCs in the lamina propria. The role of fimbriae in gaining entry into human DCs and how this modulates the inflammatory and effector immune responses, however, have not been explored. To address this, we generated monocyte-derived DCs (MDDCs) in vitro which phenotypically and functionally resemble DDCs. We show here that virulent fimbriated P. gingivalis 381, in contrast to its fimbria-deficient mutant, P. gingivalis DPG3, efficiently gains entry to MDDCs in a manner dependent on active cell metabolism and cytoskeletal rearrangement. In addition, uptake of 381, unlike DPG3, induces DCs to undergo maturation, upregulate costimulatory molecules, and secrete inflammation cytokines interleukin-1β (IL-1β), IL-6, tumor necrosis factor alpha, IL-10, and IL-12. Moreover, MDDCs pulsed with 381 also stimulated a higher autologous mixed lymphocyte reaction and induced a Th1-type response, with gamma interferon (IFN-γ) being the main cytokine. Monocytes used as controls demonstrated fimbria-dependent uptake of 381 as well but produced low levels of inflammatory cytokines compared to MDDCs. When MDDCs were pulsed with recombinant fimbrillin of P. gingivalis (10 μg/ml), maturation of MDDCs was also induced; moreover, matured MDDCs induced proliferation of autologous CD4+ T cells and release of IFN-γ. Thus, these results establish the significance of P. gingivalis fimbriae in the uptake of P. gingivalis by MDDCs and in induction of immunostimulatory Th1 responses.

scholarly journals Miltefosine Efficiently Eliminates Leishmania major Amastigotes from Infected Murine Dendritic Cells without Altering Their Immune Functions

2009 ◽  
Vol 54 (2) ◽  
pp. 652-659 ◽  
Author(s):  
Klaus Griewank ◽  
Caroline Gazeau ◽  
Andreas Eichhorn ◽  
Esther von Stebut
Keyword(s):  
Dendritic Cells ◽  
Leishmania Major ◽  
Interleukin 12 ◽  
Immune Functions ◽  
Necrosis Factor Alpha ◽  
Mhc Ii ◽  
Intracellular Parasites ◽  
Factor Alpha

ABSTRACT As a treatment for leishmaniasis, miltefosine exerts direct toxic effects on the parasites. Miltefosine also modulates immune cells such as macrophages, leading to parasite elimination via oxidative radicals. Dendritic cells (DC) are critical for initiation of protective immunity against Leishmania through induction of Th1 immunity via interleukin 12 (IL-12). Here, we investigated the effects of miltefosine on DC in Leishmania major infections. When cocultured with miltefosine for 4 days, the majority of in vitro-infected DC were free of parasites. Miltefosine treatment did not influence DC maturation (upregulation of major histocompatibility complex II [MHC II] or costimulatory molecules, e.g., CD40, CD54, and CD86) or significantly alter cytokine release (IL-12, tumor necrosis factor alpha [TNF-α], or IL-10). Further, miltefosine DC treatment did not alter antigen presentation, since unrestricted antigen-specific proliferation of CD4+ and CD8+ T cells was observed upon stimulation with miltefosine-treated, infected DC. In addition, miltefosine application in vivo did not lead to maturation/emigration of skin DC. DC NO− production, a mechanism used by phagocytes to rid themselves of intracellular parasites, was also unaltered upon miltefosine treatment. Our data confirm prior studies indicating that in contrast to, e.g., pentavalent antimonials, miltefosine functions independently of the immune system, mostly through direct toxicity against the Leishmania parasite.

scholarly journals Sialyl Lewisx (sLex) and an sLexMimetic, CGP69669A, Disrupt E-Selectin–Dependent Leukocyte Rolling In Vivo

Blood ◽  
1998 ◽  
Vol 91 (2) ◽  
pp. 475-483 ◽  
Author(s):  
Keith E. Norman ◽  
Gary P. Anderson ◽  
Hartmut C. Kolb ◽  
Klaus Ley ◽  
Beat Ernst
Keyword(s):  
Leukocyte Rolling ◽  
Sialyl Lewisx ◽  
Necrosis Factor Alpha ◽  
Rolling Velocity ◽  
Beneficial Effects ◽  
Selectin Family ◽  
Factor Alpha ◽  
Observable Event

Abstract Leukocyte rolling is the earliest observable event in their recruitment from the circulation to inflamed tissue. This rolling is mediated largely by interaction between the selectin family of adhesion molecules and their glycosylated ligands. Although the nature of these ligands and their interaction with the selectins is not fully understood, it is accepted that expression of fucosylated sialylated glycans such as sialyl Lewisx (sLex) is required for function. Despite findings that sLex inhibits binding of leukocytes to E-selectin in vitro, and has beneficial effects in inflammatory disease models, inhibition of E-selectin–dependent leukocyte rolling in vivo has not been described. Functional overlap between the selectins has been noted and reduction of rolling by E-selectin antibodies only occurs if P-selectin is absent or blocked. We demonstrate that leukocyte rolling velocity in tumor necrosis factor alpha (TNFα)-stimulated mouse cremaster is increased following treatment with either sLex or the sLex-mimetic CGP69669A and that rolling is dramatically reduced if CGP69669A is applied in the presence of anti–P-selectin antibody. These effects are characteristic of E-selectin antagonism. In contrast, surgically stimulated (L- or P-selectin–dependent) rolling is unaffected by either sLex or CGP69669A. Our data demonstrate that CGP69669A is an effective and selective antagonist of E-selectin in vivo.

P-selectin glycoprotein ligand-1 supports rolling on E- and P-selectin in vivo

Blood ◽  
2000 ◽  
Vol 96 (10) ◽  
pp. 3585-3591 ◽  
Author(s):  
Keith E. Norman ◽  
Andreas G. Katopodis ◽  
Gebhard Thoma ◽  
Frank Kolbinger ◽  
Anne E. Hicks ◽  
...  
Keyword(s):  
Tumor Necrosis ◽  
Necrosis Factor Alpha ◽  
Rolling Velocity ◽  
Selectin Ligand ◽  
Factor Alpha ◽  
Observable Event ◽  
Slow Rolling ◽  
Necrosis Factor

Abstract Selectin-dependent rolling is the earliest observable event in the recruitment of leukocytes to inflamed tissues. Several glycoproteins decorated with sialic acid, fucose, and/or sulfate have been shown to bind the selectins. The best-characterized selectin ligand is P-selectin glycoprotein-1 (PSGL-1) that supports P-selectin– dependent rolling in vitro and in vivo. In vitro studies have suggested that PSGL-1 may also be a ligand for E- and L-selectins. To study the in vivo function of PSGL-1, without the influence of other leukocyte proteins, the authors observed the interaction of PSGL-1–coated microspheres in mouse venules stimulated to express P- and/or E-selectin. Microspheres coated with functional recombinant PSGL-1 rolled in surgically stimulated and tumor necrosis factor alpha (TNFα)-stimulated mouse venules. P-selectin deficiency or inhibition abolished microsphere rolling in surgically and TNFα-stimulated venules, whereas E-selectin deficiency or inhibition increased microsphere rolling velocity in TNFα-stimulated venules. The results suggest that P-selectin–PSGL-1 interaction alone is sufficient to mediate rolling in vivo and that E-selectin–PSGL-1 interaction supports slow rolling.

scholarly journals Erythromycin Inhibits Tumor Necrosis Factor Alpha and Interleukin 6 Production Induced by Heat-Killed Streptococcus pneumoniae in Whole Blood

1998 ◽  
Vol 42 (7) ◽  
pp. 1605-1609 ◽  
Author(s):  
Marc J. Schultz ◽  
Peter Speelman ◽  
Sebastian Zaat ◽  
Sander J. H. van Deventer ◽  
Tom van der Poll
Keyword(s):  
Streptococcus Pneumoniae ◽  
Tumor Necrosis Factor ◽  
Whole Blood ◽  
Tumor Necrosis ◽  
Cytokine Production ◽  
Ex Vivo ◽  
Necrosis Factor Alpha ◽  
Factor Alpha ◽  
Necrosis Factor

ABSTRACT To determine the effects of penicillin and erythromycin on cytokine production induced by heat-killed Streptococcus pneumoniae (HKSP), we studied the effects of those drugs on cytokine production induced by S. pneumoniaein human whole blood in vitro and ex vivo. In whole blood in vitro, erythromycin, but not penicillin, caused a dose-dependent decrease in HKSP-induced production of tumor necrosis factor alpha (TNF) and interleukin 6 (IL-6), while the production of IL-10, IL-12, and gamma interferon was inhibited only at the highest erythromycin concentration tested (10−3 M). The production of TNF and IL-6 in whole blood obtained from healthy subjects after a 30-min infusion of erythromycin (1,000 mg) was lower after ex vivo stimulation with HKSP than that in blood drawn before the infusion. Inhibition of TNF contributed to erythromycin-induced inhibition of IL-6 synthesis. Inhibition of TNF and IL-6 production by erythromycin may have a negative impact on host defense mechanisms during pneumococcal pneumonia.

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 Absence of cytotoxicity towards microglia of iron oxide (α-Fe2O3) nanorhombohedra

2016 ◽  
Vol 5 (3) ◽  
pp. 836-847 ◽  
Author(s):  
Crystal S. Lewis ◽  
Luisa Torres ◽  
Jeremy T. Miyauchi ◽  
Cyrus Rastegar ◽  
Jonathan M. Patete ◽  
...  
Keyword(s):  
Interleukin 1 ◽  
Necrosis Factor Alpha ◽  
Cytotoxic Effects ◽  
Nanoparticle Exposure ◽  
Cellular Iron ◽  
Therapeutic Setting ◽  
The Central Nervous System ◽  
Factor Alpha

Abstract Understanding the nature of interactions between nanomaterials, such as commercially ubiquitous hematite (α-Fe2O3) nanorhombohedra (N-Rhomb) and biological systems is of critical importance for gaining insight into the practical applicability of nanomaterials. Microglia represent the first line of defense in the central nervous system (CNS) during severe injury or disease such as Parkinson's and Alzheimer's disease as illustrative examples. Hence, to analyze the potential cytotoxic effect of N-Rhomb exposure in the presence of microglia, we have synthesized Rhodamine B (RhB)-labeled α-Fe2O3 N-Rhomb, with lengths of 47 ± 10 nm and widths of 35 ± 8 nm. Internalization of RhB-labeled α-Fe2O3 N-Rhomb by microglia in the mouse brain was observed, and a dose-dependent increase in the cellular iron content as probed by cellular fluorescence was detected in cultured microglia after nanoparticle exposure. The cells maintained clear functional viability, exhibiting little to no cytotoxic effects after 24 and 48 hours at acceptable, physiological concentrations. Importantly, the nanoparticle exposure did not induce microglial cells to produce either tumor necrosis factor alpha (TNFα) or interleukin 1-beta (IL1β), two pro-inflammatory cytokines, nor did exposure stimulate the production of nitrites and reactive oxygen species (ROS), which are common indicators for the onset of inflammation. Finally, we propose that under the conditions of our experiments, i.e. in the presence of RhB labeled-α-Fe2O3 N-Rhomb maintaining concentrations of up to 100 μg mL−1 after 48 hours of incubation, the in vitro and in vivo internalization of RhB-labeled α-Fe2O3 N-Rhomb are likely to be clathrin-dependent, which represents a conventional mechanistic uptake route for most cells. Given the crucial role that microglia play in many neurological disorders, understanding the potential cytotoxic effects of these nanostructures is of fundamental importance if they are to be used in a therapeutic setting.

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