Search results for "Macrophages"
showing 10 items of 533 documents
MyD88 is dispensable for resistance toParacoccidioides brasiliensisin a murine model of blood-borne disseminated infection
2008
We have studied the role of MyD88, an adaptor protein of Toll-like receptors (TLRs), in murine defenses against Paracoccidioides brasiliensis in a model of blood-borne disseminated infection. Wild-type (WT) and MyD88-deficient mice infected intravenously with P. brasiliensis yeast cells showed an equivalent fungal burden, as well as similar levels of proinflammatory IL-1beta, IL-6, IL-12p70, tumor necrosis factor (TNF)-alpha and MIP-2, T-helper type 1 (Th1) (IFN-gamma) and Th2 cytokines (IL-4) in tissue homogenates. In vitro production of TNF-alpha, IFN-gamma and IL-12p70, by antigen-stimulated splenocytes from infected animals, was also similar in both types of mice; this production of Th1…
Blockade of MIF-CD74 Signalling on Macrophages and Dendritic Cells Restores the Antitumour Immune Response Against Metastatic Melanoma.
2018
Mounting an effective immune response against cancer requires the activation of innate and adaptive immune cells. Metastatic melanoma is the most aggressive form of skin cancer. While immunotherapies have shown a remarkable success in melanoma treatment, patients develop resistance by mechanisms that include the establishment of an immune suppressive tumor microenvironment. Thus, understanding how metastatic melanoma cells suppress the immune system is vital to develop effective immunotherapies against this disease. In this study, we find that macrophages (MOs) and dendritic cells (DCs) are suppressed in metastatic melanoma and that the Ig-CDR-based peptide C36L1 is able to restore MOs and …
Early Cellular Reactions in Mechanically Stimulated Gingival Connective Tissue
2001
Aim: The aim of this study was to describe early cellular reactions occuring in mechnically stimulated gingival connective tissue. Material and Method: Elastic bands were inserted between the maxillary first and second molars of male rats aged 8 weeks, which were pulse-labeled with 3H-thymidine and subsequently killed in groups together with labeled control animals after periods of 1–168 hours. Autoradiographs were prepared from plastic mesiodistal sections and parameters of cell proliferation determined in gingival connective tissue sampling areas coronal to the interdental bone crest and in the central zone of the body of the papilla between the second and third molars. The incidence of m…
Dectin-1 Stimulation of Hematopoietic Stem and Progenitor Cells Occurs In Vivo and Promotes Differentiation Toward Trained Macrophages via an Indirec…
2020
Invasive candidiasis is an increasingly frequent cause of serious and often fatal infections. Understanding host defense is essential to design novel therapeutic strategies to boost immune protection against Candida albicans. In this article, we delve into two new concepts that have arisen over the last years: (i) the delivery of myelopoiesis-inducing signals by microbial components directly sensed by hematopoietic stem and progenitor cells (HSPCs) and (ii) the concept of “trained innate immunity” that may also apply to HSPCs. We demonstrate that dectin-1 ligation in vivo activates HSPCs and induces their differentiation to trained macrophages by a cell-autonomous indirect mechanism. This p…
Interferon-γ Induces Chronic Active Myocarditis and Cardiomyopathy in Transgenic Mice
2007
Chronic heart failure is associated with an activation of the immune system characterized among other factors by the cardiac synthesis and serum expression of proinflammatory cytokines. There is unequivocal clinical and experimental evidence that the cytokine tumor necrosis factor-alpha is involved in the development of chronic heart failure, but a putative cardiotoxic potential of the proinflammatory cytokine interferon (IFN)-gamma remains primarily unknown. To investigate this issue we analyzed the cardiac phenotype of SAP-IFN-gamma transgenic mice, which constitutively express IFN-gamma in their livers and hence exhibit high circulating serum levels of this cytokine. SAP-IFN-gamma mice s…
Effect of sulfur dioxide on cytokine production of human alveolar macrophages in vitro.
1996
Tumor necrosis factor-alpha, interleukin-1beta, interleukin-6, and transforming growth factor-beta are cytokines synthesized by alveolar macrophages. We investigated the effect of sulfur dioxide, a major air pollutant, on the production of these cytokines by alveolar macrophages. The cells were layered on a polycarbonate membrane and exposed for 30 min to 0.0, 1.0, 2.5, and 5.0 ppm sulfur dioxide at 37 degrees C and 100% air humidity. The cells were incubated for 24 h after exposure, thus allowing cytokine release. Cytotoxic effects of sulfur dioxide were evaluated by trypan blue exclusion. Cytokines were measured with enzyme-linked immunosorbent assays (i.e., tumor necrosis factor-alpha, i…
Toll-like receptor 4 defective mice carrying point or null mutations do not show increased susceptibility toCandida albicansin a model of hematogenou…
2006
We have studied the role of TLR4 in murine defenses against Candida albicans in two TLR4-defective mouse strains: C3H/HeJ mice which have defective TLR4 signaling, and TLR4-/- knockout mice. Both TLR4-defective mice strains experimentally infected with virulent C. albicans cells showed no significant difference in survival as compared with their respective controls. Recruitment of neutrophils to the peritoneal cavity of i.p. infected mice was not affected in TLR4-/-animals, but significantly enhanced in C3H/HeJ mice, compared with their control mice. In vitro production of TNF-alpha by macrophages from both types of TLR4-defective mice, in response to yeasts and hyphae of C. albicans, was n…
Modulatory effect of bolinaquinone, a marine sesquiterpenoid, on acute and chronic inflammatory processes
2002
The marine metabolite bolinaquinone is a novel inhibitor of secretory phospholipase A(2) (sPLA(2)), with a potency on the human synovial enzyme (group II) higher than that of manoalide. This activity on the sPLA(2) was confirmed in vivo in the 8-h zymosan rat air pouch on the secretory enzyme accumulation in the pouch exudate. Additionally, bolinaquinone decreased potently the synthesis and release of leukotriene B(4) (LTB(4)) in calcimycin (A23187)-stimulated human neutrophils as a consequence of the inhibition of 5-lipoxygenase activity, as well as PGE(2) and NO production on zymosan-stimulated mouse peritoneal macrophages. This compound exerted anti-inflammatory effects by topical and or…
Nitrogen Dioxide-induced Reactive Oxygen Intermediates Production by Human Alveolar Macrophages and Peripheral Blood Mononuclear Cells
1994
Alveolar macrophages located on the alveolar surface have contact with air pollutants. We evaluated the dose-dependent effect of nitrogen dioxide exposure on the oxidative metabolism of alveolar macrophages and peripheral blood mononuclear cells by measuring the spontaneous and stimulated reactive oxygen intermediates production. Alveolar macrophages or peripheral blood mononuclear cells were placed on a polycarbonate membrane, which was in direct contact with the surface of a nutrient reservoir. The cells were exposed to nitrogen dioxide during different periods of time, varying between 30 and 120 min at concentrations ranging from 0.1 to 0.5 ppm. Exposure of alveolar macrophages to nitrog…
Adaptive immunity suppresses formation and progression of diethylnitrosamine-induced liver cancer
2012
Background Hepatocellular carcinoma (HCC) is a typical inflammation-associated cancer, but may also provoke antitumour immune responses whose significance and underlying mechanisms are incompletely understood. Objective To characterise immune responses in the diethylnitrosamine (DEN)-liver cancer mouse model. Design Tumour development and immune cell functions upon DEN treatment were compared between C57BL/6 wild-type (WT), chemokine scavenging receptor D6-deficient, B cell- (Igh6), CD4 T cell- (MHC-II) and T-/B cell-deficient (Rag1) mice. Relevance for human HCC was tested by comparing gene array results from 139 HCC tissues. Results The induction of premalignant lesions after 24 weeks and…