Search results for " Immune system"
showing 10 items of 893 documents
Monocyte-derived dendritic cells of patients with coronary artery disease show an increased expression of costimulatory molecules CD40, CD80 and CD86…
2007
Background Atherosclerosis is a disease triggered by diverse exogenous stimuli and sustained by chronic inflammatory processes. Dendritic cells (DCs) are key regulatory antigen-presenting cells and play a crucial role in regulating the adaptive and innate immune system in any chronic inflammatory process. DCs are present in atherosclerotic lesions in the areas of the highest T-cell density. So far, their role in atherosclerosis has not been fully elucidated. We investigated the phenotypic properties of DCs in patients with coronary artery disease (CAD) in comparison to healthy individuals. Methods Peripheral blood monocytes were isolated from 50 patients with CAD and 19 healthy individuals …
The Human T Cell Response to Mitogenic Microbial Exotoxins
1991
Nearly every infectious pathogen has to cope with the host’s adaptive immune response. Common evasion mechanisms in this complex interaction are antigenic variations, the escape to immunologically privileged sites, or the use of immunosuppressive mechanisms. Many bacteria and other microorganisms elaborate soluble factors or toxins that act suppressively on cells of the immune system, such as pore-forming molecules or proteins that interfere with the function of G proteins. Gram-positive cocci and a mycoplasma have developed an extremely potent mechanism of T cell stimulation by closely mimicking recognition of specific antigen. From the functional similarity to antigen recognition and the …
Intrinsic TNFR2 signaling in T regulatory cells provides protection in CNS autoimmunity
2018
Significance In spite of TNF involvement in the pathogenesis of multiple sclerosis (MS), systemic TNF neutralization in MS patients was not successful. One of the possible reasons is that TNF possesses both pathogenic and protective features that may be related to TNFR1 versus TNFR2 receptor engagement. This study uncovers one of such protective functions of TNF mediated by intrinsic TNFR2 signaling in Treg cells. In mice bearing humanized TNF and TNFR2 genetic loci, TNFR2 ablation restricted to Treg cells led to reduced capacity to control Th17 cell responses, exacerbated experimental autoimmune encephalomyelitis (EAE) development, and affected the maintenance of Treg cells. These findings…
Host microbiota constantly control maturation and function of microglia in the CNS.
2015
As the tissue macrophages of the CNS, microglia are critically involved in diseases of the CNS. However, it remains unknown what controls their maturation and activation under homeostatic conditions. We observed substantial contributions of the host microbiota to microglia homeostasis, as germ-free (GF) mice displayed global defects in microglia with altered cell proportions and an immature phenotype, leading to impaired innate immune responses. Temporal eradication of host microbiota severely changed microglia properties. Limited microbiota complexity also resulted in defective microglia. In contrast, recolonization with a complex microbiota partially restored microglia features. We determ…
Skull and vertebral bone marrow are myeloid cell reservoirs for the meninges and CNS parenchyma.
2021
Getting around the blood–brain barrier The meninges comprise three membranes that surround and protect the central nervous system (CNS). Recent studies have noted the existence of myeloid cells resident there, but little is known about their ontogeny and function, and whether other meningeal immune cell populations have important roles remains unclear (see the Perspective by Nguyen and Kubes). Cugurra et al. found in mice that a large proportion of continuously replenished myeloid cells in the dura mater are not blood derived, but rather transit from cranial bone marrow through specialized channels. In models of CNS injury and neuroinflammation, the authors demonstrated that these myeloid c…
Monocytes/Macrophages Are the Major Targets of the CCL3 Chemokine Produced by CD38(+)CD49d(+) Chronic Lymphocytic Leukemia Cells
2009
Abstract Abstract 2350 Poster Board II-327 Introduction: CD38 and CD49d are associated negative prognosticators in chronic lymphocytic leukemia (CLL). Recent gene expression profiling studies comparing CLL cases expressing low versus high levels of CD38 and CD49d, identified CCL3 as a gene upregulated by CD38+CD49d+ CLL. The release of CCL3 by cultured CLL cells was also demonstrated upon CD38 triggering, and CCL3 protein was found in CLL cells from bone marrow biopsies (BMB) of CD38+ cases (Zucchetto et al., Cancer Res, 2009; 69:4001-9). Given the role of CCL3 as potent chemoattractant for different cell types, we aimed at identifying the major targets of CCL3, as produced by CD38+CD49d+ C…
Advances in the understanding of mast cell function
2008
Mast cells were formerly thought to contribute mainly to, sometimes even, fatal allergic reactions through the release of biologically highly active cytokines, chemokines, lipid mediators, proteases and biogenic amines. This potential harmful response is triggered by crosslinking of cell-bound IgE by the respective allergen. This review updates our current understanding of the emerging roles of mast cells with an emphasis on their relevance in protective host immunity. The activation of mast cells independently of Immunoglobulin E can lead to the initiation of fast inflammatory reactions, which were shown to be life-saving in murine models of bacterial infections. Besides their critical fun…
Atherosclerosis as an inflammatory disease.
2011
In many ways, atherosclerosis is a chronic inflammatory disorder and this issue is confirmed by recent investigations of that have focused on inflammation, providing new insight into mechanisms of disease. Several recent studies have addressed the role of chemokines in leukocyte accumulation in atherosclerosis, extending our knowledge and understanding of the complex and cell type-specific functions of chemokines in atherosclerosis. Activated T-lymphocytes within the atherosclerotic vessel wall express the CD40 ligand surface molecule, known to play a major role in several immunological pathways. In addition to activated T-lymphocytes, functional CD40 and CD40L are coexpressed by human vasc…
Compartmentalized Production of CCL17 In Vivo
2003
Dendritic cells (DCs)**Abbreviations used in this paper: BM, bone marrow; CHS, contact hypersensitivity; cLN, cutaneous lymph node; CRP, C-reactive protein; DC, dendritic cell; DNFB, dinitrofluorobenzene; EGFP, enhanced green fluorescent protein; LC, Langerhans cell; LP, lamina propria; MACS, magnetic-activated cell sorting; mLN, mesenteric lymph node; ODN, oligodeoxynucleotide; PFA, paraformaldehyde; PP, Peyer's patch; TLR, Toll-like receptor; TRITC, tetramethylrhodamine-5-(and-6-)-isothiocyanate. fulfill an important regulatory function at the interface of the innate and adaptive immune system. The thymus and activation-regulated chemokine (TARC/CCL17) is produced by DCs and facilitates t…
Toll-like receptor 2 is dispensable for acquired host immune resistance to Candida albicans in a murine model of disseminated candidiasis
2004
Previous work by our group showed that Toll-like receptor 2 (TLR2) is essential for activation of innate immunity, playing a major role in the response of macrophages to Candida albicans, triggering cytokine and chemokine expression, and therefore TLR2 -/- mice are more susceptible to systemic primary candidiasis. In this work, we used a murine model of systemic C. albicans infection, in which resistance to reinfection with virulent wild-type cells is induced by prior exposure of mice to a low-virulence agerminative strain of C. albicans (primary sublethal infection), to study the influence of TLR2 gene deletion on (i) the ability to develop an acquired resistance upon vaccination; (ii) the…