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Nature Reviews. Immunology Oct 2011The mononuclear phagocyte system (MPS) comprises monocytes, macrophages and dendritic cells. Tissue phagocytes share several cell surface markers, phagocytic capability... (Review)
Review
The mononuclear phagocyte system (MPS) comprises monocytes, macrophages and dendritic cells. Tissue phagocytes share several cell surface markers, phagocytic capability and myeloid classification; however, the factors that regulate the differentiation, homeostasis and function of macrophages and dendritic cells remain largely unknown. The purpose of this manuscript is to review the tools that are currently available and those that are under development to study the origin and function of mononuclear phagocytes.
Topics: Animals; Cell Differentiation; Dendritic Cells; Gene Expression Profiling; Humans; Macrophages; Monocytes; Proteomics; RNA Interference; Sequence Analysis, DNA
PubMed: 22025056
DOI: 10.1038/nri3087 -
European Journal of Clinical... Oct 1991Azithromycin achieves high concentrations in phagocytic cells and in fibroblasts. The newer macrolides also have this property but the intracellular penetration of... (Review)
Review
Azithromycin achieves high concentrations in phagocytic cells and in fibroblasts. The newer macrolides also have this property but the intracellular penetration of azithromycin in relation to extracellular concentration is particularly notable. As a weak base, azithromycin is thought to concentrate in lysosomes of phagocytes and fibroblasts but many in vitro factors such as pH and temperature also affect the uptake process. Uptake of azithromycin by polymorphonuclear leucocytes results in an intracellular/extracellular concentration ratio of approximately 40 after one hour of incubation. Intraphagocytic antimicrobial activity has been demonstrated but is rather less than might be anticipated from the intracellular concentrations that are reached. Importantly, the high antibiotic levels found intracellularly do not appear to disrupt normal phagocyte function. Although azithromycin levels in the blood are low soon after administration, tissue concentrations are high and sustained. It appears that fibroblasts serve as a reservoir of drug in tissue, allowing activity against organisms and possibly transferring antibiotic to phagocytic cells for activity against intracellular pathogens and delivery to infection sites.
Topics: Azithromycin; Erythromycin; Fibroblasts; Humans; Hydrogen-Ion Concentration; Legionella; Lysosomes; Phagocytes; Phagocytosis; Staphylococcus aureus; Temperature; Tissue Distribution
PubMed: 1662626
DOI: 10.1007/BF01975835 -
Journal of Immunological Methods Dec 1999Phagocyte functions such as chemotaxis and phagocytosis involve the rapid and transient development of cellular polarity. Study of this highly complex spatial and... (Review)
Review
Phagocyte functions such as chemotaxis and phagocytosis involve the rapid and transient development of cellular polarity. Study of this highly complex spatial and temporal cellular remodelling has been limited by the static nature of immunofluorescence and immunogold microscopy and because biochemical techniques are not vectorial. The recent introduction of fluorescent proteins (FPs) provides new approaches and opportunities to study phagocyte functions non-invasively, with excellent temporal and spatial resolution. This review summarizes the main properties and possible uses of green fluorescent protein (GFP) and its variants in phagocyte biology.
Topics: Animals; Green Fluorescent Proteins; Humans; Indicators and Reagents; Luminescent Proteins; Molecular Biology; Phagocytes; Phagocytosis; Spectrometry, Fluorescence
PubMed: 10618510
DOI: 10.1016/s0022-1759(99)00155-6 -
Pediatric Annals May 1987
Review
Topics: Chemotaxis, Leukocyte; Child; Hematopoiesis; Humans; Immune System Diseases; Macrophages; Monocytes; Neutrophils; Phagocytes; Phagocytosis
PubMed: 3302888
DOI: 10.3928/0090-4481-19870501-05 -
Future Microbiology Feb 2007Group A Streptococcus (GAS) is a Gram-positive bacterium associated with a variety of mucosal and invasive human infections. GAS systemic disease reflects the diverse... (Review)
Review
Group A Streptococcus (GAS) is a Gram-positive bacterium associated with a variety of mucosal and invasive human infections. GAS systemic disease reflects the diverse abilities of this pathogen to avoid eradication by phagocytic defenses of the innate immune system. Here we review how GAS can avoid phagocyte engagement, inhibit complement and antibody functions required for opsonization, impair phagocytotic uptake mechanisms, promote phagocyte lysis or apoptosis, and resist specific effectors of phagocyte killing such as antimicrobial peptides and reactive oxygen species. Understanding the molecular basis of GAS phagocyte resistance may reveal novel therapeutic targets for treatment and prevention of invasive human infections.
Topics: Gene Expression Regulation, Bacterial; Humans; Models, Biological; Phagocytes; Phagocytosis; Streptococcal Infections; Streptococcus pyogenes; Virulence
PubMed: 17661677
DOI: 10.2217/17460913.2.1.75 -
Journal of Gynecology Obstetrics and... Apr 2021Endometriosis is a chronic systemic disease, which influence negatively the quality of life of affected women and responsible for infertility and chronic pelvic pain....
INTRODUCTION
Endometriosis is a chronic systemic disease, which influence negatively the quality of life of affected women and responsible for infertility and chronic pelvic pain. Pathophysiology of the disease is still enigmatic, but insufficient immune surveillance may play a role in it. Peripheral natural immune cell function is rarely examined. The aim of the study was to examine phagocyte function of peripheral neutrophil granulocytes and monocytes, whether this phagocytic activity is affected by the presence or removal of endometriotic lesions in women with endometriosis.
MATERIAL AND METHODS
Twenty-six preoperative, 13 postoperative samples from women with endometriosis, 23 samples from healthy women, 14 pre- and postoperative samples from the surgical control group were enrolled. Cells were isolated from peripheral blood samples, marked and evaluated for the phagocytosis index with immunofluorescent microscope after phagocyting the zymosane molecules.
RESULTS
Phagocyte function of monocytes and neutrophil granulocytes decreased significantly women with endometriosis before surgery compared to healthy controls. However, 7 days after surgery the postoperative values showed significant improvement compared to the preoperative results of women with endometriosis. This increment reached the values of the healthy women. In the surgical control group no difference was detected between the pre- and postoperative outcomes.
DISCUSSION
Decreased phagocyte function of the examined cells, which can be the result of the circulating immunosuppressive factors, may play a role in the deficient clearance of ectopic endometrial tissue. Based on the postoperative results, these immunosuppressive factors may be reduced or eliminated 7 days after surgery in women with endometriosis.
Topics: Case-Control Studies; Endometriosis; Female; Granulocytes; Humans; Immunity, Cellular; Monocytes; Neutrophils; Phagocytosis; Postoperative Period
PubMed: 32413524
DOI: 10.1016/j.jogoh.2020.101796 -
Immunological Reviews Oct 2023Phagocytosis is a fundamental immunobiological process responsible for the removal of harmful particulates. While the number of phagocytic events achieved by a single... (Review)
Review
Phagocytosis is a fundamental immunobiological process responsible for the removal of harmful particulates. While the number of phagocytic events achieved by a single phagocyte can be remarkable, exceeding hundreds per day, the same phagocytic cells are relatively long-lived. It should therefore be obvious that phagocytic meals must be resolved in order to maintain the responsiveness of the phagocyte and to avoid storage defects. In this article, we discuss the mechanisms involved in the resolution process, including solute transport pathways and membrane traffic. We describe how products liberated in phagolysosomes support phagocyte metabolism and the immune response. We also speculate on mechanisms involved in the redistribution of phagosomal metabolites back to circulation. Finally, we highlight the pathologies owed to impaired phagosome resolution, which range from storage disorders to neurodegenerative diseases.
Topics: Humans; Phagosomes; Phagocytosis; Phagocytes
PubMed: 37551912
DOI: 10.1111/imr.13260 -
Journal of the American Society of... Apr 1992The mesangium constitutes the core of the renal glomerulus. It consists of the matrix, composed of mucopolysaccharides and glycoproteins, and two cell types. The... (Review)
Review
The mesangium constitutes the core of the renal glomerulus. It consists of the matrix, composed of mucopolysaccharides and glycoproteins, and two cell types. The predominant cell type is the mesangial cell, resembling a vascular smooth muscle cell. Up to 15% of the mesangial cell population additionally consists of resident mesangial phagocytes. These are derived from the bone marrow and belong to the family of mononuclear leukocytes. They are phagocytic, express Fc and C3 receptors, and display membrane Ia antigens. They syngeneically stimulate lymphocyte proliferation via antigen presentation. They are equally potent allogeneic stimulating cells in mixed lymphocyte culture. The mesangium is also the preferred locus of the induced migration of monocytes in inflammatory and proteinuric states. The presence of both normally resident and inflammation-associated mesangial phagocyte is lipid dependent. Hyperlipidemia increases the population of mesangial phagocytes. Lipid restriction decreases their number and, as a result, diminishes the allogenicity of renal transplants and blunts the progression of glomerulonephritis. One signal regulating the infiltration of the mesangium by mononuclear phagocytes appears to be a complex neutral lipid that is highly and specifically chemotactic for monocytes. It is released by the contractile mesangial cell in response to the stimulation of its Fc receptor and to the mesangial deposition of macromolecules. Both resident and inflammatory mesangial phagocytes secrete factors that remodel the mesangial matrix, stimulate mesangial cell proliferation, alter glomerular basement membrane permeability, and regulate blood flow. The persistence of mononuclear phagocytes in an activated state within the mesangium contributes to the marked alteration in mesangial structure that eventuates in glomerulosclerosis in both immune and nonimmune models of glomerular injury.
Topics: Animals; Cell Movement; Glomerular Mesangium; Humans; Macrophage Activation; Monocytes; Phagocytes
PubMed: 1600140
DOI: 10.1681/ASN.V210s74 -
European Journal of Immunology Mar 2011Phagocytes, including neutrophils, monocytes, and macrophages, play a crucial role in host defense by recognition and elimination of invading pathogens. Phagocytic cells... (Review)
Review
Phagocytes, including neutrophils, monocytes, and macrophages, play a crucial role in host defense by recognition and elimination of invading pathogens. Phagocytic cells produce reactive oxygen species (ROS), inflammatory cytokines, and chemokines, leading to bacterial killing and to recruitment and activation of additional immune cells. However, inflammatory mediators are potentially harmful for the host and their production is therefore tightly controlled by multiple regulatory mechanisms. One such mechanism is immune suppression by immune inhibitory receptors, which are increasingly acknowledged as potent regulators of the immune response. So far, research has focused on the role of these receptors in the regulation of NK cells, B cells, and T cells. Importantly, an accumulating number of inhibitory receptors have been identified on phagocytes. Here, we review the role of inhibitory receptors in the regulation of phagocyte cytokine production, migration, apoptosis, ROS production, and phagocytosis. Furthermore, we discuss the intracellular mechanisms utilized by distinct inhibitory receptors to regulate specific phagocyte functions. We demonstrate that inhibitory receptors are important regulators of the immune response, which bacteria can use to their advantage.
Topics: Animals; Apoptosis; Bacteria; Cell Movement; Cytokines; Humans; Immunity, Innate; Ligands; Mice; Models, Immunological; Phagocytes; Phagocytosis; Reactive Oxygen Species; Receptors, Immunologic; Signal Transduction
PubMed: 21312193
DOI: 10.1002/eji.201041179 -
Archives of Biochemistry and Biophysics Apr 2009Macrophages and neutrophils are essential elements of host cellular defense systems that function, at least in part, by generating respiration-driven oxidative toxins in... (Review)
Review
Macrophages and neutrophils are essential elements of host cellular defense systems that function, at least in part, by generating respiration-driven oxidative toxins in response to external stimuli. In both cells, encapsulation by phagocytosis provides a mechanism to direct the toxins against the microbes. The toxic chemicals formed by these two phagocytic cells differ markedly, as do the enzymatic catalysts that generate them. Nitrite ion is microbicidal under certain conditions, is generated by activated macrophages, and is present at elevated concentration levels at infection sites. In this review, we consider potential roles that nitrite might play in cellular disinfection by these phagocytes within the context of available experimental information. Although the suggested roles are plausible, based upon the chemical and biochemical reactivity of NO2(-), studies to date provide little support for their implementation within phagosomes.
Topics: Animals; Bacteria; Cyclooxygenase 1; Cyclooxygenase 2; Endothelium, Vascular; Humans; Leukocytes, Mononuclear; Macrophage Activation; Macrophages; Nitrites; Oxidative Stress; Phagocytes; Phagocytosis; Phagosomes
PubMed: 19402211
DOI: 10.1016/j.abb.2009.01.010