TY - JOUR. T1 - Effects of tobacco smoking on innate immunity. T2 - A study based on neutrophil phagocytic index. AU - Thakur, Tanu. AU - Bhide, Arpana. AU - Chaudhury, Abhijit. AU - Thota, Asha. AU - Kasala, Latheef. AU - Hulikal, Narendra. PY - 2018/4/1. Y1 - 2018/4/1. N2 - The present study was undertaken to find out the effects of tobacco smoking on innate immune mechanism of the body. A total of 60 adult consenting men in the age group of 30 to 50 years were recruited of which 30 were chronic smokers and the rest were non smoking controls. 5ml of venous blood was drawn from each of the subjects and the following parameters were assessed: phagocytic index of neutrophils (which is an index of neutrophil function and is defined as number of neutrophils positive for ingested microbes per 100 neutrophils), total leucocyte count (TLC), differential count of neutrophils. The values from smokers were compared with those from non-smokers. There was a statistically significant decrease in the ...
TY - JOUR. T1 - Phagocytic signaling strategies. T2 - Fcγ receptor-mediated phagocytosis as a model system. AU - Cox, Dianne. AU - Greenberg, Steven. PY - 2001. Y1 - 2001. N2 - Phagocytosis is a phylogenetically ancient process by which eukaryotic cells engulf insoluble substances whose size exceeds approximately 0.5 μ m. The engulfment process requires the concerted action of several fundamental cellular pathways and is governed by multiple transmembrane signaling events. Here we focus on phagocytosis mediated by a well-studied class of phagocytic receptors that recognize the Fc portion of IgG (Fcγ Rs).. AB - Phagocytosis is a phylogenetically ancient process by which eukaryotic cells engulf insoluble substances whose size exceeds approximately 0.5 μ m. The engulfment process requires the concerted action of several fundamental cellular pathways and is governed by multiple transmembrane signaling events. Here we focus on phagocytosis mediated by a well-studied class of phagocytic receptors ...
article{f7336ebb-e740-4acd-bf1a-ccf3f3a2c8e1, author = {Weineisen, Maria and Sjöbring, Ulf and Fällman, Maria and Andersson, Tommy}, issn = {1550-6606}, language = {eng}, number = {6}, pages = {3798--3807}, publisher = {American Association of Immunologists}, series = {Journal of Immunology}, title = {Streptococcal M5 protein prevents neutrophil phagocytosis by interfering with CD11b/CD18 receptor-mediated association and signaling.}, volume = {172}, year = {2004 ...
In this paper we re-examine the roles of particle-bound IgG and C3 in phagocytosis of sheep erythrocytes (E) by monolayers of purified human monocytes and polymorphonuclear leukocytes (PMN). We conclude that two fragments of the C3 molecule, that is, C3b and C3d, can function as opsonins if the phagocyte has the appropriate membrane receptors. Monocytes, that bind both C3b and C3d, respond to both as opsonins. PMN, which do not bind C3d, respond only to particles opsonized with C3b. C3 and IgG have separate roles in phagocytosis. IgG, through its Fc fragment, directly stimulates particle ingestion, but is relatively inefficient at inducing particle binding. On the other hand, C3 primarily mediates the binding of the particle via complement receptors. A marked synergy exists between C3 and IgG in inducing phagocytosis. Thus, opsonization of the particle with C3 can be a necessary condition for particle ingestion, although by itself C3 does not trigger phagocytosis. The opsonic effect of C3 can be ...
Scavenger receptors are important components of the innate immune system in the lung, allowing alveolar macrophages to bind and phagocytose numerous unopsonized targets. Mice with genetic deletions of scavenger receptors, such as SR-A and MARCO, are susceptible to infection or inflammation from inhaled pathogens or dusts. However, the signaling pathways required for scavenger receptor-mediated phagocytosis of unopsonized particles have not been characterized. We developed a scanning cytometry-based high-throughput assay of macrophage phagocytosis that quantitates bound and internalized unopsonized latex beads. This assay allowed the testing of a panel of signaling inhibitors which have previously been shown to target opsonin-dependent phagocytosis for their effect on unopsonized bead uptake by human in vitro-derived alveolar macrophage-like cells. The non-selective scavenger receptor inhibitor poly(I) and the actin destabilizer cytochalasin D were used to validate the assay and caused near complete
inproceedings{226715, author = {BRUYNINCKX, W and BLANQUAERT, AM and Ysebaert, Maria and Vanneste, Walter}, language = {eng}, title = {Phagocytosis-induced functional heterogeneity of resident peritoneal macrophages. Proc. Conference of the Federation of the American Societies for Experimental Biology, Atlanta, april 1992 ...
The viscous component of the surface tension also behaves significantly differently in aspiration and phagocytosis as attested by the results shown in Fig. 4. We consider the viscous slack first; it is increased from 5% in passive aspiration to 27% in phagocytosis. From a physical standpoint, this slack corresponds to the amount of plasma membrane freely available for expansion of cell surface area without dissipative breaking of wrinkle-stabilizing bonds (Fig. 8). Two potential explanations for this difference come to the fore. Delivery of vesicular membrane to the cell surface by exocytosis may delay the need to unfurl wrinkles to create new surface area. Alternatively, the wrinkles themselves may be loosened by the cell as part of the activation of the phagocytosis pathway through enzymatic activity severing the wrinkle-stabilizing bonds described by Fig. 8. The behavior of the tension during phagocytosis of a sub-threshold bead by a pre-streched neutrophil answers this question (Fig. 7) ...
The clearance of apoptotic cells occurs throughout the lifespan of multicellular organisms and is important for development during embryogenesis, the maintenance of tissue integrity and function, and the resolution of inflammation (deCathelineau and Henson, 2003). Here, we report that macrophage ABCA7 enhances the clearance of apoptotic cells in vitro and in vivo. ABCA7 and LRP1 move to the cell surface after stimulation with C1q or apoptotic cells and localize to membrane ruffles or phagocytic cups, respectively. However, ABCA7 also localizes to phagocytic membranes during FcR-mediated phagocytosis, in which ABCA7 levels are not rate limiting. More important, ABCA7 is required for optimal ligand-induced signaling through LRP1, as shown by C1q-induced ERK phosphorylation and for sustained ERK phosphorylation during phagocytosis of apoptotic cells. Finally, ERK phosphorylation itself is shown to be essential for phagocytosis of apoptotic cells but not for FcR-mediated phagocytosis, suggesting a ...
Alveolar tissue macrophage phagocytosis of E. coli, scanning electron micrograph (SEM). Note the macrophage has short filopodia that extend from the cell and aid in finding bacteria for phagocytosis. A tissue macrophage is a large, mature phagocyte that can ingest and destroy invading microbes, foreign particles, cancerous or diseased cells and cellular debris. Alveolar (lung pleural cavity) macrophages are part of the reticuloendothelial system. Magnification: x800 when shortest axis printed at 25 millimetres. - Stock Image C036/9773
TY - JOUR. T1 - Exosome-SIRPα, a CD47 blockade increases cancer cell phagocytosis. AU - Koh, Eunee. AU - Lee, Eun Jung. AU - Nam, Gi Hoon. AU - Hong, Yeonsun. AU - Cho, Eunji. AU - Yang, Yoosoo. AU - Kim, In-San. PY - 2017/3/1. Y1 - 2017/3/1. N2 - CD47, a "dont eat me" signal, is over-expressed on the surface of most tumors that interacts with signal regulatory protein α (SIRPα) on phagocytic cells. By engaging SIRPα, CD47 limits the ability of macrophages to engulf tumor cells, which acts as a major phagocytic barrier. In this study, we developed an exosome-based immune checkpoint blockade that antagonizes the interaction between CD47 and SIRPα. These exosomes harboring SIRPα variants (SIRPα-exosomes) were sufficient to induce remarkably augmented tumor phagocytosis, lead to prime effective anti-tumor T cell response. Given that clustering of native CD47 provides a high binding avidity to ligate dimerized SIRPα on macrophage, nature-derived exosomes could be appreciable platform to ...
In myocardial infarction (MI), a plenty of cardiomyocytes undergo necrosis and necroptosis due to the lack of oxygen and nutrients. The dead cardiomyocytes are promptly engulfed by phagocytes. When the dead cells are not engulfed, the noxious contents of the cells are released outside, and thus, induce inflammation, and obstruct the function of organs. Therefore, phagocytosis is crucial for maintaining homeostasis of organs. Herein, we describe a protocol of an in vitro phagocytosis assay of necroptotic cells.
We have investigated the effect of plasma fibronectin (Fn) on binding and phagocytosis of sheep erythrocytes (E) by human peripheral blood monocytes. Unopsonized E were not phagocytosed in the absence or presence of Fn, but Fn enhanced the phagocytosis of E bearing IgG. Sheep erythrocytes sensitized with IgM and C3b were ingested only when monocytes were exposed to Fn. The Fn enhancement of phagocytosis occurred for both fluid-phase and glass-adherent monocytes. Experiments in which Fn was washed out before mixing monocytes with opsonized E demonstrated that the Fn effect occurred because of interaction with the monocytes and not the opsonized particles. Chromatography of the Fn on Biogel A 1.5m showed that the phagocytosis-enhancing activity exactly co-chromatographed with the Fn protein. Fn did not increase the number of monocyte membrane receptors for the Fc fragment of monomeric IgG. We conclude that Fn enhances monocyte phagocytosis, not by binding to particles as a conventional opsonin, ...
TY - JOUR. T1 - Tubby and tubby-like protein 1 are new MerTK ligands for phagocytosis. AU - Caberoy, Nora B.. AU - Zhou, Yixiong. AU - Li, Wei. PY - 2010/12/1. Y1 - 2010/12/1. N2 - Tubby and tubby-like protein 1 (Tulp1) are newly identified phagocytosis ligands to facilitate retinal pigment epithelium (RPE) and macrophage phagocytosis. Both proteins without classical signal peptide have been demonstrated with unconventional secretion. Here, we characterized them as novel MerTK ligands to facilitate phagocytosis. Tulp1 interacts with Tyro3, Axl and MerTK of the TAM receptor tyrosine kinase subfamily, whereas tubby binds only to MerTK. Excessive soluble MerTK extracellular domain blocked tubby- or Tulp1-mediated phagocytosis. Both ligands induced MerTK activation with receptor phosphorylation and signalling cascade, including non-muscle myosin II redistribution and co-localization with phagosomes. Tubby and Tulp1 are bridging molecules with their N-terminal region as MerTK-binding domain and ...
Phagosome formation and subsequent maturation are complex sequences of events that involve actin cytoskeleton remodeling and membrane trafficking. Here, we demonstrate that the Ras‐related protein Rab35 is involved in the early stage of FcγR‐mediated phagocytosis in macrophages. Live‐cell image analysis revealed that Rab35 was markedly concentrated at the membrane where IgG‐opsonized erythrocytes (IgG‐Es) are bound. Rab35 silencing by RNA interference (RNAi) or the expression of GDP‐ or GTP‐locked Rab35 mutant drastically reduced the rate of phagocytosis of IgG‐Es. Actin‐mediated pseudopod extension to form phagocytic cups was disturbed by the Rab35 silencing or the expression of GDP‐Rab35, although initial actin assembly at the IgG‐E binding sites was not inhibited. Furthermore, GTP‐Rab35‐dependent recruitment of ACAP2, an ARF6 GTPase‐activating protein, was shown in the phagocytic cup formation. Concomitantly, overexpression of ACAP2 along with GTP‐locked Rab35 ...
Ar plates, they must obtain nutrients from phagocytosed bacteria. This amoeboid grazing behavior on bacteria results in the formation of plaques lear zones in
Miskovich, S., Matthews, G., Mukaro, V., Holmes, M., Hodge, G., Reynolds, P.N. and Hodge, S. 2011, Defective phagocytosis of viable lung cancer cells by alveolar macrophages in COPD, Respirology, vol. 16, no. Supplement 1, pp. 16-16, doi: 10.1111/j.1440-1843.2011.01936_17.x. ...
In the analysis of highly purified surface membrane from both resting and phagocytosing neutrophils an increase in the surface membrane associated actin has been demonstrated. This change at the cell periphery is associated with a coincident increase in the F-actin content of the cells following stimulation of the cells by exposure to opsonized Oil Red O droplets. The actin which is newly associated with the surface membrane of the phagocytosing cells was more susceptible to removal by detergent than the membrane-associated actin in resting cells and it was also noted that the F-actin associated with phagosomes was readily disrupted by detergent. A redistribution of the surface membrane glycoprotein 5′-nucleotidase was observed during phagocytosis, but no change in distribution of a 125I-labelled Lens culinaris lectin was observed during the entire phagocytic process. ...
In order for the innate immune system to function properly, there must be a mechanism where Phagocytes can differentiate host cells from foreign particles. Phagocytes can identify cells using "Pattern-recognition receptors" (PRRs) located on the plasma membrane, which interact with specific conserved motifs on pathogens called "Pathogen-associated molecular patterns" (PAMPs)[19]. Examples of Pathogen-associated motifs include mannans in the cell wall of yeast, formylated peptides in bacteria, and lipopolysaccharides and lipoteichoic acids on the surface of bacteria. Furthermore, the differences in phagocytic capacity and efficiency of professional and nonprofessional phagocytes have been suggested to arise from the presence of an array of dedicated phagocytic receptors that increase particle range and phagocytic rate. Due to the complexity of phagocytosis, no single model can fully account for the diverse structures and outcomes associated with particle internalisation. This complexity can be ...
Full Text - The rapid and efficient clearance of apoptotic germ cells (GCs) by Sertoli cells (SCs) is important for spermatogenesis. High mitochondrial activity in phagocytes is critical for continued clearance of apoptotic cells. However, the underlying molecular mechanism is poorly understood. Glycogen synthase kinase-3α (GSK3α) is a protein kinase that participates in the regulation of mitochondrial activity. Immunohistochemistry evidenced the predominant presence of the Ser21 phosphorylation GSK3α (inactivation) signal in SCs. Heat shock-induced apoptosis of GCs and dephosphorylation of GSK3α in SCs is a perfect model to investigate the role of GSK3α in phagocytic action. The number of apoptotic GCs was significantly lower in GSK3α inhibitor pre-treated mice with HS compared to normal control. In vitro phagocytosis assays shown that the phagocytic activity in GSK3α activated SCs was downregulated, while GSK3α inhibitor supplementation restored this process. Moreover, GSK3α activation
Particles have always been present in APIs but guidance from health authorities (EMA, FDA, others) or Pharmacopoeias (e.g. EP, USP) about particles in APIs is very limited. The APIC Guidance on Insoluble Matter and Foreign Particles in APIs is the only document so far providing guidance for a standard approach towards an appropriate control of foreign particles in APIs ...
One vial of 2 mg sterile lyophilized solid sufficient for 100-200 live cell imaging phagocytosis tests in 96-well format. One vial of 2 mg sterile lyophilized solid sufficient for 100-200 live cell imaging phagocytosis tests in 96-well format. IncuCyte® pHrodo® Bioparticles® are sterile fluorogenic reagents ideally sui
This Application Note shows how a Microplate Reader provides an accurate, consistent method for quantifying macrophage phagocytosis. Read more.
Leptin is a cytokine/hormone produced mainly by the adipocytes which regulates the body weight. The normal level of Leptin is required for optimal immune sy ...
Lack of αvβ5 integrin impairs RPE phagocytosis of POS. We examined primary RPE in culture from wild-type (a-c) and β5−/− (d-f) mice. Confocal x-y scans of transmitted light (a and d) and of apical αvβ5 integrin (green) and nuclei (red) in the same fields (b and e) were used to compare general cell morphology and to illustrate apical αvβ5 receptors in wild-type, but not in β5−/−, RPE. (c and f) Junction marker ZO-1 (blue) and nuclei (red) appeared similar by wide-field fluorescence microscopy. However, β5−/− RPE in primary culture phagocytosed fewer FITC-POS (green) than wild-type RPE during a 1-h phagocytic challenge. (g) Quantification of in vitro phagocytosis assays showed reduced POS uptake by β5−/− RPE compared with wild-type RPE at all time points. Results represent means ± SD, n = 3, Students t test, P , 0.01 at 1-3 h. (h) RGD peptides inhibited POS uptake by wild-type but not by β5−/− RPE in a concentration-dependent manner. Bars show 1-h FITC-POS uptake ...
Phagocytosis is the terminal event of the apoptotic process (1, 2) and is also critical for the engulfment of microorganisms (3). It has been proposed that the recognition of both nonself (microorganisms) and effete self (corpses) may share common receptors (4). Blocking experiments have implicated a number of receptors as important for target recognition (2-4). Genetic studies indicate that some of these receptors participate in phagocytosis of pathogens in vivo (5, 6). However, the multiplicity and redundancy of recognition mechanisms in mammalian systems have made it difficult to evaluate the relative roles of these receptors in the phagocytosis of corpses. Although several genes of Caenorhabditis elegans are involved in the phagocytosis of corpses (7-9), none of these molecules seem to act directly as a receptor in the recognition of the corpse.. In Drosophila embryos, like in mammals and in contrast to worms, the clearance of apoptotic cells is primarily mediated by macrophages, hemocytes ...
Saving photoreceptors from degeneration. The daily big breakfast of OS material ingested by the post-mitotic RPE, summed over the life of an animal, distinguishes it as likely the most phagocytic cell type in the body. Defective RPE phagocytosis in Royal College of Surgeons (RCS) rats causes photoreceptor degeneration and demonstrates that OS phagocytosis is essential for homeostasis of the mammalian retina. By positional cloning of the mutant RCS gene, we identified MERTK as a critical part of the phagocytic mechanism. We also identified mutations in the human MERTK gene in individuals with a retinal degenerative disease known as retinitis pigmentosa, thereby defining the RP38 locus. TYRO3, AXL and MERTK constitute the TAM family of receptor tyrosine kinases. It is now appreciated that TAM receptors function in a diverse array of phagocytic processes. Our identification of Mertk as the gene mutated in RCS rats was the first connection of TAM receptors to the process of phagocytosis. Mice ...
This protocol provides an overview of the IncuCyte® Phagocytosis Assay methodology. It is compatible with the IncuCyte® Live-Cell Analysis System using your choice of phagocyte cells, in combination with IncuCyte® pHrodo® Bioparticles® for Phagocytosis reagents.. View this protocol. ...
A new MERLIN publication led by our team at Erasmus MC in Rotterdam, NL appeared in the journal Stem Cells on 17 January 2018. Authors of this paper are: Samantha F H de Witte , Franka Luk, Jesus M Sierra Parraga, Madhu Gargesha, Ana Merino, Sander S Korevaar, Anusha S Shankar, Lisa OFlynn, Steve J Elliman, Debashish Roy , Michiel G H Betjes, Philip N Newsome, Carla C Baan, Martin J Hoogduijn.. This important study demonstrates that infused MSC are rapidly phagocytosed by monocytes, which subsequently migrate from the lungs to other body sites. Phagocytosis of ucMSC induces phenotypical and functional changes in monocytes, which subsequently modulate cells of the adaptive immune system. It can be concluded that monocytes play a crucial role in mediating, distributing, and transferring the immunomodulatory effect of MSC.. Visit our Publications page for more information on this and other MERLIN publications.. ...
Definition of intracellular killing assay in the Financial Dictionary - by Free online English dictionary and encyclopedia. What is intracellular killing assay? Meaning of intracellular killing assay as a finance term. What does intracellular killing assay mean in finance?
Phagocytosis is the cellular process of engulfing solid particles by the cell membrane to form an internal phagosome, or "food vacuole." The phagosome is usually delivered to the lysosome, an organelle involved in the breakdown of cellular components, which fuses with the phagosome. The contents are subsequently degraded and either released extracellularly via exocytosis, or released intracellularly to undergo further processing. Phagocytosis is involved in the acquisition of nutrients for some cells, and in the immune system it is a major mechanism used to remove pathogens and cell debris. Bacteria, dead tissue cells, and small mineral particles are all examples of objects that may be phagocytosed. Phagocytosis is a specific form of endocytosis involving the vesicular internalization of solid particles, such as bacteria, and is therefore distinct from other forms of endocytosis such as pinocytosis, the vesicular internalization of various liquids. ...
This study shows that the initial phagocytic response in the peri-infarct region of photochemically induced ischemia of the rat cortex is mainly of microglial origin. Microglia showed signs of activation and phagocytic transformation during the first days after ischemia, while hematogenous macrophages were recruited with a remarkable delay between days 3 and 6 to participate in the removal of necrotic tissue.. The extent to which resident microglia and blood-derived macrophages contribute to the population of phagocytes after cerebral infarction was controversial because of lack of a distinctive marker. Under normal and pathological conditions, microglia represent an extremely sessile glial cell population with a low turnover and replacement rate from bone marrow-derived cells of macrophage lineage.19 However, microglia respond rapidly to brain injury by proliferation and upregulation of surface markers, including major histocompatibility complex class I and II antigens and complement receptor-3 ...
BACKGROUND Neonates and young infants manifest increased susceptibility to bacterial, viral and fungal lung infections. Previous work has identified a role for eicosanoids in mediating host defense functions of macrophages. This study examines the relationship between alveolar macrophage (AM) host defense and production of lipid mediators during the neonatal period compared to adult AMs. METHODS AMs were harvested from young (day 7 and day 14) and adult (~10 week) rats. The functionality of these cells was assessed by examining their ability to phagocytose opsonized targets, produce cytokines, eicosanoids and intracellular cAMP measured by enzyme immunoassays, and gene expression of proteins, enzymes and receptors essential for eicosanoid generation and phagocytosis measured by real time RT-PCR. RESULTS AMs from young animals (day 7 and 14) were defective in their ability to phagocytose opsonized targets and produce tumor necrosis factor (TNF)- α. In addition, young AMs produce more prostaglandin
Yes. Whilst we have focussed on J774A.1 adherent cells in developing the phagocytosis application, the use of non-adherent phagocytic cell types should be possible. Care must be taken to ensure cells remain in the field of view - this may be facilitated by the use of plate coatings such as poly-D-lysine or Matrigel™.. ...
CD36 participates in macrophage internalization of a variety of particles, and has been implicated in inflammatory responses to many of these ligands. To what extent CD36 cooperates with other receptors in mediating these processes remains unclear. Because CD36 has been shown to cooperate with TLR2, we investigated the roles and interactions of CD36 and TLRs in inflammation and phagocytosis. Using Ab-induced endocytosis of CD36 and phagocytosis of erythrocytes displaying Abs to CD36, we show that selective engagement and internalization of this receptor did not lead to proinflammatory cytokine production by primary human and murine macrophages. In addition, CD36-mediated phagocytosis of Plasmodium falciparum malaria-parasitized erythrocytes (PEs), which contain parasite components that activate TLRs, also failed to induce cytokine secretion from primary macrophages. Furthermore, we demonstrate that CD36-mediated internalization did not require TLR2 or the TLR-signaling molecule IRAK4. However, ...
Angiotensin II (AII), a product of rennin-angiotensin system, exerts an important role on the function of immune system cells. In this study, the effect of AII on the phagocytic activity of mouse peritoneal macrophages was assessed. Mice peritoneal macrophages were cultured for 48 h and the influence of different concentrations of AII (10-14 to 10-7 M) and/or losartan, 10-16 to 10-6 M), an AT1 angiotensin receptor antagonist, on phagocytic activity and superoxide anion production was determined. Dimethylthiazoldiphenyltetrazolium bromide reduction and the nucleic acid content were used to assess the cytotoxicity of losartan. A stimulatory effect on phagocytic activity (P < 0.05) was observed with 10-13 M and 10-12 M AII concentrations. The addition of losartan (up to10-14 M) to the cell cultures blocked (P < 0.001) the phagocytosis indicating the involvement of AT1 receptors. In contrast, superoxide anion production was not affected by AII or losartan. The existence of AT1 and AT2 receptors in ...
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Once pathogen recognition and attachment occurs, the pathogen is engulfed in a vesicle and brought into the internal compartment of the phagocyte in a process called phagocytosis (Figure 13.14). PRRs can aid in phagocytosis by first binding to the pathogens surface, but phagocytes are also capable of engulfing nearby items even if they are not bound to specific receptors. To engulf the pathogen, the phagocyte forms a pseudopod that wraps around the pathogen and then pinches it off into a membrane vesicle called a phagosome. Acidification of the phagosome (pH decreases to the range of 4-5) provides an important early antibacterial mechanism. The phagosome containing the pathogen fuses with one or more lysosomes, forming a phagolysosome. Formation of the phagolysosome enhances the acidification, which is essential for activation of pH-dependent digestive lysosomal enzymes and production of hydrogen peroxide and toxic reactive oxygen species. Lysosomal enzymes such as lysozyme, phospholipase, and ...
Natural antibodies, which arise without known immune exposure, have been described that specifically recognize cells dying from apoptosis but their role in innate immunity remains poorly understood. Herein, we show that the immune response to neo-antigenic determinants on apoptotic thymocytes is dominated by antibodies to oxidation-associated antigens, phosphorylcholine (PC), a head group that becomes exposed during programmed-cell death, and malondialdehyde (MDA), a reactive aldehyde degradation product of polyunsaturated lipids produced following exposure to reactive-oxidation species. While natural antibodies to apoptotic cells in naïve adult mice were dominated by PC and MDA specificities, the amounts of these antibodies were substantially boosted by treatment of mice with apoptotic cells. Moreover, the relative amounts of PC and MDA antibodies was affected by VH gene inheritance. Antibody interactions with apoptotic-cells also mediated the recruitment of C1q, which alone can promote apoptotic-cell
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Phagocytosis is the process by which a cell engulfs solid material. The molecule is then internalized in a vesicle of plasma membrane (phagosome) which fuses with a lysosome for destruction, any undigested remains of the molecule (eg. bacterium) are removed by exocytosis and the products of digestion are absorbed into the cytoplasm. It occurs in the immune system, and is carried out by phagocytes such as macrophages which are involved in the innate immune response [1]. The process of phagocytosis involves the macrophage beginning to encase the pathogen via endocytosis. Once the macrophage has engulfed the pathogen via endocytosis, the pathogen is in a phagosome. The pathogen then is broken down by the fusion of the phagocytic vesicle (phagosome) and the lysosome vesicles which contain oxidase and proteases, this process is called phagolysosome. [2] ...
2014 Project header}} =Phagocytosis= [[File:Leukocyte_phagocytosis_of_yeast.jpg,thumb,right,300px,Phagocytosis of yeast by a Leukocyte]] ==Introduction== Phagocytosis is a crucial defence mechanism of the innate immune response which eliminates debris and pathogens,ref name="PMID18085665">,pubmed>18085665,/pubmed>,/ref>. Phagocytosis is a specialised type of endocytosis where large (≥0.5 μm),ref name="PMID10358769">,pubmed>10358769,/pubmed>,/ref> solid particles are internalised through the receptor-mediated engulfment of membrane-derived vesicles called phagosomes,ref name="PMID21783028">,pubmed>21783028,/pubmed>,/ref>. After the vesicles detach from the plasma membrane (scission), the phagosome matures by fusing with endosomes and lysosomes (which contain hydrolytic enzymes) to form a phagolysosome. The hydrolytic enzymes in the phagolysosome break down the internalised solid particles. The mechanism behind Phagocytosis is clathrin (a protein that plays a major role in formation of coated ...
Phagocytosis is the process by which a cell engulfs solid material. The molecule is then internalized in a vesicle of plasma membrane (phagosome) which fuses with a lysosome for destruction, any undigested remains of the molecule (eg. bacterium) are removed by exocytosis and the products of digestion are absorbed into the cytoplasm. It occurs in the immune system, and is carried out by phagocytes such as macrophages which are involved in the innate immune response [1]. For some Eukaryotes, mainly unicellular Eukaryotes, this is a key method of obtaining nutrients. This includes Amoebas and ciliated protozoa. [2] The process of phagocytosis involves the macrophage beginning to encase the pathogen or substance via endocytosis. Once the macrophage has engulfed the substance, a phagosome is formed containning the substance. The substance is then broken down by the fusion of the phagocytic vesicle (phagosome) and the lysosome vesicles which contain oxidase and proteases, this process is called ...
The U937 cell line has been shown to generate tumour fibrosis factor α (TNF-α) in response to soluble stimuli such as PMA and LPS, but only after treatment with GM-CSF. We report here the generation of TNF-α from U937 cells following phagocytosis of opsonised zymozan particles without the need for pre-treatment with GM CSF. The release of TNF-α from U937 cells was demonstrated by a specific radioimmunoassay, L929 cell killing and neutrophil priming. The biological activities in the cell supernatant were inhibited by TNF-α affarserum. Phagocytosis was required for TNF-α production. Non-opsonised zymozan or latex particles which were not phagocytosed or pretreatment with cytochalasin B, which inhibited phagocytosis of opsonised zymozan particles, all failed to trigger TNF-α production. Phagocytosis failed to trigger detectable IL-1 generation, and production of IL-6 was insufficient to produce biological effects on neutrophils. The U937 supernatant thus provides a source of human TNF-α ...
TY - JOUR. T1 - Regulation of cytokine production during phagocytosis of apoptotic cells. AU - Chung, Elaine Y. L.. AU - Sun, Jung Kim. AU - Xiao, Jing Ma. PY - 2006/2/1. Y1 - 2006/2/1. N2 - Loss of self-tolerance and expansion of auto-reactive lymphocytes are the basis for autoimmunity. Apoptosis and the rapid clearance of apoptotic cells by phagocytes usually occur as coordinated processes that ensure regulated cellularity and stress response with non-pathological outcomes. Defects in clearance of apoptotic cells would contribute to the generation of self-reactive lymphocytes, which drive autoimmune disorders such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). The IL-12 family of cytokines (IL-12, IL-23, and IL-27) and IL-10 are produced by phagocytic macrophages and play critical roles in the regulation of antigen-presenting cells (APCs) and effector lymphocytes during an immune response to pathogens. Inappropriate expression of these cytokines and their dysregulated ...
... factor to the pathogenesis of many diseases. holding apoptotic contaminants reach the lysosomes with a hold off likened to those including IgG-opsonized contaminants. Enrichment of the apoptotic contaminants in phosphatidylserine (PS) neither transformed the kinetics of their engulfment nor the growth procedure of the phagosome. Intro Phagocytosis can be a complicated mobile event by which huge contaminants are positively identified, degraded and engulfed. Although, the main concentrate offers been on the part in sponsor protection, this procedure also takes on a essential part in removal of apoptotic cells that is usually important for cells redesigning and homeostasis [1]C[4]. This is usually especially essential in illnesses such as atherosclerosis and neurodegenerative illnesses. In both full cases, professional phagocytes are not really the just players included. The removal of apoptotic cell particles in ...
Mycobacterium tuberculosis (Mtb) is the causative agent of tuberculosis, a disease that for years was considered to belong of the past, but tuberculosis is back causing over 2 million deaths per year. The infection can be dormant for decades and an active immune response can prevent the infection from progressing into active disease. However, the HIV/AIDS epidemic has caused an alarming rise in tuberculosis cases.. The main infectious route for Mtb is through the airways into the lungs, where they encounter alveolar macrophages. Mtb are phagocytosed by these macrophages, but instead of being killing within the phagosome, Mtb modulates the cell to become a host in which the bacteria thrive. The lack of capacity to eradicate the infection stimulate cells of the immune system to gather around infected macrophages and form a granuloma that walls off the infection. Within this granuloma, Mtb can wait silently and later progress into active disease. However, only a fraction of exposed individuals ...
Our laboratory currently focuses on two major areas. 1. Engulfment of apoptotic cells - the art of eating a good meal. Everyday we turn over billions of cells as part of normal development and homeostasis. The recognition and phagocytic removal of such cells destined to die (mostly via apoptosis) is fundamentally important for our health. Failure to promptly and efficiently clear apoptotic cells can lead to chronic inflammation, autoimmunity and developmental defects. The apoptotic cell clearance is usually done by neighboring cells or by professional phagocytes such as macrophages and dendritic cells. In studying this process, we consider four broad issues related to eating an apoptotic meal. The first issue is getting to the meal itself. This involves the release of so called find-me signals from apoptotic cells that serve as attraction cues to recruit monocytes and macrophages near an apoptotic cell. We have recently identified a critical for the nucleotides ATP and UTP as find-me ...
Integral membrane proteins (natural resistance associated macrophage proteins), of the solute carrier family, expressed only in cells of the myeloid series and recruited to the phagosome membrane following phagocytosis. Mutations in Nramp1 (SLC11A1, 550 aa) impair macrophage killing of intracellular parasites such as Mycobacteria, Salmonella, and Leishmania and are also associated with the onset of rheumatoid arthritis. Nramp2 (SLC11A2, 568 aa) is very similar to Nramp1 but more widely expressed and is known to be involved in cellular iron absorption at the luminal surface of the duodenum. ...
Interleukin (IL)-12 is an integral factor that induces T helper cell type 1-mediated immunity and inflammatory Alvocidib diseases. recognition mechanisms and exhibited that transmission transducers and activator of transcription 1 (STAT1) signalling activated bacterial phagocytosis and was involved in the induction of abnormal IL-12 production. In IL-10 KO mouse bone marrow-derived (BM) macrophages activation induced increased IL-12p70 production compared to lipopolysaccharide combined with interferon (IFN)-γ treatment. Significant repression of IL-12 production was achieved by inhibition of phagocytosis with cytochalasin D and inhibition of protein synthesis with cycloheximide. Induction of IFN regulatory factors-1 and -8 downstream molecules of STAT1 and the key transcription factors for IK-12 transcription following activation were mediated by phagocytosis. Interestingly STAT1 was activated after activation with in IL-10 KO BM macrophages although IFN-γ SLRR4A could not be detected. These ...
The process by which cells engulf materials (e.g., bacteria, dead cells) that are eventually killed, destroyed or digested. The outer segment tips of photoreceptor cells are phagocytosed every day by RPE cells.
Coughing is a familiar, yet complex reflex action that functions to clear material from the airway. It protects the airway from irritants, saliva, or foreign particles that may have been inhaled (aspirated), and secretions, cellular debris, and microbes generated by the lungs or bronchial tree. Coughing can be involuntary; a reaction to inhaling a foreign particle or wayward food particle, or voluntary, intentionally taking a deep breath to clear mucus from the throat.
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Phagocytosis requires receptor-mediated recognition of particles, usually in the guise of infectious agents and apoptotic cells. Phagosomes fuse with lysosomes to generate phagolysosomes, which play a key role in enzymatic digestion of the internaliz
Simpson, D W.; Roth, R; and Loose, L D., "A rapid, inexpensive and easily quantified assay for phagocytosis and microbicidal activity of macrophages and neutrophils." (1979). Subject Strain Bibliography 1979. 3737 ...
A defect inspection method includes radiating an illumination slit-shaped beam having lights substantially parallel to a longitudinal direction to a substrate having circuit patterns in a direction inclined at a predetermined gradient relative to the direction of a line normal to the substrate and inclined at a predetermined gradient on a surface with respect to a group of main straight lines of the circuit patterns with its longitudinal direction oriented almost perpendicularly to a direction of a movement of the substrate. Scattered light reflected by a defect such as a foreign particle existing on the illuminated substrate is received and converted into a detection signal by using an image sensor, and defect judging is effected of an extracted a signal indicating a defect such as a foreign particle on the basis of the detection signal output.
Solid particles are engulfed through the process of Phagocytosis. The particles that are engulfed through this biological process are termed as phagocytes.
Aaron Neumann and his colleagues from Cell and Developmental Biology found novel dorsal pseudopodial protrusions, the "fungipods", formed by dendritic cells (red objects in the upper image) after contact with yeast cells (i.e. green blobs in the upper image).. Fungipods have a convoluted cell-proximal end and a smooth distal end. They persist for hours, and exhibit noticeable growth at the contact. Aaron Neumann et al. think that fungipods may promote yeast particle phagocytosis (i.e. process of surrounding and consuming solid particles) by dendritic cells.. ...
Phagocytosis - Greek phagein - to eat. Mechanism of uptake from particles to small cells in a single eukaryotic cell. Usually, particles are taken up by th...
Phagocytosis - Greek phagein - to eat. Mechanism of uptake from particles to small cells in a single eukaryotic cell. Usually, particles are taken up by th...
Results of phagocytosis inhibitory assays performed with use of different exogenous sugars (Glc, Gal, Man; at a final concentration 100 mM in PBS) and genistei
Our laboratory studies the process by which cells that are dying by apoptosis are recognized and cleared during the course of embryonic development in the fruit fly, Drosophila melanogaster. Our long-term goal is to compare and contrast the molecular mechanisms of phagocytosis of apoptotic cells with that of pathogens, such as bacteria. Failure to clear apoptotic cells has been associated with autoimmune diseases, such as Lupus Erythematosus, and may also contribute to neurogenerative disorders. Thus, our studies will increase our basic understanding of phagocytosis, an important aspect of the innate cellular immune response and development of all multicellular organisms, and ultimately contribute to the design of new drugs to treat diseases associated with failed apoptotic cell clearance, as well as bacterial infections ...
Macrophages are tissue-resident phagocytes initially described as end products of circulating monocytes that originate in the bone marrow. Along with this classical scheme of the mononuclear phagocytic system, it is also becoming apparent that the adult tissue macrophage population consists of distinct and diverse cell types with different developmental origins (12-14). Macrophages constitute 10% to 15% of most tissues and are required for homeostatic clearance of apoptotic cells, control of epithelial cell turnover, and assisting the adaptation of tissues to stress conditions (2, 15). The ability to phagocytose microorganisms and cell debris is shared by neutrophils, which are polymorphonuclear granulocytes that produce highly potent, albeit less specific and potentially cytotoxic, antimicrobial substances and abundant inflammatory mediators (16, 17). Neutrophils are short-lived leukocytes generated in great number in the bone marrow during steady state; they circulate in the blood stream for ...
Foreign particles and cells are cleared from the body by phagocytes that must also recognize and avoid clearance of self cells. The membrane protein CD47 is reportedly a marker of self in mice that impedes phagocytosis of self by signaling through the phagocyte receptor CD172a. Minimal Self peptides were computationally designed from human CD47 and…
Phagocytosis is a mechanism which allows some specialised cells (macrophages, granulocytes, neutrophils) and some unicellular organisms (protists) to ingest foreign particles such as bacteria,...
Apoptosis, or programmed cell death, is a controlled process by which aged or damages cells are eliminated in multicellular organisms. Neutrophils, short-lived phagocytes of the innate immune system, are highly equipped effectors that can sense, locate, ingest and kill bacterial pathogens. Inflammatory mediators and the presence of bacterial products at the foci of infection regulate the function and life span of these cells. Modulation of neutrophil apoptosis and the subsequent clearance by scavenger cells, such as macrophages, is part of a balanced inflammatory process leading to resolution of inflammation. Many pathogens are capable of modulating host cell apoptosis, and thereby influence the progression of disease. Hence, this thesis was aiming at elucidating mechanisms involved in pathogen- and host-modulated apoptosis and its contribution to the inflammatory process.We found that different routes of bacterial entry, i.e. through invasion or by receptor-mediated phagocytosis, triggered ...
Cell adhesion protein that promotes adhesion and outgrowth of hippocampal embryonic neurons. Binds directly to bacteria and their components and functions as an opsonin for macrophage phagocytosis of bacteria. Essential in the initiation of the innate immune response and represents a unique pattern-recognition molecule in the ECM for microbial pathogens (By similarity).
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The squirt bottle method is the way to go. Just dipping garments into a bucket wont give you the depth of color that you need and following the immersion dyeing method (which you could in fact do) means that the dyebath is only good for one time. This is because once the soda ash and dye mix together the chemical reaction starts. That is why it is best to keep the dye and the soda ash separate until its on the shirt ...
Cell biology. The engulfing of particles by eukaryotic cells. The particles can be microorganisms or cell fragments. The phagocytic cells are macrophages or neutrophils. The material is taken into the cell in membrane bound vesicles and then digested.. ...
தின்குழியமை (Phagocytosis) என்பது உயிரணுக்களின் கலமென்சவ்வினால், உயிரணுக்களுக்கு வெளியாக இருக்கும் திண்மப் பதார்த்தங்கள் வளைத்து எடுத்து விழுங்கப்படும் ஒரு உயிரணுச் செயல்முறையாகும். இது பெருவிழுங்கிகள் போன்ற தின்குழியங்களிலும் (phagocytes), அமீபா போன்ற அதிநுண்ணுயிரிகளிலும் நிகழும் ஒரு பொதுவான செயல்முறையாகும். அதிநுண்ணுயிரிகள் இந்த தின்குழியமை மூலம் உணவை உள்ளெடுப்பதனால், ...
There are two stages involving the severity of infection, one is the latent-stage, as the immune system has the capability of suppressing the antigens or any foreign particle so in the initial stages the germ even though is present in the body remains dormant.
Here are some very clear clips for the immune responses to infection, starting with a really well done explanation of Burnets Nobel-winning clonal selection theory: If you like that, check out some more of the videos from the Walter and Eliza Hall Institute of Medical Research. Try this animation and quiz: McGraw Hill Online Centre…
Purpose: Identifying the quality of welded and brazed joints,. Identifying the quality of castings in terms of embedded particles, discontinuity flaws, foreign particles, tramps, and control over inner geometry.. Part dimensions: 3,000 3,000 2,000 mm. Thickness of show-through: up to 26 mm. Types of control: ...
83 Essays on Infinite Lifespans Robert A. Freitas Jr. Another medical nanorobot I designed more recently is the microbivore an artificial white cell [12 15]. One main task of natural white cells is to absorb and digest microbial invaders in the bloodstream. This is called phagocytosis. Microbivore nanorobots would also perform phagocytosis, but would operate much faster, more reliably, and under human control. Like the respirocyte, the micro- bivore is much smaller than a red blood cell but is more complex than the respirocyte, having about 30 times more atoms involved in its construction. The microbivore device is a flattened sphere with the ends cut off. It measures over 3 microns in diameter along its major axis and 2 microns in diameter along its minor axis. This size helps to ensure that the nanorobot can safely pass through even the narrowest of human capillaries and other tight spots in the spleen (e.g., the interendothelial splenofenestral slits [16]) and elsewhere in the human body. The ...
Roar explosively, dealing 23,244 damage to all enemies within 8 yards and increasing all damage you deal by 16% for 6 sec. Dragon Roar ignores all armor and always critically strikes ...
Compounds, compositions, their methods of preparation and use in binding bio-affecting substances to the surface membrane of bioparticles, such as eukaryotic cells, without producing appreciable detrimental effect on morphology or physiological function of cells.
TY - JOUR. T1 - Study of histamine effects on phagocytosis and enzyme secretion of Tetrahymena pyriformis. AU - Darvas, Z.. AU - Madarasz, B.. AU - László, V.. PY - 1999. Y1 - 1999. N2 - 1. The biogenic amine histamine develops effects not only in mammalian cells and tissues but in ciliated unicellular Tetrahymena as well. In addition to binding and internalization of labelled histamine, low concentrations can stimulate the phagocytosis of cells in inorganic salt solution. 2. In inorganic solution Tetrahymena cells secrete acid hydrolases to the medium. High concentration of histamine (10 mM) decreases the secretion of three investigated acid hydrolases in a different manner. We think that in this process the primary determinant is the alkaline character of histamine. 3. The effect of histamine on phagocytosis differs from the effect on secretion since the low, physiological concentration of histamine stimulates phagocytosis, the higher concentrations inhibit it. In the background of these ...
The aim of this study was to assess the influence of different types of carbon nanotubes (CNTs) on cell phagocytosis. Three kinds of carbon nanotubes: single-walled carbon nanohorns (SWCNHs), multiwalled carbon nanotubes (MWCNTs), and ultra-long single-walled carbon nanotubes (ULSWCNTs) before and after additional chemical functionalization were seeded with macrophage cell culture. Prior to biological testing, the CNTs were subjected to dispersion process with the use of phosphate buffered solution (PBS) and PBS containing surfactant (Tween 20) or dimethyl sulfoxide (DMSO). The results indicate that the cells interaction with an individual nanotube is entirely different as compared to CNTs in the form of aggregate. The presence of the surfactant favors the CNTs dispersion in culture media and facilitates phagocytosis process, while it has disadvantageous influence on cells morphology. The cells phagocytosis is a more effective for MWCNTs and SWCNHs after their chemical functionalization. Moreover,
CD47 functions as a marker of self on red blood cells (RBCs) by binding to signal regulatory protein alpha on macrophages, preventing phagocytosis of autologous RBCs by splenic red pulp macrophages, and Fcgamma receptor (FcgammaR)- or complement receptor-mediated phagocytosis by macrophages in general. RBC senescence involves a series of biochemical changes to plasma membrane proteins or lipids, which may regulate phagocytosis by macrophages. Here, we investigated whether CD47 on experimentally senescent murine RBCs affects their phagocytosis by macrophages in vitro. Clustering of CD47 with antibodies was more pronounced in the plasma membrane of untreated RBCs, compared with that in in vitro oxidized RBCs (Ox-RBCs). Phagocytosis of Ox-RBCs was mediated by scavenger receptors (SRs) distinct from SR-A or CD36 and required serum factors. We found that wild-type (WT) and CD47(-/-) Ox-RBCs were phagocytosed equally well by macrophages in the presence of serum, suggesting that phagocytosis via SRs is ...
BACKGROUND: Traumatic injury to axons produces breakdown of axons and myelin at the site of the lesion and then further distal to this where Wallerian degeneration develops. The rapid removal of degenerated myelin by phagocytosis is advantageous for repair since molecules in myelin impede regeneration of severed axons. Thus, revealing mechanisms that regulate myelin phagocytosis by macrophages and microglia is important. We hypothesize that myelin regulates its own phagocytosis by simultaneous activation and down-regulation of microglial and macrophage responses. Activation follows myelin binding to receptors that mediate its phagocytosis (e.g. complement receptor-3), which has been previously studied. Down-regulation, which we test here, follows binding of myelin CD47 to the immune inhibitory receptor SIRPalpha (signal regulatory protein-alpha) on macrophages and microglia.. METHODS: CD47 and SIRPalpha expression was studied by confocal immunofluorescence microscopy, and myelin phagocytosis by ...
TY - JOUR. T1 - Specific IgG Subclass Antibody Levels and Phagocytosis of Serotype 14 Pneumococcus Following Immunization. AU - KANIUK, A. St C.. AU - LORTAN, J. E.. AU - MONTEIL, M. A.. PY - 1992/12. Y1 - 1992/12. N2 - Complement and specific antibody directed against capsular polysaccharide are necessary for efficient phagocytosis of pneumococci. In normal adults, specific antibody to pneumococci is predominantly of the IgG2 subclass. However, the role of IgG2 in bacterial clearance is debatable. We therefore decided to investigate the relationship between specific IgG subclass antibody levels and phagocytosis of serotype 14 pneumococcus, before and after immunization with a pneumococcal capsular polysaccharide vaccine. Specific IgG subclass antibody was measured by an ELISA technique and the effect of serum on phagocytosis of radiolabelled pneumococci by normal polymorphs was determined. We found that in the presence of complement, phagocytosis correlated significantly with both specific IgGl ...
Introduction: Hormonal and metabolic changes, as well as energy imbalance, can affect health, production and reproductive performance of dairy cows. In the present study, we evaluated phagocytosis and respiratory burst neutrophil activity during the transition period and early lactation and compared it with biochemical and hematological parameters in dairy cows. Methodology: Simmental cows (n = 21) were enrolled in the study. Whole blood samples were collected weekly from 3 weeks pre- calving until 6 weeks post calving. Basic metabolic and blood parameters were assessed by routine laboratory analyses, while neutrophil functions were analyzed by commercial test kits. Results: Optimal neutrophil response was observed pre and post calving. The highest value was recorded in the 6th week after calving (89.54 ± 7.61%) and being significantly higher (p , 0.01) as compared to values recorded at two and one week before and one week after calving. The percentage of activated neutrophils was high during ...
The recognition step in the phagocytotic process of the unicellular amoeba dictyostelium discoideum was examined by analysis of mutants defective in phagocytosis, Reliable and simple assays were developed to measure endocytotic uptake. For pinocytosis, FITC-dextran was found to be a suitable fluid-phase marker; FITC-bacteria, latex beads, and erythrocytes were used as phagocytotic substrates. Ingested material was isolated in one step by centrifuging through highly viscous poly(ethyleneglycol) solutions and was analyzed optically.. A selection procedure for isolating mutants defective in phagocytosis was devised using tungsten beads as particulate prey. Nonphagocytosing cells were isolated on the basis of their lower density. Three mutant strains were found exhibiting a clear-cut phenotype directly related to the phagocytotic event.. In contrast to the situation in wild-type cells, uptake of E. coli B/r by mutant cells is specifically and competitively inhibited by glucose. Mutant amoeba ...
The clearance of apoptotic cells is an important process in animal development and homeostasis. Failure to dispose of dead cells leads to developmental defects as well as disease. The removal of dead cells within an organism is accomplished by the process of phagocytosis. Phagocytosis of apoptotic cells is the internalization of a dead cell by another cell. Once internalized, the apoptotic cell is subject to various processing events culminating in the complete degradation of the dead cell. Phagocytosis is carried out by specialized cells, known as professional phagocytes. However, phagocytosis can also be carried out by cells that are specialized for functions other than phagocytosis. These cells are known as nonprofessional phagocytes. Although the process of phagocytosis has been extensively studied, the mechanisms are poorly understood. To better understand phagocytosis, this dissertation has focused on the Drosophila receptor Draper (Drpr). Drpr is a highly conserved transmembrane protein ...
Phagocytosis plays an essential role in host-defense mechanisms through the uptake and destruction of infectious pathogens. Specialized cell types including macrophages, neutrophils, and monocytes take part in this process in higher organisms. After opsonization with antibodies (IgG), foreign extracellular materials are recognized by Fc gamma receptors. Cross-linking of Fc gamma receptors initiates a variety of signals mediated by tyrosine phosphorylation of multiple proteins, which lead through the actin cytoskeleton rearrangements and membrane remodeling to the formation of phagosomes. Nascent phagosomes undergo a process of maturation that involves fusion with lysosomes. The acquisition of lysosomal proteases and release of reactive oxygen species are crucial for digestion of engulfed materials in phagosomes ...
Frustrated phagocytosis has been stated as an important factor in the initiation of an inflammatory response after fibre exposure. The length of fibrous structures has been linked to the potential of fibres to induce adverse health effects for at least 40 years. However, we only recently reported for the first time the threshold length for fibre-induced inflammation in the pleural space and we implicated frustrated phagocytosis in the pro-inflammatory effects of long fibres. This study extends the examination of the threshold value for frustrated phagocytosis using well-defined length classes of silver nanowires (AgNW) ranging from 3-28 μm and describes in detail the morphology of frustrated phagocytosis using a novel technique and also describes compartmentalisation of fibres in the pleural space. A novel technique, backscatter scanning electron microscopy (BSE) was used to study frustrated phagocytosis since it provides high-contrast detection of nanowires, allowing clear discrimination between the
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Human alveolar macrophages (AM) were obtained by bronchoalveolar lavage from 18 patients with a variety of conditions. For each patient the percentages of AM showing the following properties were determined: (1) staining for the enzymes non-specific esterase (NSE) and acid phosphatase (ACP); (2) in vitro phagocytosis of Candida guillermondii; (3) expression of cell surface markers detected by two monoclonal antibodies (MoAb) (1B5 and DA2) and two anti-monocyte/macrophage MoAb (UCHMI and RFD2); and (4) simultaneous phagocytosis of C. guillermondii and staining with the MoAb. In all patients the majority of AM were found to be Ia positive (90 +/- 10%) ACP positive (100%) and NSE positive (97 +/- 4%). In contrast a smaller proportion were UCHM1 and RFD2 positive (77 +/- 11%, 68 +/- 12%) and less were phagocytic (37 +/- 17%). Whilst the total percentage of cells staining with the MoAb was unaltered by phagocytosis, the proportion of UCHM1 or RFD2 positive cells was significantly higher in the phagocytic
ABSTRACT The present study was investigated the immunological effects of the lipopolysaccharide extracted from Klebsiella pneumoniae against experimental infection with toxoplasmosis in mice. Immunological changes in treated mice were compared with the +ve (mice infected with T.gondii but not treated with LPS) and -ve (mice not infected with T.gondii and not treated with LPS) group at 3,14 and 30 days post infection with tissue cysts of T.gondii in the peritoneal cavity. Total and differential WBC count of peripheral blood and innate immune response represented by the phagocytic index were the criteria taken into consideration. Results showed a significant increase in the total WBC count in mice treated with LPS after infection with T.gondii, compared with -ve and +ve control groups. For differential WBC count, an increase in lymphocytes and decrease in monocytes, neutrophils and eosinophils was noticed. Basophils were not considered because of their low number.For phagocytic index, an increase was
Methods Primary RPE cells were prepared from freshly slaughtered pigs eyes. The impact of aflibercept on cell viability was investigated with MTT and trypan blue exclusion assay. The influence of aflibercept on wound healing was assessed with a scratch assay. Intracellular uptake of aflibercept was investigated in immunohistochemistry and its influence on phagocytosis with a phagocytosis assay using opsonised latex beads.. ...
Phagocytes remove apoptotic cells during development and eliminate pathogens in the immune system. The underlying molecular and cellular mechanisms, particularly the differences between macrophages and non-professional phagocytes like glia, are not well understood. We used novel cell-based assays to screen phagocytic function of candidate genes assembled from literature and our genome-wide transcription profiling of Drosophila melanogaster embryonic glia. Gene function was knocked-down by RNAi and phagocytic efficiency assessed by flow cytometry; to explore functional specificity, we offered not only bacteria, but also apoptotic cells and beads as food. To validate results in vivo, we analysed glial clearance of apoptotic neurons in embryonic development and immune clearance of bacteria in adult flies using both genetic mutants and transgenic RNAi. Our screen provides a cross section of the different steps of phagocytosis from recognition to engulfment and phagosomal degradation. For the ...
Glycation and the accumulation of advanced glycation end products (AGEs) are known to occur during normal aging but also in the progression of several diseases, such as diabetes. Diabetes type II and aging both lead to impaired wound healing. It has been demonstrated that macrophages play an important role in impaired wound healing, however, the underlying causes remain unknown. Elevated blood glucose levels as well as elevated methylglyoxal (MGO) levels in diabetic patients result in glycation and increase of AGEs. We used MGO to investigate the influence of glycation and AGEs on macrophages. We could show that glycation, but not treatment with AGE-modified serum proteins, increased expression of pro-inflammatory cytokines interleukin 1β (IL-1β) and IL-8 but also affected IL-10 and TNF-α expression, resulting in increased inflammation. At the same time, glycation reduced phagocytic efficiency and led to impaired clearance rates of invading microbes and cellular debris. Our data
ac‐ cepted for publication February 01, 2016; available online without sub‐ scription through the open access option. ©AlphaMed Press 1066‐5099/2016/$30.00/0 This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typeset‐ ting, pagination and proofreading process which may lead to differ‐ ences between this version and the Version of Record. Please cite this article as 1,2,3,4 Key words. house dust mite asthma  mesenchymal stem cells  M2 macro‐ phage  airway hyper‐responsiveness  phagocytosis  airway smooth muscle contraction. ABSTRACT Mesenchymal stem cell (MSC) immunosuppressive functions make them attractive candidates for anti‐inflammatory therapy in allergic asthma. However the mechanisms by which they ensure therapeutic effects remain to be elucidated. In an acute mouse model of house dust mite (Der f)‐ induced asthma, one i.v. MSC injection was sufficient to normalize and stabilize lung function in
Authors: van Kessel KP, Bestebroer J, van Strijp JA. Initial elimination of invading Staphylococcus aureus from the body is mediated by professional phagocytes. The neutrophil is the major phagocyte of the innate immunity and plays a key role in the host defense against staphylococcal infections. Opsonization of the bacteria with immunoglobulins and complement factors enables efficient recognition by the neutrophil that subsequently leads to intracellular compartmentalization and killing. Here, we provide a review ofthe key processes evolved in neutrophil-mediated phagocytosis of S. aureus and briefly describe killing. As S. aureus is not helpless against the professional phagocytes, we will also highlight its immune evasion arsenal related to phagocytosis.. ...
Axol iPSC-Derived Macrophages have been validated in phagocytosis assays. Both LPS (10 ng/mL) and Cytochalasin D (10 M) have been used to increase and decrease phagocytosis activity respectively. The macrophage-specific calcium-binding protein, IBA1 and cell surface markers CD14, CD11b, CD45, typically expressed by macrophages, have been confirmed in Axol iPSC-Derived Macrophages by flow-cytometry and ICC ...
The chemiluminescent response of rabbit alveolar macrophages to foreign particles was investigated with regard to determination of the involvement of reactive forms of oxygen. The alveolar macrophages were obtained by tracheal lavage performed on New- Zealand-white-rabbits. The foreign particle used to initiate the chemiluminescent response was zymosan at a concentration of two milligrams per 10(7
Primary cultures of mouse microglia were exposed to TLR agonists: tripalmitoyl-S-glyceryl-cysteine (Pam3CSK4 at 0.1 μg/ml; TLR2), endotoxin (LPS at 0.01 μg/ml; TLR4) and oligonucleotides containing unmethylated cytosin-guanosin motifs (CpG at 1 μg/ml; TLR9) for 24 h. TLR agonists were used at the lowest concentrations inducing the maximum stimulation of microglia cells in terms of NO release. After stimulation, cultures were challenged with two S. pneumoniae strains: the encapsulated D39 or the unencapsulated R6 strains were added at a ratio of 100 bacteria per cell. Phagocytosis was left to proceed for 30 and 90 min at 37°C + 5% CO2. For phagocytosis inhibition studies, 10 μM cytochalasin D (CD) was used. After washing, the microglial cultures were incubated in medium containing gentamicin (200 μg/ml) for 1 h to kill extracellular bacteria. Thereafter, cells were washed and lysed with distilled water. Viable intracellular bacteria were enumerated by quantitative plating of serial 10-fold ...
The potential contribution of plasmacytoid dendritic cells (pDCs) in the presentation of tumor cell Ags remains unclear, and some controversies exist with regard to the ability of pDCs to phagocytose cell-derived particulate Ags and cross-present them to MHC class I-restricted T lymphocytes. In this study, we show that human pDCs, although inefficient in the internalization of cell membrane fragments by phagocytosis, can efficiently acquire membrane patches and associated molecules from cancer cells of different histotypes. The transfer of membrane patches to pDCs occurred in a very short time and required cell-to-cell contact. Membrane transfer also included intact HLA complexes, and the acquired Ags could be efficiently recognized on pDCs by tumor-specific CD8(+) T cells. Remarkably, pDCs isolated from human colon cancer tissues displayed a strong surface expression of epithelial cell adhesion molecule, indicating that the exchange of exogenous Ags between pDCs and tumor cells also can occur ...
An opsonin (from the Greek opsōneîn, to prepare for eating) is any molecule that enhances phagocytosis by marking an antigen for an immune response or marking dead cells for recycling (i.e., causes the phagocyte to "relish" the marked cell). Opson in ancient Greece referred to the delicious side-dish of any meal, versus the sitos, or the staple of the meal. Opsonization (also, opsonisation) is the molecular mechanism whereby molecules, microbes, or apoptotic cells are chemically modified to have stronger interactions with - to be more "delicious" to - cell surface receptors on phagocytes and NK cells. With the antigen coated in opsonins, binding to immune cells is greatly enhanced. Opsonization also mediates phagocytosis via signal cascades from cell surface receptors. Opsonins aid the immune system in a number of ways. In a healthy individual, they mark dead and dying self cells for clearance by macrophages and neutrophils, activate complement proteins, and target cells for destruction ...
The Mammalian Phenotype (MP) Ontology is a community effort to provide standard terms for annotating phenotypic data. You can use this browser to view terms, definitions, and term relationships in a hierarchical display. Links to summary annotated phenotype data at MGI are provided in Term Detail reports.