TY - JOUR. T1 - The efficacy of complement-mediated phagocytosis of Cryptococcus neoformans is dependent on the location of C3 in the polysaccharide capsule and involves both direct and indirect C3-mediated interactions. AU - Zaragoza, Oscar. AU - Taborda, Carlos P.. AU - Casadevall, Arturo. PY - 2003/7/1. Y1 - 2003/7/1. N2 - Complement component 3 (C3) is the major opsonin for the pathogenic fungus Cryptococcus neoformans in the non-immune host. However, the efficiency of complement-mediated opsonization varies, depending on the strain, through mechanisms that are not understood. Analysis of complement-mediated phagocytosis for 12 strains grown in Sabouraud medium revealed that phagocytic indices were inversely correlated with capsule volume. In contrast, there was no correlation between phagocytic index and capsule volume for IgG1-opsonized cells. When capsule size was increased, the efficacy of complement-mediated phagocytosis decreased, whereas that of antibody-mediated phagocytosis ...
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 - Increased monocyte phagocytosis in cancer patients. AU - Ruco, L. P.. AU - Procopio, A.. AU - Uccini, S.. AU - Baroni, C. D.. PY - 1980. Y1 - 1980. N2 - Phagocytosis of IgG opsonized sheep erythrocytes (EA) by peripheral blood monocytes was evaluated in 73 individuals: 29 patients with malignant neoplastic diseases, 24 patients with non-malignant diseases and 20 normal donors. In a 30-min assay, phagocytosis values observed in 16 of 29 cancer patients and in 3 of 24 control patients were above the upper limit of the 2 S.D. interval for the normal donor population. The enhanced EA phagocytosis was dependent on a higher percentage of phagocytic cells as well as on an increased phagocytic rate. Mean values of phagocytosis obtained for cancer patients were statistically different (P ,0.01) from those obtained for normal donors and control patients. According to a still limited number of observations, no association could be demonstrated between increased monocyte phagocytosis and ...
TY - JOUR. T1 - Phagocytic signaling strategies. T2 - Fcγ receptor-mediated phagocytosis as a model system. AU - Cox, Dianne. AU - Greenberg, Steven. PY - 2001/1/1. Y1 - 2001/1/1. 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 ...
Phagocytosis of apoptotic neutrophil granulocytes by macrophages at inflammatory sites is an important determinant of the process by which inflammation resolves. We demonstrate that phagocytosis of apoptotic neutrophils, but not apoptotic lymphocytes, by human monocyte-derived macrophages is augmented rapidly following ligation of CD44 by bivalent Abs in vitro. Previously defined inhibitors of apoptotic cell recognition did not affect CD44-augmented phagocytosis of apoptotic neutrophils, suggesting that unique molecular recognition pathways are involved. These observations, together with the lack of effect of CD44 Abs upon macrophage phagocytosis of zymosan or Ig-opsonized erythrocytes, imply that CD44 may regulate the differential clearance of apoptotic leukocytes during evolution of inflammatory responses. This represents a novel role for CD44 in inflammation and tissue repair. ...
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
Antibody-mediated phagocytosis was discovered over a century ago but little is known about antibody effects in phagolysosomes. Introduction is an encapsulated yeast that is a relatively frequent cause of human disease. infection is acquired by inhalation, and host defence against this Rabbit Polyclonal to REN. fungus is critically dependent on innate immune mechanisms including alveolar macrophages (Casadevall and Perfect, 1998). has a polysaccharide capsule that interferes with phagocytosis and phagocytic cells are not able XL-888 to ingest fungal cells without opsonins (Kozel is definitely thought to be important for sponsor defence but the effectiveness of the process is definitely variable and is made complicated by the specific particularities of this encapsulated fungus. strains have historically been grouped into three varieties on the basis of genotypic and phenotypic characteristics, including antigenic variations in their main capsular polysaccharide, glucuronoxylomannan (GXM) ...
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) ...
Phagocytosis is one of the important innate immune responses that function to eliminate invading infectious agents. Monocytes, macrophages, and neutrophils are the professional phagocytic cells. Phagocytosis is a complex process involving the recognition of invading foreign particles by specific types of phagocytic receptors and the subsequent internalization of the particles. Fc gamma receptors (FCGRs) are among the best studied phagocytic receptors that bind to Fc portion of immunoglobulin G (IgG). Through their antigen binding F(ab) end, antibodies bind to specific antigen while their constant (Fc) region binds to FCGRs on phagocytes. The clustering of FCGRs by IgG antibodies on the phagocyte initiates a variety of signals, which lead, through the reorganisation of actin cytoskeleton and membrane remodelling, to the formation of pseudopod and phagosome. Fc gamma receptors are classified into three classes: FCGRI, FCGRII and FCGRIII. Each class of these FCGRs consists of several individual ...
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.
One vial of 1 mg sterile lyophilized solid sufficient for 100-200 live cell imaging phagocytosis tests in 96-well format. pHrodo® Bioparticles® for Incucyte® are sterile fluorogenic reagents ideally suited to a simple mix-and-read, real-time live cell quantification of phagocytosis. The unique pHrodo®-based system expl
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, ...
Phagocytosis is involved in several functions including nutrient uptake, immune response, inflammation, tissue homeostasis, cellular apoptotic bodies and debris elimination. Its dysfunction has impacts on normal functioning of an organism. It is involved in several diseases including the AMD pathogenesis, and treatment approaches. Mostly an initial proof of concept is tested in a laboratory conditions. Cell and tissue cultures need proper surfaces to grow and maintain them in laboratory conditions. The study aims to evaluate effect of two surfaces; tissue culture plate polystyrene and glass coverslip, on phagocytosis performed by RPE cells growing on each surface. Fresh RPE cells and ARPE-19 cell line were grown in corresponding cell culture conditions. Phagocytosis in fresh RPE cell cultures was detected and recorded. ARPE-19 cells were incubated for 4 and 24 hours with 0.2 and 1 μl red fluorescent latex beads, and then images were taken to measure the average numbers of cells, cells ...
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 ...
TY - JOUR. T1 - HIV-1 inhibits phagocytosis and inflammatory cytokine responses of human monocyte-derived macrophages to P. falciparum infected erythrocytes. AU - Ludlow, Louise E. AU - Zhou, Jingling. AU - Tippett, Emma Dawn. AU - Cheng, Wan-Jung. AU - Hasang, Wina. AU - Rogerson, Stephen J. AU - Jaworowski, Anthony. PY - 2012. Y1 - 2012. N2 - HIV-1 infection increases the risk and severity of malaria by poorly defined mechanisms. We investigated the effect of HIV-1(Ba-L) infection of monocyte-derived macrophages (MDM) on phagocytosis of opsonised P. falciparum infected erythrocytes (IE) and subsequent proinflammatory cytokine secretion. Compared to mock-infected MDM, HIV-1 infection significantly inhibited phagocytosis of IE (median (IQR) (10 (0-28) versus (34 (27-108); IE internalised/100 MDM; p = 0.001) and decreased secretion of IL-6 (1,116 (352-3,387) versus 1,552 (889-6,331); pg/mL; p = 0.0078) and IL-1beta (16 (7-21) versus 33 (27-65); pg/mL; p = 0.0078). Thus inadequate phagocytosis and ...
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 ...
Rosiglitazone Enhances the Phagocytic Ability of Thrombin-Activated Microglia through P38mapk Signaling, Qiong Mu, Likun Wang, Siying Ren, Hang Hang, Guofeng Wu1, Jinbiao Luo
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
During efferocytosis, phagocytic cells recognize dying cells by receptors binding to ligands specifically exposed on apoptotic cells. Multiple phagocytic receptors and some of their signaling pathways have been identified. However, the downstream pathways of tethering receptors that secure apoptotic cells remain elusive. It is generally assumed that tethering receptors induce signaling to mediate engulfment via interacting with co-receptors or other engulfment receptors located nearby. However, it is poorly understood whether co-receptors for tethering receptors exist during efferocytosis, and, if they do, whether they are indispensable for this process. Here, we address this issue using glycophosphatidylinositol (GPI)-anchored annexin A5 (Anxa5-GPI), an artificial tethering receptor without a putative co-receptor. Phagocytes expressing Anxa5-GPI exhibited enhanced binding of apoptotic cells, resulting in promoted ingestion of apoptotic cells in a phosphatidylserine-dependent manner. ...
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 ...
TY - JOUR. T1 - Rab GTPase regulation of bacteria and protozoa phagocytosis occurs through the modulation of phagocytic receptor surface expression. AU - Seixas, E.. AU - Escrevente, C.. AU - Seabra, M.C.. AU - Barral, D.C.. N1 - info:eu-repo/grantAgreement/FCT/3599-PPCDT/104622/PT# info:eu-repo/grantAgreement/FCT/SFRH/SFRH%2FBPD%2F34094%2F2006/PT# info:eu-repo/grantAgreement/FCT/SFRH/SFRH%2FBPD%2F78491%2F2011/PT# This work was supported by Fundacao para a Ciencia e a Tecnologia (FCT) I.P., Portugal through grant PTDC/SAU-MII/104622/2008 (to M.C.S. and D.C.B.); the FCT Investigator Program (IF/00501/2014/CP1252/CT0001, to D.C.B.); and FCT post-doctoral fellowships SFRH/BPD/34094/2006 (to E.S.) and SFRH/BPD/78491/2011 (to C.E.). PY - 2018/8/29. Y1 - 2018/8/29. N2 - Phagocytosis of invading microorganisms by professional phagocytic cells has a central role in innate immunity. However, several microorganisms developed strategies to subvert this process. Previously, we reported that bacteria and ...
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 ...
Candida albicans adapts to various conditions in different body niches by regulating gene expression, protein synthesis, and metabolic pathways. These adaptive reactions not only allow survival but also influence the interaction with host cells, which is governed by the composition and structure of the fungal cell wall. Numerous studies had shown linkages between mitochondrial functionality, cell wall integrity and structure, and pathogenicity. Thus, we decided to inhibit single complexes of the respiratory chain of C. albicans and to analyze the resultant interaction with macrophages via their phagocytic activity. Remarkably, inhibition of the fungal bc1 complex by antimycin A increased phagocytosis, which correlated with an increased accessibility of β-glucans. To contribute to mechanistic insights, we performed metabolic studies, which highlighted significant changes in the abundance of constituents of the plasma membrane. Collectively, our results reinforce the strong linkage between fungal ...
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 ...
TY - JOUR. T1 - Live cell video microscopy of phagocytosis of fungal pathogens.. AU - Lewis, Leanne Elisabeth. AU - Bain, Judith Margaret. AU - Okai, Blessing. AU - Gow, Neil Andrew Robert. AU - Erwig, Lars-Peter. PY - 2013. Y1 - 2013. N2 - Phagocytic clearance of fungal pathogens, and microorganisms more generally, may be considered to consist of four distinct stages: (i) migration of phagocytes to the site where pathogens are located; (ii) recognition of pathogen-associated molecular patterns (PAMPs) through pattern recognition receptors (PRRs); (iii) engulfment of microorganisms bound to the phagocyte cell membrane, and (iv) processing of engulfed cells within maturing phagosomes and digestion of the ingested particle. Studies that assess phagocytosis in its entirety are informative but are limited in that they do not normally break the process down into migration, engulfment and phagosome maturation, which may be affected differentially. Furthermore, such studies assess uptake as a single ...
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 ...
Cellular and vascular responses to foreign particles. . Biblioteca virtual para leer y descargar libros, documentos, trabajos y tesis universitarias en PDF. Material universiario, documentación y tareas realizadas por universitarios en nuestra biblioteca. Para descargar gratis y para leer online.
We have studied the distribution of talin in J774 cells and mouse peritoneal macrophages undergoing Fc receptor-mediated phagocytosis. At early stages of phagocytosis, talin accumulates in the cells cortical cytoplasm adjacent to the forming phagosome and extends into pseudopods that are encircling the particle. Talin colocalizes with F-actin at these sites. After particle ingestion is completed, F-actin and talin are no longer concentrated adjacent to phagosomes. Thus, talin and F-actin undergo dynamic and coordinate changes in their cytoplasmic location during Fc receptor-mediated phagocytosis. ...
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 ...
TY - JOUR. T1 - Light microscopic and ultrastructural evidence of in vivo phagocytosis of Helicobacter pylori by neutrophils. AU - Zu, Youli. AU - Cassai, N. D.. AU - Sidhu, G. S.. PY - 2000/1/1. Y1 - 2000/1/1. N2 - Helicobacter pylori is believed to cause chronic active gastritis. Infection/colonization of the gastric mucosal surface induces a mucosal inflammatory reaction in the form of lymphocytic aggregates, plasma cells and, particularly, neutrophils, which may, in turn, damage the mucosal epithelium. In vitro studies demonstrate that, in culture, the bacilli are readily phagocytosed by neutrophils, this evoking a neutrophilic oxidative burst. However, it has been claimed that neutrophils do not phagocytose H. pylori in vivo. In this study of 19 endoscopic biopsies of gastric mucosa with H. pylori-associated gastritis, Cresyl violet staining for light microscopy and electron microscopy are used to demonstrate that, in vivo, neutrophils actively phagocytose and destroy the bacilli in the ...
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
Red Zymosan Phagocytosis Kits available through Novus Biologicals. Browse our Red Zymosan Phagocytosis Kit catalog backed by our Guarantee+.
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 ...
As a crucial step in ECM remodeling, collagen degradation occurs through different processes, including both extracellular and intracellular degradation. The extracellular pathways of collagen degradation require secretion of collagenolytic proteases, whereas intracellular collagen degradation occurs in the lysosomal compartment after uptake, involving either pre-cleaved or intact fibrillar collagen. The endocytic collagen receptor uPARAP/Endo180 plays an important role in internalization of large collagen degradation products, whereas its role in the phagocytosis of fibrillar collagen has been debated. In fact, the role of this receptor in regular collagen phagocytosis in vivo has not been established. In this study, we have studied the role of uPARAP in the phagocytosis of collagen fibrils in vivo by analyzing different connective tissues of mice lacking uPARAP. Using transmission electron microscopy (TEM), we found that fibroblasts in the periosteum of tibia and calvaria, as well as in the
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
TY - JOUR. T1 - Rab35 mediates transport of Cdc42 and Rac1 to the plasma membrane during phagocytosis. AU - Shim, Jaewon. AU - Lee, Sun Min. AU - Lee, Myeong Sup. AU - Yoon, Joonsun. AU - Kweon, Hee Seok. AU - Kim, Young Joon. PY - 2010/3. Y1 - 2010/3. N2 - Phagocytosis of invading microbes requires dynamic rearrangement of the plasma membrane and its associated cytoskeletal actin network. The polarization of Cdc42 and Rac1 Rho GTPases to the site of plasma membrane protrusion is responsible for the remodeling of actin structures. However, the mechanism of Rho GTPase recruitment to these sites and the identities of accessory molecules involved in this process are not well understood. In this study, we uncovered several new components involved in innate immunity in Drosophila melanogaster. Our data demonstrate that Rab35 is a regulator of vesicle transport required specifically for phagocytosis. Moreover, recruitment of Cdc42 and Rac1 to the sites of filopodium and lamellipodium formation is ...
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 ...
is an intracellular pathogen that runs on the crafty technique to invade and proliferate within web host cells, however the distinct signaling pathways connected with phagocytic systems of stay unclear. (BMDMs) from TLR4?/? mice, displaying the co-operation of JAK2 with TLR4. Furthermore, little GTPase Cdc42 participated in the intermediate pathway of TLR4-JAK2 signaling on phagocytosis. Therefore, TLR4-linked JAK2 activation in the first cellular signaling occasions has a pivotal part in might provide achievable strategies for inhibiting invasion. Intro varieties are Gram-negative, facultative intracellular bacteria that cause abortion and infertility in many domestic and crazy mammals and a disease known as undulant fever in humans (1). These bacteria invade and replicate within professional and nonprofessional phagocytes, suggesting that undergoes many relationships with sponsor cells (2C4). The virulence associated with bacterial invasion and chronic infections by are assumed to be because ...
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.
Pneumococcal Surface Protein A (PspA) is one of the most abundant surface molecules of Streptococcus pneumoniae (or pneumococcus). As an important structural and serological variable cell surface virulence factor, it evades complement-mediated phagocytosis of pneumococcus essential for its survival in the host. The cross-protection eliciting regions in the structure of PspA have been localized in the α-helical and proline rich regions of PspA. Recent data indicate significant variation in the ability of antibodies induced against different recombinant PspAs to recognize S. pneumoniae strains expressing distinct PspAs. Identification of topographical repertoire of B-cell epitopes that elicit a protective immune response seems essential in the engineering of a superior PspA based vaccine. Herein, we revisited the epitope identification in PspA and the advent of hybridoma technology in directing identification of protective epitopic regions of PspA, having potential to be exploited in the generation of
Nascent phagosomes need to undergo a series of fusion and fission reactions to acquire the microbicidal properties required for the innate immune response. form of RILP lacking the dynein-dynactin-recruiting domain. We conclude that full maturation of phagosomes requires the retrograde emission of tubular extensions which are generated by activation of Rab7 recruitment of RILP and consequent association of phagosomes with microtubule-associated motors. Leukocytes eliminate pathogens and apoptotic cells by in the beginning engulfing them into a phagocytic vacuole. The vacuole which is derived from the plasmalemma needs to undergo extensive remodeling to acquire microbicidal and lytic capabilities (28). Such remodeling also known as maturation entails sequential fusion with numerous components of the endolysosomal pathway and concomitant fission E 2012 events that maintain the vacuolar size nearly constant (1 28 The molecular machinery underlying maturation particularly the E 2012 process of ...
Phagocytosis is common and probably appeared early in evolution,[123] evolving first in unicellular eukaryotes.[124] Amoebae, are unicellular protists that separated from the tree leading to metazoa shortly after the divergence of plants, but they share many specific functions with mammalian phagocytic cells. [124] Dictyostelium discoideum, for example, is an amoeba that lives in the soil and feeds on bacteria. Like animal phagocytes, it engulfs bacteria by phagocytosis mainly through Toll-like receptors and has other biological functions in common with macrophages.[125] Dictyostelium discoideum is social and aggregates when starved to form a migrating slug. This multicellular organism eventually produces a fruiting body with spores that are resistant to environmental dangers. Before the formation of fruiting bodies, the cells can migrate as slug-like organisms for several days. During this time, exposure to toxins or bacterial pathogens have the potential to compromise survival of the amoebae ...
Objective: APBB1IP is a Rap1-binding protein that mainly acts as a regulator of leukocyte recruitment and pathogen clearance through complement-mediated phagocytosis. However, the role of APBB1IP in tumor immunity remains unclear. This study was carried out to evaluate the prognostic landscape of APBB1IP in pan-cancer analysis and investigate the relationship between APBB1IP expression and immune infiltration.. Methods: We explored the expression pattern and prognostic value of APBB1IP in pan-cancer analysis through Kaplan-Meier Plotter and multiple databases, including TCGA, Oncomine. We then assessed the correlation between APBB1IP expression and immune cell infiltration using the TIMER database. Furthermore, we identified the proteins that interact with APBB1IP and performed epigenetic and transcriptional analyses. Multivariate Cox regression analyses were applied to construct a prognostic model, which consisted of APBB1IP and its interacting proteins, based on the lung cancer cohorts from ...
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 then synthesized and attached to virus-size particles for intravenous injection into mice that express a CD172a variant compatible with hCD47. Self peptides delay macrophage-mediated clearance of nanoparticles, which promotes persistent circulation that enhances dye and drug delivery to tumors. Self-peptide affinity for CD172a is near the optimum measured for human CD172a variants, and Self peptide also potently inhibits nanoparticle uptake mediated by the contractile cytoskeleton. The reductionist approach reveals the importance of human Self peptides and their utility in enhancing drug delivery and imaging.. ...
Part I appeared in Foresight Update 45.. Ingestion or phagocytosis of medical nanorobots [1] by white cells will occur in a series of well-defined steps. Normally inactive white cells are activated when they encounter a foreign particle, producing a change in metabolic activity and cell shape. During contact and recognition of the foreign particle, the phagocyte plasma membrane develops a local invagination or dimple. The particle is drawn inside and the dimple closes, often pinching off to form a small vacuole or phagosome consisting of everted cell wall membrane, trapping the particle inside the cell. The phagosome then forms a phagolysosome by merging with a lysosome, whose contents (including degradative lysozymes) are released into the smaller vacuole, attacking the enclosed foreign or denatured proteins. Afterwards the phagolysosomal vacuole may be absorbed or released to the outside at the cells outer surface via exocytosis, producing a large membrane flow. In cultured macrophages an ...
In order to understand the potential role that VASP and actin polymerization might have in M. tuberculosis infection, it is important to understand how the infection initiates. The airborne transmission of M. tuberculosis bacilli from an infected individual upon inhalation places the bacteria in the inner lining of the lungs. There, the bacilli are engulfed by alveolar macrophages through phagocytosis. M. tuberculosis is able to survive the innate antimicrobial defenses of the alveolar macrophages. Mycobacteria are distinct in that they are able to live inside host macrophages, rather than as free-living organisms in the host body. It is well established that rearrangement of the actin cytoskeleton is important to the early steps of phagocytosis by host macrophages (de Chastellier et al, 2000). Entry of a particle into a cell by the process of phagocytosis entails the reorganization of the actin cytoskeleton underlying the area of the plasma membrane of the host cell that is in contact with the ...
In order to clarify whether PMNs mediate trogocytosis or phagocytosis of opsonized primary CLL B cells, we performed live-cell time-lapse microscopy experiments. Purified PMNs from healthy donors were cocultured with CLL B-cell samples in the presence of the following anti-CD20 antibodies: wild-type rituximab (RTX-WT), glycoengineered rituximab (RTX-GE), or glycoengineered obinutuzumab (OBZ-GE). Cells were followed for up to 6 hours under the microscope. To our surprise, we could not detect any phagocytic event in up to 6 hours of time-lapse experiments, but only observed the repeated close contact between PMNs and anti-CD20-opsonized CLL B-cell targets, suggesting that trogocytosis rather than phagocytosis takes place. Figure 1A shows selected images of PMNs in contact with CLL B cells opsonized with OBZ-GE. The phase-contrast images obtained at the start of the experiment, before all CLL B cells had settled down to the bottom of the well, show the clear morphological differences between the ...
Alveolar macrophage seeking E. coli with extended, twisted filopodia (phagocytosis, mammal lung pleural cavity), 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: x910 when shortest axis printed at 25 millimetres. - Stock Image C036/9793
The importance of intact host defense mechanisms for successful antimicrobial therapy was investigated in an animal model. Recovery from lobar pneumococcal pneumonia as a result of penicillin therapy was studied in normal rats and in rats treated with cobra venom factor. This factor was used to selectively suppress the phagocytosis of pneumococci as a result of complement depletion. Although complete recovery from the infection occurred in normal rats after appropriate penicillin therapy, this was not the case in cobra venom factor-treated rats. Within the limitations of this study, evidence is presented for loss of antibiotic activity as a consequence of impaired phagocytosis. ...
Kidney injury molecule 1 (KIM-1, also known as TIM-1) is markedly upregulated in the proximal tubule after injury and is maladaptive when chronically expressed. Here, we determined that early in the injury process, however, KIM-1 expression is antiinflammatory due to its mediation of phagocytic processes in tubule cells. Using various models of acute kidney injury (AKI) and mice expressing mutant forms of KIM-1, we demonstrated a mucin domain-dependent protective effect of epithelial KIM-1 expression that involves downregulation of innate immunity. Deletion of the mucin domain markedly impaired KIM-1-mediated phagocytic function, resulting in increased proinflammatory cytokine production, decreased antiinflammatory growth factor secretion by proximal epithelial cells, and a subsequent increase in tissue macrophages. Mice expressing KIM-1Δmucin had greater functional impairment, inflammatory responses, and mortality in response to ischemia- and cisplatin-induced AKI. Compared with primary renal ...
Experiments using human monocytes and the yeast Saccharomyces cerevisiae have shown that fibronectin is a major plasma opsonin. Further studies have shown that fibronectin promotes the ingestion as well as the adherence of micro-organisms. These observations are independent of the non-physiological concentrations of heparin used in other assay systems.. ...
Gómez-Muñoz, A., Kong, J.Y., Salh, B., Steinbrecher, U.P. (2004). Ceramide-1-phosphate blocks apoptosis through inhibition of acid sphingomyelinase in macrophages. J Lipid Res 45:99-105. [PubMed]Hinkovska Galcheva, V.T., Boxer, L.A.,Mansfield, P.J., Harsh, D.,Blackwood, A., Shayman, J.A.. (1998). The formation of ceramide-1-phosphate during neutrophil phagocytosis and its role in liposome fusion. J Biol Chem 273:50,33203. [PubMed]Gómez-Muñoz, A.,Duffy, P.A., Martin, A., OBrien, L., Byun, H.S., Bittman, R., Brindley, D.N. (1995). Short-chain ceramide-1-phosphates are novel stimulators of DNA synthesis and cell division: antagonism by cell-permeable ceramides. Mol Pharmacol 47:833-9. [PubMed ...
Gómez-Muñoz, A., Kong, J.Y., Salh, B., Steinbrecher, U.P. (2004). Ceramide-1-phosphate blocks apoptosis through inhibition of acid sphingomyelinase in macrophages. J Lipid Res 45:99-105. [PubMed]Hinkovska Galcheva, V.T., Boxer, L.A.,Mansfield, P.J., Harsh, D.,Blackwood, A., Shayman, J.A.. (1998). The formation of ceramide-1-phosphate during neutrophil phagocytosis and its role in liposome fusion. J Biol Chem 273:50,33203. [PubMed]Gómez-Muñoz, A.,Duffy, P.A., Martin, A., OBrien, L., Byun, H.S., Bittman, R., Brindley, D.N. (1995). Short-chain ceramide-1-phosphates are novel stimulators of DNA synthesis and cell division: antagonism by cell-permeable ceramides. Mol Pharmacol 47:833-9. [PubMed ...
Neutrophils (also called polymorphonuclear leukocytes, PMNs) are the most abundant white blood cells in humans and play a central role in innate host defense. Another distinguishing feature of PMNs is their short lifespan. Specifically, these cells survive for less than 24 hours in the bloodstream and are inherently pre-programed to die by constitutive apoptosis. Recent data indicate that this process is regulated by intracellular signaling and changes in gene expression that define an apoptosis differentiation program. Infection typically accelerates neutrophil turnover, and as such, phagocytosis-induced cell death (PICD) and subsequent clearance of the corpses by macrophages are essential for control of infection and resolution of the inflammatory response. Herein we reprise recent advances in our understanding of the molecular mechanisms of neutrophil apoptosis with a focus on regulatory factors and pathway intermediates that are specific to this cell type. In addition, we summarize mechanisms
European Society of Human Genetics 2018. Somatic mutations in specific and connected sub-pathways are associated to short neuroblastoma patients survival and indicate proteins targetable at onset of disease. Maria Rosaria Esposito, Andrea Binatti, Marcella Pantile, Alessandro Coppe, Katia Mazzocco, Luca Longo, Mario Capasso, Vito Alessandro Lasorsa, Roberto Luksch, Stefania Bortoluzzi, Gian Paolo Tonini. International Journal of Cancer. BMP9 counteracts the tumorigenic and pro-angiogenic potential of glioblastoma. Elena Porcù, Francesca Maule, Daniele Boso, Elena Rampazzo, Vito Barbieri, Gaia Zuccolotto, Antonio Rosato, Chiara Frasson, Giampietro Viola, Allesandro Della Puppa, Giuseppe Basso, Luca Persano. Official journal of the Cell Death Differentiation Association. How can nanotechnology help the fight against breast cancer?. Elisabetta Avitabile, Davide Bedognetti, Gianni Ciofani, Alberto Bianco and Lucia Gemma Delogu. Nanoscale. Analytical aspects of sunitinib and its geometric isomerism ...
Many of the cells of the immune system have a phagocytic ability, at least at some point during their life cycles. Phagocytosis is an important and effective mechanism of destroying pathogens during innate immune responses. The phagocyte takes the organism inside itself as a phagosome, which subsequently fuses with a lysosome and its digestive enzymes, effectively killing many pathogens. On the other hand, some bacteria including Mycobacteria tuberculosis, the cause of tuberculosis, may be resistant to these enzymes and are therefore much more difficult to clear from the body. Macrophages, neutrophils, and dendritic cells are the major phagocytes of the immune system.. A macrophage is an irregularly shaped phagocyte that is amoeboid in nature and is the most versatile of the phagocytes in the body. Macrophages move through tissues and squeeze through capillary walls using pseudopodia. They not only participate in innate immune responses but have also evolved to cooperate with lymphocytes as part ...
The delivery of phagocytic cells, monocytes or neutrophils, to the site of microbial infection involves two processes: Diapedisis: the migration of cells across vascular walls which is initiated by the mediators of inflammation (kinins, histamine, prostaglandins, etc.) Chemotaxis. Phagocytes are motile by ameboid action. Chemotaxis is movement of the cells in response to a chemical stimulus. The eventual concentration of phagocytes at a site of injury results from chemotactic response by the phagocytes which is analogous to bacterial chemotaxis. A number of chemotactic factors (attractants) have been identified, both for neutrophils and monocytes. These include bacterial products, cell and tissue debris, and components of the inflammatory exudate such as peptides derived from complement. Phagocytic adherence Phagocytosis is initiated by adherence of a particle to the surface of the plasma membrane of a phagocyte. This step usually involves several types of surface receptors on the phagocyte ...
casSAR Dugability of P08631 | HCK | Tyrosine-protein kinase HCK - Also known as HCK_HUMAN, HCK. Non-receptor tyrosine-protein kinase found in hematopoietic cells that transmits signals from cell surface receptors and plays an important role in the regulation of innate immune responses, including neutrophil, monocyte, macrophage and mast cell functions, phagocytosis, cell survival and proliferation, cell adhesion and migration. Acts downstream of receptors that bind the Fc region of immunoglobulins, such as FCGR1A and FCGR2A, but also CSF3R, PLAUR, the receptors for IFNG, IL2, IL6 and IL8, and integrins, such as ITGB1 and ITGB2. During the phagocytic process, mediates mobilization of secretory lysosomes, degranulation, and activation of NADPH oxidase to bring about the respiratory burst. Plays a role in the release of inflammatory molecules. Promotes reorganization of the actin cytoskeleton and actin polymerization, formation of podosomes and cell protrusions. Inhibits TP73-mediated transcription