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Journal of Insect Science (Online) 2007Tick cell lines were used to model the effects of endosymbiont infection on phagocytic immune responses. The lines tested for their ability to phagocytose the Lyme...
Phagocytosis of the Lyme disease spirochete, Borrelia burgdorferi, by cells from the ticks, Ixodes scapularis and Dermacentor andersoni, infected with an endosymbiont, Rickettsia peacockii.
Tick cell lines were used to model the effects of endosymbiont infection on phagocytic immune responses. The lines tested for their ability to phagocytose the Lyme disease spirochete, Borrelia burgdorferi (Spirochaetales: Spirochaetaceae), were ISE6 and IDE12 from the black-legged tick, Ixodes scapularis Say (Acari: Ixodidae) and DAE15 from the Rocky Mountain wood tick, Dermacentor andersoni Stiles. Rickettsia peacockii (Rickettsiales: Rickettsiaceae), an endosymbiont of D. andersoni, was used as a representative tick endosymbiont. 70-80% of uninfected or R. peacocciz-infected IDE12 and DAE15 cells phagocytosed heat-killed borreliae and 80-90% of IDE12 and DAE15 cells phagocytosed viable spirochetes. ISE6 cells were permissive of spirochetes; less than 1% of these cells phagocytosed borreliae, and spirochetes remained adherent to the cells seven days after inoculation. Cytochalasin B blocked phagocytosis of killed and viable borreliae by IDE12 cells, and prevented phagocytosis of killed spirochetes by DAE15 cells, whereas viable spirochetes successfully invaded cytochalasin-treated DAE15. IDE12 and DAE15 cells degraded borreliae within phagolysosome-like compartments. Time-lapse microscopy showed that DAE15 cells phagocytosed borreliae more rapidly than IDE12 cells. IDE12 and DAE15 cells eliminated most adherent spirochetes within 7 days of inoculation. Thus, endosymbiont infection does not significantly interfere with the phagocytic activity of immunocompetent tick cells.
Topics: Animals; Borrelia burgdorferi; Cell Line; Cytochalasin B; Dermacentor; Green Fluorescent Proteins; Ixodes; Phagocytosis; Rickettsia; Symbiosis
PubMed: 20331397
DOI: 10.1673/031.007.5801 -
Annals of Clinical and Laboratory... May 2018An aberrant production of inflammatory cytokines, with resultant febrile response, is a cardinal finding of hemophagocytic syndrome. A role of inflammatory cytokines on...
OBJECTIVE
An aberrant production of inflammatory cytokines, with resultant febrile response, is a cardinal finding of hemophagocytic syndrome. A role of inflammatory cytokines on phagocytosis and clearance of apoptotic cells or particles has been shown, but effects of cytokines or hyperthermia on phagocytosis of viable blood cells were not fully understood. We examined effects of cytokines and hyperthermia on phagocytosis, and externalization of phosphatidylserine on the surface of phagocytosed blood cells, to clarify the pathophysiology of hemophagocytic syndrome.
METHODS
THP-1 macrophage cells were incubated with non-opsonized and opsonized sheep erythrocytes (SE) in the presence of tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), macrophage-colony stimulating factor (M-CSF), interleukin (IL)-6, IL-10 or IL-18, and phagocytic activity was analyzed. Co-operative effect between cytokines was also examined. In addition, SE were incubated at 37 or 39°C, and phagocytic activity was analyzed. After treatment of SE with cytokine or hyperthermia, phosphatidylserine expression of the cell surface was analyzed by detecting Annexin V-positive cells.
RESULTS
IL-6, IL-10 and IL-18 significantly increased phagocytosis of non-opsonized SE, but IFN-γ suppressed it. Phagocytosis of opsonized SE was significantly increased by any of the cytokines. IFN-γ suppressed and IL-10 enhanced phagocytic activity induced by other cytokines in non-opsonized SE, while in opsonized SE, both cytokines co-operated with other cytokines to enhance phagocytosis. Incubation of SE at a high temperature (39°C) resulted in increased phagocytic activity, as compared to SE incubated at 37°C. Cytokines and a high temperature did not increase the number of Annexin V-positive SE.
CONCLUSIONS
IL-6, IL-10 and IL-18 can augment phagocytosis of viable blood cells, whether cells are opsonized or not. Hyperthermia also enhances phagocytosis. These in vitro data suggest that therapy for targeting cytokine (IL-6, IL-10 or IL-18) by using biologics or small molecule drugs may be beneficial for the treatment of hemophagocytic syndrome. Unlike the case of apoptotic cells, phagocytosis of viable blood cells seems to be mediated via phosphatidylserine-independent manner.
Topics: Animals; Cells, Cultured; Cytokines; Erythrocytes; Humans; Hyperthermia, Induced; Lymphohistiocytosis, Hemophagocytic; Macrophages; Phagocytosis; Phosphatidylserines; Sheep
PubMed: 29970434
DOI: No ID Found -
Journal of Immunology (Baltimore, Md. :... Jan 2010Neutrophil granulocytes are rapidly recruited from the bloodstream to the site of acute inflammation where they die in large numbers. Because release of toxic substances...
Neutrophil granulocytes are rapidly recruited from the bloodstream to the site of acute inflammation where they die in large numbers. Because release of toxic substances from dead neutrophils can propagate the inflammatory response leading to tissue destruction, clearance of dying inflammatory neutrophils has a critical function in the resolution of the inflammatory response. Apoptotic neutrophils are phagocytosed primarily by macrophages, provided these cells are present in adequate numbers. However, macrophages are rare at sites of acute inflammation, whereas the number of neutrophils can be extremely high. In the current study, in vitro experiments with human neutrophils were carried out to investigate whether neutrophils can ingest apoptotic neutrophils. We show that naïve granulocytes isolated from venous blood have a limited capacity to phagocytose apoptotic cells. However, exposure to activating stimuli such as LPS, GM-CSF and/or IFN-gamma results in enhanced phagocytosis of apoptotic cells. The efficient uptake of apoptotic cells by neutrophils was found to depend on the presence of heat labile serum factors. Importantly, the contact to or uptake of apoptotic cells inhibited neutrophil functions such as respiratory burst and the release of the proinflammatory cytokines TNF-alpha and interferon-inducible protein-10. Contact to apoptotic cells, however, induced the secretion of IL-8 and growth-related oncogene-alpha, which was independent of NF-kappaB and p38 MAPK but involved C5a and the ERK1/2 pathway. The data suggest that activated neutrophils participate in the clearance of apoptotic cells. In addition, because apoptotic cells inhibit proinflammatory functions of neutrophils, uptake of apoptotic cells by neutrophils contributes to the resolution of inflammation.
Topics: Apoptosis; Cells, Cultured; Cytokines; Humans; Inflammation; Neutrophils; Phagocytosis; Respiratory Burst; Signal Transduction
PubMed: 19949068
DOI: 10.4049/jimmunol.0900564 -
Frontiers in Immunology 2018Neutrophils recognize particulate substrates of microbial or endogenous origin and react by sequestering the cargo phagocytosis or by releasing neutrophil extracellular... (Review)
Review
Neutrophils recognize particulate substrates of microbial or endogenous origin and react by sequestering the cargo phagocytosis or by releasing neutrophil extracellular traps (NETs) outside the cell, thus modifying and alerting the environment and bystander leukocytes. The signals that determine the choice between phagocytosis and the generation of NETs are still poorly characterized. Neutrophils that had phagocytosed bulky particulate substrates, such as apoptotic cells and activated platelets, appear to be "poised" in an unresponsive state. Environmental conditions, the metabolic, adhesive and activation state of the phagocyte, and the size of and signals associated with the tethered phagocytic cargo influence the choice of the neutrophils, prompting either phagocytic clearance or the generation of NETs. The choice is dichotomic and apparently irreversible. Defects in phagocytosis may foster the intravascular generation of NETs, thus promoting vascular inflammation and morbidities associated with diseases characterized by defective phagocytic clearance, such as systemic lupus erythematosus. There is a strong potential for novel treatments based on new knowledge of the events determining the inflammatory and pro-thrombotic function of inflammatory leukocytes.
Topics: Apoptosis; Extracellular Traps; Humans; Neutrophils; Phagocytosis
PubMed: 29515586
DOI: 10.3389/fimmu.2018.00288 -
Biomaterials 1992Particles of known size ranges of carbon fibre-reinforced carbon were presented to in vitro cultures of murine macrophages. Particles of up to 20 microns diameter were...
Particles of known size ranges of carbon fibre-reinforced carbon were presented to in vitro cultures of murine macrophages. Particles of up to 20 microns diameter were phagocytosed. Larger particles were not phagocytosed but became surrounded by aggregations of macrophages, some of which migrated on to the particle surfaces. Mean rates of phagocytosis up to 2.5 particles per hour were observed. Cells presented with a large excess of particles became rounded, detached from the substrate and some underwent lysis. The implications of these findings for the fate of particulates released from implanted medical devices is discussed. It is argued that a mechanism exists where particles in the size range 8-20 microns, released from medical devices, are small enough to be phagocytosed by macrophages and transported to the lymphatics and subsequently to the vascular circulation but large enough to lodge in capillary beds of tissues remote from the implant site.
Topics: Animals; Carbon; Cells, Cultured; Macrophages; Mice; Particle Size; Phagocytosis
PubMed: 1391413
DOI: 10.1016/0142-9612(92)90035-m -
The American Journal of Pathology Oct 1971Colloidal carbon, injected intramuscularly, migrates rapidly and selectively to a corresponding lymph node by lymphatics, in which the carbon travels as free particles....
Colloidal carbon, injected intramuscularly, migrates rapidly and selectively to a corresponding lymph node by lymphatics, in which the carbon travels as free particles. In the lymph node, carbon particles are mainly phagocytosed and stored by macrophages, which exhibit morphologic changes in the plasma membrane and the tubules of endoplasmic reticulum. The subsequent migration of these cells results in wide distribution of carbon in the lymph node. Cytoplasmic changes also occur in sinusoidal macrophages, in which no carbon is seen. A possible relation of these macrophages to macrophage migration in lymph node is postulated. The lymphatic endothelial cells, like endothelial cells in any other organ, phagocytose only a small amount of carbon and only after functional overload of the macrophages.
Topics: Animals; Carbon; Cell Membrane; Colloids; Endoplasmic Reticulum; Injections, Intramuscular; Lymph Nodes; Macrophages; Microscopy, Electron; Phagocytosis; Rats; Rats, Inbred Strains; Time Factors
PubMed: 5096370
DOI: No ID Found -
Journal of Neuroimmunology Mar 2012The ability of microglial cells to phagocytose bacteria after stimulation with the endocannabinoid palmitoylethanolamide (PEA) was studied in vitro. PEA increased the...
The ability of microglial cells to phagocytose bacteria after stimulation with the endocannabinoid palmitoylethanolamide (PEA) was studied in vitro. PEA increased the phagocytosis of unencapsulated Streptococcus pneumoniae R6 and encapsulated Escherichia coli K1 by murine microglial cells significantly after 30 min of microglial stimulation. This suggested that stimulation of microglial cells by PEA can increase the resistance of the brain against CNS infections.
Topics: Amides; Animals; Anti-Inflammatory Agents, Non-Steroidal; Cells, Cultured; Endocannabinoids; Escherichia coli; Ethanolamines; Mice; Mice, Inbred C57BL; Microglia; Palmitic Acids; Phagocytosis; Streptococcus pneumoniae
PubMed: 22244572
DOI: 10.1016/j.jneuroim.2011.12.013 -
Graefe's Archive For Clinical and... Jan 2007This study is a first step to investigate phagocytosis of collagens by human retinal Müller cells, since Müller cells could be involved in remodelling of the vitreous...
PURPOSE
This study is a first step to investigate phagocytosis of collagens by human retinal Müller cells, since Müller cells could be involved in remodelling of the vitreous and vitreoretinal interface in the human eye.
METHODS
Müller cells in culture were exposed to 2.0 microm fluorescent latex beads coated with BSA and human types I, II, and IV collagen and to non-coated beads for 2, 12, 24, and 48 h. To influence phagocytosis, cytochalasin B and anti-integrin subunits (alpha1, alpha2, and beta1) were added to the cells. Phagocytosis was evaluated by flow cytometry, transmission electron microscopy (TEM) and confocal microscopy.
RESULTS
Müller cells preferred to phagocytose beads coated with type II collagen compared with type IV collagen-, BSA- and non-coated beads. Phagocytosis of type I collagen-coated beads was intermediate. TEM and confocal microscopic evaluation confirmed phagocytosis of the beads. No significant differences were observed in phagocytosis of type II collagen-coated beads in the case of addition of cytochalasin B and anti-integrin subunits. Immunohistochemical analyses revealed that Müller cells were positive, under all tested circumstances, for vimentin and CRALBP. Less than 5% of the cells tested were GFAP positive.
CONCLUSIONS
Our observations demonstrate that human Müller cells in culture prefer to phagocytose type II collagen. In contrast, the phagocytosis of type IV collagen is comparable with the control coatings. We speculate that the relatively limited collagen phagocytosis by Müller cells supports a possible role for Müller cells in the slow process of vitreoretinal remodelling in adult human eyes.
Topics: Carrier Proteins; Cell Line; Cell Survival; Collagen Type I; Collagen Type II; Collagen Type IV; Cytochalasin B; Fibroblasts; Flow Cytometry; Glial Fibrillary Acidic Protein; Humans; Immunoenzyme Techniques; Integrins; Microscopy, Confocal; Microscopy, Electron, Transmission; Microspheres; Neuroglia; Phagocytosis; Retina; Vimentin
PubMed: 16598463
DOI: 10.1007/s00417-006-0314-6 -
Tissue & Cell Jun 2010During spermatogenesis of the carnivorous sponge Asbestopluma occidentalis, follicle cells that lined the spermatocysts phagocytosed unreleased mature sperm. Such...
During spermatogenesis of the carnivorous sponge Asbestopluma occidentalis, follicle cells that lined the spermatocysts phagocytosed unreleased mature sperm. Such follicle cells are part of the complex envelope that limits spermatocysts of A. occidentalis, which is also comprised of a collagen layer, a thick layer of intertwined cells, and spicules. Follicle cells showed vesicles containing single phagocytosed spermatozoa within their cytoplasm. Additionally, lipids and other inclusions were observed within the cytoplasm of follicle cells. It is likely that follicle cells recapture nutrients by phagocytosing spermatozoa and use them to form lipids and other inclusions. Such sperm phagocytosis is usually performed in higher invertebrates and vertebrates by Sertoli cells that are located in the testis wall. While Sertoli cells develop a wide range of functions such as creating a blood-testis barrier, providing crucial factors to ensure correct progression of spermatogenesis, and phagocytosis of aberrant, degenerating, and unreleased sperm cells, sponge follicle cells may only display phagocytotic activity on spermatogenic cells.
Topics: Animals; Feeding Behavior; Male; Phagocytosis; Porifera; Spermatozoa
PubMed: 20409567
DOI: 10.1016/j.tice.2010.03.001 -
Ageing Research Reviews Dec 2021Corpora amylacea (CA) have been described in several human organs and have been associated with ageing and several pathological conditions. Although they were first... (Review)
Review
Corpora amylacea (CA) have been described in several human organs and have been associated with ageing and several pathological conditions. Although they were first discovered two centuries ago, their function and significance have not yet been identified. Here, we provide a chronological summary of the findings on CA in various organs and identify their similarities. After collecting and integrating these findings, we propose to consider CA as waste containers created by specific cells, which sequester waste products and foreign products, and assemble them within a glycan structure. The containers are then secreted into the external medium or interstitial spaces, in this latter case subsequently being phagocytosed by macrophages. This proposal explains, among others, why CA are so varied in content, why only some of them contain fibrillary amyloid proteins, why all of them contain glycan structures, why some of them contain neo-epitopes and are phagocytosed, and why they can be intracellular or extracellular structures. Lastly, in order to avoid the ambiguity of the term amyloid (which can indicate starch-like structures but also insoluble fibrillary proteins), we propose renaming CA as "wasteosomes", emphasising the waste products they entrap rather than their misleading amyloid properties.
Topics: Aging; Cytoskeleton; Epitopes; Humans; Phagocytosis
PubMed: 34634491
DOI: 10.1016/j.arr.2021.101484