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The role of the endocytic and autophagic molecular machineries in the removal of apoptotic cells

Viegas, Michelle
Fonte: Universidade de Coimbra Publicador: Universidade de Coimbra
Tipo: Tese de Doutorado
Português
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46.27%
Every day the human body turns over billions of cells ensuring the disposal of unwanted targets that die by apoptosis. The prompt and efficient removal of apoptotic cells by cell line (vascular SMC). The maturation of phagosomes containing dying cells was compared with the processing of phagosomes loaded with IgG-opsonized particles, which are internalized via Fcγ-receptors and are the best characterized phagocytic model. At the present work, we provide evidence that the nature of the cargo modulates the phagocytic response, since phagosomes carrying apoptotic particles reach the lysosomes with a delay when compared to those containing IgG-opsonized particles. Furthermore, for the first time, we have identified some canonical autophagy effectors in phagolysosome formation, suggesting that LC3-Associated Phagocytosis (LAP), a process involved in phagosome maturation, implies more than the phagosomal recruitment of LC3 (Sanjuan et al., 2007). Indeed, experiments performed in bone marrow-derived macrophages from p62-KO mice clearly suggest that p62, despite not being required for LC3 recruitment, is important for phagolysosome biogenesis. In summary, this data will improve our knowledge on the molecular machinery and mechanisms involved in efferocytosis. In the end...

Diapocynin versus apocynin as pretranscriptional inhibitors of NADPH oxidase and cytokine production by peripheral blood mononuclear cells

KANEGAE, Marilia P. P.; CONDINO-NETO, Antonio; PEDROZA, Luis Alberto; ALMEIDA, Ana Carolina de; REHDER, Jussara; FONSECA, Luiz Marcos da; XIMENES, Valdecir F.
Fonte: ACADEMIC PRESS INC ELSEVIER SCIENCE Publicador: ACADEMIC PRESS INC ELSEVIER SCIENCE
Tipo: Artigo de Revista Científica
Português
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46.17%
Apocynin has been extensively used as an inhibitor of NADPH oxidase (NOX) in many experimental models using phagocytic and non-phagocytic cells. Currently, there is some controversy about the efficacy of apocynin in non-phagocytic cells, but in phagocytes the reported results are consistent, which could be due to the presence of myeloperoxidase in these cells. This enzyme has been proposed as responsible for activating apocynin by generating its dimer, diapocynin, which is supposed to be the active compound that prevents NADPH oxidase complex assembly and activation. Here, we synthesized diapocynin and studied its effect on inhibition of gp91(phox) RNA expression. We found that diapocynin strongly inhibited the expression of gp91(phox)mRNA in peripheral blood mononuclear cells (PBMC). Only at a higher concentration, apocynin was able to exert the same effect. We also compared the apocynin and diapocynin efficacy as inhibitors of tumor necrosis factor-alpha (TNF-alpha) and interleukin-10 (IL-10) production in response to lipopolysaccharide (LPS)-activated PBMC. Although apocynin did inhibit TNF-alpha production, diapocynin had a much more pronounced effect, on both TNF-alpha and IL-10 production. In conclusion, these findings suggest that the bioconversion of apocynin to diapocynin is an important issue not limited to enzymatic activity inhibition...

Rotavirus and reovirus interaction with mouse peritoneal resident phagocytic cells

Guimarães,M.A.A.M.; Nozawa,C.M.; Guimarães,A.C.C.; Ramos,S.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/1997 Português
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66.36%
Rotaviruses and reoviruses are involved in human and animal diseases. It is known that both viruses penetrate the gastrointestinal tract but their interaction with phagocytic cells is unknown. To study this interaction, peritoneal resident phagocytic cells were used and rotavirus and reovirus replication in peritoneal phagocytic cells was observed. However, rotavirus replication in these cells led to the production of defective particles since MA-104 cells inoculated with rotavirus phagocytic cell lysate did not show any evidence of virus replication. On the basis of these results, we suggest that, although reovirus dissemination may be helped by these phagocytic cells, these cells may control rotavirus infection and probably contribute to the prevention of its dissemination.

De novo synthesis of Legionella pneumophila antigens during intracellular growth in phagocytic cells.

Susa, M; Hacker, J; Marre, R
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /05/1996 Português
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46.16%
Legionella pneumophilia is a gram-negative rod which is able to multiply within phagocytic cells. The process of phagocytosis leads to a rapid environmental change that might require a coordinate regulation of gene expression to ensure intracellular survival. Since there is little information on up- and downregulation of genes during the early phases of phagocytosis, we radiolabeled intracellular L. pneumophila at different times after phagocytosis by macrophages of the Mono Mac 6 cell line and immunoprecipitated antigens with antilegionella sera or monoclonal antibodies. We could identify two antigens which were upregulated, one of which was the Mip protein, three antigens which were downregulated, and three antigens which were not detectable in extracellularly grown L. pneumophila. The Mip protein was stained most intensively 4 to 8 h after intracellular infection, suggesting that it is needed during intracellular multiplication rather than initiation of infection. A 44-kDa antigen which was not detectable during extracellular growth was most prominent from 2 to 4 h postinfection when Mono Mac 6 cells were used as phagocytic cells. The 44-kDa antigen was also expressed during growth with Acanthamoeba castelanii, MRC-5, and U937 cells but with different kinetics. Synthesis of this antigen was not dependent on protein synthesis of the host cell. Since the 44-kDa antigen could be precipitated by an antiserum produced against a recombinant Escherichia coli harboring a plasmid with an L. pneumophila insert which also codes for the mip gene...

An in vitro-differentiated human cell line as a model system to study the interaction of Neisseria gonorrhoeae with phagocytic cells.

Hauck, C R; Lorenzen, D; Saas, J; Meyer, T F
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /05/1997 Português
Relevância na Pesquisa
46.31%
The extreme host specificity of pathogenic neisseriae limits investigations aimed at the analysis of bacterial-host interactions almost completely to the use of in vitro models. Although permanent epithelial and endothelial cell lines are already indispensable tools with respect to initial infection processes, studies concerning the interaction of neisseriae with phagocytic cells have been confined to primary human blood cells. We investigated the use of human leukemia-derived monocytic and myelomonocytic cell lines that can be differentiated in vitro towards phagocytic cells by a panel of chemical and biological reagents including cytokines, vitamin analogs, and antileukemia drugs. Whereas tumor necrosis factor alpha, gamma interferon, bufalin, or granulocyte-macrophage colony-stimulating factor only marginally increased the ability of monocytic MonoMac-6 and myelomonocytic JOSK-M cells to interact with the bacteria, retinoic acid and vitamin D3 treatment for 2 to 4 days led to highly phagocytic cells that internalized gonococci in an Opa protein-specific manner. This is comparable to the phagocytosis by primary monocytes from human blood, where more than 80% of cells are infected with intracellular bacteria. The increased phagocytic activity of JOSK-M cells following in vitro differentiation was paralleled by enhanced oxidative burst capacity. Whereas undifferentiated cells responded to neither phorbol 12-myristate 13-acetate nor other known soluble and particulate stimuli...

Evidence that Candida albicans binds via a unique adhesion system on phagocytic cells in the marginal zone of the mouse spleen.

Kanbe, T; Jutila, M A; Cutler, J E
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /05/1992 Português
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46.19%
We recently demonstrated by using an ex vivo adhesion assay that Candida albicans yeast cells exhibit a unique binding affinity for the marginal zone of the spleen. This binding event provides a working model for studying mechanisms of organ dissemination of the fungus from the blood. By using the ex vivo assays reported here, we showed by bright-field and electron microscopic techniques that mouse spleen marginal zone cells capable of ingesting India ink particles are also involved in yeast cell attachment. During splenic clearance of yeast cells from the circulation in vivo, C. albicans is also associated exclusively with marginal zone cells capable of ingesting India ink. The ability to ingest the ink particles is not necessarily related to yeast cell adherence, because the fungal cells did not bind to phagocytic cells in the splenic red pulp. In fact, the marginal zone phagocytic cells appear to have a unique binding system, because yeast cells also did not bind to phagocytes in other tissues, such as the thymus and peritoneum, or to seven different myeloid cell lines. In addition, antibodies to a number of well-characterized murine adhesion molecules, such as leukocyte integrins, LECAM-1, and CD44, had no effect on binding. On the basis of these results...

Effects of Listeria monocytogenes Hemolysin on Phagocytic Cells and Lysosomes

Kingdon, G. Charles; Sword, C. P.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /04/1970 Português
Relevância na Pesquisa
46.16%
The effects of Listeria monocytogenes hemolysin on lysosomes and phagocytic cells were investigated. Hemolysin caused release of β-glucuronidase and acid phosphatase from suspensions of rabbit and rat lysosomes prepared from liver homogenates. The degree of lysis was proportional to the concentration of hemolysin added. There appeared to be no significant difference between the sensitivities of rat and rabbit lysosomes to disruption. Studies on the effect of pH and temperature on lytic activity suggested that hemolysin could function under conditions which might exist within phagocytic cells. Peritoneal exudates from rabbits and mice were exposed to hemolysin and observed by phase microscopy. Hemolysin possessed leucocidal activity and caused degranulation of both rabbit and mouse cells. Optimal activity against lysosomes and peritoneal exudate cells required activation of hemolysin with a reducing agent and could be prevented if hemolysin was previously incubated with cholesterol.

Resistance of spores of Aspergillus fumigatus to ingestion by phagocytic cells.

Robertson, M D; Seaton, A; Milne, L J; Raeburn, J A
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /06/1987 Português
Relevância na Pesquisa
46.17%
Phagocytic cells are believed to have an important role in the eradication of fungal spores from the lung. The ability of human and mouse cells to phagocytose the opportunistic fungus Aspergillus fumigatus has been examined, spores of the non-pathogenic fungus Penicillium ochrochloron being used for comparison. Most spores became associated with cells. Those of A fumigatus appeared to remain bound to the surface of the phagocyte rather than being ingested; in contrast, P ochrochloron spores appeared to be phagocytosed more readily, although they also were seen, in small numbers, o n the cell surface. In view of the subjective nature of these observations, the effects of spore diffusates on phagocytosis were examined. Diffusates from spores of A fumigatus were shown to inhibit phagocytosis of antibody coated radiolabelled sheep red blood cells by primed mouse phagocytic cells. Diffusates of spores of P ochrochloron had no such effect. These results suggest that when spores of A fumigatus become bound to the surface of phagocytes they are able to release a substance that inhibits their ingestion while having little or no effect on surface binding.

The cells involved in cell-mediated and transplantation immunity in the normal outbred rabbit. XIII. The identity of the responder cells and the role of phagocytic cells in the mixed leucocyte culture reaction.

Lyscom, N; Richter, M
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /08/1979 Português
Relevância na Pesquisa
46.21%
The ability of rabbit spleen cells depleted of thymus, bone marrow or appendix-derived cells to respond in the one-way mixed leucocyte reaction (MLR) has been investigated. The specific subpopulations of lymphoid cells were eliminated by lysis of these cells in the presence of specific antisera and complement. Phagocytic cells (monocytes and heterophils) were removed with a strong magnet after incubation with carbonyl iron particles. The results indicate that the MLR-responding cells are thymus-derived and that neither bone marrow-derived cells nor appendix-derived cells are essential for the blastogenic response following stimulation with allogeneic cells. A minimum number of phagocytic cells is required for a significant response. These cells, however, exhibit a non-specific (accessory) role and can be supplied by either the responding or the stimulating cell population.

The binding of immune complexes to human red cells: complement requirements and fate of the RBC-bound IC after interaction with human phagocytic cells.

Sherwood, T A; Virella, G
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /04/1986 Português
Relevância na Pesquisa
46.29%
Soluble immune complexes (IC) are known to bind to human red blood cells (HRBC). Most authors have attributed this binding to the interaction between IC-bound C3b and a red cell CR1 receptor, but contradictory data has been published concerning the ability of IC to bind to HRBC in the absence of complement. Using soluble tetanus toxoid-rabbit anti-tetanus toxoid (TT-ATT) IC, we have shown that binding through the CR1 receptor takes place when IC are formed at antibody excess, while IC formed at antigen excess do not require complement for erythrocyte binding. Once absorbed to HRBC, IC are recognized by CR1 and/or Fc receptors on phagocytic cells. This interaction is not associated with red cell engulfment, but using radiolabelled S. aureus protein A as a probe, we have demonstrated the transfer of IC from HRBC to phagocytic cells. Such transfer without red blood cell (RBC) damage agrees with the postulated role of RBC in the elimination of soluble IC from circulation. However, we have also demonstrated that the interaction between HRBC-IC and phagocytic cells is associated with the release of mediators of inflammation. It is, therefore, not absolutely clear whether the interaction of RBC-adsorbed IC and phagocytic cells will always have beneficial consequences.

Generation of C5a by Phagocytic Cells

Huber-Lang, Markus; Younkin, Ellen M.; Sarma, J. Vidya; Riedemann, Niels; McGuire, Stephanie R.; Lu, Kristina T.; Kunkel, Robin; Younger, John G.; Zetoune, Firas S.; Ward, Peter A.
Fonte: American Society for Investigative Pathology Publicador: American Society for Investigative Pathology
Tipo: Artigo de Revista Científica
Publicado em /11/2002 Português
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46.16%
The complement activation product, C5a, is a powerful phlogistic factor. Using antibodies to detect human or rat C5a, incubation at pH 7.4 of human blood neutrophils or rat alveolar macrophages (AMs) with C5 in the presence of phorbol 12-myristate 13-acetate (PMA) led to generation of C5a. Rat AMs activated with lipopolysaccharide also generated C5a from C5. With activated neutrophils, extensive cleavage of C5 occurred, whereas activated macrophages had much more selective proteolytic activity for C5. Peripheral blood human or rat mononuclear cells and rat alveolar epithelial cells when stimulated with phorbol ester all failed to demonstrate an ability to cleave C5, suggesting a specificity of C5 cleavage by phagocytic cells. With rat AMs, C5a generation was time-dependent and was blocked if AMs were pretreated with inhibitors of transcription or protein synthesis (actinomycin D or cycloheximide). Similar treatment of activated human polymorphonuclear leukocytes only partially reduced C5a generation after addition of C5. C5a generated by activated AMs was biologically (chemotactically) active. This generation was sensitive to serine protease inhibitors but not to other classes of inhibitors. These data indicate that phagocytic cells...

THE FATE OF BACTERIA WITHIN PHAGOCYTIC CELLS : II. THE MODIFICATION OF INTRACELLULAR DEGRADATION

Cohn, Zanvil A.
Fonte: The Rockefeller University Press Publicador: The Rockefeller University Press
Tipo: Artigo de Revista Científica
Publicado em 01/01/1963 Português
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46.17%
The influence of immune serum, PMN leucocytes, and macrophages from immunized animals and metabolic inhibitors on the intraphagocytic degradation of isotopically labeled bacteria has been evaluated. Immune serum specifically delayed the degradation of a variety of P32- and C14-labeled organisms within both types of phagocytic cells. The active principle in immune serum was found to be a globulin which could be removed by adsorption with the homologous organism. The inhibiting action of immune serum was thought to be related to its combination with the bacterial surface and the subsequent temporary protection of the bacteria from leucocyte enzymes. PMN leucocytes and macrophages obtained from immune hosts did not differ from normal cells in their ability to degrade homologous, labeled bacteria. Immune serum had the same inhibiting influence in the presence of "immune" cells as with cells from non-immunized hosts. Iodoacetate, arsenite, and cyanide at concentrations which inhibited the glycolysis and respiration of both PMN leucocytes and macrophages had no influence on the rate of degradation of isotopically labeled bacteria engulfed by these cells. This implied that following the initial phagocytic events, the degradation of bacteria within leucocytes is not dependent upon the major pathways of energy metabolism.

Size, Charge and Concentration Dependent Uptake of Iron Oxide Particles by Non-Phagocytic Cells

Thorek, Daniel L.J.; Tsourkas, Andrew
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
46.18%
A promising new direction for contrast-enhanced magnetic resonance (MR) imaging involves tracking the migration and biodistribution of superparamagnetic iron oxide (SPIO)-labeled cells in vivo. Despite the large number of cell labeling studies that have been performed with SPIO particles of differing size and surface charge, it remains unclear which SPIO configuration provides optimal contrast in non-phagocytic cells. This is largely because contradictory findings have stemmed from the variability and imprecise control over surface charge, the general need and complexity of transfection and/or targeting agents, and the limited number of particle configurations examined in any given study. In the present study, we systematically evaluated the cellular uptake of SPIO in non-phagocytic T cells over a continuum of particle sizes ranging from 33 nm to nearly 1.5 μm, with precisely controlled surface properties, and without the need for transfection agents. SPIO labeling of T cells was analyzed by flow cytometry and contrast enhancement was determined by relaxometry. SPIO uptake was dose dependent and exhibited sigmoidal charge dependence, which was shown to saturate at different levels of functionalization. Efficient labeling of cells was observed for particles up to 300nm...

Pseudomonas aeruginosa Cytotoxin ExoU Is Injected into Phagocytic Cells during Acute Pneumonia▿

Diaz, Maureen H.; Hauser, Alan R.
Fonte: American Society for Microbiology (ASM) Publicador: American Society for Microbiology (ASM)
Tipo: Artigo de Revista Científica
Português
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46.27%
ExoU, a cytotoxin translocated into host cells via the type III secretion system of Pseudomonas aeruginosa, is associated with increased mortality and disease severity. We previously showed that impairment of recruited phagocytic cells allowed survival of ExoU-secreting P. aeruginosa in the lung. Here we analyzed types of cells injected with ExoU in vivo using translational fusions of ExoU with a β-lactamase reporter (ExoU-Bla). Cells injected with ExoU-Bla were detectable in vitro but not in vivo, presumably due to the rapid cytotoxicity induced by the toxin. Therefore, we used a noncytotoxic ExoU variant, designated ExoU(S142A)-Bla, to analyze injection in vivo. We determined that phagocytic cells in the lung were frequently injected with ExoU(S142A). Early during infection, resident macrophages constituted the majority of cells into which ExoU was injected, but neutrophils and monocytes became the predominant types of cells into which ExoU was injected upon recruitment into the lung. We observed a modest preference for injection into neutrophils over injection into other cell types, but in general the repertoire of injected immune cells reflected the relative abundance of these cells in the lung. Our results indicate that phagocytic cells in the lung are injected with ExoU and support the hypothesis that ExoU-mediated impairment of phagocytes has a role in the pathogenesis of pneumonia caused by P. aeruginosa.

Salmonella pathogenicity island 1 differentially modulates bacterial entry to dendritic and non-phagocytic cells

Bueno, Susan M; Wozniak, Aniela; Leiva, Eduardo D; Riquelme, Sebastián A; Carreño, Leandro J; Hardt, Wolf-Dietrich; Riedel, Claudia A; Kalergis, Alexis M
Fonte: Blackwell Science Inc Publicador: Blackwell Science Inc
Tipo: Artigo de Revista Científica
Publicado em /06/2010 Português
Relevância na Pesquisa
46.33%
Salmonella enterica serovar Typhimurium can enter non-phagocytic cells, such as intestinal epithelial cells, by virtue of a Type Three Secretion System (TTSS) encoded in the Salmonella Pathogenicity Island 1 (SPI-1), which translocates bacterial effector molecules into the host cell. Salmonella can also be taken up by dendritic cells (DCs). Although the role of SPI-1 in non-phagocytic cell invasion is well established, its contribution to invasion of phagocytic cells has not been evaluated. Here, we have tested the invasive capacity of a S. Typhimurium strain lacking a key component of its TTSS-1 (ΔInvC) leading to defective translocation of SPI-1-encoded effectors. Whereas this mutant Salmonella strain was impaired for invasion of non-phagocytic cells, it was taken up by DCs at a significantly higher rate than wild-type Salmonella. Similar to wild-type Salmonella, the ΔInvC mutant strain retained the capacity to avoid antigen presentation to T cells. However, mice infected with the ΔInvC mutant strain showed higher survival rate and reduced organ colonization. Our data suggest that, besides promoting phagocytosis by non-phagocytic cells, SPI-1 modulates the number of bacteria that enters DCs. The SPI-1 could be considered not only as an inducer of epithelial cell invasion but as a controller of DC entry.

Characterization of mononuclear phagocytic cells in medaka fish transgenic for a cxcr3a:gfp reporter

Aghaallaei, Narges; Bajoghli, Baubak; Schwarz, Heinz; Schorpp, Michael; Boehm, Thomas
Fonte: National Academy of Sciences Publicador: National Academy of Sciences
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
46.26%
Chemokines and chemokine receptors are key evolutionary innovations of vertebrates. They are involved in morphogenetic processes and play an important role in the immune system. Based on an analysis of the chemokine receptor gene family in teleost genomes, and the expression patterns of chemokine receptor genes during embryogenesis and the wounding response in young larvae of Oryzias latipes, we identified the chemokine receptor cxcr3a as a marker of innate immune cells. Cells expressing cxcr3a were characterized in fish transgenic for a cxcr3a:gfp reporter. In embryos and larvae, cxcr3a-expressing cells are motile in healthy and damaged tissues, and phagocytic; the majority of these cells has the morphology of tissue macrophages, whereas a small fraction has a dendritic phenotype. In adults, cxcr3a-positive cells continue to specifically express myeloid-associate markers and genes related to antigen uptake and presentation. By light microscopy and ultrastructural analysis, the majority of cxcr3a-expressing cells has a dendritic phenotype, whereas the remainder resembles macrophage-like cells. After challenge of adult fish with bacteria or CpG oligonucleotides, phagocytosing cxcr3a-positive cells in the blood up-regulated il12p40 genes...

Proton channels in non-phagocytic cells of the immune system

Capasso, Melania
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
46.24%
Proton channels are expressed in all cells of the immune system to various degrees. While their function in phagocytic cells, immune cells that engulf bacteria and cell debris for clearance, has been the object of extensive research, the function of proton channels in non-phagocytic cells has remained more elusive until recently. Further studies have been helped by the discovery of the gene coding for the mammalian proton channel, HVCN1, which has prompted a new wave of research in this area. Recent findings show how proton channels regulate cell function in non-phagocytic cells of the immune system such as basophils and lymphocytes.

Conjugates Bearing Multiple Formyl-Methionyl Peptides Display Enhanced Binding to but Not Activation of Phagocytic Cells

Pooyan, Shahriar; Qiu, Bo; Chan, Marion M.; Fong, Dunne; Sinko, Patrick J.; Leibowitz, Michael J.; Stein, Stanley
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em //2002 Português
Relevância na Pesquisa
46.25%
N -Formyl-methionyl peptides can specifically bind to surface receptors on phagocytic cells. A single copy of N-formyl-methionine-leucine-phenylalanine (fMLF) covalently linked to a poly(ethylene glycol)-based polymer displayed reduced binding avidity (Kd = 190 nM) for differentiated HL-60 cells relative to free fMLF (Kd = 28 nM). Increasing the number of fMLF residues (up to eight) attached to a single polymer results in enhanced avidity for these cells (Kd= 0.18 nM), which appears to be independent of whether the polymer backbone is linear or branched. However, no conjugate showed enhanced ability to activate phagocytic cells, relative to the free peptide (EC50= 5 nM), as measured by transient stimulation of release of calcium ions from intracellular stores into the cytoplasm. A polymer bearing four fMLF and four digoxigenin residues showed specific enhancement in binding to differentiated HL-60 cells and mouse peritoneal macrophages in situ relative to a polymer lacking fMLF; no such enhancement was seen in binding to receptor-negative lymphocytic Jurkat cells. These results suggest that multiple fMLF residues linked to a drug-delivery polymer can be used to target appended drugs to phagocytic cells with relatively little toxicity due to cellular activation.

MHC class II compartment, endocytosis and phagocytic activity of macrophages and putative dendritic cells isolated from normal tissues rich in synovium

Moghaddami, M.; Mayrhofer, G.; Cleland, L.
Fonte: Oxford Univ Press Publicador: Oxford Univ Press
Tipo: Artigo de Revista Científica
Publicado em //2005 Português
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46.4%
The endocytic and phagocytic activities of a population of MHC IIhi CD11c+ dendritic cell (DC)-like cells in synovium-rich tissues (SRTs) of normal rat paws were compared with CD163+ cells (putative macrophages) from the same tissues and pseudo-afferent lymph DCs, peritoneal macrophages and blood monocytes. Fifty percent of CD11c+ cells and 75% of CD163+ cells isolated from SRT internalized fluorescein-conjugated dextran (FITC-DX). Of these endocytic cells, half of those expressing CD11c, but only 30% of those expressing CD163, were surface MHC class II+ (sMHC II+). CD11c+ cells were more endocytic than monocytes or pseudo-afferent lymph DC, but some CD163+ cells (type A synoviocytes) were found to be highly endocytic. CD163+ cells from SRT were more phagocytic (25%) than the general MHC class II+ population (16%). Of phagocytic cells, 40% of CD163+ cells were sMHC IIvariable and they constituted 60% of all MHC class II+ phagocytic cells. Only 18% of phagocytic MHC II+ cells expressed CD11c and the most of these were MHC IIhi. In comparison, 60% of CD163+ peritoneal macrophages were phagocytic, while blood monocytes were poorly phagocytic. Intracellular MHC class II-rich compartments (MIIC) were prominent in sMHC IIhi cells in SRT but rare in CD163+ cells. Most MHC IIhi CD11c+ cells did not have a detectable MIIC.; Copyright © 2005 Japanese Society for Immunology

Isolation and functional characteristics of adherent phagocytic cells from mouse Peyer's patches.

MacDonald, T T; Carter, P B
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /04/1982 Português
Relevância na Pesquisa
46.32%
Attempts were made to isolate adherent phagocytic cells (macrophages) from mouse Peyer's patch cell suspensions. Cell suspensions prepared by teasing apart the Peyer's patches contained no adherent phagocytic cells. However, if Peyer's patch fragments were treated with collagenase to disrupt the tissue matrix, cells prepared in this way contained a subpopulation of adherent phagocytic cells. These cells comprised only 0.1-0.2% of the total nucleated cell population of the Peyer's patch. Similar cells could also be isolated from the Peyer's patches of germ-free mice, but as judged by their ability to ingest opsonized erythrocytes, these cells were less activated than cells from the Peyer's patches of normal mice. Adherent cells from the Peyer's patches of normal mice could present antigen (ovalbumin) to T cells, and Peyer's patches cell suspensions containing adherent cells could be stimulated in vitro to produce an anti-sheep red blood cell plaque-forming cell response in the absence of 2-mercaptoethanol. These studies show that although the frequency of phagocytic adherent cells is extremely low in Peyer's patches, these cells have functions consistent with that of adherent cells in other lymphoid tissues.