Surface Receptors of Mononuclear Phagocytes

Morphology ◽  
1980 ◽  
pp. 161-258 ◽  
Author(s):  
Paul E. Mckeever ◽  
Samuel S. Spicer
Blood ◽  
1972 ◽  
Vol 40 (1) ◽  
pp. 62-69 ◽  
Author(s):  
Martin J. Cline ◽  
Margaret A. Sumner

Abstract Mouse bone marrow cells were cultured in vitro under conditions that allowed little granulopoiesis but permitted proliferation of mononuclear phagocytes. During 10 days’ culture, the population gradually shifted from a preponderance of undifferentiated blast cells and promonocytes to macrophages. Cells up to the A (immature) macrophage stage were capable of DNA synthesis and mitosis. B (mature) macrophages were nondividing. Blast cells were not phagocytic and lacked glass adhesiveness and demonstrable surface receptors for IgG immunoglobulin. With progressive cellular maturation, peroxidase activity disappeared after the monocyte stage. Glass adhesiveness, phagocytic ability, and surface receptors for immunoglobulins appeared to increase with cell maturation from the promonocyte through the macrophage stage of development.


Blood ◽  
1979 ◽  
Vol 54 (2) ◽  
pp. 485-500 ◽  
Author(s):  
R van Furth ◽  
JA Raeburn ◽  
TL van Zwet

Abstract In this study human mononuclear phagocytes from the bone marrow (promonocytes and monocytes), peripheral blood monocytes, and tissue macrophages from the skin and the peritoneal cavity were studied with respect to their morphological, cytochemical, and functional characteristics, cell surface receptors, and 3H-thymidine incorporation in vitro. The results show similarities between mononuclear phagocytes of the three body compartments with respect to esterase staining, the presence of peroxidase-positive granules, the presence of IgG and C receptors, and pinocytic and phagocytic activity. Promonocytes are the most immature mononuclear phagocytes identified in human bone marrow, and since about 80% of these cells incorporate 3H-thymidine, they are actively dividing cells. Monocytes, whether in bone marrow or the peripheral blood, and both skin and peritoneal macrophages label minimally with 3H-thymidine and thus are nondividing cells. Since the characteristics of mononuclear phagocytes in man and mouse do not diverge greatly, it is probable that the cell sequence based on in vitro and in vivo 3H-thymidine labeling studies in the mouse holds for man as well. The successive stages of development of the human mononuclear phagocyte cell line will then be as follows: monoblasts (not yet characterized in man) divide to form promonocytes, and these cells in turn divide and give rise to monocytes that do not divide further; they leave the bone marrow, circulate in the peripheral blood, and finally become macrophages in the various tissues.


Blood ◽  
1979 ◽  
Vol 54 (2) ◽  
pp. 485-500 ◽  
Author(s):  
R van Furth ◽  
JA Raeburn ◽  
TL van Zwet

In this study human mononuclear phagocytes from the bone marrow (promonocytes and monocytes), peripheral blood monocytes, and tissue macrophages from the skin and the peritoneal cavity were studied with respect to their morphological, cytochemical, and functional characteristics, cell surface receptors, and 3H-thymidine incorporation in vitro. The results show similarities between mononuclear phagocytes of the three body compartments with respect to esterase staining, the presence of peroxidase-positive granules, the presence of IgG and C receptors, and pinocytic and phagocytic activity. Promonocytes are the most immature mononuclear phagocytes identified in human bone marrow, and since about 80% of these cells incorporate 3H-thymidine, they are actively dividing cells. Monocytes, whether in bone marrow or the peripheral blood, and both skin and peritoneal macrophages label minimally with 3H-thymidine and thus are nondividing cells. Since the characteristics of mononuclear phagocytes in man and mouse do not diverge greatly, it is probable that the cell sequence based on in vitro and in vivo 3H-thymidine labeling studies in the mouse holds for man as well. The successive stages of development of the human mononuclear phagocyte cell line will then be as follows: monoblasts (not yet characterized in man) divide to form promonocytes, and these cells in turn divide and give rise to monocytes that do not divide further; they leave the bone marrow, circulate in the peripheral blood, and finally become macrophages in the various tissues.


Author(s):  
K. E. Muse ◽  
D. G. Fischer ◽  
H. S. Koren

Mononuclear phagocytes, a pluripotential cell line, manifest an array of basic extracellular functions. Among these physiological regulatory functions is the expression of spontaneous cytolytic potential against tumor cell targets.The limited observations on human cells, almost exclusively blood monocytes, initially reported limited or a lack of tumoricidal activity in the absence of antibody. More recently, freshly obtained monocytes have been reported to spontaneously impair the biability of tumor target cells in vitro (Harowitz et al., 1979; Montavani et al., 1979; Hammerstrom, 1979). Although the mechanism by which effector cells express cytotoxicity is poorly understood, discrete steps can be distinguished in the process of cell mediated cytotoxicity: recognition and binding of effector to target cells,a lethal-hit stage, and subsequent lysis of the target cell. Other important parameters in monocyte-mediated cytotoxicity include, activated state of the monocyte, effector cell concentrations, and target cell suseptibility. However, limited information is available with regard to the ultrastructural changes accompanying monocyte-mediated cytotoxicity.


Author(s):  
Dean A. Handley ◽  
Cynthia M. Arbeeny ◽  
Larry D. Witte

Low density lipoproteins (LDL) are the major cholesterol carrying particles in the blood. Using cultured cells, it has been shown that LDL particles interact with specific surface receptors and are internalized via a coated pit-coated vesicle pathway for lysosomal catabolism. This (Pathway has been visualized using LDL labeled to ferritin or colloidal gold. It is now recognized that certain lysomotropic agents, such as chloroquine, inhibit lysosomal enzymes that degrade protein and cholesterol esters. By interrupting cholesterol ester hydrolysis, chloroquine treatment results in lysosomal accumulation of cholesterol esters from internalized LDL. Using LDL conjugated to colloidal gold, we have examined the ultrastructural effects of chloroquine on lipoprotein uptake by normal cultured fibroblasts.


Author(s):  
Klaus-Ruediger Peters

Topographic ultra high resolution can now routinely be established on bulk samples in cold field emission scanning electron microscopy with a second generation of microscopes (FSEM) designed to provide 0.5 nm probe diameters. If such small probes are used for high magnification imaging, topographic contrast is so high that remarkably fine details can be imaged on 2DMSO/osmium-impregnated specimens at ribosome surfaces even without a metal coating. On TCH/osmium-impregnated specimens topographic resolution can be increased further if the SE-I imaging mode is applied. This requires that beam diameter and metal coating thickness be made smaller than the SE range of ~1 nm and background signal contributions be reduced. Subnanometer small probes can be obtained (only) at high accelerating voltages. Subnanometer thin continuous metal films can be produced under the following conditions: self-shadowing effect between metal atoms must be reduced through appropriate deposition techniques and surface mobility of metal atoms must be diminished through high energy sputtering and/or specimen cooling.


2019 ◽  
Vol 47 (5) ◽  
pp. 1543-1555 ◽  
Author(s):  
Maurizio Mongiat ◽  
Simone Buraschi ◽  
Eva Andreuzzi ◽  
Thomas Neill ◽  
Renato V. Iozzo

Abstract The extracellular matrix is a network of secreted macromolecules that provides a harmonious meshwork for the growth and homeostatic development of organisms. It conveys multiple signaling cascades affecting specific surface receptors that impact cell behavior. During cancer growth, this bioactive meshwork is remodeled and enriched in newly formed blood vessels, which provide nutrients and oxygen to the growing tumor cells. Remodeling of the tumor microenvironment leads to the formation of bioactive fragments that may have a distinct function from their parent molecules, and the balance among these factors directly influence cell viability and metastatic progression. Indeed, the matrix acts as a gatekeeper by regulating the access of cancer cells to nutrients. Here, we will critically evaluate the role of selected matrix constituents in regulating tumor angiogenesis and provide up-to-date information concerning their primary mechanisms of action.


2020 ◽  
Vol 4 (6) ◽  
pp. 645-675
Author(s):  
Parasuraman Padmanabhan ◽  
Mathangi Palanivel ◽  
Ajay Kumar ◽  
Domokos Máthé ◽  
George K. Radda ◽  
...  

Neurodegenerative diseases (NDDs), including Alzheimer's disease (AD) and Parkinson's disease (PD), affect the ageing population worldwide and while severely impairing the quality of life of millions, they also cause a massive economic burden to countries with progressively ageing populations. Parallel with the search for biomarkers for early detection and prediction, the pursuit for therapeutic approaches has become growingly intensive in recent years. Various prospective therapeutic approaches have been explored with an emphasis on early prevention and protection, including, but not limited to, gene therapy, stem cell therapy, immunotherapy and radiotherapy. Many pharmacological interventions have proved to be promising novel avenues, but successful applications are often hampered by the poor delivery of the therapeutics across the blood-brain-barrier (BBB). To overcome this challenge, nanoparticle (NP)-mediated drug delivery has been considered as a promising option, as NP-based drug delivery systems can be functionalized to target specific cell surface receptors and to achieve controlled and long-term release of therapeutics to the target tissue. The usefulness of NPs for loading and delivering of drugs has been extensively studied in the context of NDDs, and their biological efficacy has been demonstrated in numerous preclinical animal models. Efforts have also been made towards the development of NPs which can be used for targeting the BBB and various cell types in the brain. The main focus of this review is to briefly discuss the advantages of functionalized NPs as promising theranostic agents for the diagnosis and therapy of NDDs. We also summarize the results of diverse studies that specifically investigated the usage of different NPs for the treatment of NDDs, with a specific emphasis on AD and PD, and the associated pathophysiological changes. Finally, we offer perspectives on the existing challenges of using NPs as theranostic agents and possible futuristic approaches to improve them.


1994 ◽  
Vol 72 (06) ◽  
pp. 964-972 ◽  
Author(s):  
Jeffery L Kutok ◽  
Barry S Coller

SummaryWe produced a murine monoclonal antibody, 7H2, and localized its epitope to one or more small regions on platelet glycoprotein (GP) Ilia. 7H2-IgG and 7H2-F(ab’)2 completely inhibit platelet aggregation and fibrinogen binding at low agonist concentrations, but only partially inhibit aggregation and fibrinogen binding at high agonist concentrations; 7H2-Fab has no effect on aggregation or fibrinogen binding at any agonist concentration. 7H2-IgG binds to the entire platelet population as judged by flow cytometry. At near saturating concentrations, ∼40,000 7H2-IgG antibody molecules bind per platelet. In contrast, ∼80,000 7H2 Fab molecules bind per platelet, suggesting that 7H2-IgG binding is bivalent. 7H2 was unable to inhibit fibrinogen binding to purified, immobilized GPIIb/IIIa. These data indicate that the bivalent binding of 7H2 to GPIIIa is required for its partial inhibition of fibrinogen binding to platelets, perhaps through dimerization of GPIIb/IIIa surface receptors (or more complex GPIIb/IIIa redistribution triggered by 7H2 binding) resulting in limited accessibility of fibrinogen to its binding site(s).


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