scholarly journals Effects of cytochalasin B on actin and myosin association with particle binding sites in mouse macrophages: implications with regard to the mechanism of action of the cytochalasins.

1981 ◽  
Vol 91 (2) ◽  
pp. 373-384 ◽  
Author(s):  
R G Painter ◽  
J Whisenand ◽  
A T McIntosh

The intracellular distribution of F-actin and myosin has been examined in mouse peritoneal macrophages by immunofluorescence microscopy. In resting, adherent cells, F-actin was distributed in a fine networklike pattern throughout the cytoplasm. Myosin, in contrast, was distributed in a punctate pattern. After treatment with cytochalasin B (CB), both proteins showed a coarse punctate pattern consistent with a condensation of protein around specific foci. After CB-pretreated cells were exposed to opsonized zymosan particles, immunofluorescent staining for F-actin and myosin showed an increased staining under particle binding sites. Transmission electron microscope (TEM) examination of whole-cell mounts of such preparations revealed a dense zone of filaments beneath the relatively electron-translucent zymosan particles. At sites where particles had detached during processing, these filament-rich areas were more clearly delineated. At such sites dense arrays of filaments that appeared more or less randomly oriented were apparent. The filaments could be decorated with heavy meromyosin, suggesting that they were composed, in part, of F-actin and were therefore identical to the structures giving rise to the immunofluorescence patterns. After viewing CB-treated preparations by whole-mount TEM, we examined the cells by scanning electron microscopy (SEM). Direct SEM comparison of the filament-rich zones seen by TEM showed that these structures resulted from the formation of short lamellipodial protrusions below the site of particle binding. Electron micrographs of thin-sectioned material established that these lamellipodial protrusions were densely packed with microfilaments that were in part associated with the cytoplasmic surface of the plasma membrane. The formation of particle-associated lamellipodia did not appear to represent merely a slower rate of ingestion in the presence of CB, because they formed within minutes of particle contact with the cell membrane and were not followed by particle ingestion even after a 1-h or longer incubation. Furthermore, their formation required cellular energy. These results suggest that cytochalasin B blocks phagocytosis of large particles by affecting the distances over which any putative actomyosin-mediated forces are generated.

1989 ◽  
Vol 94 (1) ◽  
pp. 143-153
Author(s):  
A. Toyohara ◽  
K. Inaba

Mouse macrophages were elicited by the peritoneal injection of chondroitin sulfate solution, harvested and purified, and used as experimental materials. Small and large (diameter: 0.9 microns and 3.0 microns, respectively) polystyrene beads (PB) were used as ingested particles. When the macrophages were incubated with Hank's solution containing small or large PB for 30 min, the phagosomes containing small or large PB were usually randomly distributed. When the macrophages were further incubated for 45 min in PB-free medium, both small and large phagosomes containing PB accumulated at the perinuclear region. The transport of large phagosomes containing 3.0 microns PB was inhibited by cytochalasin B, but not by vinblastine or podophyllotoxin. Conversely, the transport of small phagosomes containing 0.9 microns PB was not inhibited by cytochalasin B but was inhibited by vinblastine or podophyllotoxin. Immunofluorescence microscopy showed that the small phagosomes appeared to accumulate at the central region of the microtubule network. The large phagosomes, on the other hand, appeared to be surrounded by actin-rich cytoplasm, and in some cells actin filament-like structures could be seen around large phagosomes. These results suggest that there are two different transport systems of phagosomes in macrophages. Phagosomes smaller than 0.9 microns in diameter are, probably, mainly transported to the perinuclear region by a microtubule-based motility system and those larger than 3.0 microns in diameter by an actin-based mechanism. It was observed electron-microscopically that accumulated phagosomes containing PB could fuse with each other and form larger phagosomes.


1990 ◽  
Vol 172 (6) ◽  
pp. 1853-1856 ◽  
Author(s):  
S Greenberg ◽  
K Burridge ◽  
S C Silverstein

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.


1976 ◽  
Vol 69 (2) ◽  
pp. 407-414 ◽  
Author(s):  
T G Helantjaris ◽  
P S Lombardi ◽  
L A Glasgow

The adhesion of normal mouse macrophages to glass surfaces was reduced by nontoxic levels (1-50 mug/ml) of cytochalasin B in combination with a centrifugal force (1,000-8,000 g). Macrophages nonspecifically activated by Corynebacterium acnes were also detached by this treatment, but less effectively. The effects of cytochalasin B treatment on these cells were shown to be reversible. After detachment, the cells reattached to glass, appeared morphologically normal, and behaved like untreated cells as judged by adhesion, acid phosphatase levels, and phagocytosis. The effect of cytochalasin B on several parameters of phagocytosis by normal macrophages was also examined. The results demonstrate that cytochalasin B can be used to detach macrophages from surfaces and suggest a functional relationship between phagocytosis and macrophage adhesion to surfaces. Furthermore, the effect of cytochalasin B on adhesion of phagocytic cells provides a probe for further investigation of the adhesion of cells to surfaces.


1983 ◽  
Vol 62 (1) ◽  
pp. 287-299
Author(s):  
M.N. Meirelles ◽  
A. Martinez-Palomo ◽  
T. Souto-Padron ◽  
W. De Souza

Untreated mouse peritoneal macrophages as well as macrophages treated with concanavalin A (ConA) were incubated in the presence of untreated or ConA-treated epimastigotes and trypomastigotes of Trypanosoma cruzi. Treatment of epimastigotes or trypomastigotes with ConA increased or decreased their uptake by macrophages, respectively. Treatment of their macrophages with ConA reduced by 70% and increased by five times the ingestion of epimastigotes and trypomastigotes, respectively. These results are discussed in relation to previous studies on the mobility of ConA receptors in the membrane of the parasite. Using fluorescein- or ferritin-labelled ConA we observed that ConA binding sites located on the plasma membrane of macrophages are internalized during endocytosis of T. cruzi, and observed in association with the membrane of the endocytic vacuole. Vacuoles without parasites showed a uniform distribution of ConA binding sites, while these sites were distributed in patches in vacuoles containing parasites. These results, in association with others previously reported, suggest the involvement of glycoproteins and/or glycolipids localized on the cell surface of T. cruzi and macrophages during the T. cruzi-macrophage interaction.


1975 ◽  
Vol 142 (5) ◽  
pp. 1263-1282 ◽  
Author(s):  
F M Griffin ◽  
J A Griffin ◽  
J E Leider ◽  
S C Silverstein

These experiments were designed to evaluate the role of macrophage plasma membrane receptors for the third component of complement (C) and for the Fc portion of IgG in the ingestion phase of phagocytosis. Sheep erythrocyte (E) were coated with anti-E IgG [E(IgG)]; these E(IgG) were then attached to cultivated monolayers of mouse peritoneal macrophages under conditions which reversibly inhibit ingestion of E(IgG). The E(IgG)-macrophage complexes were further incubated under similar conditions with an antimacrophage IgG fraction which blocks Fc receptor-mediated ingestion but has no effect upon ingestion mediated by other phagocytic receptors. When these cultures were subsequently incubated under conditions optimal for particle ingestion, phagocytosis of the IgG-coated erythrocytes did not occur; the erythrocytes remained bound to the Fc receptors of the macrophage plasma membrane. To determine whether ligands must cover the entire surface of an attached particle to permit ingestion of that particle, C-coated E [E(IgM)C] were bound to the C receptors of thioglycollate-induced (activated) macrophages at 4 degrees C. E(IgM)C-macrophage complexes were then trypsinized at 4 degrees C, a procedure which resulted in cleavage of erythrocyte-bound C3b molecules to a form of C3 not recognized by the macrophage receptors for C3b. Under the conditions used, trypsin did not affect the attachment of E(IgM)C to the macrophage surface or the macrophage receptors for C3b. When these trypsin treated E(IgM)C-macrophage complexes were incubated at 37 degrees C, the bound E(IgM)C were not ingested; the erythrocytes remained attached to the macrophage plasma membrane via the macrophage's C receptors. These results indicate that attachment of a particle to specific receptors on the macrophage plasma membrane is not sufficient to trigger ingestion of that particle. Rather, ingestion requires the sequential, circumferential interaction of particle-bound ligands with specific plasma membrane receptors not involved in the initial attachment process.


1960 ◽  
Vol 112 (2) ◽  
pp. 403-417 ◽  
Author(s):  
Charles Jenkin ◽  
Baruj Benacerraf

Virulent strains of Salmonella opsonized with normal mouse plasma are never phagocytosed as well as avirulent strains. The virulent strains of Salmonella phagocytosed after opsonization with normal mouse plasma are able to multiply within normal mouse peritoneal macrophages, whereas under similar experimental conditions the avirulent strains are killed. When virulent strains of Salmonella are opsonized with specific antiserum or plasma from BCG-infected mice, they are treated by normal mouse macrophages as if they were avirulent. Virulent bacteria opsonized with BCG plasma are phagocytosed and killed better by peritoneal macrophages from BCG-infected mice, than peritoneal macrophages from normal mice.


1971 ◽  
Vol 133 (2) ◽  
pp. 231-259 ◽  
Author(s):  
Thomas C. Jones ◽  
James G. Hirsch

Methods have been devised for establishing infection in vitro of mouse macrophages and fibroblasts with Mycoplasma pulmonis. The mycoplasmas attached to the cells and under appropriate cultural conditions grew into a lawn of microorganisms covering most of the cell surface. The mycoplasmas grew abundantly on fibroblasts cultured in minimal essential medium containing 20% fetal calf serum; supplementation of this medium with heart infusion broth was necessary to obtain similar growth on macrophages. The infection of these cells appeared to be essentially an extracellular process; only rarely were partially degraded mycoplasmas seen with phagocytic vacuoles. The addition to heavily infected macrophage cultures of low concentrations of anti-mycoplasma antibody stimulated rapid, massive phagocytosis of the surface microorganisms. In sharp contrast, the same antiserum had no discernable effect on the mycoplasma-fibroblast relationship. The antibody effect in the macrophage system was apparently a direct opsonic one rather than an indirect result of microbial killing, since the mycoplasmas in macrophage or fibroblast cultures incorporated labelled thymidine into DNA after the addition of antiserum to the medium. The phagocytic event and the subsequent fate of the mycoplasmas were studied in detail after the addition of antibody to the macrophage cultures. Phase-contrast cinemicrophotography revealed membrane ruffles surrounding the surface mycoplasmas and disappearance from view of the organisms; 10–30 min later translucent grapelike clusters were seen in large phagocytic vacuoles. On electronmicroscopic study the surface mycoplasmas were surrounded by pincers-like projections of the macrophage. Numerous mycoplasmas were seen in phagocytic vacuoles; in the early minutes after the addition of antibody the intracellular mycoplasmas appeared normal, but within 2 hr they appeared partially degraded with a central electron-lucent area and electron-opaque deposits at the microbial cell margin. 24 hr after the addition of antiserum, digestion of the mycoplasmas was nearly complete; the cells appeared normal except for large residual bodies composed of amorphous moderately dense material and increased lipid deposits. Degradation of mycoplasmas within macrophages was also studied using infected cultures in which the mycoplasmas, but not the macrophages, had incorporated tritiated thymidine into DNA. The appearance of large amounts of acid-soluble radiolabel after phagocytosis stimulated by antibody confirmed the degradation of the intracellular mycoplasmas.


2003 ◽  
Vol 47 (6) ◽  
pp. 1895-1901 ◽  
Author(s):  
Maria do Socorro S. Rosa ◽  
Ricardo R. Mendonça-Filho ◽  
Humberto R. Bizzo ◽  
Igor de Almeida Rodrigues ◽  
Rosangela Maria A. Soares ◽  
...  

ABSTRACT The in vitro leishmanicidal effects of a linalool-rich essential oil from the leaves of Croton cajucara against Leishmania amazonensis were investigated. Morphological changes in L. amazonensis promastigotes treated with 15 ng of essential oil per ml were observed by transmission electron microscopy; leishmanial nuclear and kinetoplast chromatin destruction, followed by cell lysis, was observed within 1 h. Pretreatment of mouse peritoneal macrophages with 15 ng of essential oil per ml reduced by 50% the interaction between these macrophages and L. amazonensis, with a concomitant increase by 220% in the level of nitric oxide production by the infected macrophages. Treatment of preinfected macrophages with 15 ng of essential oil per ml reduced by 50% the interaction between these cells and the parasites, which led to a 60% increase in the amount of nitric oxide produced by the preinfected macrophages. These results provide new perspectives on the development of drugs with activities against Leishmania, as linalool-rich essential oil is a strikingly potent leishmanicidal plant extract (50% lethal doses, 8.3 ng/ml for promastigotes and 8.7 ng/ml for amastigotes) which inhibited the growth of L. amazonensis promastigotes at very low concentrations (MIC, 85.0 pg/ml) and which presented no cytotoxic effects against mammalian cells.


1972 ◽  
Vol 55 (1) ◽  
pp. 186-204 ◽  
Author(s):  
Ralph M. Steinman ◽  
Zanvil A. Cohn

The in vitro interaction of soluble horseradish peroxidase (HRP) with homogeneous mono layers of mouse macrophages has been studied using sensitive biochemical and cytochemical techniques. The compartmentalization of HRP in extracellular and intracellular sites has been quantitatively evaluated. A significant fraction is bound to a serum-derived layer, which coats the surface of culture vessels and may be removed by appropriate washes. Macrophages interiorize HRP as a solute in pinocytic vesicles without appreciable binding of the glycoprotein to the plasma membrane. Uptake is directly proportional to the concentration of HRP in the culture medium. 1 x 106 cells ingest 0.0025% of the administered load per hr over a wide range of concentrations. Cytochemically, all demonstrable HRP is sequestered within the endocytic vesicles and secondary lysosomes of the vacuolar apparatus. After uptake, the enzymatic activity of HRP is inactivated exponentially with a half-life of 7–9 hr, until enzyme is no longer detectable. When macrophages have pinocytosed trace-labeled HRP-125I, cell-associated isotope disappears with a t ½ of 20–30 hr and they release monoiodotyrosine-125I into the culture medium. We were unable to obtain evidence that significant amounts of HRP (>2%) can be exocytosed after uptake, can exist intact on the cell surface, or can be digested extracellularly. It is difficult to reconcile these observations with several of the postulated mechanisms whereby macrophages are thought to play a prominent role in the induction of an immune response.


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