scholarly journals Selective iodination and polypeptide composition of pinocytic vesicles.

1980 ◽  
Vol 86 (3) ◽  
pp. 712-722 ◽  
Author(s):  
I S Mellman ◽  
R M Steinman ◽  
J C Unkeless ◽  
Z A Cohn
Keyword(s):  
Monoclonal Antibodies ◽  
Polyacrylamide Gel Electrophoresis ◽  
Fluid Phase ◽  
Enzyme Concentration ◽  
Temperature Dependent ◽  
Intact Cells ◽  
Membrane Antigens ◽  
Em Autoradiography ◽  
Immune Precipitation ◽  
Pinocytic Vesicles

We describe a method for the specific radioiodination of pinocytic vesicles (PVs) based upon the simultaneous endocytosis of lactoperoxidase (LPO) and glucose oxidase (GO). Initial experiments indicated that LPO was interiorized by the macrophage cell line J774 by fluid phase pinocytosis and without detectable binding to the plasma membrane (PM). Interiorization varied linearly with enzyme concentration and exposure time, was temperature dependent, and was undetectable at 4 degrees C. Employing EM cytochemistry, LPO activity was restricted to PVs after a 3- to 5-min pulse at 37 degrees C. These results formed the basis of the method for iodinating the luminal surface of PVs: 5-min exposure to both LPO and GO at 37 degrees C followed by washes and iodination (addition of 125I and glucose) at 4 degrees C. Enzyme-dependent incorporation of iodide into the polypeptides of both PV membrane and contents occurred. Several lines of evidence indicated that there was selective labeling of PV as opposed to PM. Iodination did not occur if the pinocytic uptake of LPO ad GO was inhibited by low temperature. EM autoradiography showed a cytoplasmic localization of grains, whereas a clear PM association was evident with surface labeling. LPO was iodinated only after PV labeling and was present within organelles demonstrating latency. After PV iodination, > 75% of several labeled membrane antigens could be immunoprecipitated by monoclonal antibodies only after cell lysis. In contrast, all labeled antigens were accessible to antibody on intact cells after surface labeling. The polypeptide compositions of PM and PV membrane were compared by SDS polyacrylamide gel electrophoresis and by quantitative immune precipitation using a panel of anti-J774 monoclonal antibodies. The electrophoretic profiles of iodinated proteins (15-20 bands) were strikingly similar in NP-40 lysates of both PV and PM iodinated cells. In addition, eight membrane antigens examined by immune precipitation, including the trypsin-resistant immunoglobulin (Fc) receptor and the H-2Dd histocompatibility antigen, were found to be iodinated to the same relative extents by both labeling procedures. We conclude that PV membrane is formed from a representative sample of PM polypeptide components.

scholarly journals The membrane proteins of the vacuolar system. II. Bidirectional flow between secondary lysosomes and plasma membrane.

1980 ◽  
Vol 86 (1) ◽  
pp. 304-314 ◽  
Author(s):  
W A Muller ◽  
R M Steinman ◽  
Z A Cohn
Keyword(s):  
Plasma Membrane ◽  
Culture Medium ◽  
Fluid Phase ◽  
Membrane Flow ◽  
Em Autoradiography ◽  
Secondary Lysosomes ◽  
Bidirectional Flow ◽  
Vacuolar System ◽  
Representative Samples ◽  
Pinocytic Vesicles

Lactoperoxidase covalently coupled to latex spheres (LPO-latex) has been used to selectively iodinate the phagolysome (PL) membrane within living macrophages, as discussed in the accompanying article. This procedure labeled approximately 24 polypeptides in the PL membrane; these were similar to those iodinatable on the external surface of the plasma membrane (PM). We now report on the translocation and fate of these proteins when the cells are returned to culture. TCA-precipitable radioactivity was lost from cells with biphasic kinetics. 20-50% of the cell-associated radiolabel was rapidly digested (t 1/2 approximately equal to 1 h) and recovered in the culture medium as monoiodotyrosine. 50-80% of the label was lost slowly from cells ( 1/2 approximately equal to 24-30 h). Quantitative analysis of gel autoradiograms showed that all radiolabeled proteins were lost at the same rate in both the rapid and slow phases of digestion. Within 15-30 min aftr labeling of the PL membrane, EM autoradiography revealed that the majority of the cell-associated grains, which at time 0 were associated with PL, were now randomly dispersed over the plasmalemma. At this time, analysis of PM captured by a second phagocytic load revealed the presence of all labeled species originally present in the PL membrane. This demonstrated the rapid, synchronous centrifugal flow of PL polypeptides to the cell surface. Evidence was also obtained for the continuous influx of representative samples of the PM into the PL compartment by way of pinocytic vesicles. This was based on the constant flow of fluid phase markers into latex-containing PL and on the internalization of all iodinatable PM polypeptides into this locus. These observations provide evidence for the continuous, bidirectional flow of membrane polypeptides between the PM and the secondary lysosome and represent an example of a membrane flow and recycling mechanism.

Discordant expression of selectin ligands and sialyl Lewis x–related epitopes on murine myeloid cells

Blood ◽  
2002 ◽  
Vol 100 (13) ◽  
pp. 4485-4494 ◽  
Author(s):  
Marcin M. A. Kobzdej ◽  
Anne Leppänen ◽  
Vishwanath Ramachandran ◽  
Richard D. Cummings ◽  
Rodger P. McEver
Keyword(s):  
Monoclonal Antibodies ◽  
Sialic Acid ◽  
Fluid Phase ◽  
Sialyl Lewis X ◽  
Lewis X ◽  
Intact Cells ◽  
Sialyl Lewis ◽  
Selectin Ligands ◽  
Low Levels ◽  
Myeloid Leukocytes

Murine leukocytes are thought to express α2-3-sialylated and α1-3-fucosylated selectin ligands such as sialyl Lewis x (sLex), although monoclonal antibodies (mAbs) to sLex or Lex reportedly do not bind to murine leukocytes. We observed that P- and E-selectin bound to pronase-sensitive ligands on murine monocytic WEHI-3 cells and murine neutrophils, indicating that the ligands for both selectins are glycoproteins. CSLEX-1, HECA-452, and other widely used mAbs to sLex and Lex did not bind to WEHI-3 cells and bound at very low levels to murine neutrophils. Only the anti-sLex mAbs 2H5 and KM93, which also recognize nonfucosylated glycans, bound to WEHI-3 cells. 2H5 and KM93 bound to pronase-resistant structures, indicating that the mAbs did not identify selectin ligands. Treatment of WEHI-3 cells with glycosidases or chlorate demonstrated that sialic acid modifications, α1-3-galactosylation, or sulfation did not mask epitopes for mAbs to sLex or Lex. Compared to human promyelocytic HL-60 cells, WEHI-3 cells and murine neutrophils expressed low α1-3-fucosyltransferase activities. Consistent with very low endogenous fucosylation, forced fucosylation of intact WEHI-3 cells or murine neutrophils by exogenous α1-3-fucosyltransferase FTVI and GDP-fucose created many new epitopes for anti-sLexmAbs such as HECA-452 and CSLEX-1. Nevertheless, forced fucosylation of intact cells did not significantly augment their ability to bind to fluid-phase P- or E-selectin or to roll on immobilized P- or E-selectin under flow. These data suggest that murine myeloid leukocytes fucosylate only a few specific glycans, which interact preferentially with P- and E-selectin.

NEUROBLASTOMA IMMUNOTHERAPY

2019 ◽  
Vol 65 (2) ◽  
pp. 181-187
Author(s):  
Aleksandr Druy ◽  
Svetlana Kuleva
Keyword(s):  
T Cells ◽  
Monoclonal Antibodies ◽  
High Risk ◽  
Checkpoint Inhibitors ◽  
Innate And Adaptive Immunity ◽  
Car T Cells ◽  
Car T ◽  
Membrane Antigens ◽  
Theoretical Evidence ◽  
Blocking Antibodies

The recent data about innate and adaptive immunity against neuroblastoma are described in the article. The era of neuroblastoma immunotherapy started since the evidence of anti-GD2 monoclonal antibodies efficiency. Nowadays monoclonal antibodies against GD2 are introduced into schemes of maintenance therapy for high-risk neuroblastoma patients. Developing of T-cells expressing chimeric antigen receptor (CAR-T cells) directed to membrane antigens is the perspective of neuroblastoma immunotherapy. PD1/PD-L1 blocking antibodies as immune checkpoint inhibitors have the theoretical evidence of potential effectiveness. Application of immunotherapeutic approaches in high-risk neuroblastoma patients together with conventional multimodal therapies requires further investigation.

Monoclonal antibodies against surface antigens of schistosomula of Schistosoma mansoni

Parasitology ◽  
1982 ◽  
Vol 84 (1) ◽  
pp. 65-82 ◽  
Author(s):  
D. W. Taylor ◽  
A. F. Butterworth
Keyword(s):  
Monoclonal Antibodies ◽  
Gel Electrophoresis ◽  
Primary Infection ◽  
Polyacrylamide Gel Electrophoresis ◽  
Apparent Molecular Weight ◽  
Surface Antigens ◽  
Soft Agar ◽  
Surface Proteins ◽  
Spleen Cells

SUMMARYMonoclonal antibodies have been produced after fusion of NS-1 murine myeloma cells with spleen cells from mice immunized either by chronic primary infection or with irradiated cercariae: in both cases, animals were challenged with live cercariae 7 days before fusion. The initial cultures were screened for anti-schistosomular antibodies both by a radioimmunoassay with whole schistosomulum extracts and by immunofluorescence. There was no correlation between the two techniques and subsequent screening was carried out by immunofluorescence. Cloning was carried out in soft agar and 7 cloned cell lines, from 5 initial cultures, were selected for detailed study. Products of 6 of these 7 lines were monoclonal, as judged by isoelectricfocusing of [35S]methionine-labelled supernatant fluids, and their binding to live schistosomula was specific. None of the antibodies showed detectable activity in mediating eosinophil- or complement-dependent damage to schistosomula in vitro. However, 2 antibodies were successfully used to isolate surface proteins with an apparent molecular weight of 24000 on SDS-polyacrylamide gel electrophoresis.

scholarly journals Low viscosity in the aqueous domain of cell cytoplasm measured by picosecond polarization microfluorimetry.

1991 ◽  
Vol 112 (4) ◽  
pp. 719-725 ◽  
Author(s):  
K Fushimi ◽  
A S Verkman
Keyword(s):  
Free Water ◽  
Fluid Phase ◽  
Rotational Correlation Time ◽  
Cell Cytoplasm ◽  
Intact Cells ◽  
Low Viscosity ◽  
3T3 Fibroblasts ◽  
Anisotropy Decay ◽  
Novel Method ◽  
Swiss 3T3 Fibroblasts

Information about the rheological characteristics of the aqueous cytoplasm can be provided by analysis of the rotational motion of small polar molecules introduced into the cell. To determine fluid-phase cytoplasmic viscosity in intact cells, a polarization microscope was constructed for measurement of picosecond anisotropy decay of fluorescent probes in the cell cytoplasm. We found that the rotational correlation time (tc) of the probes, 2,7-bis-(2-carboxyethyl)-5-(and-6-)carboxyfluorescein (BCECF), 6-carboxyfluorescein, and 8-hydroxypyrene-1,3,6-trisulfonic acid (HPTS) provided a direct measure of fluid-phase cytoplasmic viscosity that was independent of probe binding. In quiescent Swiss 3T3 fibroblasts, tc values were 20-40% longer than those in water, indicating that the fluid-phase cytoplasm is only 1.2-1.4 times as viscous as water. The activation energy of fluid-phase cytoplasmic viscosity was 4 kcal/mol, which is similar to that of water. Fluid-phase cytoplasmic viscosity was altered by less than 10% upon addition of sucrose to decrease cell volume, cytochalasin B to disrupt cell cytoskeleton, and vasopressin to activate phospholipase C. Nucleoplasmic and peripheral cytoplasmic viscosities were not different. Our results establish a novel method to measure fluid-phase cytoplasmic viscosity, and indicate that fluid-phase cytoplasmic viscosity in fibroblasts is similar to that of free water.

Temperature-dependent binding of monoclonal antibodies to C hordein

2002 ◽  
Vol 1594 (1) ◽  
pp. 17-26 ◽  
Author(s):  
Gary M Brett ◽  
E.N.Clare Mills ◽  
James Bacon ◽  
Nikolaus Wellner ◽  
Rhonda D Husain ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Temperature Dependent
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