scholarly journals Characterization of a monoclonal antibody that specifically binds to choline phospholipids and its use in immunocytochemistry.

1992 ◽  
Vol 40 (6) ◽  
pp. 827-838 ◽  
Author(s):  
M P Mark ◽  
T Tsuji ◽  
J Portoukalian ◽  
A Rebbaa ◽  
G Zidan ◽  
...  

A monoclonal IgM (MC22-33F), raised in response to mouse embryonic dental papilla cells, was selected for further analysis on the basis of the unusual resistance of its epitope to detergent extractions and protease treatments of cell cultures. Binding of MC22-33F to cultured cells was abolished after either pre-treatment of the cells with phospholypase C or pre-incubation of the hybridoma culture supernatant with multilamellar phosphatidylcholine-containing vesicles. MC22-33F reacted with phosphatidylcholine, with the phosphatidylcholine analogue dimethylphosphatidylethanolamine, and with sphingomyelin immobilized on polystyrene surfaces or in thin-layer chromatograms. Crossreaction with other phospholipids was not observed. The surface of cultured epithelial cells was labeled by MC22-33F at sites of bleb formation. Combining immunostaining by MC22-33F and histochemical staining of cultured cells revealed codistribution of phospholipid-containing inclusions with either lysosomes or neutral fat droplets, and inhibition of lipid degradation by kanamycin resulted in a parallel accumulation of these inclusions and of neutral fats in the cytoplasm. Immunolabeling by MC22-33F of frozen mouse tissues was maximal in fat-storing and steroid-producing cells. Extracellular phospholipids present in calcifying cartilage septa strongly reacted with MC22-33F. This monoclonal antibody offers an interesting alternative to histochemical lipid stains for investigating fatty metamorphosis and extracellular lipid deposition under physiological and pathological conditions.

1994 ◽  
Vol 107 (10) ◽  
pp. 2669-2677 ◽  
Author(s):  
P. Pavasant ◽  
T.M. Shizari ◽  
C.B. Underhill

In the present study, we have examined the distribution of both hyaluronan and its receptor, CD44, during the process of endochondral ossification in the mouse tibia. Histochemical staining revealed that a large amount of hyaluronan was present in the lacunae located in the zone of hypertrophy, but it was greatly reduced or absent from the zone of erosion. In addition, hyaluronan was present in the cytoplasm of osteoprogenitor cells located in the zone of erosion. These cells also expressed CD44 on their surfaces, as revealed by double-label immunohistochemistry. These results suggested that the osteoprogenitor cells may use CD44 to bind and internalize hyaluronan, and subsequently degrade it with lysosomal enzymes. To test this possibility, we examined the human cell line, MG-63, which closely resembles osteoprogenitor cells. These cells produced several different forms of CD44, as determined by western blotting (85, 116 and 150 kDa). In addition, the binding of isotopically labeled hyaluronan to detergent extracts of these cells was blocked by a monoclonal antibody to CD44. Similarly, the degradation of hyaluronan by these cultured cells was also inhibited by a monoclonal antibody to CD44. To determine if these cells could remove hyaluronan from the growth plate, the cells were cultured directly on top of thin sections of the epiphysial region of long bone. After 16 hours, the sections were stained for hyaluronan. The MG-63 cells removed significant amounts of hyaluronan present in the zone of hypertrophy, and this effect was blocked by an excess of soluble hyaluronan and by a monoclonal antibody to CD44.(ABSTRACT TRUNCATED AT 250 WORDS)


2000 ◽  
Vol 150 (3) ◽  
pp. 643-656 ◽  
Author(s):  
Mana M. Parast ◽  
Carol A. Otey

Here, we describe the identification of a novel phosphoprotein named palladin, which colocalizes with α-actinin in the stress fibers, focal adhesions, cell–cell junctions, and embryonic Z-lines. Palladin is expressed as a 90–92-kD doublet in fibroblasts and coimmunoprecipitates in a complex with α-actinin in fibroblast lysates. A cDNA encoding palladin was isolated by screening a mouse embryo library with mAbs. Palladin has a proline-rich region in the NH2-terminal half of the molecule and three tandem Ig C2 domains in the COOH-terminal half. In Northern and Western blots of chick and mouse tissues, multiple isoforms of palladin were detected. Palladin expression is ubiquitous in embryonic tissues, and is downregulated in certain adult tissues in the mouse. To probe the function of palladin in cultured cells, the Rcho-1 trophoblast model was used. Palladin expression was observed to increase in Rcho-1 cells when they began to assemble stress fibers. Antisense constructs were used to attenuate expression of palladin in Rcho-1 cells and fibroblasts, and disruption of the cytoskeleton was observed in both cell types. At longer times after antisense treatment, fibroblasts became fully rounded. These results suggest that palladin is required for the normal organization of the actin cytoskeleton and focal adhesions.


1989 ◽  
Vol 37 (6) ◽  
pp. 831-841 ◽  
Author(s):  
F G Williams ◽  
A J Beitz

We developed a mouse monoclonal antibody against neurotensin (NT), termed NT8, for applications in immunohistochemistry and for ELISA analysis of NT. The antibody's paratope was determined by competitive ELISA using several peptide fragments of NT. That paratope requires intact peptide bonds between NT residues proline-7, arginine-8, and arginine-9. The antibody is of the IgG2B sub-isotype, having an IC50 for intact NT of approximately 3 nM when measured by competitive ELISA. Light microscopic immunohistochemical studies in the periaqueductal gray (PAG) and hypothalamus demonstrated staining patterns that agreed well with previous reports. Neuron perikarya were visualized even in the absence of colchicine pre-treatment, indicating that NT8 antibody is very sensitive in immunohistochemical applications. At the EM level, the antibody stained axon terminals, dendrites, and perikarya in the PAG. In lightly immunoreactive perikarya, rough endoplasmic reticula were visualized, suggesting that biosynthetic precursors to NT might be recognized by NT8.


1998 ◽  
Vol 79 (01) ◽  
pp. 177-185 ◽  
Author(s):  
Ashia Siddiqua ◽  
Michael Wilkinson ◽  
Vijay Kakkar ◽  
Yatin Patel ◽  
Salman Rahman ◽  
...  

SummaryWe report the characterization of a monoclonal antibody (MAb) PM6/13 which recognises glycoprotein IIIa (GPIIIa) on platelet membranes and in functional studies inhibits platelet aggregation induced by all agonists examined. In platelet-rich plasma, inhibition of aggregation induced by ADP or low concentrations of collagen was accompanied by inhibition of 5-hydroxytryptamine secretion. EC50 values were 10 and 9 [H9262]g/ml antibody against ADP and collagen induced responses respectively. In washed platelets treated with the cyclooxygenase inhibitor, indomethacin, PM6/13 inhibited platelet aggregation induced by thrombin (0.2 U/ml), collagen (10 [H9262]g/ml) and U46619 (3 [H9262]M) with EC50 = 4, 8 and 4 [H9262]g/ml respectively, without affecting [14C]5-hydroxytryptamine secretion or [3H]arachidonate release in appropriately labelled cells. Studies in Fura 2-labelled platelets revealed that elevation of intracellular calcium by ADP, thrombin or U46619 was unaffected by PM6/13 suggesting that the epitope recognised by the antibody did not influence Ca2+ regulation. In agreement with the results from the platelet aggregation studies, PM6/13 was found to potently inhibit binding of 125I-fibrinogen to ADP activated platelets. Binding of this ligand was also inhibited by two other MAbs tested, namely SZ-21 (also to GPIIIa) and PM6/248 (to the GPIIb-IIIa complex). However when tested against binding of 125I-fibronectin to thrombin stimulated platelets, PM6/13 was ineffective in contrast with SZ-21 and PM6/248, that were both potent inhibitors. This suggested that the epitopes recognised by PM6/13 and SZ-21 on GPIIIa were distinct. Studies employing proteolytic dissection of 125I-labelled GPIIIa by trypsin followed by immunoprecipitation with PM6/13 and analysis by SDS-PAGE, revealed the presence of four fragments at 70, 55, 30 and 28 kDa. PM6/13 did not recognize any protein bands on Western blots performed under reducing conditions. However Western blotting analysis with PM6/13 under non-reducing conditions revealed strong detection of the parent GP IIIa molecule, of trypsin treated samples revealed recognition of an 80 kDa fragment at 1 min, faint recognition of a 60 kDa fragment at 60 min and no recognition of any product at 18 h treatment. Under similar conditions, SZ-21 recognized fragments at 80, 75 and 55 kDa with the 55kDa species persisting even after 18 h trypsin treatment. These studies confirm the epitopes recognised by PM6/13 and SZ-21 to be distinct and that PM6/13 represents a useful tool to differentiate the characteristics of fibrinogen and fibronectin binding to the GPIIb-IIIa complex on activated platelets.


Diabetes ◽  
1986 ◽  
Vol 35 (5) ◽  
pp. 517-522 ◽  
Author(s):  
J. Hari ◽  
K. Yokono ◽  
K. Yonezawa ◽  
K. Amano ◽  
S. Yaso ◽  
...  

2017 ◽  
Vol 2017 (7) ◽  
pp. 4255-4262
Author(s):  
Elena Torfs ◽  
Julie Doucet ◽  
Domenico Santoro ◽  
Dang Ho ◽  
Medhavi Gupta ◽  
...  

2020 ◽  
Vol 109 (1) ◽  
pp. 443-451 ◽  
Author(s):  
Lorenzo Gentiluomo ◽  
Dierk Roessner ◽  
Werner Streicher ◽  
Sujata Mahapatra ◽  
Pernille Harris ◽  
...  

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