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Biomedical subjects

J L Magnani

Publications and source records attributed to J L Magnani.

At least 55 records · Page 3Linked to original sources
PubMed1983

A monoclonal antibody that precipitates the glycoprotein receptor for epidermal growth factor is directed against the human blood group H type 1 antigen.

Monoclonal antibody 101 produced by a hybridoma obtained by fusion with NS-1 myeloma cells of spleen cells from a mouse immunized with the human epidermoid carcinoma cell line, A431, specifically precipitates epidermal growth factor receptor, a glycoprotein of 170,000 Mr solubilized from A431 cell membranes (Richert, N. D., Willingham, M. C., and Pastan, I. H. (1983) J. Biol. Chem. 258, 8902-8907). The antibody also binds to neutral glycolipids extracted from A431 cells as evidenced by solid phase radioimmunoassay and by autoradiography. Binding of antibody to its target is inhibited by lacto-N-fucopentaose I but not by 2'-fucosyllactose or related oligosaccharides. Thus, antibody 101 is probably directed against the human blood group H type 1 sugar sequence Fuc alpha 1-2Gal beta 1-3GlcNAc . . .. This sequence presumably occurs on the epidermal growth factor receptor. Monoclonal antibody 102 produced by another hybridoma from the same fusion has the same cell specificity as antibody 101 and also binds to neutral glycolipids. However, binding of antibody 102 to its target is inhibited by 2'-fucosyllactose and not by lacto-N-fucopentaose I or related oligosaccharides. Thus, antibody 102 is probably directed against the human blood group H type 2 sugar sequence Fuc alpha 1-2Gal beta 1-4GlcNAc . . .. Antibody 102 does not precipitate solubilized epidermal growth factor receptor. Both antibodies bind to neutral glycolipids extracted from human erythrocytes belonging to blood group O but not to neutral glycolipids extracted from human erythrocytes with the "Bombay" phenotype.

ABO Blood-Group System↗
PubMed1983

Identification of the gastrointestinal and pancreatic cancer-associated antigen detected by monoclonal antibody 19-9 in the sera of patients as a mucin.

Monoclonal antibody 19-9, produced by a hybridoma prepared from spleen cells of a mouse immunized with a human colon carcinoma cell line, detects an antigen in the serum from most patients with gastrointestinal and pancreatic cancer (M. Herlyn, H.F. Sears, Z. Steplewski, and H. Koprowski, J. Clin. Immunol., 2: 135-140, 1982). The epitope of this antibody is a carbohydrate with the sugar sequence (formula; see text) in which NeuNAc is N-acetylneuraminic acid, Gal is galactose, GlcNAc is N-acetylglucosamine, and Fuc is fucose. In the colon carcinoma cell line and many gastrointestinal and pancreatic cancers, this sequence occurs in a monosialoganglioside containing a sialylated Lea-active pentasaccharide (sialylated lacto-N-fucopentaose II, IV3-alpha-NeuNAc-III4-alpha-Fuc-LcOse4, in which LcOse4 is Gal beta 1-3GlcNAc beta 1-3Gal beta 1-4Glc) (J. L. Magnani et al. J. Biol. Chem., 257: 14365-14369, 1982). However, the antigen in the sera of patients occurs mainly as a mucin, not a ganglioside, based on the following evidence. Little antigen is extracted by organic solvents from sera, and that which is extracted remains at the origin under conditions of thin-layer chromatography where the ganglioside antigen migrates up the plate. Upon gel filtration of serum on Sephacryl S-400, the antigen is eluted in the void volume, indicating a molecular weight of greater than or equal to 5 X 10(6). Incubation for 5 hr at 37 degrees in 0.1 N NaOH destroys the serum antigen but does not affect the ganglioside antigen. The density of the serum antigen as determined in a CsCl gradient is 1.50 g/ml, while in 4 M guanidine. HCl its density is 1.43 g/ml. Finally, antigen affinity purified by antibody 19-9 from the serum of a cancer patient belonging to the Le(a-b+) blood group contains Leb antigen, consistent with the multiple antigenic specificities exhibited by mucins.

Antibodies, Monoclonal↗
PubMed1982

A monoclonal antibody-defined antigen associated with gastrointestinal cancer is a ganglioside containing sialylated lacto-N-fucopentaose II.

Two monoclonal antibodies produced by hybridomas obtained from a mouse immunized with a colorectal carcinoma cell line bind specifically to human gastrointestinal cancer cells. The antigen of this antibody in the carcinoma cell line, a monosialoganglioside, has been isolated. Its carbohydrate structure is probably (formula: see text). This oligosaccharide is a sialyl derivative of lacto-N-fucopentaose II, a hapten of the human Lea blood group antigen. About 30 micrograms of ganglioside is obtained from 1 g of cells, wet weight. The ganglioside was detected by autoradiography in lipid extracts of some carcinomas and of meconium, but not in lipid extracts of normal adult tissues. Antigen was detected by solid phase radioimmunoassay in lipid extracts from 12 out of 21 adenocarcinomas of the colon, from 4 out of 5 gastric adenocarcinomas, and from 4 out of 7 pancreatic carcinomas. Antigen was not detected in lipid extracts from 5 esophageal carcinomas or from normal colon and gastric mucosa, pancreas, kidney, liver, and bone marrow.

Animals↗
PubMed1981

Monoclonal antibodies directed against the human Leb blood group antigen.

Four monoclonal antibodies produced by hybridomas obtained from a mouse immunized with a human adenocarcinoma cell line SW1116 (Koprowski, H., Steplewski, Z., Mitchell, K., Herlyn, M., Herlyn, D., and Fuhrer, P. (1979) Somatic Cell Genet. 5, 957-972) are directed against the Leb antigen of the human Lewis blood group system. Their specificities were established by binding studies using purified Leb-active ceramide hexasaccharide and by hapten inhibition studies involving oligosaccharides obtained from human milk.

Antibodies, Monoclonal↗
PubMed1981

A monosialoganglioside is a monoclonal antibody-defined antigen of colon carcinoma.

The antigen of a monoclonal antibody that is specific for cells of human carcinoma of the colon is a monosialoganglioside as determined by the direct binding of antibody to thin-layer chromatograms of total lipid extracts of tissues. Binding of antibody to chromatograms is detected by autoradiography after the application of iodine-125-labeled F(ab')2 of rabbit immunoglobulin G antibodies to mouse immunoglobulins.

Adenocarcinoma↗
PubMed1979

Contribution of cyclic adenosine 3':5'-monophosphate to the regulation of bacterial glycogen synthesis in vivo. Effect of carbon source and cyclic adenosine 3':5'-monophosphate on the quantitative relationship between the rate of glycogen synthesis and the cellular concentrations of glucose 6-phosphate and fructose 1,6-diphosphate in Escherichia coli.

When either fructose, glycerol, or succinate served as a sole source of carbon and energy in nitrogen-starved cultures of Escherichia coli W4597(K) the values of the kinetic constants of the equation that expresses the relationship between glycogen synthesis and hexose phosphates were different from the values observed when glucose was the sole source of carbon and energy. Addition of glucose during either exponential growth or nitrogen starvation to a culture using one of the other carbon sources slowed the rate of glycogen synthesis and shifted the values of the constants toward the values observed in cultures using glucose alone. Addition of cyclic AMP (cyclic adenosine 3':5'-monophosphate) during exponential growth of a culture using glucose caused the values of the constants to be shifted toward the values observed in cultures using a carbon source other than glucose. In all of the metabolic conditions studied in this report the adenylate energy charge ((ATP + 1/2 ADP)/(ATP + ADP + AMP)) and the level of the rate-limiting enzyme of glycogen synthesis, ADP-glucose synthetase (glucose 1-phosphate adenylyltransferase, EC 2.7.7.27), were the same. The data presented here indicate that the difference we observed in the quantitative relationship for glycogen synthesis is the result of the different cellular levels of cyclic AMP in the cells using glucose and the cells using one of the other carbon sources. Since cyclic AMP does not affect the velocity of ADP-glucose synthetase in vitro, apparently a change in the cellular level of cyclic AMP causes a shift in the cellular level of a presently unknown (and previously undetected) effector of this enzyme. The shift in the level of this effector evidently alters the response of the enzyme in vivo to the substrate glucose 1-phosphate and the activator fructose 1,6-diphosphate.

Adenine Nucleotides↗
PubMed1975

Evidence for the coordinate control of glycogen synthesis, glucose utilization, and glycolysis in Escherichia coli. II. Quantitative correlation of the inhibition of glycogen synthesis and the stimulation of glucose utilization by 2,4-dinitrophenol with the effects on the cellular levels of glucose 6-phosphate, fructose, 1,6-diphosphate, and total adenylates.

In cultures of Escherichia coli W4597(K) and G34 under various nutritional conditions the rates of glucose utilization and cellular levels of fructose-1,6-P2 are quantitatively related by the Hill equation where the value of the Hill coefficient is approximately equal to 2. This is the first evidence that fructose-P2, or any metabolite which covaries with fructose-P2, modulates glucose utilization in E. coli. In light of previous observations from our laboratory this new observation and those in the succeeding report provide the first evidence that in E. coli glycolsis, glycogen synthesis and glucose utilization are coordinately regulated, thus providing for the coupling of ATP utilization and production under various metabolic circumstances. Alterations in the level of ATP apparently affect the velocity of phosphofructokinase, the rate-limiting enzyme in glycolsis, altering the cellular levels of glucose-6-P or fructose-P2. Changes in the levels of these hexose phosphates are quantitatively related to alterations in the rates of glucose utilization and glycogen synthesis in the intact E. coli cell.

Adenosine Diphosphate↗
PubMed1975

Evidence for the allosteric regulation of glycogen synthesis in the intact Escherichia coli cell. Agreement of the values of the parameters of the Hill equation fitted to data for glycogen synthesis in vivo with the abailable values obtained in vitro with adenosine diphosphoglucose synthetase.

In various nutrient-limited cultures of either Escherichia coli W4597(K) or G34 a 10-fold range of rates of glycogen synthesis is observed while the energy charge values (0.86 plus or minus 0.01) and glucose 6-phosphate levels are essentially the same in each condition. The steady state level of fructose 1,6-diphosphate in these cultures varies from experiment to experiment as a function of the observed rate of glycogen synthesis. These data were fitted to the Hill equation by a nonlinear regression analysis and the statistically most probable values obtained for the Hill coefficient (n), A0.5, and V were, respectively, 2.08, 0.82mM, and 1030 mumol/g of protein per hour. The values of the first two parameters agree well with values available at energy charge 0.85 for the in vitro synthesis of ADPG by the ADPG synthetase of E. coli. When the difference in the glucose 1-phosphate concentration used in the studies in vitro from the apparent glucose 1-phosphate concentration in vivo (estimated from the glucose 6-phosphate levels) is considered, the in vitro value of V (1140 mumol of ADPG synthesized per g of protein per hour) is quite similar to the value of V (1030 mumol of glucose incorporated into glycogen per g of protein per hour) for glycogen synthesis in vivo. The close agreement of the values of the parameters of the Hill equation for glycogen synthesis in vivo to the values obtained for ADPG synthesis in vitro provides the most quantitative evidence yet obtained that allosteric regulation of bacterial glycogen synthesis functions in vivo.

Adenosine Diphosphate↗