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T Feizi

Publications and source records attributed to T Feizi.

At least 163 records · Page 9Linked to original sources
PubMed1984

The effect of mild alkali and alkaline borohydride on the carbohydrate and peptide moieties of fetuin.

In the light of recent reports, based on radioactive labelling studies, that substantial amounts of N-linked oligosaccharides are released from protein under the mild-alkaline borohydride degradation conditions that are usually used to release O-linked oligosaccharides, we have investigated by chemical methods the effects of alkali alone and alkaline borohydride on the carbohydrate and peptide moieties of fetuin. The chromatographic profiles on Sephadex G50 columns, of the hexose- and ninhydrin-positive components of the native and Pronase-treated glycoprotein have been compared with those obtained after treatment with mild alkali alone (0.05 M-NaOH, 50 degrees C, 16 h) or mild-alkaline borohydride (0.05 M-NaOH containing 1 M-NaBH4, 50 degrees C, 16 h). Composition and methylation analyses have been performed on carbohydrate-containing peaks and the following conclusions were drawn: mild alkali treatment alone liberated a minor hexose- and ninhydrin-positive component and mild-alkaline borohydride treatment gave a major hexose-containing peak: both of these co-chromatographed on a Sephadex G50 column with Pronase glycopeptides. The polypeptide backbone was totally broken down by the alkaline borohydride treatment. The presence of released N-linked chains after alkaline borohydride treatment was confirmed. However, from the carbohydrate composition it was calculated that no more than 10-20% of the N-linked chains were released from protein. The results of methylation analysis have raised the possibility that this release is in part due to cleavage of the chitobiosyl core.

Asialoglycoproteins↗
PubMed1983

High-molecular-weight glycoproteins are the major carriers of the carbohydrate differentiation antigens I, i and SSEA-1 of mouse teratocarcinoma cells.

The carriers of the carbohydrate differentiation antigens I, i and SSEA-1 were investigated in embryonal carcinoma cell lines of mouse and differentiated cell lines derived from them. Glycoproteins were studied by immunostaining ('Western blotting') of total cell lysates and immunoprecipitation from lysates of galactose oxidase/NaB3H4-labelled cells; glycolipids were investigated by immunostaining of thin layer chromatograms. The antigenic activities detected by immunofluorescence of cell smears were reflected in the antigenicities of high-molecular-weight glycoproteins. These were polydisperse and markedly susceptible to digestion with endo-beta-galactosidase. Only the I antigen was detected on minor glycolipids. These observations indicate that glycoproteins rather than glycolipids are the major carriers of carbohydrate differentiation antigens I, i and SSEA-1 in the teratocarcinoma cell lines.

Animals↗
PubMed1983

Two mouse hybridoma antibodies against human milk-fat globules recognise the I(Ma) antigenic determinant beta-D-Galp-(1 leads to 4)-beta-D-GlcpNAc-(1 leads to 6).

Two mouse hybridoma antibodies (LICR-LON-M39 and LICR-LON-M18) against the human-milk-fat globules were found to resemble human autoantibodies of anti-I type in their cold agglutinating property and their preferential reactions with erythrocytes of I- rather than i-type. From inhibition of binding assays with glycoproteins having known A, B, H, Lea, Leb, I, and i activities, and oligosaccharides of the Type 1 and Type 2 lacto-N-glycosyl series, it was established that these antibodies are directed at Type 2 structures, and that the I(Ma) determinant, beta-D-Galp-(1 leads to 4)-beta-D-GlcpNAc-(1 leads to 6), which is usually found on branched oligosaccharides, is the preferred sequence. The hybridoma antibodies as well as anti-I Ma were shown to react well with the beta-D-Galp-(1 leads to 4)-beta-D-GlcpNAc-(1 leads to 6)-D-Gal or -D-Man sequence. Studies of the reactions of these antibodies with glycolipids on thin-layer plates showed that the two hybridoma antibodies differ from anti-I Ma in reacting weakly with the unbranched i-type sequence beta-D-Galp-(1 leads to 4)-beta-D-GlcpNAc-(1 leads to 3)-beta-D-Galp-(1 leads to 4)-beta-D-GlcpNAc-(1 leads to 3)-beta-D-galp-(1 leads to 4) as found on lacto-N-norhexasylceramide. Furthermore, they differ from anti-I Ma but resemble anti-I Woj and Sti, and a hybridoma antibody 1B2 in their failure to react with their determinant in the presence of alpha-D-(1 leads to 3)-linked galactosyl groups. From their lack of reactions with blood-group-A and -H active glycoproteins, and their reactions with neuraminidase-treated erythrocytes, it was deduced that the determinants recognised by the two hybridoma antibodies are also masked in the presence of alpha-L-(1 leads to 2)-linked fucosyl groups and sialic acid.

Animals↗
PubMed1983

Isolation and characterization of an endo-beta-galactosidase from Bacteroides fragilis.

Six strains of Bacteroides fragilis were examined and all found to produce endo-beta-galactosidase, an enzyme that hydrolyses internal beta-galactosidic linkages of oligosaccharides belonging to the poly-N-acetyl-lactosamine series, with the common structure GlcNAc beta 1 leads to 3Gal beta 1 leads to 4GlcNAc/Glc. The enzyme was produced without the addition of an inducer such as keratan sulphate. It was purified 7000-fold from the culture supernatant and obtained with a yield 4-10-fold greater than from sources described previously. The specificity of the enzyme towards bovine corneal keratan sulphate, milk oligosaccharides and the glycolipids lacto-N-neotetraosylceramide and lacto-N-tetraosylceramide closely resembled that of the endo-beta-galactosidase isolated from Escherichia freundii. A novel observation was that both enzymes hydrolysed the type 2 sequence, Gal beta 1 leads to 4GlcNAc beta 1 leads to 3Gal beta 1 leads to 4Glc, at about twice the rate of the type 1 isomer, Gal beta 1 leads to 3GlcNAc beta 1 leads to 3Gal beta 1 leads to 4Glc. Because of the ease of purification of the enzyme and high yield in the absence of contaminating glycosidases and proteinases, Bacteroides fragilis is a valuable source of endo-beta-galactosidase for the structural analysis of carbohydrate chains.

Bacteroides fragilis↗
PubMed1983

Evidence for the occurrence of O-glycosidically linked oligosaccharides of poly-N-acetyllactosamine type on the human leucocyte common antigen.

High molecular weight glycoproteins of human B and T lymphocytes known as leucocyte common antigen or T200 have been shown to carry O- and N-glycosidically linked, sialylated, carbohydrate chains. The O-linked chains are polydisperse and those of B rather than T cell type are highly susceptible to degradation by endo-beta-galactosidase. These differences among lymphocytes that are functionally distinct raise the possibility that the oligosaccharides may contribute to the functions of these differentiation molecules as well as to their electrophoretic diversity.

Antigens↗
PubMed1983

Marker of peripheral blood granulocytes and monocytes of man recognized by two monoclonal antibodies VEP8 and VEP9 involves the trisaccharide 3-fucosyl-N-acetyllactosamine.

Two hybridoma antibodies (VEP8 and VEP9) raised against the promyelomonocytic leukemia cell line HL60 have previously been shown to distinguish human granulocytes and monocytes from other cells of the peripheral blood. We report here that both antibodies recognize the carbohydrate structure 3-fucosyl-N-acetyllactosamine with the following sequence: (formula; see text) This structure is the same as that recognized by a hybridoma antibody against mouse teratocarcinoma cells (anti-SSEA-1) which recognizes an early embryonic antigen in the mouse. Until recently this carbohydrate structure was considered to be rare among glycoproteins and glycosphingolipids. However, there is a growing list of human and animal glycoproteins in which this sequence has been detected by chemical and immunochemical methods. In this article we survey this information and discuss how this and other carbohydrate structures behave as differentiation- or tumor-associated antigens.

Animals↗
PubMed1983

Interactions of a mammalian beta-galactoside-binding lectin with hamster fibroblasts.

A beta-galactoside-binding endogenous lectin extracted from bovine heart binds to the surface of baby hamster kidney (BHK) cells. The binding to and agglutination of cells is reduced in certain ricin-resistant mutants (Ric cells) in parallel with the decreased number of binding sites for the selective agent, ricin, a galactose-specific plant lectin. However, clear differences in the binding specificities of bovine lectin and ricin are shown by the effect of neuraminidase. BHK cells and Ric mutant cells treated with neuraminidase bind similar amounts of the bovine lectin compared with untreated cells, and ricin binding is greatly increased. The mammalian lectin immobilised on inert glass mediates the attachment and spreading of normal BHK cells and agglutinates these cells in solution. Ricin-resistant mutant cells respond poorly. These results are consistent with a role of endogenous lectins in cellular adhesiveness and show that cell adhesion may be regulated by the density of specific surface receptors for lectins.

Animals↗
PubMed1983

A multiplicity of erythrocyte glycolipids of the neolacto series revealed by immuno-thin-layer chromatography with monoclonal anti-I and anti-i antibodies.

The thin-layer-chromatography immunostaining procedure was applied to human erythrocyte glycolipids using monoclonal anti-i and anti-I antibodies which are directed against epitopes on linear and branched carbohydrate chains of the neolacto (poly-N-acetyllactosamine) series. An examination of native and mild-acid-treated glycolipids from normal adult (I(adult) antigen type), neonatal (i(cord)), and I-antigen-deficient adult (i(adult)) erythrocytes enabled certain structural inferences to be made as follows: (a) cells of both I and i phenotypes contain a multiplicity of glycolipids of the neolacto series whose backbones consist of 8 or more sugar residues; (b) the octasaccharide backbones are predominantly linear in cells of i phenotype and branched in those of I type; and (c) more complex glycolipids having decasaccharide and larger backbones with both linear and branched sequences occur in erythrocytes of both phenotypes.

Adult↗
PubMed1983

Monoclonal antibody reactive with the human epidermal-growth-factor receptor recognizes the blood-group-A antigen.

The hybridoma antibody TL5, which precipitates the EGF receptor from the human epidermoid carcinoma cell line A431, has been shown to recognize the blood-group-A carbohydrate structure. This conclusion has been reached from studies of (a) the binding of the antibody to glycoproteins and haemagglutination of erythrocytes with known blood-group-antigen activities and (b) the inhibition of binding of the antibody to a radiolabelled blood-group-A-active glycoprotein by structurally defined oligosaccharides.

ABO Blood-Group System↗
PubMed1983

A monoclonal antibody against human colonic adenoma recognizes difucosylated Type-2-blood-group chains.

A monoclonal antibody C14/1/46/10 showing preferential binding to membranes of human colorectal carcinomas over normal colon mucosae was obtained by immunization of mice with extra-nuclear membranes of a human colonic adenoma. Binding and inhibition of binding assays using blood cells or glycoproteins with known blood-group activities indicated that the antibody recognizes a carbohydrate antigen co-existing with the blood-group-H determinant: Fuc alpha 1 leads to 2 Gal. Inhibition assays with structurally defined oligosaccharides showed that the antigenic determinant involves difucosylated Type-2-blood-group chains with the structure: (formula; see text)

Adenoma↗
PubMed1983

A marker of human foetal endoderm defined by a monoclonal antibody involves Type 1 blood group chains.

This report demonstrates that a marker of human embryonic endoderm and embryonal carcinoma cells recognized by a hybridoma antibody FC 10.2, involves Type 1 blood group chains with the sequence Gal beta 1 leads to 3G1cNAc beta 1 leads to 3Gal beta 1 leads to 4G1c. This conclusion has been reached from antigenic analyses of meconium, ovarian cyst glycoproteins, oligosaccharides and glycolipids having Type 1 or Type 2 blood group chains. From knowledge of saccharide sequences and blood group related antigens in gastrointestinal tissues of man, we deduce that the 'disappearance' of FC 10.2 antigen from the normal, differentiated cells of the adult may result from masking by additional glycosylations or other substitutions.

Acetylglucosamine↗
PubMed1983

Monoclonal antibody against a cross-reactive idiotypic determinant found on human autoantibodies with anti-I and -i specificities.

A monoclonal antibody has been raised against a cross-reactive idiotypic determinant expressed on human autoantibodies with anti-I and -i specificities. The McAb is directed against a conformational epitope requiring interaction of H- and L-chains for maximal expression. This epitope was strongly expressed on the monoclonal protein of one out of 100 patients with paraproteinaemia and the peripheral blood lymphocytes of one out of 50 cases of B-cell leukaemia. A small amount of the epitope is detectable among immunoglobulins in normal serum.

Agglutinins↗
PubMed1983

Peanut lectin and anti-Ii antibodies reveal structural differences among human gastrointestinal glycoproteins.

Human gastrointestinal glycoproteins (mucins), isolated by pepsin digestion from foetal stomachs and meconia, and from paired tumour and non-neoplastic mucosal samples of patients with gastric and colorectal carcinomas, were tested for precipitating reactions with peanut lectin (PNL) and four anti-carbohydrate antibodies (two anti-I, Ma and Low, and two anti-i, Den and Galli). There was remarkable correlation between reactivities with PNL and anti-I (Ma): both reagents reacted with non-neoplastic gastric glycoproteins of "non-secretors", but not with those of "secretors", and also with the majority of gastric tumour and meconium extracts regardless of secretor status. Colorectal tissue extracts (with the exception of one tumour extract) reacted with neither reagent. The various precipitating activities, and results of mild acid hydrolysis and affinity chromatography experiments, enable certain inferences to be made regarding the oligosaccharide moieties of gastrointestinal glycoproteins: (a) expression of PNL and anti-I (Ma) determinants in gastric glycoproteins is dependent on secretor status; (b) extracts reacting with PNL and anti-I (Ma) are mixtures of macromolecules: minor populations react with both reagents, or with PNL only; the major population lacks both determinants, or they are masked by other substitutions; (c) determinants reactive with anti-Ii sera other than anti-I (Ma) are less frequently expressed; and (d) colonic glycoproteins in their lack of PNL and Ii determinants. This suggests that there are structural differences in the oligosaccharide backbones of the two types of glycoprotein.

Antibodies, Monoclonal↗
PubMed1983

Blood group antigens in the normal and neoplastic bladder epithelium.

The indirect immunofluorescence technique was used to study the expression of the blood group A and H antigens in fresh-frozen and formalin-fixed paraffin-embedded sections of the bladder mucosa of 21 patients with non-neoplastic diseases of the bladder. Reliable assessment of these antigens could only be made using cryostat sections of fresh-frozen tissues. Also included in this study were tumour tissues of 5 patients with bladder cancer. The blood group A antigen was totally deleted in cryostat sections of the tumour of one patient with aggressive carcinoma and the appropriate antigens were diminished or focally deleted in the four patients with tumours that were non-invasive during one to three years of follow-up. It is concluded that sections of fresh-frozen tissues or sections processed in the absence of glycolipid-extracting solvents should be used for visualising the expression of blood group antigens in bladder tissues and assessing their value as prognosticators of the malignant potential of bladder tumours.

ABO Blood-Group System↗