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Biomedical subjects

R Oriol

Publications and source records attributed to R Oriol.

At least 91 records · Page 5Linked to original sources
PubMed1993

alpha GalNAc is essential for recognition of Exo-1 epithelial antigen by mouse monoclonal antibody Pa-G-14.

Mouse monoclonal antibody Pa-G-14 detects Exo-1, an antigen whose expression is regulated in the processes of epithelial-cell differentiation and transformation. The epitope recognized by Pa-G-14 is present both in glycosphingolipids and in mucin glycoproteins. To characterize the specificity of Pa-G-14, immuno-thin-layer chromatography, biochemical, and enzymatic treatment of glycosphingolipid extracts from human pancreas were used. The antibody bound to all blood-group-A substances; alpha GalNAc, but not fucose, was essential for reactivity. In ELISA, Pa-G-14 also reacted with ovine and bovine submaxillary mucins but not with porcine submaxillary mucin. Binding to ovine submaxillary mucin was resistant to neuraminidase treatment. In solid-phase absorption assays on synthetic carbohydrate structures, Pa-G-14 recognized broadly blood group A, Tn and sialyl-Tn. Using immuno-electron-microscopic techniques, reactivity with all Golgi cisternae and mucin droplets of mucous cells in ovine submaxillary gland was demonstrated. All these assays indicate that Pa-G-14 shows a novel specificity, since it binds blood group A, Tn and sialyl-Tn, the common structural feature of these epitopes being the presence of a terminal alpha GalNAc sugar unit.

Acetylgalactosamine↗
PubMed1993

A fucose residue can mask the MUC-1 epitopes in normal and cancerous gastric mucosae.

MUSE11, DF3 and SM3 MAbs react with a synthetic peptide of 20 amino-acids: VTSAPDTRPAPGSTAPPAHG. This sequence is a tandem repeat domain of the mucin-type glycoprotein coded by the muc-1 gene. MUSE11 and DF3 MAbs immunoreact strongly with mucus cells of the normal surface gastric epithelium of Le(a+b-) non-secretors, but in spite of the peptidic nature of the recognized epitope, the same tissue of Le(a-b+) secretors reacts only after treatment with alpha-fucosidase. These reactions are inhibited by the PNA lectin, which recognizes the T disaccharide antigen (beta Gal 1-3 alpha GalNAc), suggesting that the peptide epitope may be close to the T-saccharide structure. The SM3 MAb reacted on the surface gastric epithelium of all individuals after a more drastic deglycosylation using 20 mM periodate. Computer modeling of the MUC-1 immunoreactive glycopeptide containing the H type-3 trisaccharide alpha Fuc 1-2 beta Gal 1-3 alpha GalNAc- bound to the threonine of the PDTRP-pentapeptide shows that the peptide epitope might be masked when the fucose is positioned over the arginine. Thus, a single fucose linked to the T structure could mask the MUC-1 epitopes. In gastric adenocarcinomas, MUSE11 and SM3 epitopes are expressed in 75% (25/33) and 9% (3/33) respectively, while, after partial deglycosylation by periodate treatment, they are positive in 100% (33/33) and 70% (23/33) of cases, respectively.

Adolescent↗
PubMed1993

Histochemical localization of a beta-galactoside-binding lectin and its binding-sites in developing and adult rat cochlea.

The presence of an endogenous rat beta-galactoside-specific lectin (S-Lac) and its specific binding ligands was analyzed, using a rabbit anti-human brain lectin of 14 kDa antibody (anti-HBL-14) and a probe consisting of a biotinylated derivative of the human lectin (HBL-biot) in adult and in developing rat cochleas. At PD1, some epithelial cells of the outer spiral sulcus (OSS) were specifically recognized by the anti-HBL-14 antibody. Then, anti-HBL-14 immunoreactivity progressively appeared in all OSS epithelial cells, and, from PD9 on, it also appeared in inner spiral sulcus (ISS) epithelial cells. Finally, young adult rats exhibited a well defined anti-HBL-14 immunoreactivity in epithelial cells of the inner and outer spiral sulcus. Using the biotinylated probe, from PD3 on, tectorial membrane (TM) and the sensory cells apical surfaces were labelled. The glycoconjugate expression within the developing organ of Corti seems to be highly complex. Lectin was detected in developing and adult epithelial cells surrounding the organ of Corti. In contrast, other glycoconjugates related to B and H human blood group antigens, were transiently present on sensory cells of the organ of Corti. Present findings can be correlated with significant events in development of the cochlea, mainly with cell-cell recognition or cellular adhesion.

Animals↗
PubMed1993

Immunocytochemical approach to the structure of human blood group B and H glycoconjugate antigens in the three days old rat cochlea.

The possible structure of human blood-group antigens, as found in cochlear hair cells of 3-day-old rats, is suggested. Data were obtained from immunocytochemical studies using 77 antibodies against the major human blood group antigens of the ABO, H, I and Lewis genetic systems. Neither the anti-A-related nor the anti-Lewis-related antibodies showed any positive immunoreaction on hair cells. In contrast, anti-B, anti-AB and anti-H antibodies displayed specific positive immunoreactive patterns on the hair cells. The results suggest that, in immature hair cells, two main glycoconjugate structures of the lactoseries are present: H type 2 antigen, which is the precursor of the B type 2 antigen, and the B type 2 antigen itself. Similar H and B carbohydrate structures have been reported in rat olfactory receptors. The type 2 glycoconjugates carrying these H and B antigens of auditive and olfactory receptors are resistant to fixation and paraffin embedding, suggesting that they might be glycoproteins. These auditive and olfactory H and B antigens must be different from the B-related antigens that are expressed by pseudo-unipolar neurons of rat posterior root ganglia, that are built from type 4 core chains, and that are destroyed by routine paraffin embedding procedures.

ABO Blood-Group System↗
PubMed1993

Identification of alpha-galactosyl and other carbohydrate epitopes that are bound by human anti-pig antibodies: relevance to discordant xenografting in man.

Human anti-pig antibodies were obtained by perfusing pig hearts (n = 4) and kidneys (n = 8) with human AB or O plasma followed by elution with 3 M NaSCN. The antibodies were screened against a panel of 132 synthetic carbohydrates conjugated to bovine serum albumin using an enzyme-linked immunoassay. An anti-immunoglobulin antibody was also used to detect immunoglobulin deposits on pig tissues. Four carbohydrate molecules with a terminal alpha-galactose residue bound all but one of the human anti-pig kidney antibodies and most of the anti-pig heart antibodies. These were: (i) alpha Gal(1-->3)beta Gal(1-->4)beta GlcNac (linear B type 2); (ii) alpha Gal(1-->3)beta Gal(1-->4)beta Glc (linear B type 6); (iii) alpha Gal(1-->3)beta Gal(B disaccharide); and (iv) alpha Gal(alpha-D-galactose). Immunoglobulin deposition was documented post-plasma perfusion in all pig hearts and particularly strongly in all pig kidneys. These results suggest that human anti-pig antibodies are mainly directed against alpha-galactosyl structures. Extracorporeal immunoadsorption of human plasma through columns of the specific synthetic carbohydrate(s) might lead to depletion of anti-pig antibodies and allow discordant xenografting in man. Alternatively, the infusion of the specific carbohydrate(s) for a period of several days might result in neutralization of the anti-pig antibodies and allow accommodation to take place.

ABO Blood-Group System↗
PubMed1993

Carbohydrate antigens of pig tissues reacting with human natural antibodies as potential targets for hyperacute vascular rejection in pig-to-man organ xenotransplantation.

Pig tissues were screened by immunofluorescence with lectins, mAb, and human natural antibodies for the presence of carbohydrate antigens, which may be potential targets for hyperacute vascular rejection in pig to man xenotransplantation. The unfucosylated monomorph linear B-antigen was found at the surface of all porcine vascular endothelial cells. This pig linear-B antigen reacts strongly with the anti-alpha Gal isolectin B4 from Griffonia simplicifolia 1 and with human natural anti-alpha Gal antibodies specifically purified by affinity chromatography on synthetic oligosaccharides containing the terminal nonreducing alpha Gal1-->3 beta Gal-R disaccharide. This antigenic activity is destroyed by treatment of pig tissues with alpha-galactosidase. The localization of this linear-B epitope on vascular endothelium and its reactivity with natural human anti-alpha Gal antibodies suggest that it may play a major role in the hyperacute vascular rejection of pig to man organ xenografts. The lectin from Maackia amurensis reacting with alpha NeuAc2-->3 beta Gal1-->4GlcNAc/Glc was also positive on pig vascular endothelium, but we do not know yet whether there are human natural antibodies reacting with the carbohydrate recognized by this lectin. Epithelial cells of pig renal proximal convoluted tubules, respiratory epithelium, pancreatic ducts, and epidermis express the linear-B antigen, but they are less likely to trigger a hyperacute vascular rejection because they are not directly exposed to the blood. The genetically defined pig A+/A- system controls the expression of A and H antigens in pig epithelial cells from renal distal and collecting tubules, biliary ducts, pancreatic ducts, large bronchi, and digestive mucosa. The pig A antigen may trigger an immune response in human O or B recipients if they are transplanted with organs from A+ pigs, but the pig A antigen is probably not involved in the hyperacute vascular rejection of a xenograft because it is not expressed on vascular endothelium.

Acute Disease↗
PubMed1993

Plasma and red-cell glycolipid patterns of Le(a+b+) and Le(a+b-) Polynesians as further evidence of the weak secretor gene Se(w).

Monoclonal antibodies and thin-layer chromatography were used to study the unusual erythrocyte Lewis phenotypes found in healthy Polynesians. A single monoclonal anti-Leb reagent 073 (clone LM129) was found which could detect Leb antigen on the Polynesian erythrocytes of samples that were unreactive with various polyclonal and monoclonal anti-Leb reagents. Glycolipid fractions prepared from the plasma and erythrocytes of selected Polynesian samples of red-cell Le(a-b-), Le(a+b-) and Le(a+b+) phenotypes were found to have Leb glycolipids. The Leb antigen in some individuals is so weakly expressed that it is undetectable by routine erythrocyte phenotyping. Unusually large glycolipids bearing the Leb epitope were also found in some Polynesian samples, although the contribution of these novel glycolipids to phenotyping is unclear. The inability to detect Leb by routine methods and the presence of novel structures can be partially explained in terms of the presence of a weak secretor gene Se(w).

Chromatography, Thin Layer↗
PubMed1993

Alpha-3-fucosyltransferases and their glycoconjugate antigen products in the developing human kidney.

BACKGROUND: Three patterns of alpha-3-fucosyltransferase activity have been described in human adult tissues with different acceptor specificity: myeloid, plasma and Lewis. Five- to ten-week embryos express the myeloid enzyme in all tissues tested, then this enzyme is replaced by plasma or Lewis enzymes, with the exception of leukocytes that continue to express the myeloid form of the enzyme in the adult. These enzymes have not been studied as yet in the developing human kidney. EXPERIMENTAL DESIGN: The three different alpha-3-fucosyltransferases were studied in homogenates of mesonephros and metanephros with synthetic oligosaccharide acceptors. The oligosaccharide precursors and products of these enzymes (precursor, H, Le(a), sialyl-Le(a) and Le(b) for type 1 and precursor, H, Le(x), sialyl-Le(x) and Le(y) for type 2) were localized by immunofluorescence with specific antibodies. RESULTS: Only the myeloid alpha-3-fucosyltransferase is detected at 5 weeks in mesonephros and it disappears at 8 weeks. In metanephros, the myeloid enzyme alone is detected between weeks 6 and 8. The plasma enzyme then appears and only at the last trimester of gestation does the Lewis enzyme appear. Three histologic patterns that are concordant with the expression of the alpha-3-fucosyltransferases are observed: I. Inducer, S-shaped body, Bellini and calyce express Le(x) at an early stage when, only the myeloid alpha-3-fucosyltransferase is detected; II. Later, the proximal tubules and descending limbs of Henle's loop express Le(x) (week 9) and sialyl-Le(x) (week 16) when the plasma alpha-3-fucosyltransferase appears; III. Calyceal and collecting systems always express Le(x) and after week 12 Le(a) and Le(b) appear, in accordance with the late appearance of Lewis alpha-3/4-fucosyltransferase. CONCLUSIONS: The sequential appearance of enzymes and their products suggests that during renal organogenesis the myeloid alpha-3-fucosyltransferase is progressively replaced by the plasma enzyme in the proximal tubules and later by the Lewis enzyme in Bellini's ducts and calyce.

Adult↗
PubMed1992

Immunohistological characterization of mucin epitopes by pre-treatment of gastro-intestinal sections with periodic acid.

Periodate pretreatment of paraffin sections of ethanol-fixed gastrointestinal mucosae was used to characterize the carbohydrate or peptidic nature of mucin epitopes by immunoperoxidase. Immunoreactivity of monoclonal antibodies (MAbs) against histo-blood group related carbohydrate epitopes such as A, Lea, Lec, Sialosyl Lea, H type 2, I, T, Tn and sialosyl Tn dramatically decreased or even disappeared after periodate pretreatment of deparaffinized sections. In contrast, the immunoreactivity of MAbs against peptide mucin epitopes such as the gastric M1 mucin epitopes was almost unaffected by this treatment. Moreover, periodate treatment revealed cryptic peptide M1 mucin epitopes and the peptide MUSE11 epitope associated with the 20 amino acid tandem repeat (PDTRPAPGSTAPPAHGVTSA). An increase of cross-reactions of anti-human M1 MAbs with gastric epithelium of different vertebrate species was detected with periodate treatment. Our results suggest that this method can be useful for preliminary characterization of the biochemical nature of mucin epitopes (peptidic or saccharidic) and for demasking peptidic tumour markers which are hidden by saccharide molecules in normal tissues.

Adolescent↗
PubMed1992

Five specificity patterns of (1----3)-alpha-L-fucosyltransferase activity defined by use of synthetic oligosaccharide acceptors. Differential expression of the enzymes during human embryonic development and in adult tissues.

The use of synthetic trisaccharides as acceptors led to the definition of five main (1----3)-alpha-L-fucosyltransferase activity patterns in human adult tissues: (I). Myeliod cells, granulocytes, monocytes, and lymphoblasts, transfer an alpha-L-fucopyranosyl group to O-3 of a 2-acetamido-2-deoxy-D-glucosyl residue of H blood-group Type 2 oligosaccharide [alpha-L-Fucp-(1----2)-beta-D-Galp-(1----4)-beta-D-GlcpNAc----R] with Mn2+ as activator. (II) Brain has the same acceptor specificity pattern as myeloid cells, but can also use Co2+ as activator. (III) Plasma and liver transfer an alpha-L-furopyranosyl group to H blood-group Type 2 and to sialyl-N-acetyllactosamine [alpha-NeuAc-(2----3)-beta-D-Galp-(1----4)-beta-D-GlcpNAc----R]. (IV) Intestine, gall bladder, kidney, and milk have the same activity as (III), but also transfer an alpha-L-fucopyranosyl group to O-4 of a 2-acetamido-2-deoxy-D-glucose residue of H blood-group Type 1 [alpha-L-Fucp-(1----2)-beta-D-Galp-(1----3)-beta-D-GlcpNAc----R] and sialyl Type 1 [alpha-NeuAc-(1----3)-beta-D-Galp-(1----3)-beta-D-GlcpNAc----R]. (V) Stomach mucosa is not able to use sialyl-N-acetyllactosamine, but can transfer an alpha-L-fucopyranosyl group to the other Type 1 and Type 2 acceptors. Unlike in adult tissue, a single myeloid-like pattern of (1----3)-alpha-L-fucosyltransferase activity was found at early stages of development in all tissues tested. This embryonic enzyme is later progressively replaced by enzymes or mixtures of enzymes having the corresponding adult patterns of enzyme expression. All lymphoblastoid cell lines and half of the tumor epithelial cell lines tested expressed the myeloid-like pattern of enzyme found in normal embryonic tissues. The remaining tumor epithelial cell lines expressed different forms of (1----3/4)-alpha-L-fucosyltransferase acceptor specificity patterns.

Aging↗
PubMed1992

Neuronal influence on B and H human blood-group antigen expression in rat cochlear cultures.

The presence of B and H human blood-group antigens was analyzed by immunocytochemistry in rat cochleas developing either in vivo or in vitro. Developing animals, on embryonic day (E) 18 and postnatal day (P) 3, were used for in vivo studies. For in vitro studies, cochleas were removed at E18 and placed for 3 or 8 days in organotypic culture either directly or after partial spiral ganglion removal. Results from epithelial regions from cochleas developing in vivo were similar to those observed in corresponding areas of direct organotypic cultures where the innervation from spiral ganglion neurons was present. Antibodies to human blood group antigens, anti B and anti AB, selectively labeled hair cells. The intensity of labeling was weak at E18, but increased at P3 in vivo or after 3-8 days in organotypic culture. Anti H antibodies showed weak labeling of the apical surface of hair cells and other epithelial cells at E18; this labeling also increased at P3 or after 3-8 days in culture. In contrast, the non-innervated regions from organotypic cultures, where ganglia were partially removed, exhibited an epithelial disorganization and no hair cell labeling with any of the antibodies studied. The present findings suggest that human blood-group antigen expression on developing cochlear hair cells of rats may be related to afferent nerve fiber influence.

ABO Blood-Group System↗
PubMed1992

Histological reactivity of a monoclonal antibody against rat colon cancer cells on human and rat normal gut and colonic tumours.

A monoclonal antibody, F11C, was raised against rat colon cancer cells. Its immunoreactivity on normal human and rat gut as well as human and rat colonic tumours was studied by the avidin-biotin-peroxidase complex technique. In both normal rat and human gastrointestinal tract, F11C stained surface epithelial cells from the fundus to distal colon, mainly as supranuclear vesicles. These vesicles appeared to be part of the Golgi apparatus on electron microscopy with immunogold labelling. Twenty primary rat colon tumours and 28 of 43 human colon tumours were also stained, with a heterogeneous pattern but much more strongly than the normal colonic mucosa. Biochemical purification suggested that in rat tumours F11C epitope was carried by a high molecular weight glycoprotein. Absorption experiments with synthetic oligosaccharides showed that F11C monoclonal antibody reacted with blood group A-related oligosaccharides. Nevertheless, F11C reactivity on human tissues was not related to the individual ABO or Lewis phenotype.

1,2-Dimethylhydrazine↗