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Hans-joachim Gabius - One of the best experts on this subject based on the ideXlab platform.
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Histochemical identification of endogenous lectins using labelled Neoglycoproteins in human head-and-neck squamous cell carcinoma
Laryngo- rhino- otologie, 2008Co-Authors: Miriam Katharina Steuer, Hans-joachim Gabius, A. Bardosi, R. MatthiasAbstract:According to the "Population-based cancer register" of the Federal Republic of Germany only malignant neoplasms of the buccal cavity, the pharynx and larynx as well as cancers of the respiratory tract show an increasing rate of incidence and mortality. The molecular mechanisms and etiological factors causing this phenomenon are still little understood despite intensive research work. Recognition between receptors on a cellular level may be mediated by specific amino acid sequences on the level of protein-protein recognition. Additionally, the interactions between cell sugars and the corresponding protein receptor may play a decisive role in development, regeneration and organisation of cells and tissue. The high specificity of the binding of biotinylated Neoglycoproteins in tissue sections enables to detect glycohistochemically binding sites for the carbohydrate ligands of the glycosylated carrier protein. The evidence of lectins in squamous cell cancer of the oral cavity, oropharynx, larynx, and hypopharynx has not been established so far. Squamous cell cancer tissue samples of twelve patients with different tumour locations were investigated by incubation of sections of paraffin-embedded samples and application of an avidin-biotin-peroxidase complex for visualisation with synthetic biotinylated Neoglycoproteins. Altogether 168 stained sections were evaluated including controls. Pronounced cytoplasmatic staining was seen with the following Neoglycoproteins: sialic acid-bovine serum albumin (BSA), glucuronic acid-BSA, N-acetylglucosamine (glcNAc)-BSA, N-acetylgalactosamine (beta-galNAc)-BSA, lactose-BSA, maltose-BSA, mannose-BSA, mannose-6-phosphate-BSA. No corresponding lectins seems to exist for the following investigated sugars: fucoidan, heparin, and the alpha-anomeric form of N-acetylgalactosamine, because no specific staining was seen.(ABSTRACT TRUNCATED AT 250 WORDS)
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Differential binding activities of lectins and Neoglycoproteins in human testicular tumors
Urological research, 2000Co-Authors: Ulrich Brinck, Alfred Schauer, Hans-joachim GabiusAbstract:Testicular germ-cell tumors, a morphologically and clinically diverse group of malignancies provide an ideal model for investigating the biology of glycoconjugates because the biosynthesis of oligosaccharide chains of glycoproteins monitored by plant/invertebrate lectins often changes during tumorigenesis, tumor progression, and metastasis. To investigate such changes in germ-cell tumors, we analyzed 67 surgical specimens from 31 seminomas, 32 embryonic carcinomas, and four choriocarcinomas using glyco- and immunohistochemistry that involved five plant/invertebrate lectins, 16 Neoglycoproteins, and galectin-1 antibody. The results showed that some of these markers, such as melibiose-, lactose-, and β-N-acetylgalactosamine-BSA-biotin were clearly differentially expressed amongst these tumors and between primary and metastatic embryonic carcinomas. The differences in staining for positivity, intensity, and heterogeneity indicate that the differential display of glycoconjugates in tumor cells may be important in tumor growth, metastasis, or prognosis because subtypes of these tumors behave quite differently from one another. Furthermore, we also found identical staining for positivity between most Neoglycoproteins and their corresponding lectins, though the staining intensity of Neoglycoproteins was weaker. This suggests that Neoglycoproteins may be useful markers to replace their plant lectins.
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Neoglycoproteins with the Synthetic Complex Biantennary Nonasaccharide or Its α2,3/α2,6-Sialylated Derivatives: Their Preparation, Assessment of Their Ligand Properties for Purified Lectins, for Tumor Cells in Vitro, and in Tissue Sections, and Their
Bioconjugate Chemistry, 1997Co-Authors: Sabine Andre, Shuji Kojima, Christian Fink, Klaus Kayser, Carlo Unverzagt, Xin Dong, Hans-joachim GabiusAbstract:Neoglycoproteins were prepared with chemoenzymatically synthesized complex biantennary N-glycan derivatives the nonreducing ends of which bear typical sequences found in glycoproteins. A chemically obtained biantennary heptasaccharide−azide was reduced and acylated with a 6-aminohexanoyl spacer. Elongation of the deprotected heptasaccharide using glycosyltransferases yielded a biantennary nonasaccharide with terminal galactose residues and two undecasaccharides terminating with α2,6- or α2,3-linked sialic acid. The free amino group of the spacer of these oligosaccharides was converted into an isothiocyanate. Its subsequent coupling to bovine serum albumin gave Neoglycoproteins with a yield of 2.4−3.6 glycan chains per carrier molecule. This versatile synthetic pathway allows employment of a wide variety of complex-type glycans, which can be introduced to various test systems in vitro and in vivo to evaluate potential biomedical applications. Solid-phase assays with biotinylated sugar receptors revealed di...
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histochemical study of the epithelia of nasal polyps by biotinylated lectins and Neoglycoprotein a comparison with the normal human respiratory epithelium
European Journal of Morphology, 1997Co-Authors: Sergio Hassid, Hans-joachim Gabius, Isabelle Salmon, M Brugmans, Sandra Dawance, Robert Kiss, André DanguyAbstract:Formalin-fixed, paraffin-embedded sections from human nasal polyps and the normal respiratory epithelium were glycohistochemically investigated. Three biotinylated lectins were used: peanut (Arachis hypogaea) agglutinin (PNA) which, binds to terminal galactose (beta 1-3) N-acetylgalactosamine residues that can be unmasked by a neuraminidase digestion; wheat germ (Triticum vulgare) agglutinin (WGA), which binds to N-acetylglucosamine and N-acetylneuraminic acids; and gorse seed (Ulex europaeus) agglutinin (UEA-1), which binds to L-fucose. In addition, the presence of accessible galactose (beta 1-3) N-acetylgalactosamine (T-antigen) glycan receptors (endolectins) was also assessed. The avidin-biotin-peroxidase complex (ABC) and diaminobenzidine (DAB) were used as chromogen. The ciliated cells of the normal respiratory epithelium and those of the pseudostratified epithelium of nasal polyps possess similar glycohistochemical characteristics suggesting no major alterations on the level of lectin-reactive carbohydrate epitopes as indicators of cellular glycosylations. Notably, this parameter can respond sensitively to changes in cell differentiation or activation. The basal and mucus-secreting cells in the two epithelia display different reactivity patterns emphasizing the presence of dissimilar sugar residues. Similarly, the dysplasia reflecting squamous epithelium of nasal polyps shows a distinct staining behaviour, indicative for disparate glycoconjugate display. Thus, quantitative differences in the lectin-selective staining of various cell types are detectable. The expression of T-antigen-bearing Neoglycoprotein binding is weak and similar in both the normal epithelium and the pseudostratified epithelium lining nasal polyps. Only the most superficial cells of the squamous epithelium disclose a moderate labelling with this probe. These results indicate that further studies in this field are warranted, employing Neoglycoproteins and also endolectins from human tissues to correlate glycobiological properties of the epithelium of the conducting airways and its diseased forms with functional features.
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Potential usefulness of biotinylated Neoglycoproteins as tumor markers.
Nutrition (Burbank Los Angeles County Calif.), 1995Co-Authors: D. T. Lincoln, Hans-joachim Gabius, Temmin L, Fred Sinowatz, Hifnawi El-s, Dashti HAbstract:We used several biotinylated Neoglycoproteins as tumor markers to detect and localize endogenous carbohydrate-binding proteins in cultured hepatoblastoma, melanoma, and bladder carcinoma tumor cells. The Neoglycoproteins used consisted of cellobiose, fucose, N-acetyl-galactosamine, N-acetyl-glucosamine, lactose, maltose, mannose, melibiose, and xylose. In addition, naturally occurring asialofetuin that was chemically disialylated was also used. Binding to the cultured tumor cells was made visible with the avidin-peroxidase technique. Depending on the type of Neoglycoprotein used, markedly different expression of cytoplasmic and nuclear receptors for sugars (endogenous lectins) was obtained from rat hepatoblastoma, human melanoma, and bladder carcinoma tumor cells. The most pronounced staining differences were documented for asialofetuin and the Neoglycoproteins containing fucose, N-acetyl-galactosamine, and lactose.
Michel Monsigny - One of the best experts on this subject based on the ideXlab platform.
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Glyco-dependent nuclear import of glycoproteins, glycoplexes and glycosylated plasmids.
Biochimica et Biophysica Acta, 2004Co-Authors: Michel Monsigny, Christine Rondanino, Eric Duverger, Isabelle Fajac, Annie Claude RocheAbstract:This short review deals with some properties of nuclear sugar-binding proteins also called nuclear lectins, the sugar-dependent nuclear import of Neoglycoproteins and the attempts of using this pathway to enhance the nuclear import of plasmids in order to hopefully increase the expression of transferred genes.
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Mannose dependent tightening of the rat ependymal cell barrier. In vivo and in vitro study using Neoglycoproteins.
Neurochemistry International, 2003Co-Authors: Sabine Kuchler, Michel Monsigny, Marie-noelle Graff, Serge Gobaille, Guy Vincendon, Anne-claude Roche, Jean-pierre Delaunoy, Jean-pierre ZanettaAbstract:Abstract The possible role of carbohydrate binding proteins (lectins) and glycoconjugates in the formation of junctions ensuring tightening between ependymal cells was studied using synthetic glycoconjugates, the Neoglycoproteins. These compounds are prepared by substituting bovine serum albumin with sugar residues and additional labelling (or not) with fluorescein or biotin. Injections of these components into the cerebral ventricles of adult rats resulted in a binding pattern which could be related to their carbohydrate composition. Mannose-containing Neoglycoproteins were bound to ependymal cell cilia and penetrated rapidly the brain tissue. Such phenomenon was not seen with glucose- or galactose-containing Neoglycoprotein molecules. In contrast, mannose-, galactose- and glucose- containing Neoglycoproteins bound strongly to some endothelial cells around blood vessels. Fluorescent unglycosylated serum albumin did not bind to any brain structures. In contrast, co-injection of mannose-containing non-fluorescent Neoglycoproteins with the other fluorescent compounds (including fluorescent sugar-free BSA) resulted in the penetration of the fluorescent compounds into the brain tissue. This internalization into brain was attributed to disaggregation of junctions between ependymal cells. Cultured ependymal cells behaved likewise. In short term experiments (5 min–1 h), only the mannose-containing Neoglycoproteins bound strongly to the ependymal cells, particularly to the cilia. In long term experiments (1–9 days), mannose-containing Neoglycoproteins specifically induced the disappearance of junctions between the cultured cells. These results emphasize the importance of mannose-dependent recognition system in the maintenance of junctions between ependymal cells, where a mannose-binding lectin has been previously detected.
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Expression of a mannose/fucose membrane lectin on human dendritic cells
European Journal of Immunology, 1996Co-Authors: Alexandre Avraméas, Annie Claude Roche, Michel Monsigny, Dorian Mcilroy, Anne Hosmalin, Brigitte Autran, Patrice Debré, Patrick MidouxAbstract:Dendritic cells (CD) are the most efficient antigen presenting cells for T lymphocytes. CD1a+ CD14- CD with high antigen-presenting capacities can now be obtained easily from adherent peripheral blood monocytes by culture in the presence of granulocyte/macrophage colony-stimulating factor and interleukin-4 (Sallusto et al., J. Exp. Med. 1994. 179: 1109). Human macrophages express a membrane lectin, or sugar-specific receptor, which specifically mediates the binding and endocytosis of mannose- and fucose-terminated glycoproteins and is involved in the phagocytosis of pathogens. A similar lectin activity was sought on cultured human DC using flow cytometry and confocal microscopy to detect binding and internalization of fluoresceinated Neoglycoproteins [bovine serum albumin (BSA) substituted with sugar residues]. Several Neoglycoproteins, especially alpha-L-fucosyl-, alpha-D-mannosyl-, N,N'-di-acetyl-beta-chitobiosyl- and beta-D-glucosyl-BSA, were endocytosed by cultured human CD1a+ DC as well as by CD1a- CD14- cells which were also obtained in the culture. Fuc-BSA and Man-BSA had the same number of binding sites (1.7 x 10(6)/cell) on CD1a+ DC, and bound with an affinity constant close to 10(7) 1/mol. Inhibition experiments indicated that these two Neoglycoproteins bound to the same membrane lectin. CD1a+ and CD1a- cells were both labeled by an antiserum specific for the human macrophage mannose receptor. The membrane lectin specific for mannose and fucose that is evidenced in these experiments on cultured DC may be similar to the macrophage membrane lectin or may share functional and structural properties with it.
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Nuclear import of glycoconjugates is distinct from the classical NLS pathway.
Journal of cell science, 1995Co-Authors: Eric Duverger, C Pellerin-mendes, A C Roche, R. Mayer, Michel MonsignyAbstract:The nuclear import of many proteins depends on a short peptide sequence called the nuclear localization signal. However, glycosylated proteins, which lack such a nuclear localization signal, upon their injection into the cytosol by electroporation, enter the nucleus in a sugar-dependent manner. This paper brings new insights on the mechanism of this process, based on a study of Neoglycoprotein nuclear uptake by digitonin-permeabilized cells. The nuclear import of Neoglycoproteins is energy dependent: it does not occur when cells are maintained at 4 degrees C or when cells are ATP-depleted by treatment with apyrase. The nuclear import of Neoglycoproteins occurs through the nuclear pore: it is inhibited by preincubation of cells with wheat germ agglutinin, a lectin which binds the nuclear pore glycoproteins and blocks the translocation step of nuclear localization signal bearing proteins through the nuclear pore. Furthermore, the nuclear import of Neoglycoproteins does not use the pathway of nuclear localization signal bearing proteins: nuclear import of nuclear localization signal bearing proteins depends on cytosolic factors and is inhibited by treatment of cells with N-ethylmaleimide, while the nuclear import of Neoglycoproteins neither requires added cytosolic factors nor is sensitive to alkylation by N-ethylmaleimide. In addition, upon incubation in the presence of a large excess of nuclear localization signal bearing protein, the nuclear import of Neoglycoproteins is not inhibited.
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Inhibition of Human Mammary Cell Line Proliferation by Membrane Lectin-Mediated Uptake of Ha- ras Antisense Oligodeoxynucleotide
Drug Delivery, 1994Co-Authors: Nadia Sdiqui, Khalil Arar, Patrick Midoux, Roger Mayer, Michel Monsigny, Annie Claude RocheAbstract:The Ha-ras oncogene promotes cell proliferation. Antisense oligonucleotides complementary to the ras gene sequence encompassing a mutated codon 12 selectively induce a cell proliferation inhibition. However, the concentration required to reach an effective inhibition is high due to the low efficiency of the oligonucleotide crossing through cell membranes, leading to a low concentration in the cytosol and/or the nucleoplasm. In the present paper, we show that anti-ras oligonucleotides linked to a glycosylated carrier, serum albumin bearing mannose 6-phosphate residues, are more efficient than free oligonucleotides or oligonucleotides bound to an unglycosylated carrier at inhibiting proliferation of a human tumor mammary cell line expressing the mutated Ha-ras. Using fluorescein-labeled Neoglycoproteins and fluorescein-labeled oligonucleotides bound to Neoglycoproteins, flow cytometry and confocal microscopy revealed that (i) these tumor cells express a membrane lectin specific for mannose 6-phosphate-bearing proteins, (ii) the membrane lectin actively mediates the uptake of macromolecules substituted with mannose 6-phosphate, and (iii) the fluorescein-labeled oligonucleotides bound to the Neoglycoprotein accumulate in intracellular vesicles. Furthermore, with antisense oligonucleotides carried by the Neoglycoproteins, the concentration required to inhibit cell proliferation is lower than that of the carrier-free antisense oligonucleotides.
Svend Kirkeby - One of the best experts on this subject based on the ideXlab platform.
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comparison of the binding properties of the mushroom marasmius oreades lectin and griffonia simplicifolia i b4 isolectin to αgalactosyl carbohydrate antigens in the surface phase
Xenotransplantation, 2004Co-Authors: Svend Kirkeby, Harry C. Winter, Irwin J. GoldsteinAbstract:The binding of two alpha-galactophilic lectins, Marasmius oreades agglutinin (MOA), and Griffonia simplicifolia I isolectin B(4) (GS I-B(4)) to Neoglycoproteins and natural glycoproteins were compared in a surface phase assay. Neoglycoproteins carrying various alpha-galactosylated glycans and laminin from basement membrane of mouse sarcoma that contains the xenogenic Galalpha1-3Gal1-4GlcNAc epitope were immobilized in microtiter plate wells and lectin binding determined with an enzyme-linked assay. After 24 h of incubation, MOA had higher affinity for the xenogenic pentasaccharide (Galalpha1-3Gal1-4GlcNAcbeta1-3Galbeta1-4Glc) than for the Galalpha-monosaccharide. The binding properties of MOA and GS I-B(4) to the xenogenic disaccharide (Galalpha1-3Galbeta1) were comparable while the binding of MOA to the xenogenic pentasaccharide was much stronger than the binding of GS I-B(4) to the same epitope. Non-xenogenic disaccharide-coupled Neoglycoproteins having galactose end groups linked alpha1-2 or alpha1-4 to Gal or linked alpha1-3 to GalNAc bound very weakly to MOA, whereas GS I-B(4) recognized all of these disaccharides with similarly high affinity. MOA also showed high affinity for laminin. The results indicate that the Marasmius oreades lectin has nearly the same affinities as does GS I-B(4) for the simple xenogenic carbohydrate antigens, but MOA has greater affinity for the pentasaccharide and is far more specific in its binding preferences than the Griffonia lectin.
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Comparison of the binding properties of the mushroom Marasmius oreades lectin and Griffonia simplicifolia I‐B4 isolectin to αgalactosyl carbohydrate antigens in the surface phase
Xenotransplantation, 2004Co-Authors: Svend Kirkeby, Harry C. Winter, Irwin J. GoldsteinAbstract:The binding of two alpha-galactophilic lectins, Marasmius oreades agglutinin (MOA), and Griffonia simplicifolia I isolectin B(4) (GS I-B(4)) to Neoglycoproteins and natural glycoproteins were compared in a surface phase assay. Neoglycoproteins carrying various alpha-galactosylated glycans and laminin from basement membrane of mouse sarcoma that contains the xenogenic Galalpha1-3Gal1-4GlcNAc epitope were immobilized in microtiter plate wells and lectin binding determined with an enzyme-linked assay. After 24 h of incubation, MOA had higher affinity for the xenogenic pentasaccharide (Galalpha1-3Gal1-4GlcNAcbeta1-3Galbeta1-4Glc) than for the Galalpha-monosaccharide. The binding properties of MOA and GS I-B(4) to the xenogenic disaccharide (Galalpha1-3Galbeta1) were comparable while the binding of MOA to the xenogenic pentasaccharide was much stronger than the binding of GS I-B(4) to the same epitope. Non-xenogenic disaccharide-coupled Neoglycoproteins having galactose end groups linked alpha1-2 or alpha1-4 to Gal or linked alpha1-3 to GalNAc bound very weakly to MOA, whereas GS I-B(4) recognized all of these disaccharides with similarly high affinity. MOA also showed high affinity for laminin. The results indicate that the Marasmius oreades lectin has nearly the same affinities as does GS I-B(4) for the simple xenogenic carbohydrate antigens, but MOA has greater affinity for the pentasaccharide and is far more specific in its binding preferences than the Griffonia lectin.
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binding of griffonia simplicifolia 1 isolectin b4 gs1 b4 to α galactose antigens
Immunology and Cell Biology, 2001Co-Authors: Svend KirkebyAbstract:: Glycoconjugates with terminal Galalpha1-3Galbeta1-4GlcNAc sequences (alpha-galactosyl epitopes, natural xenoreactive antigens) are present on various tissues in pigs and are recognized by human anti-alphagalactosyl (alphaGal) antibodies1. Hence xenotransplantation (pig-to-human) would trigger immune reactions involving complement activation and lead to the hyperactute rejection of the graft. Xenoreactive antigens are often studied by using the lectin Griffonia simplicifolia 1 isolectin B4 (GS1 B4), which shows high affinity to galactose. We here estimate the specificity of GS1 B4 for detecting various galactosyl epitopes by measuring lectin binding to Neoglycoproteins, thyroglobulin and pig skeletal muscle. Enzyme linked lectin assays confirmed that GS1 B4 was highly specific to alpha-galactosylated Neoglycoproteins while the lectin did not detect a beta-galactosylated ligand. The length of the sugar chains influenced the lectin-carbohydrate interaction. A monosaccharide linked to serum albumin showed higher lectin affinity than did Neoglycoproteins with di- and tri-alpha-galactosyl epitopes. When the carbohydrate was extended, as in the xenoreactive pentasaccharide (Galalpha1-3Galbeta1-4GlcNAcbeta1-3Galbeta1-4Glc), the carbohydrate- lectin interaction was meagre. Not only the terminal, but also the subterminal sugar affected the lectin binding because the GS1 B4 affinity to Galalpha1-3Gal was much stronger than to Galalpha1-3GalNAc. In bovine and porcine thyroglobulin most alphaGal epitopes appear to be cryptic, but are unmasked by a heat denaturation. In pig skeletal muscle there was lectin reaction not only in the muscle capillaries, but also in the connective tissue and intracellularly in muscle fibres. In Western blots of isolated proteins from pig muscle at least three bands were strongly stained after incubation with lectin.
Irwin J. Goldstein - One of the best experts on this subject based on the ideXlab platform.
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comparison of the binding properties of the mushroom marasmius oreades lectin and griffonia simplicifolia i b4 isolectin to αgalactosyl carbohydrate antigens in the surface phase
Xenotransplantation, 2004Co-Authors: Svend Kirkeby, Harry C. Winter, Irwin J. GoldsteinAbstract:The binding of two alpha-galactophilic lectins, Marasmius oreades agglutinin (MOA), and Griffonia simplicifolia I isolectin B(4) (GS I-B(4)) to Neoglycoproteins and natural glycoproteins were compared in a surface phase assay. Neoglycoproteins carrying various alpha-galactosylated glycans and laminin from basement membrane of mouse sarcoma that contains the xenogenic Galalpha1-3Gal1-4GlcNAc epitope were immobilized in microtiter plate wells and lectin binding determined with an enzyme-linked assay. After 24 h of incubation, MOA had higher affinity for the xenogenic pentasaccharide (Galalpha1-3Gal1-4GlcNAcbeta1-3Galbeta1-4Glc) than for the Galalpha-monosaccharide. The binding properties of MOA and GS I-B(4) to the xenogenic disaccharide (Galalpha1-3Galbeta1) were comparable while the binding of MOA to the xenogenic pentasaccharide was much stronger than the binding of GS I-B(4) to the same epitope. Non-xenogenic disaccharide-coupled Neoglycoproteins having galactose end groups linked alpha1-2 or alpha1-4 to Gal or linked alpha1-3 to GalNAc bound very weakly to MOA, whereas GS I-B(4) recognized all of these disaccharides with similarly high affinity. MOA also showed high affinity for laminin. The results indicate that the Marasmius oreades lectin has nearly the same affinities as does GS I-B(4) for the simple xenogenic carbohydrate antigens, but MOA has greater affinity for the pentasaccharide and is far more specific in its binding preferences than the Griffonia lectin.
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Comparison of the binding properties of the mushroom Marasmius oreades lectin and Griffonia simplicifolia I‐B4 isolectin to αgalactosyl carbohydrate antigens in the surface phase
Xenotransplantation, 2004Co-Authors: Svend Kirkeby, Harry C. Winter, Irwin J. GoldsteinAbstract:The binding of two alpha-galactophilic lectins, Marasmius oreades agglutinin (MOA), and Griffonia simplicifolia I isolectin B(4) (GS I-B(4)) to Neoglycoproteins and natural glycoproteins were compared in a surface phase assay. Neoglycoproteins carrying various alpha-galactosylated glycans and laminin from basement membrane of mouse sarcoma that contains the xenogenic Galalpha1-3Gal1-4GlcNAc epitope were immobilized in microtiter plate wells and lectin binding determined with an enzyme-linked assay. After 24 h of incubation, MOA had higher affinity for the xenogenic pentasaccharide (Galalpha1-3Gal1-4GlcNAcbeta1-3Galbeta1-4Glc) than for the Galalpha-monosaccharide. The binding properties of MOA and GS I-B(4) to the xenogenic disaccharide (Galalpha1-3Galbeta1) were comparable while the binding of MOA to the xenogenic pentasaccharide was much stronger than the binding of GS I-B(4) to the same epitope. Non-xenogenic disaccharide-coupled Neoglycoproteins having galactose end groups linked alpha1-2 or alpha1-4 to Gal or linked alpha1-3 to GalNAc bound very weakly to MOA, whereas GS I-B(4) recognized all of these disaccharides with similarly high affinity. MOA also showed high affinity for laminin. The results indicate that the Marasmius oreades lectin has nearly the same affinities as does GS I-B(4) for the simple xenogenic carbohydrate antigens, but MOA has greater affinity for the pentasaccharide and is far more specific in its binding preferences than the Griffonia lectin.
Pijush K. Das - One of the best experts on this subject based on the ideXlab platform.
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Protective effect of Neoglycoprotein-conjugated muramyl dipeptide against Leishmania donovani infection: the role of cytokines.
Journal of immunology (Baltimore Md. : 1950), 1997Co-Authors: Kakali Sarkar, Pijush K. DasAbstract:Active targeting of muramyl dipeptide (MDP) to macrophages was studied by conjugation with the Neoglycoprotein, mannosyl human serum albumin (mannose-HSA) using visceral leishmaniasis as the model macrophage disease. Conjugation did not decrease the affinity of the Neoglycoprotein for macrophage mannose receptor. Mannose-HSA-MDP was 50 times more efficient than free MDP in inhibiting the growth of Leishmania donovani inside peritoneal macrophages. Moreover, in a 60-day murine model of visceral leishmaniasis, 95% of the spleen parasite burden was reduced by mannose-HSA-MDP at a dose of 0.5 mg/kg/day given for 4 days. Free MDP at a similar dose had very little effect. In vitro exposure of MDP caused enhanced generation of O2- by macrophages, whereas generation of nitric oxide (NO) was not induced. The elevated antileishmanial activity of MDP-treated macrophages in culture was abrogated by O2- scavengers. In contrast, considerably enhanced amounts of NO and O2- were generated from macrophages of mannose-HSA-MDP-treated animals, and their splenocytes secreted soluble factors providing all the signals required for the induction of NO biosynthesis. The increase in NO production was paralleled by a concomitant increase in antileishmanial activity, which was reversed by NO synthesis inhibitors. Splenocyte supernatants treated with anti-IFN-gamma or anti-TNF-alpha Abs suppressed inducible NO generation by macrophages. Moreover, i.v. administration of anti-IFN-gamma and anti-TNF-alpha along with mannose-HSA-MDP greatly reduced protection against L. donovani infection. Neoglycoprotein-conjugated MDP, therefore, activated mouse macrophages in vivo to kill L. donovani, and this may depend on the physiologic generation of NO induced by IFN-gamma and TNF-alpha.
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Receptor-mediated endocytosis of fucosylated Neoglycoprotein by macrophages
Molecular and Cellular Biochemistry, 1996Co-Authors: Kakali Arkar, Himadri Sekhar Sarkar, Labanyamoy Kole, Pijush K. DasAbstract:The characteristics of the recognition system involved in the receptor mediated endocytosis of the Neoglycoprotein, fucose human serum albumin (HSA) were studied. It was found that (i) fucose-HSA showed strong affinity binding and uptake by various macrophages; (ii) binding was specific for L-fucose and D-mannose; (iii) binding was found to be inhibited by oxidant like H_2O_2 and swainsonine whereas it was elevated by dexamethasone; (iv) clearance of^125I-fucose-HSA was rapid and strongly inhibited by unlabelled fucose-HSA. Greater than 70% of fucose-HSA was found in liver and more than 60% of this was found in liver lysosomes; (v) uptake of fucose-HSA was thirty-fold more efficient in liver macrophages (Kupffer cells) than in hepatocytes; (vi) moreover, mannose-HSA and ovalbumin which are potent inhibitors of mannose/N-acetylglucosamine receptors inhibited clearance and uptake of fucose-HSA by liver as well as by isolated Kupffer cells suggesting the involvement of both fucose and mannose receptors or a single type of receptor having greater affinity for fucose-HSA than for mannose-HSA. These results emphasize the important role of fucose-terminated glycoproteins in site-specific drug targeting.
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Neoglycoprotein Conjugated Liposomes as Macrophage Specific Drug Carrier in the Therapy of Leishmaniasis
Biochemical and biophysical research communications, 1994Co-Authors: Labanyanoy Kole, Kakali Sarkar, S. B. Mahato, Pijush K. DasAbstract:Abstract The potential utility of Neoglycoprotein conjugated multilamellar liposomes as macrophage specific drug delivery system was studied using hamycin as the model drug and visceral leishmaniasis as the model macrophage disease. Hamycin, a polyene antibiotic, was found to have a growth inhibitory effect on cultured Leishmania donovani promastigotes at a concentration of 0.05 μg/ml. Hamycin entrapped in Neoglycoprotein conjugated liposome (neohamysome) eliminated intracellular amastigotes of L . donovani in peritoneal macrophages 10 and 1.5 times more efficiently than did the free and liposome entrapped drug (hamysome), respectively. Moreover, neohamysome possibly could completely eliminate splenic intracellular parasites in a 45 day BALB/c mouse model of visceral leishmaniasis at a dose of 1.5 mg/Kg/day given for 4 consecutive days. Hamysome at a similar dose had 80% parasite suppressive effect whereas free drug could not be administered more than the dosage of 0.5 mg/Kg/day due to mortality problem. Neohamysome and hamysome were generally less toxic than the free drug as judged by erythrocyte lysis and several clinical parameters of liver toxicity. These results suggest a possible use of Neoglycoprotein conjugated liposomes in macrophage-associated diseases.
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Macrophage-Directed Delivery of Doxorubicin Conjugated to Neoglycoprotein Using Leishmaniasis as the Model Disease
The Journal of infectious diseases, 1993Co-Authors: Rupnarayan Sett, Kakali Sarkar, Pijush K. DasAbstract:The antileishmanial potency of doxorubicin conjugated to mannose-human serum albumin (man-HSA) was tested in experimental visceral leishmaniasis. Conjugation of doxorubicin did not decrease the affinity of the Neoglycoprotein for the macrophage mannose receptor. Conjugated doxorubicin eliminated intracellular amastigotes of Leishmania donovani in peritoneal macrophages almost 12.5 times more efficiently than did the free drug and greatly reduced and possibly eliminated splenic intracellular parasites in four consecutive dosages at 5 micrograms/kg/day for 45 days. Free drug at a similar dose had little effect. The leishmanicidal effect of doxorubicin conjugate can be prevented by competitive inhibitors such as man-HSA or mannan and inhibitors of receptor-mediated endocytosis such as colchicine and monensin. These results not only indicate the potential of doxorubicin as an effective chemotherapeutic agent for leishmaniasis but also establish the use of mannosylated Neoglycoprotein as a drug carrier in the therapy of macrophage-associated diseases.
