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PubMed1981

A method for the preparation of Vicia villosa lectin and a rosette procedure for fractionation of lectin-binding lymphocytes.

We describe a simple procedure for isolation of Vicia villosa lectin with binding specificity for N-acetyl-D-galactosamine greater than D-galactose. Also, a rosette assay using V. villosa lectin coupled-SRBC is described which enables us to both visualize lectin binding cells and to fractionate lymphocytes from vitro primary mixed lymphocyte cultures on the basis of ability to bind V. villosa lectin.

Acetylgalactosamine↗

PubMed1979

Age-related cell surface changes in human diploid fibroblasts revealed by lectin-mediated red blood cell adsorption assay: a lectin survey.

Two types of age-related cell surface changes could be demonstrated in human diploid fibroblasts with the two methods of the lectin-mediated red blood cell (RBC) adsorption assay: the fibroblast coating method (in which RBCs are adsorbed to lectin-coated fibroblasts) and the RBC coating method (in which lectin-coated RBCs are adsorbed to fibroblasts). With the fibroblast coating method, concanavalin A and agglutinin L from Phaseolus vulgaris gave a change in RBC adsorption which did not occur throughout the phase II period, but increased with the advance of the phase III period (type I). With the RBC coating method, these lectins gave another type of change in RBC adsorption which increased continuously from early phases of cell passage up through cell senescence (type II). Ricinus communis agglutinin 120 also gave the type I change in RBC adsorption with the fibroblast coating method. On the other hand, even with the fibroblast coating method, Phaseolus vulgaris agglutinin E and wheat-germ agglutinin gave the type II change in RBC adsorption. Soy bean agglutinin and Bauhinia purpurea agglutinin gave only a restricted amount of RBC adsorption. Lens culinaris agglutin, pokeweed mitogen, Dolichos biflorus agglutinin, Lotus tetragonolobus agglutinin, Limulus polyhemus agglutinin and divalent succinylated concanavalin A did not give any RBC adsorption throughout the life span of human diploid fibroblasts.

Cell Membrane↗

PubMed1987

[Lymphocyte markers in domestic animals. I. Mitogenic lectins and non-mitogenic lectins].

The authors reviewed the lymphocyte markers in domestic animals. The first part is devoted to lectins. The general and methodologic aspects of lectins as mitogens are studied. The main mitogen lectins are emphasized in regard to their field of utilisation and the technical aspect of their use. The non-mitogen lectins are presented for cell suspension or tissue section staining.

Animals↗

PubMed1977

Studies on lectins. XXXI. Determination of dissociation constants of lectin. Sugar complexes by means of affinity electrophoresis.

A modification of affinity electrophoresis in polyacrylamide gels containing immobilized sugar residues is described. The immobilization of sugar residues is achieved by addition of a water soluble O-glycosyl polyacrylamide copolymer to the polymerization mixture, which serves for the preparation of gels for commonly used discontinuous polyacrylamide gel electrophoresis. The electrophoretic mobility of lectins in affinity gels containing specific immobilized sugar decreases with increasing sugar concentration. The addition of free sugar into the affinity gel abolishes retardation of the electrophoretic mobility caused by immobilized sugar. The relationship between electrophoretic mobility of lectins and concentration of immobilized and free sugar was used for the calculation of dissociation constants of the various complexes lectin-immobilized sugar and lectin-free sugar.

Electrophoresis, Polyacrylamide Gel↗

PubMed1978

Studies on lectins. XXXVI. Properties of some lectins prepared by affinity chromatography on O-glycosyl polyacrylamide gels.

A number of lectins has been purified by affinity chromatography on O-glycosyl polyacrylamide gels. The lectins isolated (and the particular sugar ligands used in the affinity carriers) are as follows: Anguilla anguilla, serum (alpha-L-fucosyl-), Vicia cracca, seeds; Phaseolus lunatus, seeds; Glycine soja, seeds; Dolichos biflorus, seeds; Maclura pomifera, seeds; Sarothamnus scoparius, seeds; Helix pomatia, ablumin glands; Clitocybe nebularis, fruiting bodies (all N-acetyl-alpha-D-galactosaminyl-); Ricinus communis, seeds (beta-lactosyl-); Ononis spinosa, root; Fomes fomentarius, fruiting bodies; Marasmius oreades, fruiting bodies (all alpha-D-galactosyl-), Canavalia ensiformis, seeds, (i.e., concanavalin A) (alpha-D-glucosyl-). Physicochemical properties of Glycine soja, Dolichos biflorus, Phaseolus lunatus, Helix Pomatia and Ricinus communis lectins corresponded well to properties of the preparations studied earlier by other workers. For the other purified lectins the essential physiochemical data (sedimentation coefficient, molecular weight, subunit composition, electrophoretic patterns, amino acid composition, carbohydrate content, isoelectric point) were established and their precipitating, hemagglutinating and mitogenic activities determined.

Agglutinins↗

PubMed2004

A new lectin family with structure similarity to actinoporins revealed by the crystal structure of Xerocomus chrysenteron lectin XCL.

A newly defined family of fungal lectins displays no significant sequence similarity to any protein in the databases. These proteins, made of about 140 amino acid residues, have sequence identities ranging from 38% to 65% and share binding specificity to N-acetyl galactosamine. One member of this family, the lectin XCL from Xerocomus chrysenteron, induces drastic changes in the actin cytoskeleton after sugar binding at the cell surface and internalization, and has potent insecticidal activity. The crystal structure of XCL to 1.4 A resolution reveals the architecture of this new lectin family. The fold of the protein is not related to any of the several lectin folds documented so far. Unexpectedly, the structure similarity is significant with actinoporins, a family of pore-forming toxins. The specific structural features and sequence signatures in each protein family suggest a potential sugar binding site in XCL and a possible evolutionary relationship between these proteins. Finally, the tetrameric assembly of XCL reveals a complex network of protomer-protomer interfaces and generates a large, hydrated cavity of 1000 A3, which may become accessible to larger solutes after a small conformational change of the protein.

Amino Acid Sequence↗

PubMed2005

The vaccine potential of Streptococcus pneumoniae surface lectin- and non-lectin proteins.

We have fractionated S. pneumoniae surface proteins into lectin and non-lectin fractions and tested their ability to elicit protective immune responses in the mouse model system. The total cell wall protein fraction (CW-T) was separated into lectin (CW-L), and non-lectin (CW-NL) fractions and used for immunization of mice. Immunized mice were challenged intranasally or intraperitoneally with S. pneumoniae strain WU2 (serotype 3). CW-T, CW-NL and CW-L and adjuvant only vaccination protected 55%, 43%, 44% and 0% of the intranasally challenged mice, respectively and 67%, 86%, 11% and 0% of mice challenged intraperitoneally, respectively. Immunogenic proteins in each fraction were sequenced and identified using MALDI-TOF. CW-L proteins provided a significantly better protection against intranasal inoculation and CW-NL proteins provided a significantly better protection from intraperitoneal inoculation. Proteins identified by sera from mice immunized with the cell-wall derived fractions may constitute candidates for future development of anti S. pneumoniae vaccines.

Animals↗

PubMed1993

Analysis of lectin binding sites in the gut of hooded Lister rats with special emphasis on recently detected lectins.

Seven recently isolated lectins were tested for their ability to bind to tissue sections of rat gut. Binding sites for N-Acetylgalactosamine specific lectins were found in mucins, in the brush border membrane and in goblet cells. Non-reducing terminal mannose residues were absent from cell surface membranes but were detected in the supranuclear region of goblet cells and enterocytes. The results of lectin binding obtained in this study were generally similar to lectin-gut interactions observed in vivo.

Acetylgalactosamine↗

PubMed1982

Lectin affinity chromatography of glycopeptides and oligosaccharides from normal and lectin-resistant Chinese-hamster ovary cells.

The [3H]mannose-labelled glycopeptides from two lectin-resistant lines of Chinese-hamster ovary cells were fractionated by chromatography on lentil lectin-Sepharose and concanavalin A-agarose columns and subsequently analysed by gel filtration in comparison with the glycopeptides of the parental cell line. Essentially all of the [3H]mannose-labelled asparaginyl-oligosaccharides from the 'single-mutant' cells selected for resistance to phytohaemagglutinin and the 'double-mutant' cells selected for additional resistance to concanavalin A were not bound to lentil lectin, whereas approximately one-sixth of the parental-cell glycopeptides were bound and specifically eluted with alpha-methyl mannoside. These bound and eluted glycopeptides represented a specific subset of the complex acidic-type asparaginyl-oligosaccharides. The percentage of radiolabelled glycopeptides and oligosaccharides from each cell line that were specifically bound to concanavalin A was consistent with the relative sensitivities of the three cell lines to this lectin. The major radiolabelled species in the endoglycosidase digest of the 'double-mutant'-cell glycopeptides (Man4GlcNAc1-size neutral oligosaccharides) were not bound to concanavalin A, whereas essentially all of the other neutral-type oligosaccharides were bound. In addition, the larger neutral-type oligosaccharides (Man8--9GlcNAc1) were more strongly bound to concanavalin A than were either the smaller neutral-type or the di-antennary acidic-type structures.

Animals↗

PubMed2003

Crystal structure of fungal lectin: six-bladed beta-propeller fold and novel fucose recognition mode for Aleuria aurantia lectin.

Aleuria aurantia lectin is a fungal protein composed of two identical 312-amino acid subunits that specifically recognizes fucosylated glycans. The crystal structure of the lectin complexed with fucose reveals that each monomer consists of a six-bladed beta-propeller fold and of a small antiparallel two-stranded beta-sheet that plays a role in dimerization. Five fucose residues were located in binding pockets between the adjacent propeller blades. Due to repeats in the amino acid sequence, there are strong similarities between the sites. Oxygen atoms O-3, O-4, and O-5 of fucose are involved in hydrogen bonds with side chains of amino acids conserved in all repeats, whereas O-1 and O-2 interact with a large number of water molecules. The nonpolar face of each fucose residue is stacked against the aromatic ring of a Trp or Tyr amino acid, and the methyl group is located in a highly hydrophobic pocket. Depending on the precise binding site geometry, the alpha- or beta-anomer of the fucose ligand is observed bound in the crystal. Surface plasmon resonance experiments conducted on a series of oligosaccharides confirm the broad specificity of the lectin, with a slight preference for alphaFuc1-2Gal disaccharide. This multivalent carbohydrate recognition fold is a new prototype of lectins that is proposed to be involved in the host recognition strategy of several pathogenic organisms including not only the fungi Aspergillus but also the phytopathogenic bacterium Ralstonia solanacearum.

Amino Acid Sequence↗

PubMed2000

Diagnosis of invasive amebiasis by enzyme-linked immunosorbent assay of saliva to detect amebic lectin antigen and anti-lectin immunoglobulin G antibodies.

Saliva from subjects with amebic liver abscess (ALA), acute amebic colitis, asymptomatic infection with Entamoeba histolytica or Entamoeba dispar, and uninfected controls was tested by enzyme-linked immunosorbent assay (ELISA) for the presence of E. histolytica galactose-inhibitable lectin antigen and salivary immunoglobulin (IgG) antibodies to a recombinant cysteine-rich lectin-derived protein (LC3). Salivary lectin antigen was found in 65.8% of subjects with acute colitis, compared to 22.2% of those convalescent from ALA, 10.0% with asymptomatic E. histolytica infection, 9.8% with E. dispar infection, and 2.6% of controls (subjects from the United States and study patients with nonamebic diarrhea) (P < 0.001 for each compared to values for subjects with colitis). Salivary anti-LC3 IgG antibodies were found in 92% of ALA patients regardless of duration of illness and in 83.3% of colitis patients who were symptomatic for at least 7 days (P < 0.001 compared to other study groups). Serum anti-LC3 IgG antibodies were detected in 56.3% of subjects with acute colitis, 100% of subjects with ALA or prolonged colitis, 45% of subjects with asymptomatic E. histolytica infection, 32.3% of subjects with E. dispar infection, and 23.4% of diarrhea controls. In comparison to ELISA for serum anti-LC3 IgG antibodies, the salivary lectin antigen assay is a more sensitive and specific test for acute amebic colitis. Detection of salivary anti-LC3 IgG antibodies by ELISA is an effective means for the diagnosis of ALA and prolonged cases of amebic colitis.

Antibodies, Protozoan↗

PubMed1987

Lectin receptors on preimplantation mouse embryos. The solidity of lectin binding.

Receptor sites for 7 FITC-conjugated lectins were examined on preimplantation mouse embryos at various stages of development: zygotes; 2; 6-8 cells; morulae; blastocyst; expanded blastocyst, and isolated inner cell mass. In order to determine the solidity of the binding, the embryos were incubated with lectins, washed and incubated for an additional time with the specific hapten sugar. Receptor sites for all 7 lectins were found on the cell surface of all preimplantation mouse embryonic stages examined. The binding was found to be specific. The solidity of the lectins' binding to the receptors was found to be high, since it could not be removed by the corresponding sugar hapten.

Animals↗

PubMed1984

Characterization of glycoconjugates of human gastrointestinal mucosa by lectins. I. Histochemical distribution of lectin binding sites in normal alimentary tract as well as in benign and malignant gastric neoplasms.

Labeled lectins with binding specificity to the hexose components of mucus glycoproteins (HPA, RCA I, PNA, Con A, WGA, and UEA I) were used to demonstrate structural differences in the glycoprotein composition of various cell types of the normal, benign and malignant gastrointestinal mucosa. While in the RCA I, UEA I, and WGA binding of normal mucus secreting cell types only quantitative differences were observed, the mucus in the surface epithelial cells of gastric mucosa and in the colonic goblet cells was characterized by the absence of PNA, Con A, and PNA, HPA binding sites, respectively. These lectins, however, showed a strong binding to the supranuclear, Golgi-region in the undifferentiated or activated forms of these cells. Even the staining intensity of the luminal membrane surfaces of the non mucinous parietal and chief cells was often stronger by PNA, HPA, and RCA I lectins than that of the mucus secretions in the highly differentiated mucus cells. These results indicate the existence of either heterogeneous glycoprotein components or mucus molecules with variations in the degree of glycosylation of their oligosaccharide chains in the different cells. The latter seems more likely since in benign and malignant alterations lectin binding sites appear in great density, which were found to be characteristic of the undifferentiated mucus cells or for the non mucinous cells of the normal gastric mucosa. Similarly in some gastric cancers which do not stain with the periodic acid-Schiff reaction at all, large amount of free or neuraminic acid substituted PNA binding sites can be detected.

Adenocarcinoma↗

PubMed2006

Spectroscopic studies on Erythrina lysistemon seed lectin: effect of denaturing agents on lectin quaternary structure.

The equilibrium unfolding of ElysL, a homodimeric legume lectin, was studied using different denaturing agents such as guanidinium chloride (GdnHCl), temperature and pH. Simultaneously, changes in the secondary as well as tertiary structure of lectin were followed by CD spectroscopy examination in both far and near-UV region, respectively. The hydrophobic cluster binding dye, 1-anilino-8-naphthalene sulfonate (ANS), was used to further explore intermediates and to follow the unfolding pathway of lectin. The adenine binding ability of lectin was examined and monitored via absorption spectra and the intrinsic tryptophan fluorescence. Our findings indicate that the ElysL unfolding process occurs via a three state pathway with an intermediate state. We also showed that ElysL binds adenine in a manner that involves a hydrophobic binding pocket that is independent of the carbohydrate binding sites.

Plant Lectins↗

PubMed2002

Dendritic cell-associated lectin-1: a novel dendritic cell-associated, C-type lectin-like molecule enhances T cell secretion of IL-4.

We have characterized dendritic cell (DC)-associated lectin-1 (DCAL-1), a novel, type II, transmembrane, C-type lectin-like protein. DCAL-1 has restricted expression in hemopoietic cells, in particular, DCs and B cells, but T cells and monocytes do not express it. The DCAL-1 locus is within a cluster of C-type lectin-like loci on human chromosome 12p12-13 just 3' to the CD69 locus. The consensus sequence of the DCAL-1 gene was confirmed by RACE-PCR; however, based on sequence alignment with genomic DNA and with various human expressed sequence tags, we predict that DCAL-1 has two splice variants. C-type lectins share a common sequence motif of 14 invariable and 18 highly conserved aa residues known as the carbohydrate recognition domain. DCAL-1, however, is missing three of the cysteine residues required to form the standard carbohydrate recognition domain. DCAL-1 mRNA and protein expression are increased upon the differentiation of monocytes to CD1a(+) DCs. B cells also express high levels of DCAL-1 on their cell surface. Using a DCAL-1 fusion protein we identified a population of CD4(+) CD45RA(+) T cells that express DCAL-1 ligand. Coincubation with soluble DCAL-1 enhanced the proliferation of CD4(+) T cells in response to CD3 ligation and significantly increased IL-4 secretion. In contrast, coincubation with soluble DC-specific ICAM-3-grabbing nonintegrin (CD209) fusion protein as a control had no effect on CD4(+) T cell proliferation or IL-4 and IFN-gamma secretion. Therefore, the function of DCAL-1 on DCs and B cells may act as a T cell costimulatory molecule, which skews CD4(+) T cells toward a Th2 response by enhancing their secretion of IL-4.

Adjuvants, Immunologic↗

PubMed2002

Enhancement of complement activation and opsonophagocytosis by complexes of mannose-binding lectin with mannose-binding lectin-associated serine protease after binding to Staphylococcus aureus.

Human mannose-binding lectin (MBL) is a serum protein of the innate immune system that circulates as a complex with a group of so-called MBL-associated serine proteases (MASP-1, MASP-2, and MASP-3). Complexes of MBL-MASP2 are able to activate the complement system in an Ab and C1-independent fashion after binding of the lectin to appropriate microbial sugar arrays. We have evaluated the additive effect of the lectin pathway relative to other complement activation pathways and the subsequent effect on neutrophil phagocytosis. Complement activation in the sera of MBL-deficient individuals was studied with and without the addition of exogenous MBL-MASP. Flow cytometry was used to measure the deposition of C4, factor B, C3b, and iC3b on Staphylococcus aureus. Deposition of the first cleavage product of the lectin pathway, C4b, was increased using the sera of three different MBL-deficient individuals when exogenous MBL-MASP was added. Factor B was deposited in association with C4, but there was no evidence of independent alternative pathway activation. Similar enhancement of C3b deposition was also observed, with evidence of elevated amounts of C3b processed to iC3b. The increase in opsonic C3 fragments mediated by MBL was associated with a significant increase in the uptake of organisms by neutrophils. We also observed significant increases in phagocytosis with MBL-MASPs that were independent of complement activation. We conclude that MBL-MASP makes a major contribution to complement-mediated host defense mechanisms.

Adjuvants, Immunologic↗

PubMed2006

[Lectins, adhesins, and lectin-like substances of lactobacilli and bifidobacteria].

Cell-surface adhesion factors of lactobacilli and bifidobacteria, such as lectin/adhesin proteins of S-layers, secreted lectin-like bacteriocins, and lectin-like complexes, are considered and classified in the article. Certain general and specific properties of these factors are noted, such as in vitro and in vivo adhesion, cell co(aggregation), participation in the forming of microbial biofilms and colonization of mammalian alimentary tract, as well as complexation with biopolymers and bioeffectors, specificity to glycanes and natural glycoconjugates, domain and spatial organization of adhesion factors, co-functioning with other cytokines (pro- and anti-inflammatory ones), regulation of target cell properties, and other biological and physiological activities. The authors also note possibilities of application of lectins and lectin-like proteins of probiotic strains of lactobacilli and bifidobacteria in medicine and biotechnology.

Adhesins, Bacterial↗

PubMed1976

Effect of neuraminidase and papain treatment on lectin-induced agglutination of Novikoff tumor cells and assay of lectin receptor activity of the glycopeptides released from the cell surface by papain.

Lectins, plant proteins that bind specific saccharide determinants, have been utilized to examine the effect of neuraminidase digestion on the structure and/or expression of oligosaccharide moieties present at the periphery of Novikoff ascites hepatoma cells. Five lectins were utilized: concanavalin A (Con A), specific for alpha-D-manno- or alpha-D-glucopyranosyl residues; wheat germ agglutinin, specific for 2-acetamido-2-deoxy-D-glucopyranosyl residues; Ricinus communis agglutinin I (RCAI), specific for D-glucopyranosyl residues; R. communis agglutinin II (RCAII), specific for D-galacto- or 2-acetamido-2-deoxy-D-galactopyranosyl residues; and soybean agglutinin, specific for 2-acetamido-2-deoxy-D-galactopyranosyl residues. Neuraminidase treatment of Novikoff cells did not alter their agglutination by Con A or wheat germ agglutinin. Similar treatment produced only a 2-fold increase in their agglutination by RCAI but a 12-fold increase in their agglutination by RCAII, indicating that 2-acetamido-2-deoxy-D-galactopyranosyl residues become expressed upon neuraminidase treatment. This conclusion was confirmed by the observation that neuraminidase-treated Novikoff cells acquired agglutinability by soybean agglutinin. Binding studies using ferritin-conjugated RCAII indicated that neuraminidase treatment exposed cryptic cell surface receptors for RCAII. To ascertain the role of cell surface glycoproteins in lectin-induced agglutination of Novikoff cells, glycopeptides cleaved from the cell surface by papain were assayed for lectin receptor activity. The cell surface glycopeptides exhibited receptor activity for Con A, wheat germ agglutinin and RCAI but not for RCAII and soybean agglutinin. A cell surface macrosialoglycopeptide fraction, resolved by gel filtration and ion-exchange chromatography, possessed a major portion of the Con A and RCAI receptor activity.

Agglutination↗