Vicia Villosa B4 Research Articles

Chemical modification of carbohydrates in tissue sections may unmask mucin antigens

Expression of mucins in cells and tissues is of great diagnostic and prognostic importance, and immunohistochemistry frequently is used to detect them. Reports concerning mucin localization in sections sometimes are conflicting, however, partly because immunogenic regions of the mucin molecule may be masked and thus not available for binding to an antibody. We modified carbohydrates in tissue sections chemically to enhance the binding of monoclonal mucin antibodies and of the lectin, Vicia villosa B4, to human tissue. The immunohistochemical localization of MUC1 and the simple mucin-type antigens, Tn and sialyl-Tn, was influenced by oxidation with periodic acid and by β-elimination before incubation. In some epithelial cells the staining was prevented by these procedures while in other cells it was evident. It appears that chemical modification can either destroy some antigen binding sites or unmask cryptic antigen binding sites in the mucin molecule and thereby make them accessible for immunohistochemical detection.

The Thomsen-Friedenreich Antigen-Binding Lectin Jacalin Interacts with Desmoglein-1 and Abrogates the Pathogenicity of Pemphigus Foliaceus Autoantibodies In Vivo

Pemphigus foliaceus (PF) is an autoimmune skin blistering disease mediated by pathogenic autoantibodies against the desmosomal core glycoprotein desmoglein-1 (Dsg1). This study demonstrated that the O-glycan-specific plant lectin jacalin binds Dsg1 and inhibits the interaction of Dsg1/PF IgG. N-glycosylation is not involved in the interaction of Dsg1/jacalin or Dsg1/PF IgG. Subcutaneous injection of jacalin into neonatal mice drastically reduced PF IgG deposition at the epidermal cell surface and blocked PF IgG-induced skin blisters, both clinically and histologically. Interestingly, another plant lectin, peanut agglutinin, which shares the same carbohydrate specificity toward the O-linked carbohydrate structure known as Thomsen-Friedenreich antigen (TF antigen, Galβ1-3GalNAcα-O-Ser/Thr), also bound Dsg1 and blocked the skin blistering. In contrast, the plant lectin vicia villosa-B4 (VVL-B4), which shares the carbohydrate specificity toward the O-linked monosaccharide known as Thomsen-nouveau antigen (GalNAc-α1-O-Ser/Thr), did not bind Dsg1 and did not show a protective effect against the disease induced by the autoantibodies. Collectively, these results suggest that the binding of jacalin to O-linked TF carbohydrate motifs on Dsg1 impairs the Dsg1/PF autoantibody interactions and abrogates its pathogenicity in vivo. TF-specific binding ligands may have a potential therapeutic value for PF.

Spatiotemporal distribution of proteoglycans in the developing rat's barrel field and the effects of early deafferentation

The isolectin Vicia villosa B(4) (VV) selectively recognizes N-acetyl-galactosamine-terminal glycoconjugates that form perineuronal nets (PNNs) around a subset of neurons in the cerebral cortex. PNNs are thought to participate in the guidance of incoming thalamic axons and in the posterior stabilization and maintenance of synaptic contacts. Here we examine the spatial and temporal distribution of biotinylated VV in tangential sections through layer IV of the posteromedial barrel subfield in the primary somatosensory cortex (PMBSF) of rats ranging from postnatal day (P)3 to P60, which underwent unilateral deafferentation of whiskers at birth. In the afferented hemisphere, labeling first appears at P5, with a diffuse distribution, probably associated with neuropil, inside PMBSF barrels. VV distribution remains diffuse during the following week, and declines around P17. From P24 onward, however, proteoglycans form PNNs around cell bodies preferentially localized in septal regions of the PMBSF. In the contralateral, deafferented PMBSF the diffuse labeling also appears on P5, but first develops into elongated, homogeneous stripes, which disappear after P24, leaving only scattered cell bodies along layer IV. Our results indicate that proteoglycans appear simultaneous to barrel formation in the developing rat while segregation of PNNs to septal cells might be driven by afferent activity.

Polyvalency of Tn (GalNAcα1→Ser/Thr) glycotope as a critical factor for Vicia villosa B4 and glycoprotein interactions

Vicia villosa B4 (VVL-B4) is an important lectin for detecting exposed Tn (GalNAcα1-Ser/Thr) determinants on cancer cells. In order to elucidate the binding factors involved in VVL-B4 and glycotope interaction, the binding properties of this lectin were analyzed by enzyme-linked lectinosorbent and inhibition assays. From the results, it is concluded that the most critical factor affecting VVL-B4 binding is polyvalency at the α anomer of Gal with –NH CH3CO at carbon-2 (Tn epitope), which enhances the reactivity by 3.3×105 times over monovalent Gal. The reactivities of glycotopes can be ranked as follows: high density Tn cluster≫Tn glycopeptides (MW<3.0×103)≫monomeric Tn to tri- Tn glycopeptides⋙other GalNAcα/β-related structural units>Gal and Galα- or β-linked ligands, demonstrating the essential role of the polyvalency of Tn glycotopes in the enhancement of the binding.

Differential reactivities of the Arachis hypogaea (peanut) and Vicia villosa B4 lectins with human ovarian carcinoma cells, grown either in vitro or in vivo xenograft model

PNA and VVA B4 recognize the tumor-associated T antigen and its immediate precursor Tn, respectively. We found that both lectins are highly reactive in vitro, with human ovarian carcinoma cell lines, but only VVA B4 bound significantly to breast and oral cancer cells. This binding is inhibited by specific monosaccharides. The lectin binding receptors were purified, revealing a glycoprotein of 32 kDa for PNA, and two glycoproteins of 35 and 38 kDa for VVA B4. In vivo localization of PNA was almost exclusive (except for the kidneys) to the ovarian tumor xenografts. VVA B4 showed wider tissue biodistribution being preferentially accumulated in the tumors and ovaries.

Development of an immuno-lectin-enzymatic assay for the detection of serum cancer-associated glycoproteins bearing Tn determinant

We report the development of an immuno-lectin-enzymatic assay (CA83.4) with the purpose of quantifying serum glycoproteins bearing Tn determinant (GalNAc alpha-O-Ser/Thr). An anti-Tn monoclonal antibody (83D4) is bound to the solid phase in order to capture glycoproteins. After the addition of a test sample, we used biotinylated isolectin B4 from Vicia villosa and avidin-peroxydase to act as a detection system. The linear relationship between CA83.4 determinations and the serum dilutions, the reproducibility of the dosage in intra- and inter-assay, and the specificity of the test for the N-acetylgalactosamine residue in a-glycosidic O-linkages, demonstrated the reliability of this trial. Self-recognition of Vicia villosa B4 molecules (K-D: 0.73x10(-6) M determined using biosensor technology) could determine an additional step of signal amplification in this assay. Using 0.25 units/ml of CA83.4 antigen as the cut-off level, higher values were found in 25/49 patients with breast cancer, 8/13 with colorectal carcinoma, 3/11 with lung cancer, but in none of the 49 patients with non-malignant diseases nor in 97 healthy controls. This first report on soluble Tn-glycoprotein detection assays suggests that Tn-glycoproteins are specific serological tumor markers and we believe that they could represent a valuable tool in the diagnosis of cancer.

Vicia villosa B4 lectin is the second anti-Tn lectin shown to react better with blood group N than M antigen.

Earlier studies showed that Moluccella laevis lectin, which has anti-Tn specificity, reacts more strongly with native or desialylated blood group N glycophorin A than with the respective glycophorins of blood group M. We now present results indicating that Vicia villosa B4 anti-Tn lectin, which does not show detectable reaction with untreated glycophorins or erythrocytes, reacts better with desialylated blood group N antigen than with asialo M antigen. This was demonstrated by three assays: (1) agglutination of asialoerythrocytes; (2) binding of biotinylated lectin to asialoerythrocytes immobilized on ELISA plates; and (3) inhibition of lectin binding to asialo-agalactoglycophorin with asialoglycophorins M and N. These results supply further support for the conclusion that glycophorin of blood group N has more GalNAc residues unsubstituted with Gal (Tn receptors) than glycophorin of blood group M.

Interaction of a Novel Tn (GalNAcα1→)Ser/Thr) Glycoprotein with Gal, GalNAc and GlcNAc Specific Lectins

A naturally occurring Tn glycoprotein (Native ASG-Tn) with GalNAcα1→Ser/Thr as the only carbohydrate side chains, has been prepared from armadillo submandibular glands. In a quantitative preciptin assay, this glycoprotein completely precipitated Maclura pomifera (MPA), Vicia villosa B4 (VVL-B4) and Artocarpus integrifolia (Jacalin, AIL) . It also reacted well with Helix pomatia (HPL) and Wistaria floribunda (WFL) and precipitated over 75% of the lectin nitrogen added, but poorly with Ricinus communis agglutinin (RCA1), ricin, peanut ( Arachis hypogaea, PNA), Abrus precatorius agglutinin (APA) and Triticum vulgaris (WGA). This finding suggests that this novel Tn-glycoprotein may serve as a useful reagent for differentiating Tn and T specific monoclonal antibodies and lectins.

Quantitation of Thmm-Horsfall Protein Binding to Uropathogenic Escherichia coli and Lectins

In quantitative experiments using ELISA, binding of Tamm-Horsfall protein (THP) to uropathogenic Escherichia coli was studied with monoclonal antibody to THP. Adherence to E. coli bearing type 1 fimbriae was proportional to THP concentration and size of the bacterial inoculum. Type 1 fimbriae-bearing E. coli bound 50 times more THP than did non-type 1-fimbriated or P-fimbriated strains. Concanavalin A and wheat germ agglutinin bound THP in a dose-dependent fashion, whereas pokeweed mitogen and Vicia villosa B4 isolectin did not. Addition of mannose and N-acetylglucosamine reduced adherence of THP to concanavalin A and wheat germ agglutinin by 50%-80%. Sugar inhibition studies suggested that the fimbrial receptor site for THP has lectin-like properties and that THP binds to fimbriae via its mannose side chains. This quantitative assay is useful for studying the interaction between THP, uroepithelial cells, and bacteria in vitro.

Detection of Bovine Pathogenic Virus By Lectin Cytochemistry

AbstractLectin cytochemistry was used to detect viral specific proteins in infected bovine turbinate cells as a means of diagnosing the presence of various virus. Six lectins having different properties were evaluated for binding to bovine respiratory syncytial virus (BRSV), bovine viral diarrhea (BVD), bovine herpesvirus-I (BHV-l), and bovine herpesvirus-II (BHV-2). BRSV, BHV-1, and BHV-2 were detected. Three lectins, Phaseolus limensis, Phaseolus vulgaris, and Glycine max could not detect any virus, Three lectins that could detect one or more virus included Vicia villosa B4, Helix pomatia, and Helix aspersa Lectins as a detection tool have a considerable level of specificity for binding to virus associated proteins. This work shows that this characteristic and others allow lectins to be a powerful means to diagnose viral infection. (The J Histotechnol 12:115, 1989).

Detection of Bovine Pathogenic Virus By Lectin Cytochemistry

Lectin cytochemistry was used to detect viral specific proteins in infected bovine turbinate cells as a means of diagnosing the presence of various virus. Six lectins having different properties were evaluated for binding to bovine respiratory syncytial virus (BRSV), bovine viral diarrhea (BVD), bovine herpesvirus-I (BHV-l), and bovine herpesvirus-II (BHV-2). BRSV, BHV-1, and BHV-2 were detected. Three lectins, Phaseolus limensis, Phaseolus vulgaris, and Glycine max could not detect any virus, Three lectins that could detect one or more virus included Vicia villosa B4, Helix pomatia, and Helix aspersa Lectins as a detection tool have a considerable level of specificity for binding to virus associated proteins. This work shows that this characteristic and others allow lectins to be a powerful means to diagnose viral infection. (The J Histotechnol 12:115, 1989).

A synapse-specific carbohydrate at the neuromuscular junction: association with both acetylcholinesterase and a glycolipid

With the aim of investigating the roles of carbohydrates in synapse formation, we have characterized a synapse-specific saccharide at the vertebrate neuromuscular junction. Two lectins of similar specificity (Dolichos biflorus agglutinin, DBA, and Vicia villosa-B4 agglutinin, VVA-B4) stain synaptic but not extrasynaptic regions of the rat muscle fiber surface and thus define a synapse-specific carbohydrate. Using these and other probes, we show that the carbohydrate moiety concentrated at the neuromuscular junction resembles N-acetylgalactosamine (GalNAc) linked in the beta-anomeric form to the termini of oligosaccharides. VVA-B4 also selectively stains neuromuscular junctions in human, mouse, rabbit, guinea pig, chick, frog, axolotl, snake, fish, and lamprey muscles, a phylogenetic conservatism that suggests a synapse-related role for GalNAc beta-terminal saccharides. AChE from muscle binds to DBA- and VVA-B4-agarose, and is thereby identified as a glycoconjugate bearing the synapse-specific carbohydrate. Assay of AChE isoforms reveals that asymmetric, collagen-tailed forms, known to be highly concentrated at the rat neuromuscular junction, bind DBA and VVA-B4, while globular forms, which are more widely distributed, do not. A second class of GalNAc-bearing glycoconjugates is demonstrable immunohistochemically with monoclonal antibodies to stage-specific embryonic antigen (SSEA)-3 (Shevinsky et al., 1982) and GM2 (Natoli et al., 1986), which recognize GalNAc-bearing glycolipids. These antibodies selectively stain neuromuscular junctions, where they recognize glycolipid-like molecules that bind VVA-B4 but are distinguishable from AChE. The association of a synapse-specific carbohydrate with at least 2 different synapse-specific molecules raises the possibility that the former plays a role in determining a property that the latter share, such as concentration at the synapse.

The B 4 lectin from Vicia villosa seeds interacts with N-acetylgalactosamine residues on erythrocytes with blood group Cad specificity

We have previously shown that the B4 lectin from Vicia villosa seeds interacts with N-acetylgalactosamine alpha-linked to serine or threonine in cell surface glycoproteins. In the present study, we show that the lectin also binds to Cad erythrocytes (0.44-2.78 X 10(6) sites/cell) with an association constant of 0.61-0.84 X 10(7)M-1. Variability in the number of B4 lectin binding sites in Cad erythrocytes from different individuals parallels reactivity of these erythrocytes with other N-acetylgalactosamine-binding lectins. Agglutination of Cad erythrocytes with B4 lectin is inhibited by urinary Tamm-Horsfall Sda-active glycoprotein. Since the Cad and Sda determinants share the terminal GalNAc beta 1.4----Gal sequence, our results indicate that Vicia villosa B4 lectin can also interact with terminal beta-linked N-acetylgalactosamine in closely-spaced oligosaccharide units of cell surface glycoproteins.