Structural requirements of carbohydrates to bind Agaricus bisporus lectin

Fernando J. Irazoqui1,2, Miguel A. Vides and Gustavo A. Nores1

Departamento de Bioquímica Clínica and 1Departamento de Química Biológica-CIQUIBIC-CONICET, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Agencia Postal 4, CC 61, 5000 Córdoba, Argentina

Received on March 31, 1998; revised on May 11, 1998; accepted on May 27, 1998

Gal[beta]1-3GalNAc (T-disaccharide) and related molecules were assayed to describe the structural requirements of carbohydrates to bind Agaricus bisporus lectin (ABL). Results provide insight into the most relevant regions of T-disaccharide involved in the binding of ABL. It was found that monosaccharides bind ABL weakly indicating a more extended carbohydrate-binding site as compared to those involvedin the T-disaccharide specific lectins such as jacalin and peanut agglutinin. Lacto-N-biose (Gal[beta]1-3GlcNAc) unlike T-disaccharide, is unable to inhibit the ABL interaction, thus showing the great importance of the position of the axial C-4 hydroxyl group of GalNAc in T-disaccharide. This finding could explain the inhibitory ability of Gal[beta]1-6GlcNAc and lactose because C-4 and C-3 hydroxyl groups of reducing Glc, respectively, occupy a similar position as reported by conformational analysis. From the comparison of different glycolipids bearing terminal T-disaccharide bound to different linkages, it can be seen than ABL binding is even more impaired by an adjacent C-6 residual position than by the anomeric influence of T-disaccharide. Furthermore, the addition of [beta]-GlcNAc to the terminal T-disaccharide in C-3 position of Gal does not affect the ABL binding whereas if an anionic group such as glucuronic acid is added to C-3, the binding is partially affected. These findings demonstrate that ABL holds a particular binding nature different from that of other T-disaccharide specific lectins.

Key words: Agaricus bisporus lectin/Thomsen-Friedenreich disaccharide

Introduction

Lectins are carbohydrate-binding proteins other than enzymes or antibodies, which may contain a second type of binding site specific for noncarbohydrate ligands (Barondes, 1988). Agaricus bisporus lectin (ABL) was first reported by Presant and Kornfeld (1972), exhibiting erythrocyte agglutinating activity. This lectin (Mr 64,000) is a tetramer with four apparently identical subunits (Mr 16,000). Moreover, four different isoelectric forms that have quite similar carbohydrate-binding specificities were reported previously (Sueyoshi et al., 1985).

The ABL specificity has been related to alcali-labile carbohydrate chains of glycoproteins (Presant and Kornfeld, 1972; Chatterjee et al., 1985; Sueyoshi et al., 1985). There has been a recently renewed interest in the post-translational modification of serine and threonine hydroxyl groups by glycosylation because the resulting O-linked oligosaccharide chains tend to cluster over short stretches of peptides and hence display multivalent carbohydrate antigenic or functional determinants for antibody recognition, mammalian cell adhesion, and microorganism binding (Hounsell et al., 1996; Taylor-Papadimitriou and Finn, 1997). The majority of the O-linked chains on serum and membrane glycoproteins are the sialylated tri- and tetrasaccharide type based on type I core (Gal[beta]1-3GalNAc[alpha]1-Ser/Thr) having sialic acid linked [alpha]2-3 to Gal and/or [alpha]2-6 to GalNAc. The nonsialylated type I core, also called T-disaccharide (Thomsen-Friedenreich disaccharide), was reported as a tumor-associated antigen of non-oncofetal origin and probably as one of the few chemically well-defined antigens with a proven link to malignancy (Springer, 1984; Cao et al., 1995; Yang and Shamsuddin, 1996). Hence, anti-T probes have an enormous potential in cancer research (Carneiro et al., 1994; Desai et al., 1995; Langkilde, 1996). In addition, T-disaccharide and related carbohydrates were assayed as antigens in active specific immunotherapy of tumor-bearing hosts (Toyokuni and Singhal, 1995; Koganty et al., 1996; Graham et al., 1996; Springer, 1997). Moreover, ABL, which mainly binds Gal[beta]1-3GalNAc, is a reversible noncytotoxic inhibitor of epithelial cell proliferation (Yu et al., 1993) unlike the classical T-disaccharide specific lectin, peanut agglutinin, which stimulates proliferation of these cells (Ryder et al., 1992).

The aim of the present work is to further understand the structural requirements of carbohydrates for ABL binding in an attempt to explain these interactions, and perhaps contribute to the design of new antigens for specific cancer therapies.

Results and discussion

In preliminary experiments, the concentration of ABL-peroxidase (ABL-HRP) and human monoclonal IgA1k Pan (containing O-linked oligosaccharides) which proved to be optimal for hapten inhibition of competitive enzyme-lectin assays (CELA) was determined (data not shown). Optimal conditions for CELA were 0.04 µg/ml ABL-HRP and 10 µg/ml IgA1k Pan. We first sought to elucidate the relevancy of free monosaccharides and anomeric linkage in binding since free Gal and GalNAc were compared to the [alpha]- and [beta]-anomer of the methyl and p-nitrophenyl glycosides, respectively. As seen in Figure 1A and Table I, both monosaccharides are poor inhibitors of ABL interaction. However, GalNAc is a more potent inhibitor than Gal and no differences between anomeric forms were detected. In addition, GlcNAc has no inhibitory capacity. The observation that monosaccharides related to the T-disaccharide are not inhibitors of ABL agglutination has been previously reported (Presant and Kornfeld, 1972; Sueyoshi et al., 1985; Irazoqui et al., 1992). However, using a more sensitive method such as CELA, the greater importance of GalNAc over Gal in ABL binding was tested. These results indicate that C-2 acetamido addition improves the binding of Gal and that the axial C-4 hydroxyl group in GalNAc provides a more significant binding locus as shown by the fact that GlcNAc does not bind to ABL.


Figure 1. Competitive enzyme-lectin assay (CELA) using carbohydrates as inhibitors of ABL interaction. The importance of free saccharides and anomeric linkage derivatives were examined. Wells coated with IgA1k Pan (which contains O-linked oligosaccharides) were assayed against ABL-HRP, previous incubation of the lectin with the following carbohydrates: (A) monosaccharides: Gal (solid squares), Me[alpha]Gal (open triangles), Me[beta]Gal (open squares), GalNAc (open circles), pNO2Ph[alpha]GalNAc (solid circles), pNO2Ph[beta]GalNAc (inverted open triangles) and GlcNAc (inverted solid triangles). (B) disaccharides: Gal[beta]1-4Glc (solid diamonds), Gal[alpha]1-6Glc (open circles), Gal[beta]1-3GlcNAc (inverted open triangles), Gal[beta]1-4GlcNAc (solid circles), Gal[beta]1-6GlcNAc (open diamonds), Gal[beta]1-3GalNAc (solid triangles) and Gal[beta]1-3GalNAc[alpha]pNO2Ph (open triangles). The washes and color reaction were developed as described under Material and methods.

Among the monosaccharides and disaccharides tested, Gal[beta]1-3GalNAc and Gal[beta]1-3GalNAc[alpha]pNO2Ph were the most powerful inhibitors (Figure 1). Both T-disaccharides were 2000-fold more inhibitory than GalNAc (the best monosaccharide inhibitor) (Table I). The introduction of bulky hydrophobic substituents as in Gal[beta]1-3GalNAc[alpha]pNO2Ph did not change binding over Gal[beta]1-3GalNAc significantly. These results suggest the absence of hydrophobic interactions between a phenyl group and the corresponding binding loci in the combining region of the ABL, unlike jacalin, a T-disaccharide specific lectin that shows great influence of a hydrophobic region adjacent to the carbohydrate-binding site (Gupta et al., 1992). Of great importance on ABL binding is the axial C-4 hydroxyl group position of GalNAc from T-disaccharide since the inversion in lacto-N-biose (Gal[beta]1-3GlcNAc) turns it inactive, having both disaccharides identical structures except for the position of the C-4 hydroxyl group on the reducing residue. It may be that the change in configuration of this hydroxyl group not only leads to a loss of a favorable contact of the disaccharide with the lectin binding site, but also to an unfavorable interaction. It is possible that the hydrophilic hydroxyl group in the equatorial configuration were in contact with a hydrophobic region in the ligand-binding site of the lectin since this equatorial position breaks an aliphatic path formed by 3, 4, 5, and 6-carbons of GalNAc (Weis and Drickamer, 1996).

Table I. Inhibition of ABL binding by using related T-disaccharide carbohydrates
Carbohydrates Concentration (mM) required for 50% inhibition Relative inhibitory potency
Gal >200 <0.2
Me[alpha]Gal >200 <0.2
Me[beta]Gal >200 <0.2
GalNAc 40 1
pNO2Ph[alpha]GalNAc 40 1
pNO2Ph[beta]GalNAc 40 1
Gal[beta]1-4Glc 5 8
Gal[beta]1-6GlcNAc 4 10
Gal[beta]1-3GalNAc 0.02 2000
Gal[beta]1-3GalNAc[alpha]pNO2Ph 0.02 2000

In addition, lactose and Gal[beta]1-6GlcNAc have a significantly inhibitory activity on the binding of ABL. Both disaccharides are ~10-fold more powerful inhibitors than GalNAc. From minimum energy conformations of disaccharides obtained by theoretical studies as well as from the structures obtained by x-ray crystallography (Sastry et al., 1986; Sharma et al., 1996), it was found that the C-4 hydroxyl group of the reducing sugar moiety in T-disaccharide occupies a similar position regarding terminal Gal to that of the C-3 and C-4 hydroxyl groups in lactose and Gal[beta]1-6GlcNAc, respectively. The relevance of the C-4 hydroxyl group position in the reducing sugar moiety of T-disaccharide on the interaction with ABL, and the similar position of C-3 and C-4 hydroxyl groups in lactose and Gal[beta]1-6GlcNAc, respectively, could be an explanation of the interaction of ABL with both disaccharides. Moreover, melibiose (Gal[alpha]1-6Glc), which has no hydroxyl group in a position similar to that of the C-4 hydroxyl group of the reducing sugar moiety from T-disaccharide, shows no interaction with ABL. N-Acetyllactosamine (Figure 1B) does not show any binding to ABL, even though it has an hydroxyl group in a position similar to the C-4 hydroxyl of GalNAc in T-disaccharide, thus indicating a possible steric hindrance by the acetamido group in position C-2 of GlcNAc. However, the ABL-N-acetyllactosamine interaction was observed when multiple N-acetyllactosamine molecules were conjugated to a protein (Irazoqui et al., 1997). This result may be explained by the fact that a single molecule of this glycoconjugate possesses several carbohydrate determinants than could be bound by lectin, and as a consequence, the affinity (or more correctly avidity) of the lectin for the glycoconjugate would be greatly enhanced (Cummings, 1994).

In an attempt to obtain additional information from the study of carbohydrate requirements on ABL interaction, we used glycolipids in binding analysis. Their relative mobility and binding to ABL were analyzed by chromatographic separation on HPTLC-silica gel plates and HPTLC-lectin staining, respectively (Figure 2). From the glycolipids assayed, it was observed that N3, N4, N5a, A5b, GA1, and nLcose4 did not interact with ABL-HRP in the HPTLC-lectin staining, whereas N5b, N6, N7, and A6 showed significant lectin binding. The interactions of ABL with glycolipids were also studied by direct enzyme-lectin assays (DELA, Figure 3), and their affinity constants were measured (Table II). It was found that ABL mainly binds N6, which has an [alpha]-anomeric Gal[beta]1-3GalNAc as its terminal structure. This interaction (ABL-[alpha]-anomeric Gal[beta]1-3GalNAc) is in agreement with CELA data, in which T-disaccharide was the best inhibitor of ABL interaction. From DELA assays it can be seen that structures unrelated to T-disaccharide, such as N3 and N4, do not bind ABL. From the comparison of GA1 with N6 (both glycolipids have terminal Gal[beta]1-3GalNAc but differ in their anomeric forms), it was noted that ABL could bind [alpha]-anomeric but not [beta]-anomeric terminal T-disaccharide, in agreement with previous reports on the ability of ABL to distinguish between T-disaccharide anomers (Chatterjee et al., 1985; Sueyoshi et al., 1985). However, here we found a significant interaction between ABL and N5b, a glycolipid bearing T-disaccharide bound in [beta]-anomeric configuration. This phenomenon could be explained by a steric hindrance of neighboring regions to T-disaccharide more than to an interaction contributed by an [alpha]-anomeric oxygen position. GA1 has T-disaccharide [beta]-linked through the axial C-4 oxygen atom of adjacent Gal, placing its C-6 residue in a position that could impair binding as observed in conformational analysis (Figure 4). In contrast, T-disaccharide in N5b is carried by GlcNAc through the equatorial C-4 oxygen atom and thus the remaining GlcNAc molecule is located in a plane intermediate to that corresponding to GA1 and to [alpha]-anomeric T-disaccharide derivatives. This interpretation is also supported by the fact that free T-disaccharide ([alpha]/[beta] anomeric mixture) and [alpha]pNO2Ph T-disaccharide do not differ in their inhibitory abilities in CELA assays, confirming that the [alpha]-anomeric oxygen position does not contribute to the interaction with ABL. Similar findings were previously reported by Saito et al. (1994) in the analysis of carbohydrate-binding specificity of monoclonal antibodies. It was shown that the antibody-binding specificity to the tetrasaccharide determinant, NeuAc[alpha]2-3Gal[beta]1-3(NeuAc[alpha]2-6)GalNAc, was highly dependent on the type of either glycosylceramide or O-linked peptide carriers. Our results are in agreement with the statement that a common carbohydrate epitope presented by different carriers may react differently against a lectin (Saito et al., 1994).


Figure 2. HPTLC-lectin binding with glycolipids. N3 (1), N4 (2), N5a (3), N5b (4), N6 (5), N7 (6), A5b (7), A6 (8), GA1 (9), and nLcose4 (10) glycolipids were assayed on HPTLC plates using chloroform/methanol/aqueous 0.2% CaCl2 (45:45:10) as the running solvent. The glycolipids were visualized either chemically (A) using orcinol-sulfuric acid spray reagent, for 5 min at 120°C; or according to ABL interaction (B) incubating with ABL-HRP (0.08 µg/ml) in PBS-t for 2 h at 23°C. After washes, the color reaction was developed by using 0.5 mg/ml 4-chloro-1-naphthol and 0.02% H2O2 in methanol-PBS (1:29) during 30 min. Reactions were stopped by washes with distilled water.


Figure 3. Reactivity of ABL binding with glycolipids by using direct enzyme-lectin assay (DELA). Glycolipids, N3 (solid circles), N4 (multiplication signs), N5a (dotted line), N5b (solid triangles), N6 (open squares), N7 (solid squares), A5b (open circles), A6 (open triangles), GA1 (plus signs), and nLcose4 (asterisks) were dissolved in methanol, pipetted in triplicated into the wells of a microtiter plate, and evaporated at 60°C. The plates were incubated with a concentration range of ABL-HRP in PBS-t during 2 h at 23°C. The washes and color reaction was developed as described under Material and methods.

Table II. Affinity constants for the interaction of ABL with glycolipidsa
Glycolipids 10-7 × Ka (M-1)b
N6 22 (±3.2)c
N7 20 (±3.1)
A6 7.3 (±0.61)
N5 b6.9 (±0.59)
GA1 N. B.
N. B., No binding.
aValues were calculated at 23°C.
bData of measurement were fitted by using LIGAND soft (Munson and Rodbard, 1980).
cParentheses indicate standard deviation (n = 3).

On the other hand, when the C-3 hydroxyl residue of a terminal Gal is substituted by [beta]-GlcA, the binding of ABL to glycolipids is reduced as seen in the comparison of N6 with A6 as well as N5b against A5b (where ABL-A5b interaction is not observed). In agreement with these data are those previously reported (Sueyoshi et al., 1988; Chen et al., 1995), evidencing the influence of sialic acid [beta]-linked to the C-3 oxygen atom of terminal Gal, on the ABL interaction. This property is unlike that observed in peanut agglutinin, in which the C-3 addition to Gal from T-disaccharide inactivated it. However, no adverse effect was observed when [beta]-GlcNAc was added to the C-3 hydroxyl residue on terminal Gal of N6, as shown in the ABL binding relationship between N6 and N7. This clearly shows that the addition of a neutral carbohydrate [beta]-linked to the C-3 oxygen atom of Gal from T-disaccharide does not impair ABL interaction. As the substitution of C-3 and C-6 (Chen et al., 1995) hydroxyl groups show low influence on ABL binding and this lectin has high specificity by Gal[beta]1-3GalNAc compared to GalNAc, it is possible that the axial C-4 hydroxyl group of Gal from T-disaccharide may also interact with ABL. The recognition of an internal region in oligosaccharides is not frequent in lectins (Goldstein and Hayes, 1978) and antibodies anti-carbohydrates (Bundle and Young, 1992) which mainly bind terminal structures. Consequently, the ability of ABL to bind to an internal [alpha]-anomeric T-disaccharide of an oligosaccharide in which the T-disaccharide is [beta]-substituted in its C-3 hydroxyl residue is a particular feature of this lectin.


When comparing ABL specificity with other T-disaccharide specific lectins such as AOL (Arthrobotrys oligospora lectin), jacalin, and peanut agglutinin (Sastry et al., 1986; Gupta et al., 1992; Rosen et al., 1996; Sharma et al., 1996), one important difference is that the last two lectins, unlike ABL, significantly bind to monosaccharides related to T-disaccharide. This ABL feature may be due to a more extensive carbohydrate-binding site in comparison to jacalin and peanut agglutinin, and thus higher selectivity of binding is achieved by extending binding sites through contacts between oligosaccharides and the protein surface (Weis and Drickamer, 1996). While, the fungal lectin AOL has an apparent major similarity to ABL binding properties.

In conclusion, we find than ABL only interacts with certain regions and under defined stereochemical requirements of the carbohydrates, showing a particular binding nature different from that of other T-disaccharide specific lectins. Based on previous studies that involved T-disaccharide in epithelial tumor cells (Springer, 1984; Cao et al., 1995; Yang and Shamsuddin, 1996), the level of anti-T and anti-related carbohydrate antibodies with the progression and aggressiveness of malignancy (Chen et al., 1995; Desai et al., 1995), and the inhibitory effect of ABL on the growth of tumor cell lines (Yu et al., 1993), we hypothesize that the achievement of immune response with a carbohydrate-binding specificity similar to ABL could be a new approach to the inhibition of tumor cell proliferation. Thus, the use of an adequately processed T-disaccharide, exposing relevant regions of the disaccharide that mainly interact with ABL such as the major significance of GalNAc over Gal, could be an alternative antigen for active immunization in cancer therapy.


Figure 4. CPK models of terminal trisaccharide corresponding to N6 (a), N5b (b), and GA1 (c). The side view of trisaccharides show the common Gal[beta]1-3GalNAc terminal as well as the adjacent carbohydrate that carried it. The arrows show the C-4 hydroxyl group positions of Gal (left) and GalNAc (right) from terminal T-disaccharide and arrowhead shows the differential position of C-6 residue from carbohydrate carrier to common T-disaccharide.

Materials and methods

Materials

Carbohydrates: Gal, Me[alpha]Gal, Me[beta]Gal, GalNAc, pNO2Ph[alpha]GalNAc, pNO2Ph[beta]GalNAc, GlcNAc, Gal[alpha]1-6Glc, Gal[beta]1-4Glc, Gal[beta]1-3GalNAc, Gal[beta]1-3GalNAc[alpha]pNO2Ph, Gal[beta]1-3GlcNAc, Gal[beta]1-4GlcNAc, and Gal[beta]1-6GlcNAc were purchased from Sigma Chemical Co. (St. Louis, MO). Human monoclonal IgA1k Pan was a gift from Dr. P. Aucouturier (Hospital Necker, Paris, France). The glycolipids used in this study were obtained from the following sources: N3, N4, N5a, N5b, N6, N7, A5b, and A6 were obtained from Calliphora vicina as previously reported (Dennis et al., 1985; Nores et al., 1991); GA1 and nLcose4 were prepared by mild acid hydrolysis of cow brain GM1 and human red blood cell LM1, respectively. ABL was purified and conjugated to horseradish peroxidase (ABL-HRP) as described previously (Irazoqui et al., 1997).

Competitive enzyme-lectin assays (CELA)

CELA was performed as described previously (Irazoqui et al., 1997). Briefly, polystyrene microtitration plates (Corning, NY) were coated with 10 µg/ml human IgA1k Pan (100 µl/well) in 0.1 M carbonate buffer pH 9.6 overnight at 4°C, and saturated with PBS (10 mM potassium phosphate, pH 7.2, 150 mM NaCl)-0.05% Tween 20 (PBS-t) for 1 h at 37°C. Carbohydrates were preincubated with 0.04 µg/ml ABL-HRP for 1 h at 23°C, before adding 100 µl/well. The plates were incubated for 2 h at 23°C and washed six times with PBS-t. The color reaction was developed by using 2 mg/ml o-phenylenediamine and 0.02% H2O2 in 0.1 M sodium citrate pH 5.0 at 23°C for 30 min. Reactions were stopped by adding 100 µl/well of 2.5 M sulfuric acid and absorbance values were read at 492 nm with a microplate reader (model 450, Bio-Rad).

HPTLC-lectin staining

The glycolipids were separated on HPTLC silica gel 60 (Merck) in the running solvent chloroform/methanol/aqueous 0.2% CaCl2 (45:45:10) by using a tank to obtain highly reproducible chromatograms (Nores et al., 1994). After air-drying for 15 min, the plates were coated by dipping in a 0.5% solution of polyisobutylmethacrylate (Plexigum P 28, Rohm and Haas, Darmstadt, Germany) in hexane/chloroform (9:1) for 1 min and air-dried again for 10 min. The plates were incubated with 0.08 µg/ml ABL-HRP in PBS-t for 2 h at 23°C. After five washes with PBS-t during 5 min, the color reaction was developed by using 0.5 mg/ml 4-chloro-1-naphthol and 0.02% H2O2 in methanol-PBS (1:29) for 30 min. Reactions were stopped by washing with distilled water (Mizutamari et al., 1994).

Direct enzyme-lectin assays (DELA)

Glycolipids dissolved in methanol were pipetted into the wells of a microtiter plate and evaporated at 60°C. The plates were incubated with a concentration range (0.036-4.6 µg/ml) of ABL-HRP in PBS-t (100 µl/well) for 2 h at 23°C. The final washes and color reaction were performed as CELA. The data of DELA were fitted with LIGAND soft v. 3.1 (Munson and Rodbard, 1980; Hendriks et al., 1987) for the measurement of affinity constants (Ka) between ABL and glycolipids. All assays were performed in triplicate.

Molecular modeling

Minimum energy conformations of the carbohydrates were performed using molecular mechanic calculations with MM2 force field. Three-dimensional structures were constructed using CPK models (Harvard Apparatus, South Natick, MA).

Acknowledgments

We thank Dr. P. Aucouturier for his generous supply of human monoclonal IgA1k Pan, Dr. P. Munson for kindly providing us with LIGAND soft, Dr. B. Caputto and Dr. L. Castagna for their critical reading of the manuscript and Mrs. I. Orsingher for the language assistance. This work was supported in part by grants (to G.A.N.) from CONICET (PMT-PICT 0462), CONICOR and SeCyT (UNC), and by a grant (to M.A.V.) from CONICOR. F.J.I. acknowledges a fellowship assistance from CONICET.

Abbreviations

ABL, Agaricus bisporus lectin; AOL, Arthrobotrys oligospora lectin; CELA, competitive enzyme-lectin assays; DELA, direct enzyme-lectin assays; Gal, d-galactose; GalNAc, N-acetyl-d-galactosamine; Glc, d-glucose; GlcA, glucuronic acid; GlcNAc, N-acetyl-d-glucosamine; GM1, Gal[beta]1-3GalNAc[beta]1-4(NeuAc[alpha]2-3)Gal[beta]1-4Glc[beta]-Cer; HRP, horseradish peroxidase; LM1, NeuAc[alpha]2-3Gal[beta]1-4GlcNAc[beta]1-4Gal[beta]1-4Glc[beta]-Cer; Ka, affinity constant, Me, methyl; NeuAc, neuraminic acid; O.D., optical density; pNO2Ph, p-nitrophenyl; SD, standard deviation;T-disaccharide, Thomsen-Friedenreich disaccharide.

References

Barondes ,S.H. (1988) Bifunctional properties of lectins: lectins redefined. Trends Biochem. Sci., 13, 480-482. MEDLINE Abstract

Bundle ,D.R. and Young,N.M. (1992) Carbohydrate-protein interaction in antibodies and lectins. Current Opin. Struct. Biol. 2, 666-673.

Cao ,Y., Karsten,U.R., Liebrich,W., Springer,G.F. and Schlag,P.M. (1995) Expression of Thomsen-Friedenreich-related antigens in primary and metastatic colorectal carcinomas. A reevaluation. Cancer, 76, 1700-1708. MEDLINE Abstract

Carneiro ,F., Santos,L., David,L., Dabelsteen,E., Clausen,H. and Sobrinho-Simoes, M. (1994) T (Thomsen-Friedenreich) antigen and other simple mucin-type carbohydrate antigens in precursor lesions of gastric carcinoma. Histopatology, 24, 105-113.

Chatterjee ,B.P., Ahmed,H., Uhlenbruck,G., Janssen,E., Kolar,C. and Seiler,F.R. (1985) Jackfruit (Artocarpus integrifolia) and the Agaricus mushroom lectin fit also to the so-called peanut receptor. Behring Inst. Mitt., 78, 148-158. MEDLINE Abstract

Chen ,Y., Jain,R.K., Chandrasekaran,E.V. and Matta,K.L. (1995) Use of sialylated or sulfated derivatives and acrylamide copolymers of Gal beta 1,3GalNAc alpha- and GalNAc alpha- to determine the specificities of blood group T- and Tn-specific lectins and the copolymers to measure anti-T and anti-Tn antibody levels in cancer patients. Glycoconjugate J., 12, 55-62

Cummings ,R.D. (1994) Use of lectins in analysis of glycoconjugates. Methods Enzymol., 230, 66-86. MEDLINE Abstract

Dennis ,R.D., Geyer,R., Egge,H., Peter-Katalinic,H., Li,S.-C., Stirm,S. and Wiegandt,H. (1985) Glycosphingolipids in insects. Chemical structures of ceramide tetra-, penta-, hexa-, and heptasaccharides from Calliphora vicina pupae (Insecta: Diptera). J. Biol. Chem., 260, 5370-5375. MEDLINE Abstract

Desai ,P.R., Ujjainwala,L.H., Carlstedt,S.C. and Springer,G.F. (1995) Anti-Thomsen-Friedenreich (T) antibody-based ELISA and its application to human breast carcinoma detection. J. Immunol. Methods, 188, 175-185. MEDLINE Abstract

Goldstein ,I.J. and Hayes,C.E. (1978) The lectins: carbohydrate-binding proteins of plants and animals. Adv. Carbohydr. Chem. Biochem., 35, 127-340. MEDLINE Abstract

Graham ,R.A., Burchell,J.M. and Taylor-Papadimitriou,J. (1996) The polymorphic epithelial mucin: potential as an immunogen for a cancer vaccine. Cancer Immunol. Immunother., 42, 71-80. MEDLINE Abstract

Gupta ,D., Prasad Rao,N.V.S.A.V., Deep Puri,K., Matta,K.L. and Surolia,A. (1992) Thermodynamic and kinetic studies on the mechanism of binding of methylumbelliferyl glycosides to jacalin. J. Biol. Chem., 267, 8909-8918. MEDLINE Abstract

Hendriks ,H.G.C.J.M., Koninkx,J.F.J.G., Draaijer,M., van Dijk,J.E., Raaijmakers, J.A.M. and Mouwen,J.M.V.M. (1987) Quantitative determination of the lectin binding capacity of small intestinal brush-border membrane. An enzyme linked lectin sorbent assay (ELLSA). Biochim. Biophys. Acta, 905, 371-375. MEDLINE Abstract

Hounsell ,E.F., Davies,M.J. and Renouf,D.V. (1996) O-linked protein glycosylation structure and function. Glycoconjugate J., 13, 19-26.

Irazoqui ,F.J., Zalazar,F.E., Chiabrando,G.A., Romero,O. and Vides,M.A. (1992) Differential reactivity of Agaricus bisporus lectin with human IgA subclasses in gel precipitation. J. Immunol. Methods, 156, 199-204. MEDLINE Abstract

Irazoqui ,F.J., Zalazar,F.E., Nores,G.A. and Vides,M.A. (1997) Agaricus bisporus lectin binds mainly O-glycans but also N-glycans of human IgA subclasses. Glycoconjugate J., 14, 313-319.

Koganty ,R.R., Reddish,M.A. and Longenecker,B.M. (1996) Glycopeptide- and carbohydrate-base synthetic vaccines for the therapy of cancer. Drug Discovery Today, 1, 190-198.

Langkilde ,N.C. (1996) Studies on the expression of T-(Gal beta (1-3) GalNAc alpha 1-O-R) and T-like antigens in normal and pathologic human and rat urothelium. Scand. J. Urol. Nephrol., Suppl. 172, 45-49.

Mizutamari ,K.R., Wiegandt,H. and Nores,G.A. (1994) Characterization of anti-ganglioside antibodies present in normal human plasma. J. Neuroimmunol., 50, 215-220. MEDLINE Abstract

Munson ,P.J. and Rodbard,D. (1980) LIGAND: a versatile computerized approach for characterization of ligand-binding systems. Anal. Biochem., 107, 220-239. MEDLINE Abstract

Nores ,G.A., Dennis,R.D., Helling,F. and Wiegandt,H. (1991) Human heterophile antibodies recognizing epitopes present on insect glycolipids. J. Biochem., 110, 1-8. MEDLINE Abstract

Nores ,G.A., Mizutamari,R.K. and Kremer,D.M. (1994) Chromatographic tank designed to obtain highly reproducible high-performance thin-layer chromatograms of gangliosides and neutral glycosphingolipids. J. Chromatogr. A, 686, 155-157.

Presant ,C.A. and Kornfeld,S. (1972) Characterization of the cell surface receptor for the Agaricus bisporus hemagglutinin. J. Biol. Chem., 247, 6937-6945. MEDLINE Abstract

Rosen ,S., Bergstrom,J., Karlsson,K.A. and Tunlid,A. (1996) A multispecific saline-soluble lectin from the parasitic fungus Arthrobotrys oligospora. Similarities in the binding specificities compared with a lectin from the mushroom agaricus bisporus. Eur. J. Biochem., 238, 830-837. MEDLINE Abstract

Ryder ,S.D., Smith,J.A. and Rhodes,J.M. (1992) Peanut lectin: a mitogen for normal human colonic epithelium and human HT29 colorectal cancer cells. J. Natl. Cancer Inst., 84, 1410-1416. MEDLINE Abstract

Saito ,S., Levery,S.B., Salyan,M.E.K., Goldberg,R.I. and Hakomori,S.-I. (1994) Common tetrasaccharide epitope NeuAc alpha 2-3Gal beta 1-3(Neu-Ac alpha 2-6)GalNAc, presented by different carrier glycosylceramides or O-linked peptides, is recognized by different antibodies and ligands having distinct specificities. J. Biol. Chem., 269, 5644-5652. MEDLINE Abstract

Sastry ,M.V.K., Banarjee,P., Patanjali,S.R., Swamy,M.J., Swarnalatha,G.V. and Surolia,A. (1986) Analysis of saccharide binding to Artocarpus integrifolia lectin reveals specific recognition of T-antigen (beta-d-Gal(1-3)d-GalNAc). J. Biol. Chem., 261, 11726-11733. MEDLINE Abstract

Sharma ,V., Vijayan,M. and Surolia,A. (1996) Imparting exquisite specificity to peanut agglutinin for the tumor-associated Thomsen-Friedenreich antigen by redesign of its combining site. J. Biol. Chem., 271, 21209-21213. MEDLINE Abstract

Springer ,G.F. (1984) T and Tn, general carcinoma autoantigens. Science, 224, 1198-1206. MEDLINE Abstract

Springer ,G.F. (1997) Immunoreactive T and Tn epitopes in cancer diagnosis, prognosis, and immunotherapy. J. Mol. Med., 75, 594-602. MEDLINE Abstract

Sueyoshi ,S., Tsuji,T. and Osawa,T. (1985) Purification and characterization of four isolectins of mushroom (Agaricus bisporus). Biol. Chem. Hoppe-Seyler, 366, 213-221. MEDLINE Abstract

Sueyoshi ,S., Tsuji,T. and Osawa,T. (1988) Carbohydrate-binding specificities of five lectins that bind to O-glycosyl-linked carbohydrate chains. Quantitative analysis by frontal-affinity chromatography. Carbohydr. Res., 178, 213-224. MEDLINE Abstract

Taylor-Papadimitriou ,J. and Finn,O.J. (1997) Biology, biochemistry and immunology of carcinoma-associated mucins. Immunol. Today, 18, 105-107. MEDLINE Abstract

Toyokuni ,T. and Singhal,A.K. (1995) Synthetic carbohydrate vaccines based on tumour-associated antigens. Chem. Soc. Rev., 116, 231-242.

Weis ,W.I. and Drickamer,K. (1996) Structural basis of lectin-carbohydrate recognition. Annu. Rev. Biochem., 65, 441-473. MEDLINE Abstract

Yang ,G.-Y. and Shamsuddin,A. M. (1996) Gal-GalNAc: a biomarker of colon carcinogenesis. Histol. Histophatol., 11, 801-806.

Yu ,L., Fernig,D.G., Smith,J.A., Milton,J.D. and Rhodes,J.M. (1993) Reversible inhibition of proliferation of epithelial cell lines by Agaricus bisporus (edible mushroom) lectin. Cancer Res., 53, 4627-4632. MEDLINE Abstract


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