Affinity chromatography of carbohydrate-specific immunoglobulins: coupling of oligosaccharides to sepharose.

A simple method has been developed for the coupling of oligosaccharides to Sepharose. The sugars are reacted with β-(p-aminophenyl)-ethylamine to form N-alkylglycosides which are then reduced with sodium borohydride to stable secondary amines. The derivatives are then coupled to cyanogen bromide-activated Sepharose through their arylamino groups. Yields are essentially quantitative based on starting oligosaccharides. An affinity column containing lacto-N-difucohexaose I coupled to Sepharose by this method was used for the purification of an antibody directed against this oligosaccharide. The antibody is absorbed by the gel and is specifically eluted by the free sugar.     

Microassay analyses of protein glycosylation

To accurately characterize the carbohydrate moieties of oligosaccharide chains in glycosylated proteins, it is necessary to distinguish exactly which types of oligosaccharides are present at which site. We describe lectin overlay assays, which take advantage of the ability of lectins to distinguish between different types of glycoproteins via recognition of terminal sugars, thus allowing the chain type and peripheral antigenic components to be determined. Three microassays involving lectins are reported in this paper: non-proteasetreated intact glycoproteins; glycopeptides released by prior digestion of the glycoprotein and then separated by HPLC; and release of sugars from glycoproteins by hydrazinolysis and then coupling them to a multivalent support.     

Recognition of the blood group H type 2 trisaccharide epitope by 28 monoclonal antibodies and three lectins

The patterns of cross-reaction of 30 monoclonal antibodies and three lectins were determined by ELISA with 21 ABH, Ii or Lewis related synthetic oligosaccharides coupled to bovine serum albumin. At least seven main groups of cross-reactive patterns were identified among the antibodies, plus several intermediate patterns between two of the main antibody groups. The three lectins had different cross-reaction patterns,Galactia tenuiflora was different from all the antibodies,Ulex europaeus lectin 1 andLotus tetragonolobus were similar, but not identical to groups III and V of antibodies respectively. The anti-H antibodies cross-reacting with A type 2 gave similar agglutination scores with all the normal ABO erythrocytes, while the anti-H antibodies not cross-reacting with A type 2 reacted with different scores: O>A₂>A₂B>B>A₁>A₁B>O_h, suggesting that these antibodies react better with the free H epitopes and do not recognize the H in A or B epitopes. Based on the ELISA and agglutination results and the lowest energy conformations of each oligosaccharide obtained by computer modelling, the most probable oligosaccharide surface areas recognized by each antibody main group are illustrated.     

Binding and precipitation of lectins from Erythrina indica and Ricinus communis (agglutinin I) with synthetic cluster glycosides

We recently reported that tri- and tetraantennary complex type oligosaccharides with nonreducing terminal galactose residues and the triantennary asialofetuin glycopeptide can bind and precipitate certain galactose specific lectins (L. Bhattacharyya, and C.F. Brewer (1986) Biochem. Biophys. Res. Commun. 141, 963-967; L. Bhattacharyya, M. Haraldsson, and C.F. Brewer (1988) Biochemistry 27, 1034-1041). The present study investigates the binding interactions of two of these lectins, those from Erythrina indica and Ricinus communis (Agglutinin I), with mono-, bi-, and triantennary synthetic cluster glycosides, which have little structural resemblance to complex type oligosaccharides other than they possess nonreducing terminal galactose residues (R.T. Lee, P. Lin, and Y.C. Lee (1984) Biochemistry 23, 4255-4261). The enhanced affinities of the bi- and triantennary glycosides relative to the monoantennary glycoside for the two lectins are consistent with an increase in the probability of binding due to multiple binding residues in the multiantennary glycosides. The triantennary glycoside is capable of precipitating the two lectins, and quantitative precipitation data indicate that it is a trivalent ligand. The results show that the binding and precipitation activities of complex type oligosaccharides with these lectins is due solely to the presence of multiple terminal galactose residues and not to the overall structures of the oligosaccharides.     

New derivatives of reducing oligosaccharides and their use in enzymatic reactions: efficient synthesis of sialyl Lewis a and sialyl dimeric Lewis x glycoconjugates

The reducing oligosaccharides lactose and lacto-N-tetraose were reductively aminated with benzyloxycarbonylaminoaniline and sodium cyanoborohydride, followed by treatment of the resulting secondary amines with acetic anhydride. The resulting N-acetyl-N-(4-benzyloxycarbonylaminophenyl)-1-amino-1-deoxyaldi tol oligosaccharide derivatives were subjected to stepwise enzymatic elongation with various glycosyltransferases/nucleotide sugars. Purification of the products after each enzymatic step was conveniently performed by solid-phase extraction on silica gel C-18 cartridges. Two oligosaccharide derivatives (with sialyl Lewis a and sialyl dimeric Lewis x structures) were prepared. Conversion of the obtained derivatives into neoglycoproteins by the sequence hydrogenolysis, thiophosgene treatment, and protein coupling was carried out.     

植物凝集素的分子生物学研究

植物凝集素是一类具有高度特异性糖结合活性的蛋白,含有一个或多个可与单糖或寡聚糖特异可逆结合的非催化结构域。它的糖结合特异性主要针对外源寡糖,主要生理功能是介异植物的防御反应。到目前为止已克隆了２２２个植物凝集素基因。作者就植物凝集素的分类、性质、功能、凝集素基因的克隆和凝集素的翻译后加工过程作一综述。     

Direct carbohydrate analysis of glycoproteins electroblotted onto polyvinylidene difluoride membrane from sodium dodecyl sulfate-polyacrylamide gel.

A procedure for the carbohydrate analysis of glycoproteins electrotransferred to a polyvinylidene difluoride membrane is described. The glycoproteins (plant lectins, transferrin, and vitronectin) were first separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and then electroblotted onto a membrane. Each of the glycoprotein bands visualized by staining with Coomassie brilliant blue R-250 was excised from the membrane and subjected to direct hydrolysis either in 2.5 M trifluoroacetic acid at 100 degrees C for 6 h for neutral sugars and hexosamines, or in 0.05 M H2SO4 at 80 degrees C for 1 h for sialic acids. The hydrolysate obtained was analyzed for neutral sugars, hexosamines, and sialic acids independently by three different systems of high-performance liquid chromatography. The analytical values were reproducible with reasonable accuracy and agreed with those expected with recoveries of 57-66%. The method was successfully applied to a mannose-specific lectin of Sophora japonica bark, which is composed of four different subunits that aggregate sugar specifically. Because the four subunits could be separated by SDS-PAGE alone, the method proved useful for determining their carbohydrate compositions. Three of them were shown to contain carbohydrates typical of N-linked oligosaccharides of plant origin, which agreed well with the results of the binding assay carried out on a membrane using various horseradish peroxidase-labeled lectins.     

Lectin affinity high-performance liquid chromatography: interactions of N-glycanase-released oligosaccharides with leukoagglutinating phytohemagglutinin, concanavalin A, Datura stramonium agglutinin, and Vicia villosa agglutinin

We have developed a lectin affinity high-performance liquid chromatography technique for analysis of oligosaccharides using columns of silica-bound lectins. Purified leukoagglutinating phytohemagglutinin (L-PHA), concanavalin A (Con A), Datura stramonium agglutinin (DSA), and Vicia villosa agglutinin (VVA) were covalently coupled to periodate-oxidized diol-silica by reductive amination. Homogeneous oligosaccharides of known structure, purified following release from Asn with N-glycanase and reduction with NaBH4, were tested for their ability to interact with the silica-bound lectins. The characteristic elution position obtained for each oligosaccharide was reproducible and correlated with specific structural features. The oligosaccharide specificities displayed by silica-bound L-PHA, Con A, and DSA were virtually identical to those established utilizing lectin-agarose conjugates. Analysis of oligosaccharides by lectin affinity HPLC allowed further definition of the specificity of VVA for N-glycanase-released, reduced oligosaccharides. Lectin affinity HPLC is rapid and convenient, providing an important structure-specific dimension to oligosaccharide analysis. This technique is particularly useful when utilized in conjunction with anion-exchange and ion-suppression amine adsorption HPLC methods, which fractionate on the basis of charge and size, respectively. In addition to their utility for oligosaccharide characterization, these affinity columns demonstrate the high degree of oligosaccharide specificity displayed by plant and animal lectins.     

Characterization of bovine serum albumin glycated with glucose, galactose and lactose

The non-enzymatic reaction between reducing sugars and proteins, known as glycation, has received increased attention from nutritional and medical research. In addition, there is a large interest in obtaining glycoconjugates of pure well-characterized oligosaccharides for biological research. In this study, glycation of bovine serum albumin (BSA) by d-glucose, d-galactose and d-lactose under dry-heat at 60 degrees C for 30, 60, 120, 180 or 240 min was assessed and the glycated products studied in order to establish their biological recognition by lectins. BSA glycation was monitored using gel electrophoresis, determination of available amino groups and lectin binding assays. The BSA molecular mass increase and glycation sites were investigated by mass spectrometry and through digestion with trypsin and chymotrypsin. Depending on time and type of sugar, differences in BSA conjugation were achieved. Modified BSA revealed reduction of amino groups' availability and slower migration through SDS/PAGE. d-galactose was more reactive than d-glucose or d-lactose, leading to the coupling of 10, 3 and 1 sugar residues, respectively, after 120 minutes of reaction. BSA lysines (K) were the preferred modified amino acids; both K256 and K420 appeared the most available for conjugation. Only BSA-lactose showed biological recognition by specific lectins.     

Photochemical addition of 2-propanol and of acetone to methyl 5-deoxy-2,3-O-isopropylidene-β-d-erythro-pent-4-enofuranoside

High-capacity adsorbents for lectins, including Lotus tetragonolobusl-fucose-binding protein, were readily prepared by conjugation of monosaccharides with commercially available, epoxy-activated Sepharose. Purified, radioiodinated lectins were bound to cells of the mosquito Aedes aegyptii and of human KB tumour. Relative to human KB cells, mosquito cells bound less of lectins specific for the sugars (l-fucose and d-galactose) that are terminal residues in many mammalian glycoproteins, whereas the number of binding sites of lectins specific for core-region sugars (d-mannose and 2-acetamido-2-deoxy-d-glucose) were similar. Neuraminidase, which greatly enhanced binding of peanut agglutinin or soybean agglutinin to human KB cells, had negligible effects on binding of these lectins to mosquito cells. The comparative structures of surface oligosaccharides of mosquito and KB cells are discussed in relation to the lectin-binding studies.     

Oligosaccharide specificities of Phaseolus vulgaris leukoagglutinating and erythroagglutinating phytohemagglutinins. Interactions with N-glycanase-released oligosaccharides

The structural determinants required for interaction of oligosaccharides with leukoagglutinating phytohemagglutinin (L-PHA) and erythroagglutinating phytohemagglutinin (E-PHA) from Phaseolus vulgaris have been studied by immobilized lectin affinity chromatography. Homogeneous oligosaccharides of known structure, purified following release from Asn with N-glycanase and reduction with NaBH4, were tested for their ability to interact with columns of L- and E-PHA-agarose. The characteristic elution position obtained for each oligosaccharide was reproducible and correlated with specific structural features. In virtually all cases, L- and E-PHA yielded identical results, indicating that their specificities for reduced oligosaccharides are similar. Both lectins retarded oligosaccharides bearing alpha 2,3- but not alpha 2,6-linked sialic acid. Desialylated oligosaccharides containing one, two, three, or four peripheral N-acetyllactosamine-type branches were retarded to varying extents by both lectins; however, this interaction was decreased or eliminated by removal of Gal. Desialylated oligosaccharides containing a bisecting GlcNAc residue attached to the beta-linked core Man displayed the greatest interaction with both lectins. Structures containing terminal sulfate or GalNAc did not interact with either lectin. In some instances, the specificities of L- and E-PHA lectins for free, reduced oligosaccharides differed from those established using glycopeptides. Therefore, the structural requirements for interaction with lectins such as L- and E-PHA must be fully and systematically defined using the appropriate authentic standards in order to use lectin affinity chromatography for the fractionation and characterization of free oligosaccharides.     

Distribution of glycoconjugates in ion transport cells of gerbil inner ear.

Ion transport cells in gerbil inner ear were differentiated histochemically by staining glycoconjugates (GCs) with a battery of horseradish peroxidase-conjugated lectins. Strong staining with PSA and LCA showed a high content of N-linked oligosaccharides in transport cell GCs. Reactivity with PHA-L and PHA-E identified GC with triantennary and with bisected biantennary N-linked oligosaccharides, respectively, in these cells. High affinity for DSA and PWM demonstrated abundant N-acetyl lactosamine in N-linked side chains. Ion transporting epithelial cells reacting with lectins specific for N-linked oligosaccharides included strial marginal cells and outer sulcus cells of the cochlea and dark cells, transitional cells, and planum semilunatum cells of the vestibular system. In general, all of the inner ear transport epithelial cells revealed a similar lectin binding profile, with the one exception that SBA reacted strongly with ion transporting cells in the vestibular system but only weakly with those in the cochlea. Fibrocytes specialized for ion transport located in distinct areas in the suprastrial and inferior regions of the spiral ligament also stained with lectins that demonstrate N-glycosylation. However, transport fibrocytes differed from transport epithelial cells in two ways. First, they reacted e with HPA, DBA, VVA, and SJA specific for O-linkages and second, they failed to react with UEA I. The staining pattern for N-glycosylated GC resembled that for Na+, K(+)-ATPase in inner ear, suggesting a relationship between these constituents.     

Chemoenzymatic synthesis of glycopolypeptides carrying alpha-Neu5Ac-(2-->3)-beta-D-Gal-(1-->3)-alpha-D-GalNAc, beta-D-Gal-(1-->3)-alpha-D-GalNAc, and related compounds and analysis of their specific interactions with lectins

Glycopolypeptide (1) carrying the beta-D-Gal-(1-->3)-alpha-D-GalNAc unit as a kind model of asialo-type mucin was synthesized through three steps: enzymatic synthesis of p-nitrophenyl disaccharide glycoside, reduction of the p-nitrophenyl group, and coupling of the amino group with the carboxyl group of poly(L-glutamic acid)s (PGA). In a similar manner, glycopolypeptides (2-7) carrying beta-D-Gal-(1-->3)-beta-D-GalNAc, beta-D-Gal-(1-->3)-beta-D-GlcNAc, beta-D-Gal-(1-->6)-alpha-D-GalNAc, beta-D-Gal-(1-->6)-beta-D-GalNAc, alpha-D-GalNAc, and beta-D-GalNAc, respectively, were synthesized as analogous polymers of polymer 1. Glycopolypeptides 8 and 9 as a mimic of sialo-type mucin were further prepared from polymers 1 and 2 as the acceptor of CMP-Neu5Ac by alpha2,3-(O)-sialyltransferase, respectively. Interactions of these glycopolypeptides with lectins were investigated with the double-diffusion test and the hemagglutination-inhibition assay and in terms of an optical biosensor based on surface plasmon resonance. Polymers 1 and 2 reacted strongly with peanut (Arachis hypogaea) agglutinin (PNA) and Agaricus bisporus agglutinin (ABA). On the other hand, polymers 8 and 9 through sialylation from polymers 1 and 2 reacted with ABA, but did not with PNA. Other polymers 3-7 did not show any reactivity for both the lectins. These results show that PNA acts precisely in an exo manner on the beta-D-Gal-(1-->3)-D-GalNAc sequence, while ABA acts in an endo manner. Polymers 6 and 7 substituted with GalNAc reacted strongly with soybean (Glycine max) agglutinin and Vicia villosa agglutinin B4, regardless of the configuration of the glycosidic linkage. The interaction of all polymers with Bauhinia purpurea agglutinin was much stronger than that of the corresponding sugars. Polymers 8 and 9 reacted with wheat germ (Triticum vulgaris) agglutinin (WGA), to which Neu5Ac residues are needed for binding, but polymers 1 and 2 did not. These sugar-substituted glycopolypeptides interacted specifically with the corresponding lectins. Furthermore, polymers 4-7 reacted with WGA, but the corresponding sugars did not. It suggests that the N-acetyl group along the PGA backbone has a cluster effect for WGA. The artificial glycopolypeptides were shown to be useful as tools and probes of carbohydrate recognition and modeling in the analysis of glycoprotein-lectin interactions.     

Properties of a lectin purified from the seeds of Cicer arietinum

A lectin was isolated from seed extracts of Cicer arietinum by (NH4)2SO4 precipitation and subsequent ion exchange chromatography and gel filtration. Affinity chromatography on desialylated human IgM coupled to AH-Sepharose was also performed, but the amount bound was very low. The lectin has a molecular mass of about 44000 Da, as determined by ultracentrifugation and gel filtration. Dodecyl sulphate polyacrylamide-gel electrophoresis showed one band corresponding to a molecular mass of 26000 Da. N-Terminal amino acid sequence analyses indicate only one type of chain, suggesting that the lectin is probably dimeric. The amino acid composition is given. Papainized human erythrocytes of the different ABO groups were agglutinated equally well by the Cicer lectin, whereas untreated cells reacted weakly and only in the presence of bovine serum albumin. Simple sugars did not inhibit the agglutination, but some glycoproteins did inhibit. The lectin is probably nonmitogenic against human lymphocytes. Antigenic analyses in an enzyme-linked immunosorbent assay (ELISA) showed only a weak cross-reaction between Cicer and the lectins in the Vicieae tribe. Thus, our physicochemical and antigenic studies of the Cicer lectin support the botanical reasons recently given for removing the genus Cicer from the Vicieae tribe.     

Quantitative analysis of sugar constituents of glycoproteins by capillary electrophoresis

A method for quantitative analysis of monosaccharides including N- acetylneuraminic acid derived from sialic acid-containing oligosaccharides and glycoproteins is presented. The analysis is based on the combination of chemical and enzymatic methods coupled with capillary electrophoretic (CE) separation and laser-induced fluorescence (LIF) detection. The present method utilizes a simplified acid hydrolysis procedure consisting of mild hydrolysis (0.1 M TFA) to release sialic acid and strong acid hydrolysis (2.0 N TFA) to produce amino and neutral sugars. Amino sugars released from strong acid hydrolysis of oligosaccharides and glycoproteins were reacetylated and derivatized with 8-aminopyrene-1,3,6-trisulfonate (APTS) along with neutral sugars in the presence of sodium cyanoborohydride to yield quantitatively the highly stable fluorescent APTS adducts. N- acetylneuraminic acid (Neu5Ac), a major component of most mammalian glycoproteins, was converted in a fast specific reaction by the action of neuraminic acid aldolase (N-acylneuraminate pyruvate-lyase EC 4.1.3.3) to N-acetylmannosamine (ManNAc) and pyruvate. ManNAc was then derivatized with APTS in the same manner as the other monosaccharides. This method was demonstrated for the quantitation of pure Neu5Ac and the species derived from mild acid hydrolysis of 6'-sialyl-N- acetyllactosamine and bovine fetuin glycan. Quantitative recovery of the N-acetylmannosamine was obtained from a known amount of Neu5Ac in a mixture of seven other monosaccharides or from the sialylated oligosaccharides occurring in glycoproteins. The sequence of procedures consists of acid hydrolysis, enzymatic conversion and APTS derivatization which produced quantitative recovery of APTS- monosaccharide adducts. The detection limits for sugars derivatized with APTS and detected by CE-LIF are 100 pmol for Neu5Ac and 50 pmol for the other sugars.      

Identification and partial characterization of multiple native and neoantigenic epitopes of human C-reactive protein by using monoclonal antibodies

Multiple mAb to human C-reactive protein (CRP) were prepared which reacted preferentially with either native CRP, modified CRP (expressing "neo-CRP" determinants) or both forms of the molecule. These mAb were divided into four groups according to their binding characteristics to various CRP preparations and CRP peptides by using a combination of ELISA, dot blot, and Western blot assays; they were further characterized based upon their reactivity with CRP in the presence of calcium and inhibition by phosphorylcholine. The first group consisted of mAb that reacted only with native CRP, and served to define four distinct native CRP epitopes. The second group consisted of mAb that reacted with native CRP and also with CRP modified by direct immobilization on polystyrene plates, urea-chelation or SDS treatment in the absence of calcium, thus identifying a fifth native CRP epitope; these mAb displayed significantly greater reactivity with native than with modified CRP. The third group included mAb that reacted only with modified CRP and with the larger amino-terminal fragment (residues 1-146) of pronase-cleaved CRP. The fourth group included mAb that reacted only with modified CRP and with the smaller carboxyl-terminal fragment (residues 147-206) of pronase-cleaved CRP; most of these antibodies also reacted with the carboxyl-terminal octapeptide (residues 199-206) of CRP. These experiments have identified mAb that react preferentially with distinct conformational and sequence-determined epitopes of native and modified forms of the CRP molecule, respectively; provide partial identification of the epitopes with which they interact; point to the presence of at least five epitopes on native CRP and at least three epitopes on modified CRP; and provide antibodies suitable for identification and quantitation of native and modified forms of CRP. The mAb directed against neo-CRP epitopes may help identify the presence of this pentraxin and antigenically-related proteins at previously unappreciated sites.     

Stereospecific synthesis of sugar-1-phosphates and their conversion to sugar nucleotides

As Leloir glycosyltransferases are increasingly being used to prepare oligosaccharides, glycoconjugates, and glycosylated natural products, efficient access to stereopure sugar nucleotide donor substrates is required. Herein, the rapid synthesis and purification of eight sugar nucleotides is described by a facile 30 min activation of nucleoside 5'-monophosphates bearing purine and pyrimidine bases with trifluoroacetic anhydride and N-methylimidazole, followed by a 2 h coupling with stereospecifically prepared sugar-1-phosphates. Tributylammonium bicarbonate and tributylammonium acetate were the ion-pair reagents of choice for the C18 reversed-phase purification of 6-deoxysugar nucleotides, and hexose or pentose-derived sugar nucleotides, respectively.     

A solid-phase substrate of heparanase: its application to assay of human melanoma for heparan sulfate degradative activity

We found a tumor metastasis-associated heparan sulfate (HS)-degrading endoglycosidase in melanoma cells that is a unique endo-beta-glucuronidase (heparanase) capable of specifically cleaving HS at intrachain sites (M. Nakajima, T. Irimura, N. DiFerrante, and G. L. Nicolson, 1984, J. Biol. Chem. 259, 2283-2290). To perform rapid and microscale quantitative assays of heparanase we developed a solid-phase HS substrate by crosslinking radiolabeled HS onto agarose gel beads using one covalent linkage. The HS from bovine lung was partially N-desulfated and labeled with [14C]acetic anhydride. Free HS amino groups were completely acetylated, and reducing terminal saccharides were reductively aminated. The HS derivatives with amino groups at their reducing termini were coupled to amino-reactive agarose beads. Incubation of the solid-phase HS substrates with B16 melanoma cell extracts in the presence of D-saccharic acid 1,4-lactone (a potent exo-beta-glucuronidase inhibitor) resulted in the time- and dose-dependent release of [14C]HS fragments. Human melanoma cell lines were tested for HS-degrading endoglycosidase using the newly developed solid-phase HS substrates. The human malignant melanoma cells tested had high levels of HS-degrading activity that were comparable to those of highly metastatic murine B16-F10 melanoma cells.     

Identification and distribution of carbohydrate moieties on the salivary glands of Rhodnius prolixus and their possible involvement in attachment/invasion by Trypanosoma rangeli

In the present study, FITC-labelled lectins (WGA, Con A, PNA, HPA, and TPA) were utilized to investigate carbohydrate residues on the surface of Rhodnius prolixus salivary glands. The results revealed that the salivary glands are rich in carbohydrate moieties and the diversity in binding pattern of particular lectins showed the presence of specific carbohydrate residues in the basal lamina, muscle, and cell layers of the glands. Subsequently, the sugars detected on the salivary gland surface were employed to investigate the interaction between Trypanosoma rangeli and the R. prolixus salivary glands. In vitro adhesion inhibition assays using long epimastigote forms (the invasion/adhesion forms) showed that some sugars tested were able to block the receptors on both the surfaces of the salivary glands and on T. rangeli. Among the sugars tested, GlcNAc, GalNAc, and galactose showed the highest overall inhibitory effect, following pre-incubation of either the salivary glands or parasites. These results are discussed in relation to previous work on the role of carbohydrates and lectins in insect vector/parasite interactions.     

Lectin histochemistry of mouse vagina during the estrous cycle

Estrous cycle-related histochemical changes in the vaginal epithelium of sexually mature female mice were studied with 30 fluorescein isothiocyanate (FITC)-labeled lectins. On the basis of the staining pattern the lectins were divided into five groups: I, seventeen lectins that reacted with mucinous surface layer of proestrus. This group comprised two subgroups: Ia, seven lectins that reacted exclusively with the mucinous layer, and Ib, ten lectins that reacted with mucinous cells and the underlying squamous epithelium of proestrus; II, two lectins that reacted with squamous epithelium of proestrus only but were unreactive with mucinous cells; III, three lectins that reacted in a phase-specific manner with squamous epithelium; IV, six lectins that showed increased luminal surface reactivity in diestrus and/or metestrus; and V, eleven lectins that were unreactive with vaginal epithelium. These data indicate that the cyclic changes in the morphology of the vaginal epithelium are accompanied by distinct lectin reactivity patterns.