Anaplasma marginale, Eperythrozoon wenyoni: lectin reactions with bovine erythrocytes

Normal bovine erythrocytes were agglutinated with four of five lectins specific for different oligosaccharides. The order of reactivity was wheat germ greater than ricin greater than soybean greater than peanut. Concanavalin A did not agglutinate normal bovine erythrocytes. After neuraminidase treatment of normal bovine erythrocytes, each lectin agglutinated the cells with decreased concentrations of lectin, verifying that partial removal of sialic acid exposes more of each lectin's binding sites or alters the binding site such that fewer molecules of lectin are required to initiate agglutination. A change in agglutination of erythrocytes using soybean agglutinin and peanut agglutinin occurred when cells were obtained from cattle infected with Eperythrozoon wenyoni. The results suggested that an alteration in erythrocyte membranes occurred as a result of this infection as manifested by the increased recognition of both the soybean agglutinin and peanut agglutinin receptor carbohydrates. A similar effect was indicated with erythrocytes obtained during an acute Anaplasma marginale infection; however, an ensuing reticulocytosis masked the effect, requiring the use of fluoresceinated lectins to verify that increased binding of each lectin occurred with infected cells when compared to normal cells.     

Alteration of cell surface carbohydrates associated with ordered and disordered proliferation of oral epithelia: a lectin histochemical study in oral leukoplakias, papillomas and carcinomas

Cell surface carbohydrates in healthy oral mucosa (n = 15), leukoplakias without (n = 48) and with (n = 62) dysplasia, oral papillomas (n = 6) and squamous cell carcinomas (SCCs) (n = 40) were examined using the lectins peanut agglutinin (PNA), Ulex europaeus agglutinin I (UEA I), soybean agglutinin (SBA), Helix pomatia agglutinin (HPA), and Griffonia simplicifolia agglutinin I (GS I-B4). Binding of these lectins in formalin-fixed, paraffin-embedded tissues was demonstrated using either the peroxidase-anti-peroxidase (PAP) method or the avidin-biotin method. Healthy oral epithelia revealed binding sites for these lectins mostly in the suprabasal keratinocytes with occasional PNA binding also in their basal cells. Unlike healthy mucosa, a number of leukoplakias without and with dysplasia revealed receptor sites for UEA I also in their basal layer. Only those keratinocytes undergoing squamoidal differentiation exhibited SBA binding. Staining patterns of UEA I and SBA did not vary significantly between either leukoplakias without and with dysplasia or papillomas and SCCs. Conversely, a reduction or lack of binding sites for PNA (Gal beta 1-3GalNAc), HPA (D-GalNAc alpha) and GS I-B4 (alpha D-Gal) was observed more frequently in leukoplakias with dysplasia and SCCs contrasting their counterparts lacking epithelial dysplasia. Cell surface glycosyl residues play an important role in the regulation of cell proliferation and epithelial growth. Aberrant glycosylation in oral dysplastic leukoplakias and carcinomas leading to the lack of the relevant terminal sugar residues from their cell surface carbohydrates is probably a major reason for the hyper-/disordered proliferation.     

Distribution of glycoconjugates in normal human skin using biotinyl lectins and avidin-horseradish peroxidase

Lectin binding patterns in normal human skin were studied using five different biotinyl lectins and avidin-horseradish peroxidase. The staining pattern was specific for each lectin. In the epidermis, peanut agglutinin (PNA) and soybean agglutinin (SBA) preferentially stained the cell membranes of keratinocytes in the spinous and granular cell layers, indicating changes in the saccharide residues during keratinocyte differentiation. In the secretory segment of an eccrine sweat gland, the superficial cells gave a strong granular staining with Ricinus communis agglutinin (RCA). Dolichos biflorus agglutinin (DBA) and SBA, on the other hand, strongly stained the basal cells. With these lectins, two types of cells in the secretory segment were clearly distinguished. These results show that (1) PNA and SBA binding sites increase during the course of keratinocyte differentiation, and (2) RCA, DBA, and SBA are good markers to distinguish two types of cells in the secretory segment of an eccrine sweat gland.     

On the importance of the binding of lectins to cell surface receptors at low lectin concentrations

The binding of soybean agglutinin to human and rabbit erythrocytes, before and after treatment with trypsin, was reinvestigated with special emphasis on measurements at very low lectin concentrations. This communication presents two features of the binding that are observed only at the low concentrations used. (1) The trypsinized erythrocytes bind more lectin molecules than untreated cells at low concentrations (0.1–1.0 μg/ml), even though the total number of binding sites appears to be the same for both treated and untreated cells. It is suggested that this difference could explain, at least in part, the much higher susceptibility of the trypsin-treated cells to agglutination by soybean agglutinin. (2) At low site occupancy the binding of soybean agglutinin exhibits positive cooperativity, indicating a conformational change in the membrane. Trypsin-treated cells exhibit this effect at much lower lectin concentrations than untreated cells.     

Carbohydrate determinants of organs of the reproductive tract of the mouse according to the results of using lectins with different specificities

Histotopography of lectin receptor sites in adult mice ovary, oviduct, uterus, testis and epididymis has been investigated on light-optic level by means of lectin-peroxidase technique. Paraffin sections are treated with peanut agglutinin (PNA), soybean agglutinin (SBA), wheat germ agglutinin (WGA) and Laburnum anagyroides lectin (LAL), conjugated with horseradish peroxidase. Concanavalin A (Con A) receptor sites are visualized by indirect method. The usefulness of lectins for selective histochemic evaluation of definite organ structures is demonstrated. Zona pellucida, luteocytes, oviductal and uterine epitheliocytes are rich in receptor sites for all lectin used in the investigation. The most intense binding to zonae pellucidae glycoconjugates possess WGA and LAL, to luteocytes--PNA, SBA and LAL, to oviductal and uterine epitheliocytes--Con A and LAL. The preferential SBA binding to the acrosomal system and plasma membranes of spermatogenic cells is demonstrated. Changes in lectin-binding patterns during the maturation of intraovarian oocytes and spermatogenic cells are also studied. The perspectives of practical application of the results obtained, as well as trends in further lectin histochemistry investigations of the reproductive system are discussed.     

Distinguishing benign from malignant pleural effusions by lectin immunocytochemistry

Since distinguishing malignant from benign cells in pleural effusions can be difficult, with reactive mesothelial cells simulating adenocarcinoma cells, the binding patterns of a battery of lectins on cells in eight benign and eight malignant effusions were studied using the avidin-biotin peroxidase complex method. The following lectins were used: concanavalin A, Dolichos biflorus agglutinin, peanut agglutinin, Phaseolus vulgaris agglutinin, Ricinus communis germ agglutinin, soybean agglutinin, Ulex europeaus agglutinin (UEA) and wheat germ agglutinin. Several patterns of staining were seen with the lectins, but only UEA was helpful in distinguishing between benign and malignant effusions. Sixty percent of the adenocarcinomas stained with UEA, whereas none of the cells in the benign effusions did. These results imply that UEA positivity is indicative of carcinoma and can be useful in separating reactive or atypical mesothelial cells from adenocarcinoma cells.     

Temporal changes in lectin binding of peri-implantation mouse blastocysts

Mouse blastocysts were exposed to a series of ferritin-conjugated lectins during Day 5 (preadhesive) and Day 6 (adhesive; collected Day 5, 24 hr in vitro) of embryogenesis to determine whether there were any changes in lectin binding characteristics that coincided with the acquisition of adhesiveness. After exposure to lectin, the blastocysts were processed for electron microscopy and lectin binding sites were determined by visualization of ferritin particles with the electron microscope. No binding sites were observed for either Dolichos biflorus agglutinin or soybean agglutinin on blastocysts from either stage examined. Binding sites for Ulex europaeus agglutinin, Con A, and wheat germ agglutinin were seen on blastocysts from both stages without apparent increase or reduction in binding sites from either stage. Ricinus communis agglutinin-I (RCA-I) bound heavily to the surface of Day 5 blastocysts and did not bind at all to $\text{3}\text{12}$ Day 6 blastocysts and did bind, though with apparent diminution, to $\text{9}\text{12}$ Day 6 blastocysts, as compared with the binding observed on Day 5 blastocysts. Peanut agglutinin (PNA) did not bind at all to Day 5 blastocysts but did bind heavily to the surface of Day 6 blastocysts. Both RCA-I and PNA bound to the surface of embryos during Day 5 of delayed implantation, thus indicating that neither the appearance of PNA binding sites on Day 6 blastocysts nor the apparent reduction of RCA-I binding sites on Day 6 blastocysts could be solely implicated in the acquisition of adhesiveness. PNA binding sites were abolished from the surface of Day 6 blastocysts by treatment with Pronase, indicating that the PNA binding molecule was associated with a glycoprotein rather than a glycolipid.     

Effect of trypsinization on lectin binding to germ cells from ICR and T/t6 mice

Flow cytometry was used to quantify the binding of fluorescein isothiocyanate (FITC)-labeled lectins to testis cells from ICR and T/t6 mice before and after trypsin treatment. Soybean agglutinin, wheat germ agglutinin, and concanavalin A bound well to testis cells of both mouse strains. Limax flavus agglutinin (LFA) bound very slightly and Ulex europeas agglutinin (UEA) did not bind at all. Trypsinization increased binding of soybean agglutinin and decreased binding of wheat germ agglutinin in both mouse strains, providing evidence for masked carbohydrate-binding sites on the surface of germ cells. It did not affect binding of the other lectins. Trypsin treatment was an attempt to increase lectin binding, particularly the binding of LFA and UEA to the reported T/t-specific carbohydrates, sialic acid, and L-fucose, respectively. These studies indicate that the T/t6 locus alleles do not alter the surface carbohydrate content of testis cells sufficiently to be detected by lectin-binding differences.     

Mechanical release and lectin labeling of maize root protoplasts

Summary An improved method for the mechanical release of protoplasts from plant tissues is described. The historically-low yield of mechanically-released protoplasts is greatly increased by use of a simple electrically-driven tissue sheer and by optimization of various other steps in the procedure. As counted by light microscopy of a purified preparation, the number of mechanically-released protoplasts obtained is about 6×10⁴ per gram fresh weight of cortical tissue from the primary root of maize (Zea mays L. WF9×Mo 17) seedlings. Nuclear staining of the preparation, however, shows that about half of these protoplasts lack a nucleus and thus are actually subprotoplasts. Comparison of lectin binding to the plasma membranes of mechanically-and enzymatically-released protoplasts shows that both types contain binding sites forRicinus communis agglutinin. Binding sites for peanut (Arachis hypogaea) agglutinin are not naturally present on mechanically-released protoplasts but are generated by exposure to a mixture of Cellulysin and Pectolyase Y-23, the cell wall-degrading enzymes used to prepare enzymatically-released protoplasts.Abbreviations BSA bovine serum albumin - DDT dithiothreitol - gfw gram fresh weight - Mes 2-(N-morpholino) ethanesulfonic acid - PNA peanut (Arachis hypogaea) agglutinin - RCA Ricinus communis agglutinin - Tris tris(hydroxymethyl)aminomethane     

Characterization by lectin binding of the sugar moiety of glycocompounds stored in inherited diseases

Summary Kidney and liver samples from two cases of Fabry's disease and spleen and liver samples from Gaucher and Niemann—Pick diseases were tested for binding to lectins such as peanut agglutinin (PNA),Bandeiraea simplicifolia, (BSA),canavalia ensiformis (Con A), soybean agglutinin (SBA) and wheat germ agglutinin (WGA) labelled with horseradish peroxidase using histochemical techniques. These techniques allowed the localization of compounds with -galactosyl residues in tissues from Fabry's disease. In tissues from the Gaucher and Niemann—Pick cases, the storage material was found to be more complex than expected, and some problems regarding the significance of lectin binding are discussed.     

Differentiated microdomains on the luminal surface of capillary endothelium: distribution of lectin receptors

Lectins conjugated with either peroxidase or ferritin were used to detect specific monosaccharide residues on the luminal front of he fenestrated endothelium in the capillaries of murine pancreas and intestinal mucosa. The lectins tested recognize, if accessible, the following residues: alpha-N-acetylgalactosaminyl (soybean lectin), beta- D-galactosyl (peanut agglutinin [PA] and Ricinus communis agglutinin- 120 [RCA]), beta-N-acetylglucosaminyl and sialyl residues (wheat germ agglutinin [WGA]), alpha-L-fucosyl (lotus tetragonolobus lectin), and alpha-D-glucosyl and beta-D-mannosyl (concanavalin A [ConA]). Thi labeled lectins were introduced by perfusion in situ after thoroughly flushing with phosphate-buffered saline the microvascular beds under investigation. Specimens were fixed by perfusion, and subsequently processed for peroxidase detection and electron microscopy. Control experiments included perfusion with: (a) unlabeled lectin before lectin conjugate; (b) labeled lectin together with the cognate hapten sugar, and (c) horseradish peroxidase or ferritin alone. Binding sites were found to be relatively homogeneously distributed on the plasmalemma proper, except for Lotus tetragonolobus lectin and Con A, which frequently bound in patches. Plasmalemmal vesicles, transendothelial channels, and their associated diaphragms were particularly rich in residues recognized by RCA and PA (beta-D-galactosyl residues) and by WGA (beta-N-acetylglucosaminyl residues). Receptors for all lectins tested appeared to be absent or considerably less concentrated on fenestral diaphragms. The results reported here extend and complement previous findings on the existence of microdomains generated by the preferential distribution of chemically different anionic sites (Simionescu et al., 1981, J. Cell Biol., 9:605-613 and 614-621).     

Effects of exogenous fatty acids on calcium uptake by brush-border membrane vesicles from rabbit small intestine

The uptake of a variety of fatty acids by isolated brush-border membranes from rabbit small intestine was studied. This uptake increased with acyl chain-length and was not diminished by washing of the lipid-treated membranes with 0.25 M CsBr. The binding of fatty acid was not accompanied by a decrease in endogenous acyl groups or of cholesterol and therefore corresponded to a net uptake accountable qualitatively and quantitatively by the fatty acid added to the membranes. The uptake of Ca2+ was stimulated by treatment of the membranes with low concentrations of unsaturated fatty acids (0.05 mM) as well as with various concentrations of caprylic acid (0.10-3.00 mM) and inhibited by treatment with higher concentrations of unsaturated fatty acids (0.20-0.60 mM). Saturated fatty acids had no marked effects on Ca2+ uptake. The stimulatory concentrations of unsaturated fatty acids did not change the Ca2+-binding characteristics of the membranes, whereas the higher concentrations decreased equilibrium binding of Ca2+ and very probably the number of high-affinity binding sites. The results of this study are assessed in terms of the effects of normal fatty acids found in the diet on the absorptive properties of the brush-border membranes.     

Ca2+ binding sites in plasma membranes of rat liver and hepatoma cells, and effect of concanavalin A on the Ca2+ binding sites and cellular uptake of Ca2+

1. Plasma membranes isolated from rat livers and ascites hepatoma cells (AH-130, AH-7974) were assayed for specific Ca2+ binding sites using 45Ca2+ and a Millipore filtration technique. The presence of higher (Kd = 1.4--1.5 . 10(-5) M) and lower (Kd = 0.9--1.0 . 10(-4) M) affinity sites in both liver and hepatoma membranes was observed. The hepatoma plasma membranes however, showed 1.4--2.1-fold as many Ca2+ binding sites (higher and lower affinity sites) as the liver plasma membranes on the basis of protein. 2. Concanavalin A stimulated the specific Ca2+ binding to liver and hepatoma plasma membranes, showing a maximal stimulation (3--5-fold) at 100 microgram/ml. Succinyl concanavalin A was less effective, whereas wheat germ agglutinin and ricinus lectin were ineffective. 3. Concanavalin A stimulated the Ca2+ uptake by AH-7974 cells. The concanavalin A-mediated stimulation of Ca2+ uptake showed lectin-concentrations and Ca2+-concentration dependencies similar to those in the concanavalin A-mediated stimulation of Ca2+ binding.     

Detection of acrosome-reacted toad sperm based on specific lectin binding to the inner acrosomal membrane

When the sperm of the toad Bufo japonicus were treated with fluorescein isothiocyanate (FITC)-conjugated peanut agglutinin (PNA), soybean agglutinin (SBA), or Dolichos biflorus agglutinin (DBA), a few sperm fluoresced at the acrosomal region. The number of sperm showing this lectin binding to the acrosome increased significantly upon mild sonication of the sperm suspension. Electron microscopy revealed that ferritin-conjugated PNA bind not to the outer acrosomal and overlying plasma membranes, but specifically to the surface of the inner acrosomal membrane exposed by sonication. Both the percentage of FITC-PNA-labeled sperm and the activity of vitelline coat lysin released by sperm increased in good correlation with increasing sonication time, although the PNA-labeled sperm decreased in number upon longer sonication. These results indicate that the binding of FITC-PNA to the sperm provides a reliable measure of the acrosome reaction of Bufo sperm.     

Decrease in human lymphocyte surface glycoconjugates in leukemia as demonstrated by lectin binding

Qualitative variations in the glycoconjugates which make up the lectin receptor sites on the membranes of leukemic lymphocytes, compared with those of normal cells, have been studied by the use of three tritiated lectins: Robinia pseudoacacia lectin, Concanavalin A and Ricinus communis (var. Sanquineus) agglutinin (RCA 120). The binding specificity of these lectins has been demonstrated using specific determinants: alpha-methylmannoside and galactose for Concanavalin A and Ricinus communis agglutinin respectively. For the Robinia lectin this specificity was determined by saturation of the receptor sites with the unlabeled Robinia lectin before the addition of isotopically labeled Robinia lectin. The results show a decrease in the number of receptor sites on the leukemia cells, especially in chronic lymphoid leukemia, relative to that on normal cells. The apparent affinity constants of leukemic cells in all cases remain higher than those of normal cells.     

An ultrastructural search for lectin-binding sites on surfaces of spinach leaf organelles

Organelles isolated from leaves of spinach (Spinacia oleracea L.) were prefixed in glutaraldehyde and then incubated with ferritin conjugates of four lectins — Concanavalin A (Con A), Ricinus communis L. agglutinin, MW 120,000 (RCA), soybean agglutinin (SBA), and wheat germ agglutinin (WGA) — in order to probe their cytoplasmic surfaces for saccharide residues. In each case the major leaf organelles, including microbodies, mitochondria and chloroplast derivatives, failed to exhibit labeling when examined with the electron microscope. Tobacco (Nicotiana tabacum L.) leaf protoplasts, incubated simultaneously with and under identical conditions to the spinach organelles, showed specific labeling of their plasma membranes with all four lectin conjugates, thus establishing the efficacy of the procedure for demonstrating the presence of binding sites when they exist. Further attempts to show binding of one of the lectins, Con A, by labeling with fluorescein-Con A and by organelle agglutination, yielded results consistent with the absence of ultrastructural labeling. It is concluded that no saccharide residues recognized by the four lectins are present on the cytoplasmic surfaces of organelles and that those residues reported to be constituents of intracellular membranes, therefore, are most likely exposed on the luminal (extracytoplasmic) surfaces.Abbreviations Con A Concanavalin A - RCA Ricinus communis agglutinin, MW 120,000 - SBA soybean agglutinin - WGA wheat germ agglutinin     

Endogenous lectin from cultured soybean cells: exposure of the SB-1 lectin on the cell wall

Digestion of seed soybean agglutinin with V-8 protease yielded seven distinct fragments (Mr 10,000-20,000) that were well-resolved by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. Each individual peptide (F1 through F7) was isolated; determination of the amino acid sequence at the NH2-terminal portion of each peptide established its position in the intact polypeptide of soybean agglutinin. The isolated peptides were used as affinity adsorbents to obtain antibodies that bound individual fragments (anti-F1 through anti-F7). These antibody preparations were, in turn, used in immunofluorescence staining of intact cultured soybean (SB-1) cells. Only those antibody preparations that bind to the NH2-terminal portion (residues 1-124) of the intact soybean agglutinin showed significant cell surface labeling. In contrast, the antibody preparations that bound to residues 125-253 failed to bind to intact SB-1 cells. These results suggest that the SB-1 lectin has the NH2-terminal portion of the polypeptide chain exposed and accessible at the cell surface, while the COOH-terminal portion of the same molecule may be masked, either through protein folding or through embedding in the cell wall. Limited digestion of the cell wall polysaccharides by cellulase or pectinase released the majority of the cell surface lectin.     

The use of streptavidin-biotinylglycans as a tool for characterization of oligosaccharide-binding specificity of lectin.

A new rapid and sensitive method for characterizing lectin specificity using streptavidin-biotinylglycans as a tool is presented. This assay is analogous to enzyme immunoassay and takes advantage of the strong, irreversible adsorption of streptavidin to the wells of the chambers of titer plates. A series of streptavidin-biotinylglycans was first coated on a microtiter plate, and then one of six lectins, concanavalin A, wheat germ agglutinin, Phaseolus vulgaris (red kidney bean) erythro-agglutinin, Lens culinaris (lentil) agglutinin, Datura stramoniun agglutinin, or Sambucus nigra (elderberry bark) agglutinin coupled to horseradish peroxidase, was added. After incubation and thorough washing, only the lectin bound to a complementary glycan remained and could be detected and quantified by the peroxidase reaction. It was established that the lectins retained their oligosaccharide-binding specificities after coupling to the peroxidase, that the binding was inhibited by addition of the corresponding sugar inhibitors, and that the color intensity produced by the enzyme reaction is proportional to the amount of lectin-peroxidase bound to biotinylglycan complexed with streptavidin immobilized on the plate. As an example, it was found that the peroxidase-D. stramoniun agglutinin conjugate strongly bound biotinylglycans, GlcNAc3-Man5-R, GalGlcNAc3Man5-R, and GlcNAc3-4Man3-R (R = GlcNAc2-[6-(biotinamido)hexanoyl]-Asn). As little as 10 pmol/ml of lectin was detected. With the growing availability of biotinylglycans, the method should represent a reliable and simple procedure for screening lectin-oligosaccharide recognition qualitatively and quantitatively.     

Identification of insulin receptors on the mucosal surface of colon epithelial cells

Brush-border membranes were isolated from the mucosal surface of rabbit proximal colon epithelial cells by a procedure involving Ca2+ precipitation. Ouabain-insensitive K+-phosphatase, a marker enzyme for the colon brush-border membrane, was enriched 17-fold by this technique, while no enrichment was observed in the activity of ouabain-sensitive K+-phosphatase, a marker for the basal-lateral membrane. Insulin binding studies revealed a dose-dependent inhibition of 125I-insulin binding with porcine insulin and approximately 4 X 10(-9) M insulin was required to produce 50% inhibition of 125I-insulin binding, while desoctapeptide insulin, insulin-like growth factor I, and A chain of insulin had less effect on 125I-insulin binding. This is the first demonstration of the existence of high-affinity insulin binding sites on the brush-border membrane of mammalian colon epithelial cells. Subsequent studies with the cross-linking agent disuccinimidyl suberate confirmed the presence of insulin binding sites in these membranes and autoradiography of polyacrylamide gels revealed that the binding subunit of the colon epithelial cell brush-border insulin receptor is similar in size to that observed in hepatic tissue. Interestingly, the insulin binding capacity/mg of protein of this preparation is high, suggesting that large numbers of insulin receptors are present in vivo on the mucosal surface of colon epithelial cells. The potential physiological role of these previously unrecognized insulin receptors is discussed.     

Alteration of cell surface carbohydrates associated with ordered and disordered proliferation of oral epithelia: a lectin histochemical study in oral leukoplakias, papillomas and carcinomas

Abstract. Cell surface carbohydrates in healthy oral mucosa (n = 15), leukoplakias without ( n = 48) and with (n = 62) dysplasia, oral papillomas (n = 6) and squamous cell carcinomas (SCCs) (n – 40) were examined using the lectins peanut agglutinin (PNA), Ulex europaeus agglutinin I (UEA I), soybean agglutinin (SBA), Helix pomatia agglutinin (HPA), and Griffonia simplicifolia agglutinin I (GS I-B₄). Binding of these lectins in formalin-fixed, paraffin-embedded tissues was demonstrated using either the peroxidase-anti-peroxidase (PAP) method or the avidin-biotin method. Healthy oral epithelia revealed binding sites for these lectins mostly in the suprabasal keratinocytes with occasional PNA binding also in their basal cells. Unlike healthy mucosa, a number of leukoplakias without and with dysplasia revealed receptor sites for UEA I also in their basal layer. Only those keratinocytes undergoing squamoidal differentiation exhibited SBA binding. Staining patterns of UEA I and SBA did not vary significantly between either leukoplakias without and with dysplasia or papillomas and SCCs. Conversely, a reduction or lack of binding sites for PNA (Galβl-3GalNAc), HPA (D-GalNAcα) and GS I-B₄ (αD-Gal) was observed more frequently in leukoplakias with dysplasia and SCCs contrasting their counterparts lacking epithelial dysplasia.
Cell surface glycosyl residues play an important role in the regulation of cell proliferation and epithelial growth. Aberrant glycosylation in oral dysplastic leukoplakias and carcinomas leading to the lack of the relevant terminal sugar residues from their cell surface carbohydrates is probably a major reason for the hyper-/ disordered proliferation.