Distribution of cell surface glycoconjugates during secondary neurulation in the chick embryo

Lectin histochemistry was used to examine the expression of cell surface glycoconjugates during secondary neurulation in chick embryos. Fourteen lectins were applied to serial sections of the caudal region of embryos at the various stages of tail bud development. The lectins Bandeiraea simplicifolia, Dolichos biflorus agglutinin, Phaseolus vulgaris leukoagglutinin, soybean agglutinin, Sophora japonica agglutinin, Ulex europaeus agglutinin and succinylated wheat germ agglutinin (sWGA) showed very light or no binding to the developing medullary cord of the tail bud. With the other lectins, staining occurred throughout the early tail bud and solid medullary cord. During cavitation, however, differential expression of cell surface glycoconjugates by different cell populations was observed. The lectins concanavalin A, Lens culinaris agglutinin, Pisum sativum agglutinin, Phaseolus vulgaris erythroagglutinin, Ricinus communis agglutinin and WGA showed basic similarities in the distribution of lectin binding. Of these, the binding pattern of WGA was the most striking. As the medullary cord cells were separating into central mesenchymal and peripheral epithelial populations, WGA bound preferentially to the epithelial cells and the notochord. The lectin PNA, however, became preferentially bound to the mesenchymal cells. Heavy staining by WGA (specific for N-acetylglucosamine and sialic acid) where sWGA staining (specific for N-acetylglucosamine only) was faint suggested that WGA binding was due to the presence of sialic acid containing glycoconjugates.     

Changes in glycoconjugate expression during early chick embryo development: a lectin-binding study.

A selection of lectins was used to investigate developmentally regulated changes in the distribution of cell surface oligosaccharides during the gastrulation and neurulation stages of early chick embryo development. Lectins from three specificity classes were used: glucose/mannose specificity (concanavalin A [Con A], Lens culinaris agglutinin [LCA], Pisum sativum agglutinin [PSA]); N-acetylglucosamine specificity (Lycopersicon esculentum agglutinin [LEA], wheat germ agglutinin [WGA], succinylated WGA [sWGA]); N-acetylgalactosamine/galactose specificity (Dolichos biflorus agglutinin [DBA], soybean agglutinin [SBA], Sophora japonica agglutinin [SJA], Bandeiraea (Griffonia) simplicifolia lectin I [BSL I], peanut agglutinin [PNA], Artocarpus integrifolia lectin [Jacalin], Ricinus communis agglutinin-1 [RCA-1], Erythrina cristagalli lectin [ECL]). At gastrulation stages, patterns of lectin binding could be distinguished in the epiblast, mesoderm, and endoderm cell layers. The primitive streak failed to bind any of the lectins, but LEA and WGA bound to the epiblast in regions lateral to the streak, indicating the loss of some glucosamine residues medially in preparation for the ingression movements of gastrulation. Several lectins showed marked binding to the mesoderm cells after their passage through the primitive streak; these were LCA, PSA, WGA, sWGA, BSL, and most particularly PNA. Therefore, the epithelial-mesenchymal transformation from epiblast to mesoderm at the primitive streak is accompanied by cell surface oligosaccharide changes in the epiblast and mesoderm that involve all classes of lectins including the PNA-binding sequence Gal beta 1-3GalNAc. Ultrastructurally, PNA was shown to bind extracellularly to matrix fibrils. Jacalin, having the same sugar specificity as PNA, but binding to serine/threonine linked chains rather than asparagine linked chains showed no binding to the mesoderm.(ABSTRACT TRUNCATED AT 250 WORDS)     

Changes in glycoconjugate expression during early chick embryo development: A lectin-binding study

A selection of lectins was used to investigate developmentally regulated changes in the distribution of cell surface oligosaccharides during the gastrulation and neurulation stages of early chick embryo development. Lectins from three specificity classes were used: glucose/mannose specificity (concanavalin A [Con A], Lens culinaris agglutinin [LCA], Pisum sativum agglutinin [PSA]); N-acetylglucosamine specificity (Lycopersicon esculentum agglutinin [LEA], wheat germ agglutinin [WGA], succinylated WGA [sWGA]); N-acetylgalactosamine/galactose specificity (Dolichos biflorus agglutinin [DBA], soybean agglutinin [SBA], Sophora japonica agglutinin [SJA], Bandeiraea (Griffonia) simplicifolia lectin I [BSL I], peanut agglutinin [PNA], Artocarpus integrifolia lectin [Jacalin], Ricinus communis agglutinin-1 [RCA-1], Erythrina cristagalli lectin [ECL]). At gastrulation stages, patterns of lectin binding could be distinguished in the epiblast, mesoderm, and endoderm cell layers. The primitive streak failed to bind any of the lectins, but LEA and WGA bound to the epiblast in regions lateral to the streak, indicating the loss of some glucosamine residues medially in preparation for the ingression movements of gastrulation. Several lectins showed marked binding to the mesoderm cells after their passage through the primitive streak; these were LCA, PSA, WGA, sWGA, BSL, and most particularly PNA. Therefore, the epithelial-mesenchymal transformation from epiblast to mesoderm at the primitive streak is accompanied by cell surface oligosaccharide changes in the epiblast and mesoderm that involve all classes of lectins including the PNA-binding sequence Galβ1-3GalNAc. Ultrastructurally, PNA was shown to bind extracellularly to matrix fibrils. Jacalin, having the same sugar specificity as PNA, but binding to serine/threonine linked chains rather than asparagine linked chains showed no binding to the mesoderm. The endoderm layer most clearly bound WGA and BSL. At neurulation stages, medio-lateral domains in the ectoderm could again be demonstrated. Neural plate cells bound only PNA, although the hinge point of the neural plate, the future floor plate, failed to bind PNA unless pre-treated with neuraminidase to remove sialic acid residues. Caudally, where the primitive streak persisted, all mesoderm cells reacted very strongly with PNA, but rostrally this binding became more restricted to the mesodermal regions immediately adjacent to the streak. This mesodermal PNA-binding was abolished by hyaluronidase pre-treatment, suggesting extracellular matrix association, whereas the neural plate binding was unaffected by this treatment, suggesting a more intimate developmentally regulated association with the cell surface of early neural cells. Neuraminidase treatment and sWGA-binding indicated patterns of sialylation on cells of several tissues at the later stages of development. These sialic acid residues had the effect of masking both PNA and ECL reactivity. The latter, specific for sequences of the poly-N-lactosamine series, (Galβ1-4GlcNAc)_n, bound to mesoderm only after removal of sialic acids. Basement membranes bound lectins of glucose/mannose and galactose specificities at both stages, and RCA-binding was localized ultrastructurally to the fibronectin-rich interstitial bodies of the lamina densa.     

Lectin binding by Giardia lamblia.

Surface carbohydrates of Giardia lamblia were examined using six plant lectins chosen because of their specificity for major carbohydrates moieties. The binding to axenically grown G. lamblia trophozoites was assessed in both a quantitative microagglutination assay and a fluorescence assay. Of the six lectins tested, wheat germ agglutinin (WGA) agglutinated the highest percentage (22.9 +/- 3.7%) of live trophozoites, and fluorescein-labeled WGA (100 micrograms/ml) bound to 98 +/- 5% of them. Since the carbohydrate specificity of WGA includes both N-acetyl-D-glucosamine (GlcNAc) and sialic acid, inhibition experiments were performed. GlcNAc inhibited he binding of WGA to G. lamblia in both assays to a greater extent than did sialic acid. Binding of WGA was not altered by prior treatment of trophozoites with neuraminidase, suggesting that WGA was binding to GlcNAc moieties on G. lamblia and not to sialic acid. The remaining five lectins either bound nonspecifically or exhibited low percentages of binding. The apparent presence of GlcNAc but not sialic acid or other exposed surface carbohydrates may be important in the interaction of G. lamblia with its human host.     

Interaction of lectins with human IgE: IgE-binding property and histamine-releasing activity of twelve plant lectins.

We examined the IgE-binding reaction and the histamine-releasing response of basophils to a panel of 12 lectins: concanavalin A (Con A), Lens culinaris hemagglutinin (LcH), Pisum sativum agglutinin (PSA), wheat germ agglutinin (WGA), soybean agglutinin (SBA), Bauhinia purpurea agglutinin (BPA), peanut agglutinin (PNA), Ricinus communis agglutinin I (RCA-I), Lotus tetragonolobus agglutinin (Lotus A), Ulex europeus agglutinin I (UEA-I), phytohemagglutinin E (PHA-E) and phytohemagglutinin L (PHA-L), IgE from allergic patients bound with high affinity to Con A, LcH, PSA, RCA-I and PHA-E, and with lower affinity to WGA, BPA, Lotus A and UEA-I, but they did not bind to SBA, PNA or PHA-L. There was no apparent individual difference in the reactivity of IgE to these lectins between 10 IgE preparations from allergic patients. The binding to these lectins, except Lotus A and UEA-I, were competitively inhibited by the lectin-specific sugars or glycopeptide. Upon stimulation by Con A, LcH, PSA, WGA, RCA-1 and PHA-E, leukocytes from allergic patients showed a significant release of histamine, but cells from IgE-deficient subjects did not respond to these lectins. The histamine-releasing responses by these lectins were also inhibited by specific sugars or glycopeptides.     

Glycoconjugate expression in the chick embryonic chorioallantoic membrane: Comparisons of the chorionic ectoderm and allantoic endoderm

Background: The chorioallantoic membrne (CAM) of the chick embryo expands during embryogenesis to meet the increased oxygen demands during growth and differentiation. Temporal and spatial glycosylation patterns of CAM ectodermal and endodermal proteins likely contribute to differentiation of the functional attributes of the CAM. Methods: Using lectins for light and electron microscopic observations, we studied the patterns of glycoconjugate expression on the ectoderm and endoderm of the chorioallantoic membrane (CAM) of the chick at days 4.5, 5.0, 6.0, and 10 of morphogenesis. For light microscopy, samples of unfixed CAM were incubated with the following FITC lectins: Con A, DBA, GSA-I, GSA-II, PNA, SBA, UEA-I, and WGA. Results: All lectins, except GSA-I and -II, gave positive results. The positive lectins, labeled with HRP, served to ultrastructurally localize PNA, SBA, and WGA, but not DBA binding to the luminal surface of the endoderm. UEA-I and Con A bound similarly except on day 10 when UEA-I no longer bound. On the ectodermal surface, only WGA bound at all times studied. PNA and SBA binding were present from days 5.0 to 6.0 but absent at days 4.5 and 10. DBA binding occurred through day 5.0 but was absent thereafter. UEA-I bound to the ectoderm at days 4.5, 5.0, and 10 but not days 5.5 and 6.0 Con A bound only on days 5.0 and 10. Conclusion: That the ultrastructurally similar ectoderm and endoderm of the CAM display functional differences conforms to the hypothesis that differential expression of glycoconjugate microdoains likely contributes to such functional specialization. © 1995 Wiley-Liss, Inc.     

Lectin-binding patterns of small lymphocytes in bone marrow,thymus and spleen: demonstration of lymphocyte subsets by quantitative radioautography

Cells from mouse bone marrow, thymus and spleen were exposed to ¹²⁵I-labeled concanavalin A (Con A), Lens culinaris lectin (LCL), soybean agglutinin (SBA), Helix pomatia agglutinin (HPA), phytohemagglutinin-P (PHA-P), peanut agglutinin (PNA), or wheat germ agglutinin (WGA) in a range of concentrations and examined radioautographically. Small lymphocytes in the three organs differed in the minimal concentration of each lectin which gave detectable surface labeling, while at optimal lectin concentrations, their labeling intensity profiles differed markedly. Inhibition by sugars demonstrated the labeling specificity. Major populations of bone marrow small lymphocytes bound WGA strongly, while Con A, SBA, HPA, PHA-P and LCL were bound only weakly, and PNA binding was lacking. Most thymus cells bound Con A, SBA, HPA, PHA-P and PNA strongly, WGA and LCL weakly. Subsets of bone marrow and thymus small lymphocytes differed from the major populations in their lectin-binding intensities. Spleen small lymphocytes were heterogeneous in the binding of each lectin. However, a major population bound LCL exceptionally strongly, while few cells bound PNA. Using a panel of lectins under standardized conditions, these studies show distinctive lectin-binding patterns for small lymphocytes in the bone marrow, thymus and spleen, respectively. Major and minor cell populations are distinguishable in each organ, providing an approach to discriminating lymphocyte lineages, subtypes and differentiation stages.     

Lectin histochemistry of palatine glands in the developing rat

This study examined the binding pattern of lectins, soybean agglutinin (SBA), Dolichos biflorus agglutinin (DBA), Vicia villosa agglutinin (VVA), Ulex europaeus agglutinin-I (UEA-I), peanut agglutinin (PNA), wheat germ agglutinin (WGA), and succinylated WGA (sucWGA) in the developing rat palatine glands. In adult rats, heterogeneous lectin binding patterns were revealed between the anterior and posterior portions of palatine glands, as DBA, VVA, and WGA were bound more intensely and broadly in the posterior portion. SBA, PNA, and sucWGA showed far less reactivity in the anterior than in the posterior portion. At embryonic day 18 (E18), weak labeling was observed with UEA-I and WGA at the basal membrane of terminal buds, UEA-I and PNA labeled the epithelial cord, and there was no apparent binding for SBA, DBA, VVA, and sucWGA. At E20, after acinar lumenization, all lectins were detected at the acinar cell basal membranes. After birth, all lectins detectably labeled at the mucous cell apical membranes and progressively, with maturation, extended from the apical to basal portions of the cytoplasm. Apparent serous cells were observed around postnatal day 10 (PN10) and bound UEA-I. Lectins reached peak reactivity at PN21 and the binding patterns became identical to those of adults around PN28.     

Lectin binding studies on adult filariae,intrauterine developing stages and microfilariae of Brugia malayi and Litomosoides carinii

Sections of macrofilariae of Brugia malayi and Litomosoides carinii revealed binding of the gold-labelled lectins WGA, DBA and PNA. Specificity of binding was controlled by competitive inhibition with the respective sugars. N-acetylglucosamine, N-acetylgalactosamine and galactose residues seem to be present in the respective tissues. The lectins were bound preferentially to parts of the reproductive organs and to the fluid contents of their lumina. The results of the chitosan test and binding experiments with WGA-gold conjugate suggest the presence of chitin in the sheath of oocytes or zygotes. Binding of WGA could not be inhibited with 0.5 M N-acetylglucosamine, but only with 10 mM triacetyl chitotriose. In older stages, binding of WGA to the sheath could be inhibited by 0.5 M N-acetylglucosamine. In mature microfilariae, the outer surface of the sheath did not show affinity for WGA, but small amounts were bound to the inner surface. Therefore, the sheath of later developmental stages and microfilariae does not contain chitin but only N-acetylglucosamine residues. The degradation of the chitin content might enable the elongation and flexibility of the sheath of microfilariae.Supported by WHO/OCT-Project number 85011     

Differences in lectin binding of malignant pleural mesothelioma and adenocarcinoma of the lung.

In order to differentiate between malignant pleural mesothelioma and adenocarcinoma of the lung, the glycoconjugate profiles of 6 reactive mesothelial lesions, 23 mesotheliomas (17 epithelial, 1 desmoplastic, 2 biphasic, and 3 fibrous types), and 28 well-differentiated pulmonary adenocarcinomas were evaluated with the use of 8 lectins in addition to anti-carcinoembryonic, anti-keratin and anti-epithelial membrane antigen. Formalin-fixed, paraffin-embedded tissues were stained with the avidin-biotin peroxidase complex method. Reactions of wheat germ (WGA) and peanut (PNA) agglutinin with neuraminidase treatment lectins were positive in 5 of 6 (83%) and 3 of 6 (50%) cases, respectively, in reactive mesothelial lesions. Thirteen of 23 (57%) malignant mesotheliomas of the pleura showed a positive reaction for WGA and PNA with neuraminidase treatment; other lectins were low-positive, below 9%. In contrast, pulmonary adenocarcinomas showed positive reactions in 27 of 28 cases (96%) for PNA, 26 of 28 (93%) for Ricinus communis (RCA-I), 25 of 28 (89%) for WGA, and 22 of 28 (79%) for succinylated WGA (SucWGA). The findings suggest that malignant pleural mesothelioma and pulmonary adenocarcinoma have consistent and distinct glycoconjugate profiles, and that stains for RCA-I and SucWGA may be useful for differential diagnosis.     

An immunofluorescent analysis of lectin binding to normal and regenerating skeletal muscle of rat

Ten different fluorescein-conjugated lectins of various known sugar specificities were used to study cell surface glycoconjugates of normal and regenerating rat skeletal muscle. In normal muscle, Canavalia ensiformis agglutinin, Triticum vulgaris agglutinin (wheat germ agglutinin, WGA), Ricinus communis agglutinin-I, and Maclura pomifera agglutinin bound strongly to the endomysial region of the myofibers. No binding was observed in the cytoplasm of the myofibers. Other lectins (Dolichos biflorus agglutinin, Griffonia simplifolia agglutinin I and II, Ulex europaeus agglutinin, Arachis hypogaea agglutinin, Glycine max agglutinin) bound very poorly or not at all in the normal muscle. Skeletal muscle degeneration and regeneration was induced by autotransplantation of the extensor digitorum longus muscle. In the transplanted muscles, the endomysial lectin binding of the degenerating myofibers became weak and lacked continuity, indicating a breakdown of the endomysium. Of all the lectins tested, only WGA revealed intense binding in the myogenic zone of regenerating muscle. As the regeneration progressed, this WGA binding became restricted to the new endomysium. In completely regenerated muscle, binding of all lectins was similar to that seen in normal muscle. The specific binding of WGA to the myogenic zone may be important in identifying factors or glycoconjugates, which constitute a favorable environment for skeletal muscle regeneration.     

Expression of glycoconjugates on normally developing and immunologically impairedHymenolepis diminuta

The carbohydrates on the surface ofHymenolepis diminuta were analyzed with gold-labelled lectins, and it was found that the surface coat of the anterior body differs from that of the strobila in its lectin-binding properties. Binding sites for lectins fromAbrus precatorius (APA),Arachis hypogaea (PNA),Glycine max (SBA) and for wheat germ agglutinin (WGA) and succinylated WGA were located on the scolex and strobilation zone. Lectin-gold particles attached mainly to the electron-dense spines. The surface coat may therefore expose sugar residues of theN-acetylglucosamine and galactose types. In contrast, the strobila had few binding sites for the above-mentioned lectins but bound concanavalin A (ConA). Lectins fromDolichos biflorus (DBA) andUlex europaeus (UEA-I) were not bound toH. diminuta. In juvenile worms from rats, the extension of the WGA- and SBA-positive region of the strobilation zone increased in length with the development of the worms. Lectin binding in juveniles from mice was similar when the mice had been immunosuppressed with cortisone. After the onset of the immune defense againstH. diminuta in nontreated mice, a moderate expression of lectin-binding substance also occurred on the strobila. Destrobilated worms were entirely covered with theN-acetylglucosamine- and galactose-containing glycoconjugates, and it is suggested that these worm remnants correspond to the lectin-binding part of normal, growing juveniles. The presence of the carbohydrates is discussed with respect to the relative resistance of the scolex-strobilation zone ofH. diminuta to immune rejection.     

Lectins binding on human sperm surface increase membrane permeability and stimulate acrosomal exocytosis

Cross-linked complexes formed between certain lectins and theirspecific multivalent carbohydrates and glycoconjugates on thesperm surface were studied for their ability to modify spermmembrane permeability and to induce the acrosome reaction. Wheatgerm agglutinin (WGA), concanavalin A (Con A) and peanut agglutinin(PNA) increased the proportions of human spermatozoa permeableto the impermeable propidium iodide (31.9 compared with 13.8%,38.4 compared with 18.4% and 72.7 compared with 18.9% respectively).Removal of sperm surface sialic acid by neuraminidase treatmentwas a prerequisite for Con A and PNA binding to the sperm surface.The percentage of permeable and acrosome-reacted spermatozoawas not affected by sperm treatment with 500 mlU/ml Arthrobacterureafaciens neuraminidase. WGA did not induce the acrosome reaction,whereas PNA induced the acrosome reaction regardless of thesperm capacitation status, allowing the proportion of acrosome-reactedspermatozoa to reach 27.7% of capacitated spermatozoa. However,the ability of Con A to induce the acrosome reaction was limitedto uncapacitated spermatozoa. To test the physiological relevanceof this study, uncapacitated human spermatozoa were incubatedwith human zonae pellucidae and the permeability of spermatozoabound to the zona surface was analysed according to the timepost-insemination. Two-thirds of spermatozoa bound to zona pellucidabecame permeable to propidium iodide in the first 30 min post-inseminationand almost all bound spermatozoa became permeable to the impermeabledye after 60 min. Our results show that molecular interactionsbetween human zona pellucida and sperm surface increase thepermeability of sperm membranes; the cross-linked complexesformed by PNA lectin and its specific multivalent carbohydratesand glycoconjugates on the sperm surface were also able to increasesperm membrane permeability and to induce the acrosome reaction.These results suggest a role for the saccharide moieties ofsperm surface glycoconjugates in the induction of the acrosomereaction. acrosome reaction/capacitation/lectins/peanut agglutinin/receptor aggregation     

Conjunctival cell glycoprotein pattern of healthy persons and of patients with primary Sj?gren's syndrome--light microscopical investigation using lectin probes

Formalin-fixed biopsies of conjunctival tissue from the lower fornix of 10 healthy persons and of 10 patients with primary Sj?gren's syndrome (primary SS) were examined by light microscopy. Deparaffinized, rehydrated sections of 5 microns were incubated overnight, each with one of 15 different biotinylated lectins. Bound lectins were visualized using avidin-HRP-substrate complexes. Five lectins did not bind to conjunctival cells, and further six lectins bound in an unspecific manner to conjunctival cells of both healthy persons and of primary SS patients. Jacalin lectin bound selectively to goblet cells of all specimens. Peanut agglutinin (PNA) and wheat germ agglutinin (WGA) bound significantly stronger to basal conjunctival epithelial cells of patients with primary SS. This binding pattern may be of diagnostic value.     

Carbohydrate profiling of fungal cell wall surface glycoconjugates of Aspergillus species in brain and lung tissues using lectin histochemistry

The aim of this study was to evaluate, through lectin histochemistry, the expression of N-acetyl-D-glucosamine, L-fucose, D-galactose and glucose/mannose on the cell wall surfaces of Aspergillus species in histopathological specimens of brain (n = 1) and lung (n = 6) tissues obtained during autopsy of patients diagnosed postmortem as having had invasive aspergillosis. Concanavalin A (Con A), wheat germ agglutinin (WGA), Ulex europeus agglutinin I (UEA-I) and peanut agglutinin (PNA), all conjugated with horseradish peroxidase, were employed. Lectin-binding was visualized using 3,3-diaminobendizine (DAB) and hydrogen peroxide in phosphate buffer solution (PBS). We observed expression of N-acetyl-D-glucosamine and methyl-α-D-mannoside on the cell wall surfaces of all evaluated Aspergillus species, while the expression of L-fucose and D-galactose demonstrated inter and intra-specific variations. The results obtained from this study indicate that the use of WGA and Con A lectins permits visualization of Aspergillus structures such as hyphae, conidial heads and conidia in histopathological specimens of brain and lung tissues.     

Biorecognition of HPMA copolymer-lectin conjugates as an indicator of differentiation of cell-surface glycoproteins in development, maturation, and diseases of human and rodent gastrointestinal tissues

Lectins are proteins that bind glycoproteins; binding patterns are altered with changes in glycoprotein expression accompanying maturation or disease. Binding of two lectins, wheat germ agglutinin (WGA) and peanut agglutinin (PNA), in human and rodent colon were previously examined. Normal tissue showed intense WGA binding; PNA binding was minimal. Diseased tissues showed increased PNA binding. We hypothesized that N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer-lectin-drug conjugates could deliver therapeutic agents to diseased tissues by targeting colonic glycoproteins. We examined biorecognition of free and HPMA copolymer-conjugated WGA and PNA and anti-Thomsen-Friedenreich (TF) antigen antibody binding in normal neonatal, adult, and diseased rodent tissues, human specimens of inflammation, and Barrett's esophagus. Neonatal WGA binding was comparable to the adult, with additional luminal columnar cell binding. PNA binding was more prevalent; luminal columnar cell binding existed during the first 2.5 weeks of life. WGA binding was strong in both normal and diseased adult tissues; a slight decrease was noted in disease. PNA binding was minimal in normal tissues; increases were seen in disease. Anti-TF antigen antibody studies showed that PNA did not bind to the antigen. The results suggest that HPMA copolymer-lectin-drug conjugates may provide site-specific treatment of conditions such as colitis and Barrett's esophagus.     

The Binding of Different Lectins on Peripheral Blood Mononuclear Cells from Patients with Chronic Inflammatory and Malignant Diseases

Peripheral blood mononuclear cells from patients with multiple myeloma, gastrointestinal tumors, and inflammatory bowel disease were analyzed for binding of various lectins. The results demonstrated that in most of the patients with multiple myeloma a significantly increased percentage of cells positive for Lotus tetragonolobus agglutinin (LTA), peanut agglutinin (PNA), soybean agglutinin (SBA), and wheat germ agglutinin (WGA), and a decreased number of Agaricus bisporus agglutinin (ABA) positive cells were present as compared to a normal control group. This could not be shown in malignant or inflammatory disorders of the gastrointestinal tract where only some patients exhibited an increased PNA and LTA binding, respectively. Patients with the systemic malignant disease differed from patients with solid localized tumors by a significantly altered number of ABA, LTA and SBA-positive peripheral blood mononuclear cells. Double fluorescence studies using monoclonal antibodies and lectins revealed that most of the cells expressing receptors for ABA had also receptors for OKT3, whereas most of the cells with receptors for LTA, PNA SBA, and WGA were found to be positive for OKM.     

Developmental changes affecting lectin binding in the vomeronasal organ of domestic pigs, Sus scrofa

This study investigated the developmental changes of glycoconjugate patterns in the porcine vomeronasal organs (VNOs) and associated glands (Jacobson's glands) from prenatal (9 weeks of gestation) and postnatal (2 days after birth) to the sexually mature stage (6 months old). The VNO of pigs (Sus scrofa) was examined using the following: Dolichos biflorus agglutinin (DBA), Bandeiraea simplicifolia agglutinin isolectin B4 (BSI-B4), Triticum vulgaris agglutinin (WGA), Ulex europaeus agglutinin I (UEA-I), and soybean agglutinin (SBA). At the fetal stage, all lectins examined were detected mainly in the free border of the vomeronasal epithelium, but few (WGA and UEA-I) and or absent in the VNO cell bodies. At the postnatal and sexually mature stages, the reactivity of some lectins, including WGA, UEA-I, DBA and SBA, were shown to increase in the VNO sensory epithelium as well as the free border. The increased reactivity of lectins as development progressed was also observed in Jacobson's gland acini. These findings suggest that binding sites of lectins, including those of WGA, UEA-I, DBA, and SBA, increase during development from fetal to postnatal growth, possibly contributing to the increased ability of chemoreception in the pig.     

Surface carbohydrates of procyclic forms of African trypanosomes studied using fluorescence activated cell sorter analysis and agglutination with lectins

Living culture form procyclics of Trypanosoma brucei brucei, T.b. rhodesiense, T.b. gambiense, T. congolense and T. simiae were tested for binding of eight different lectins. The binding of fluorescein isothiocyanate (FITC)-conjugated lectins was measured using a fluorescence activated cell sorter (FACS) and by agglutination with unlabelled lectins. Five of the lectins failed to bind to any of the procyclic organisms in both tests. All parasites bound concanavalin A (Con A) and all T.b. brucei, T.b. rhodesiense and T. congolense procyclics bound Ricinus communis agglutinin 120 (RCA) and wheat germ agglutinin (WGA). Trypanosoma b. gambiense procyclics failed to bind RCA and thus could be easily discriminated from other subspecies of T. brucei. Similarly, T. simiae did not bind WGA, unlike T. congolense, the other species of the genus Nannomonas. All positive reactions were inhibited by 0.2 M concentrations of the relevant sugars. The results indicate that all species and subspecies of the procyclic culture forms tested have surface-exposed structures resembling alpha-D-mannose moieties and that T.b. brucei, T.b. rhodesiense and T. congolense have surface-exposed molecules resembling D-galactose and N-acetyl D-glucosamine (or sialic acid) moieties. Molecules resembling D-galactose and N-acetyl D-glucosamine residues are absent or inaccessible in T.b. gambiense and T. simiae respectively. A group of T. congolense clones of parasite stocks isolated at Kilifi on the Kenyan coast showed quantitatively different binding of RCA when compared to the other T. congolense clones tested indicating that these organisms differ in surface carbohydrate structure.     

Distribution of lectin receptors in postimplantation mouse embryos at 6–8 days gestation

We have examined the pattern of binding of eleven lectins—BSL-II, WGA, LPA, Con A, DBA, SBA, LTA, UEA-I, MPA, PNA, and RCA-I, with specificity for a range of saccharides, to postimplantation mouse embryos from 6 to 8 days of gestation. The lectins were used to stain sections of ethanol-fixed paraffin-embedded and formaldehyde-fixed gelatin-embedded embryonic material. Our observations reveal a complex pattern of lectin binding to both cell surfaces and cytoplasm. Many of the lectins bind particularly to the outer surface of visceral endoderm (e.g., DBA, WGA, SBA, and RCA-I) and to the surface of the proamniotic cavity (e.g., RCA-I, PNA, and WGA). In the newly formed mesenchyme of primitive-streak-stage embryos, galactose and N-Acneuraminic acid are present but lectins with specificity for other sugars either did not bind to the cells or bound only in small amounts.