Lectin histochemistry of rainbow trout (Oncorhynchus mykiss) gill and skin

In order to characterize the glycoconjugate residues in skin and gills of the adult rainbow trout, the binding pattern of five biotinylated lectins with different carbohydrate specificities was examined. In the skin, mucous cells revealed binding sites for PNA and SBA; filament-containing cells were additionally labelled with Con A. However, the basal cell layer showed no reaction. In the gill, subpopulations of mucous cells reacted with Con A, PNA, SBA and UEA-I. This broader spectrum of glycoconjugates in gill mucous cells compared with the epidermal mucous cells could point to the additional function of gill mucus in ion and osmoregulation. Lectin binding sites were less common in the respiratory epithelial cells of the secondary lamellae than in those of the primary lamellae. Chloride cells revealed mannose, galactose and fucose residues. Immature chloride cells, as indicated by a comparison with Na⁺/K⁺ ATPase immunolabelling, reacted with Con A; subpopulations of them reacted with PNA, SBA and UEA-I. The results form the basis for further investigations in which these cell populations can be analysed under different environmental conditions     

Eosinophilic globule cells in mouse MFH-like sarcomas: lectin histochemistry.

Lectin binding patterns in ten mouse malignant fibrous histiocytoma (MFH)-like sarcomas containing eosinophilic globule (EG) cells and in granular metrial gland (GMG) cells of mouse placenta were stained with nine lectins (Con A, LCA, WGA, DBA, SBA, e-PHA, PNA, RCA-I and UEA-I) by an avidin-biotin-peroxidase-complex method. EG cells stained strongly with DBA, SBA and PNA which are specific for N-acetyl-D-galactosamine and/or D-galactose. DBA and SBA bound throughout the cytoplasm including the globules; PNA reacted preferentially at the cell surface. There was no evidence that these three lectins were reactive for immature EG cells. WGA, RCA-I and e-PHA also gave a slightly to moderately positive reaction to globules of EG cells. The results indicate that the globules contain abundant O-linked sequences of sugars, but also a few N-linked residues. MFH tumor cells showed a variable degree of binding with Con A, RCA-I, and WGA, but did not react with DBA, SBA and PNA. On the other hand, GMG cells exhibited specific affinities for DBA, SBA and PNA with staining patterns similar to those of EG cells. These findings suggest that EG and GMG cells may be of the same cellular lineage.     

Light microscopic characterization of glycoconjugates in secretory cells of the carp (Cyprinus carpio) gill epithelium

Secretory products of granular and mucous cells in the gill epithelium of the carp, Cyprinus carpio, were distinguished by their cytochemical reactions with peroxidase-labelled lectins and with the galactose oxidase (GO)-Schiff reagents. Secretory products of granular cells reacted with lectins from Triticum vulgaris (WGA), Arachis hypogaea (PNA), Dolichos biflorus (DBA), Glycine max (SAB), and Lotus tetragonolobus (LTA). They also reacted with GO-Schiff reagents. After sialic acid cleavage with HCl, new binding sites for DBA and SBA appeared, suggesting the terminal sequence sialic acid-N-acetylgalactosamine (SA-GalNAc) for the secretion of this cell type. In mucous cells, binding sites for WGA, DBA, and SBA and, after acid hydrolysis, binding sites for PNA and a positive GO-Schiff reaction were detected. The terminal trisaccharide sialic acid-galactose (beta 1-3)-N-acetylgalactosamine (SA-Gal-GalNAc) is proposed for the secretion of mucous cells. These cytochemical differences are discussed in light of the involvement of both cell types in fish mucus elaboration.     

Light microscopic characterization of glycoconjugates in secretory cells of the carp (Cyprinus carpio) gill epithelium

Summary Secretory products of granular and mucous cells in the gill epithelium of the carp, Cyprinus carpio, were distinguished by their cytochemical reactions with peroxidase-labelled lectins and with the galactose oxidase (GO)-Schiff reagents. Secretory products of granular cells reacted with lectins from Triticum vulgaris (WGA), Arachis hypogaea (PNA), Dolichos biflorus (DBA), Glycine max (SAB), and Lotus tetragonolobus (LTA). They also reacted with GO-Schiff reagents. After sialic acid cleavage with HCl, new binding sites for DBA and SBA appeared, suggesting the terminal sequence sialic acid-N-acetylgalactosamine (SA-GalNAc) for the secretion of this cell type. In mucous cells, binding sites for WGA, DBA, and SBA and, after acid hydrolysis, binding sites for PNA and a positive GO-Schiff reaction were detected. The terminal trisaccharide sialic acid-galactose (1-3)-N-acetylgalactosamine (SA-Gal-GalNAc) is proposed for the secretion of mucuous cells. These cytochemical differences are discussed in light of the involvement of both cell types in fish mucus elaboration.     

Histochemical study of rabbit duodenal mucosa carried out using lectins

The Authors report histochemical findings about rabbit's duodenal mucosa. The present study has been carried out using five different lectins (Peanut Agglutinin (PNA), Dolichos Biflorus Agglutinin (DBA), Wheat Germ Agglutinin (WGA), Soybean Agglutinin (SBA), Ulex Europaeus Agglutinin I (UEA-I). These lectins have been labelled with Horseradish Peroxidase and binding sites have been stained with 3-3' Diaminobenzidine, according to Farragiana et al. The PNA reacted with the glandular cells, while the reaction was negative in the superficial cells. The DBA reacted exclusively with the glandular cells. The superficial and the glandular cells showed strong positive binding sites to the WGA and slight positive binding sites to the SBA. The UEA-I did not react with the epithelial cells. The presence of binding sites for the lectins we have used in the present study, shows a different glycoprotein composition of the cellular secretion, in comparison with the other animals we have already studied. In addition, these lectins can not be used as cellular differentiation markers in the epithelial cells of the rabbit's duodenal mucosa.     

Lectin histochemistry of epidermal glandular cells in the earthworm Lumbricus terrestris (Annelida Oligochaeta)

Carbohydrate residues were localized in the glandular cells of the epidermis of Lumbricus terrestris by lectin histochemistry. The following biotinylated lectins were used: ConA, PNA, WGA, UEA-I. Each lectin has a specific binding pattern in the epidermal glandular cells. The ConA binding is evident in the orthochromatic mucous cells; PNA in the metachromatic mucous cells; WGA in the neuroendocrine-like cells; UEA-I in the cuticle. The epidermal glandular cells possess specific sites for the different lectins in relation to their functional characteristics. Therefore, these sugar residues indicate different behaviours of the cells in epidermal functions related to ion transport, receptor-secretory processes and defence.     

Changes in lectin-binding pattern in the digestive tract of Xenopus laevis during metamorphosis. I. Gastric region.

The distribution of structural and secretory glycoconjugates in the gastric region of metamorphosing Xenopus laevis was studied by the avidin-biotin-peroxidase (ABC) histochemical staining method using seven lectins (concanavalin A, Con A; Dolichos biflorus agglutinin, DBA; peanut agglutinin, PNA; Ricinus communis agglutinin I, RCA-I; soybean agglutinin, SBA; Ulex europeus agglutinin I, UEA-I; and wheat germ agglutinin, WGA). Throughout the larval period to stage 60, the epithelium consisting of surface cells and gland cells was stained in various patterns with all lectins examined, whereas the thin layer of connective tissue was positive only for RCA-I. At the beginning of metamorphic climax, the connective tissue became stained with Con A, SBA, and WGA, and its staining pattern varied with different lectins. The region just beneath the surface cells was strongly stained only with RCA-I. With the progression of development, both the epithelium and the connective tissue gradually changed their staining patterns. The surface cells, the gland cells, and the connective tissue conspicuously changed their staining patterns, respectively, for Con A and WGA; for Con A, PNA, RCA-I, SBA, and WGA; and for Con A, RCA-I, and WGA. At the completion of metamorphosis (stage 66), mucous neck cells became clearly identifiable in the epithelium, and their cytoplasm was strongly stained with DBA, PNA, RCA-I, and SBA. These results indicate that lectin histochemistry can provide good criteria for distinguishing among three epithelial cell types, namely, surface cells, gland cells, and mucous neck cells, and between adult and larval cells of each type.     

Lectin binding sites on CD34+ human haematopoietic stem cells and lymphocytes from peripheral blood: an ultrastructural post-embedding study

This study was performed to obtain a better insight into the glycosylation pattern of human CD34⁺ haematopoietic stem cells and lymphocytes from peripheral blood using an ultrastructural post-embedding technique. Lectins applied were derived from Canavalia ensiformis (Con A), Triticum vulgare (WGA), Lycopersicon esculentum (LEA), Limulus polyphemus (LPA), Ulex europaeus-I (UEA-I), Bauhinia purpurea (BPA), Glycine max (SBA), Helix pomatia (HPA), Arachis hypogaea (PNA) and Erythrina cristagalli (ECA). Our results showed almost identical staining patterns with both CD34⁺ cells and mature lymphocytes from peripheral blood. Con A displayed a prominent reactivity with the nuclear envelope and a weak staining of the plasma membrane. As demonstrated by an elaborate lectin double-labelling technique, WGA revealed an opposite staining pattern. Following neuraminidase treatment of sections, BPA, PNA and SBA exhibited a prominent staining of the plasma membrane in CD34⁺ cells and lymphocytes as well. Membrane reactivity with HPA was restricted to the majority of lymphocytes, presumably T-lymphocytes. Infrequently occurring dense cytoplasmic (lysosomal) bodies were reactive with a variety of lectins, and a weak diffuse nuclear labelling was observable with LPA, UEA-I, WGA and Con A. It is tempting to speculate that carbohydrate moieties on plasma membranes may be involved in the complex mechanisms characterizing cell-to-cell interactions (adhesion) and particularly in the so-called phenomenon of homing. This revised version was published online in November 2006 with corrections to the Cover Date.     

Changes in marine turbot (Scophthalmus maximus) epidermis and skin mucus composition during development from bilateral larvae to juvenile flat fish

Alike other flat fish, marine turbot has the particularity that changes from larvae with bilateral symmetry to adult with asymmetry, in terms of the position of the eyes. As expected, the skin configuration of this species is also affected by the development and transformation suffered by fish during metamorphosis. In this context, changes in the epidermis of marine turbot were studied using conventional staining and histochemical techniques using six lectins (UEA-I, PNA, RCA-I, WGA, Con A and SBA). During development from larvae to juvenile (3–300 days post-hatching), the epidermis increased in both thickness and the number of cell layers. In fact, the simple cuboidal epithelium observed in larvae at day 3 already became stratified at days 10–12, which sequentially increase in thickness with fish development. Turbot epidermis is composed basically of four cell types: epithelial and mucous or secretory cells that are present through the development, and pigmented cells and a type that the authors described as club-like cells that appear during and post-metamorphosis. The Alcian blue-periodic acid Schiff (AB-PAS) histochemical method revealed the presence of neutral glycoconjugates in mucous and club-like cells at post-metamorphic stages of fish. Accordingly, lectin analysis showed mucous cells containing glycoproteins rich in fucose (UEA-I labelling) and glycoconjugates rich in the sequence galactose-N-acetyl galactosamine (PNA and RCA-I labelling) when this cell type appears. Interestingly, melanophores were observed in the dorsal epidermis of post-metamorphic juveniles. This type of cell contains a black-to-brown pigment that provides the skin the typical colour of this fish species. Changes in mucous coat composition were observed during fish development, which was attributed to different roles of the glycoconjugates.     

Histochemical characterization of glycoconjugates in the epithelium of the extrapulmonary airways of several vertebrates

Summary The glycoconjugates of the extrapulmonary airways of 11 tetrapode vertebrates have been characterized by means of both conventional and lectin histochemistry. Abundant sialosulphomucins were detected in the secretory cells and periciliary layer of turtles, snakes, birds and mammals while only sialomucins were observed in amphibians. Neutral and traces of acidic mucins were detected in the secretory cells of lizards. The secretory cells of the amphibian airways were reactive to Con-A, DBA and WGA. No -l-fucose residues reactive with UEA-I or LTA were detected in amphibians. The goblet cells of the turtles were stained by DBA, SBA and WGA. Secretory cells of snakes and lizards reacted with Con-A and WGA. The mucous goblet cells of the birds were reactive to Con-A, LTA and WGA. In the chicken, they also showed affinity for PNA and SBA. The ciliated cells ofthe avian species studied were stained by Con-A and WGA. Mammalian goblet cells were reactive to Con-A, UEA-I and WGA. In the rat, affinity for DBA and SBA was also observed. The present results reveal the existence of marked differences in the sugar residues of the glycoconjugates of the extrapulmonary airways of tetrapode vertebrates. Only sialic acid residues appear to be constant constituents of the glycoconjugates of the airways of all species studied.     

Changes in lectin-binding pattern in the digestive tract of Xenopus laevis during metamorphosis. II. Small intestine.

The binding of seven lectins (concanavalin A, Con A; Dolichos biflorus agglutinin, DBA; peanut agglutinin, PNA; Ricinus communis agglutinin I, RCA-I; soybean agglutinin, SBA; Ulex europeus agglutinin, UEA-I; and wheat germ agglutinin, WGA) to the small intestine in metamorphosing Xenopus laevis was studied by the avidin-biotin-peroxidase (ABC) method. The staining pattern of the epithelium with all lectins except for UEA-I and Con A changed gradually during metamorphic climax; the main component of the epithelium, absorptive cells, gradually became positive for DBA, PNA, and SBA and the scattered goblet cells for RCA-I and WGA. On the other hand, the change of the staining pattern in the connective tissue occurred only for Con A, RCA-I, and WGA, and this change took place rapidly at the beginning of climax (stage 60). Increased staining for Con A and WGA at stage 60 was observed only in a group of connective tissue cells close to the epithelium and in the basement membrane. As metamorphosis progressed, this localization of the staining intensity became less clear. At the completion of metamorphosis (stage 66), the absorptive cells were stained with all lectins except for UEA-I, whereas the goblet cells stained only with RCA-I and WGA. These results indicate that lectin histochemistry can distinguish between larval and adult cells of both two epithelial types (absorptive and goblet cells). The technique may also identify a group of connective tissue cells, close to the epithelium, that possibly induce the metamorphic epithelial changes.     

Lectin histochemistry study in the human vas deferens

The oligosaccharide sequences of glycoconjugates in the normal human vas deferens and the nature of the saccharide linkage were studied by lectin histochemistry. The cytoplasm of all epithelial cell types (principal cells, basal cells, and mitochondria-rich cells) and luminal contents reacted positively with WGA, MAA, PNA, DSA, LTA, UEA-I, AAA, and ConA. The reaction was more intense in the stereocilia of principal cells. Cytoplasmic staining was diffuse except for PNA and DSA labeling which was limited to the apical cytoplasm and stereocilia of columnar cells. The cytoplasm of all cell types also reacted diffusely with HPA, although staining was weak and was not observed in the stereocilia. Positive reaction with SBA only was encountered in the stereocilia of principal cells. SNA, LTA, and DBA were unreactive. GNA-labeling showed a granular distribution in the supranuclear cytoplasm of columnar epithelial cells. Reactions with MAA, PNA, DSA, AAA, HPA and SBA disappeared after the -elimination reaction. Reactions with WGA and UEA-I decreased after -elimination or Endo-F digestion. Reactions with ConA and GNA were suppressed by Endo-F digestion. Reactions with PNA, HPA, and SBA increased after desialylation. Of all the lectins that label the luminal contents of the vas deferens, only UEA-I was not found in the luminal contents of seminiferous tubules and epididymis and, thus, this lectin would probably bind to glycoproteins secreted by the vas deferens. The chemical treatments used suggest that this secretion contains fucose residues located in both N- and O-linked oligosaccharides. The other lectins may label secreted proteins, but also structural proteins or proteins reabsorbed from the luminal fluid. The lectin- binding pattern of mitochondria-rich cells in the vas deferens differed from that found in the epididymis.     

Glycoconjugates in normal human kidney. A histochemical study using 13 biotinylated lectins

The avidin-biotin-peroxidase complex technique was used with 13 lectins to study the glycoconjugates of normal human renal tissue. The evaluated lectins included Triticum vulgaris (WGA), Concanavalin ensiformis (ConA), Phaseolus vulgaris leukoagglutinin and erythroagglutinin (PHA-L and PHA-E), Lens culinaris (LCA), Pisum sativum (PSA), Dolichos biflorus (DBA), Glycine max (SBA), Arachis hypogaea (PNA), Sophora japonica (SJA), Bandeiraea simplicifolia I (BSL-I), Ulex europaeus I (UEA-I) and Ricinus communis I (RCA-I). Characteristic and reproducible staining patterns were observed. WGA and ConA stained all tubules; PHA-L, PHA-E, LCA, PSA stained predominantly proximal tubules; DBA, SBA, PNA, SJA and BSL-I stained predominantly distal portions of nephrons. In glomeruli, WGA and PHA-L stained predominantly visceral epithelial cells; ConA stained predominantly basement membranes and UEA-I stained exclusively endothelial cells. UEA-I also stained endothelial cells of other blood vessels and medullary collecting ducts. Sialidase treatment before staining caused marked changes of the binding patterns of several lectins including a focal loss of glomerular and tubular staining by WGA; an acquired staining of endothelium by PNA and SBA; and of glomeruli by PNA, SBA, PHA-E, LCA, PSA and RCA-I. The known saccharide specificities and binding patterns of the lectins employed in this study allowed some conclusions about the nature and the distribution of the sugar residues in the oligosaccharide chains of renal glycoconjugates. The technique used in this report may be applicable to other studies such as evaluation of normal renal maturation, classification of renal cysts and pathogenesis of nephrotic syndrome. The observations herein reported may serve as a reference for these studies.     

The lectin binding pattern of normal and pathologically altered synovial tissue

Light-microscopical lectin-binding studies were carried out in healthy and pathologically altered synovial tissue (osteoarthrosis, rheumatoid arthritis (RA)). Seven lectins were studied: Con A, DBA, PNA, RCA, SBA, UEA-I, and WGA. Con A and WGA mark all lining cells and the majority of subintimal synovial cells. RCA and SBA stain only a portion of lining cells, regardless of the basic pathology. The lectin PNA reacts only with RA and arthrotic material, and is thus suitable for the diagnosis of inflammatory changes in synovial tissue. UEA-1 is a consistent marker for capillary endothelium and large vessels.     

Lectin histochemistry of the hyaline layer in the asteroid,pisaster ochraceus

Six different lectins were used to study the carbohydrate nature of the hyaline layer (HL), the external extracellular matrix of the starfish embryo. Thin sections of embryos fixed in the late gastrula stage were incubated with five fluoresceinated lectins: Con A, WGA, RCA, UEA-I, and SBA. All but UEA-I labelled the HL, suggesting that the following sugars are present: mannose and/or glucose, glcNAc and/or Neu5Ac, galactose, and galNAc. The different lectins produced variable degrees of labelling, with WGA, RCA, and SBA producing more intense labelling than Con A. Binding of lectins by the HL was studied at the ultrastructural level by exposing ultrathin sections to the following lectin-gold conjugates: Con A, WGA, PNA, SBA, and LFA. Lectin binding was observed over the various regions of the HL, recognized by Crawford and Abed (J. Morphol. 176:235–246, '86), i.e., the intervillus layer, the supporting layer and the coarse outer meshwork. Local differences in labelling patterns were observed among the various lectins, with SBA labelling all regions intensely, WGA and PNA labelling the supporting layer predominantly, and Con A labelling the HL only lightly. No labelling was observed with LFA. These lectin-labelling patterns in the HL demonstrate the presence of different glycoconjugates in different regions of the HL, suggesting that the layers differ biochemically. The existence of biochemical differences strengthens the idea that each layer may have different functions in the developing starfish embryo.     

Differential localization of lectin binding sites and neuropeptides in human dorsal root ganglia

The subpopulations were compared of neurons in human dorsal root ganglia (DRG), as substance P, identified by somatostatin, Glycine max lectin (SBA) specific to terminal N-acetylgalactosamine, and Ulex europaeus I agglutinin (UEA-I) specific to l-fucose. The lectins and neuropeptides all bound to neurons of small diameter. Furthermore, the majority of the SBA binding neurons or somatostatin positive neurons were also UEA-I binding neurons. However, SBA binding neurons were not colocalized with somatostatin or substance P. Less than 20% of substance P positive neurons showed colocalization with l-fucosyl residues, and approximately 10% of l-fucosyl residues showed colocalization with substance P. Our results suggest that both l-fucose and terminal N-acetylgalactosamine containing neurons in the human DRG are subjected to different subpopulations from substance P or somatostatin positive neurons.     

Changes in lectin binding patterns of Leydig cells during fetal and postnatal development in mice

Summary Changes in the lectin binding of mouse Leydig cells during fetal and postnatal development were examined by light- and electron-microscopy using eight different biotinylated lectins (ConA, WGA, RCA-I, UEA-I, GS-I, PNA, SBA and GS-II). At the light-microscopic level, ConA, WGA, RCA-I, UEA-I and GS-I showed the same binding pattern in which all five lectins bound to the plasma membrane and cytoplasm of Leydig cells from the 13th day post coitum (p.c.) to the 8th postnatal week. PNA, SBA and GS-II reactions were positive in the plasma membrane and cytoplasm of Leydig cells from the 13th day p.c. to 15th day post partum (p.p.) but disappeared completely by day 20. At the electron-microscopic level, gold particles representing the GS-I or GS-II binding sites were distributed primarily along the cell surface membrane, including that of microvilli, as well as in the cytoplasm. These results indicate that certain glycoconjugates bearingD-galactose,N-acetyl-D-galactosamine, andN-acetyl-D-glucosamine residues are expressed on the cell surface and in the cytoplasm of Leydig cells during the period from the 13th day p.c. to around the 20th day p.p. The results suggest that these glycoconjugates might play some role in modulating hormone-receptor interaction in the Leydig cells before the 20th day. Furthermore, these results may indicate that sugar residues expressed on the cell surface and in the cytoplasm of Leydig cells are different from those in the fetal-neonatal and adult phases.     

Glycoconjugates in normal human kidney

Summary The avidin-biotin-peroxidase complex technique was used with 13 lectins to study the glycoconjugates of normal human renal tissue. The evaluated lectins included Triticum vulgaris (WGA), Concanavalin ensiformis (ConA), Phaseolus vulgaris leukoagglutinin and erythroagglutinin (PHA-L and PHA-E), Lens culinaris (LCA), Pisum sativum (PSA), Dolichos biflorus (DBA), Glycine max (SBA), Bandeiraea simplicifolia I (BSL-I), Ulex europaeus I (UEA-I) and Ricinus communis I (RCA-I). Characteristic and reproducible staining patterns were observed. WGA and ConA stained all tubules; PHA-L, PHA-E, LCA, PSA stained predominantly proximal tubules; DBA, SBA, PNA, SJA and BSL-I stained predominantly distal portions of nephrons. In glomeruli, WGA and PHA-L stained predominantly visceral epithelial cells; ConA stained predominantly basement membranes and UEA-I stained exclusively endothelial cells. UEA-I also stained endothelial cells of other blood vessels and medullary collecting ducts. Sialidase treatment before staining caused marked changes of the binding patterns of several lectins including a focal loss of glomerular and tubular staining by WGA; an acquired staining of endothelium by PNA and SBA; and of glomeruli by PNA, SBA, PHA-E, LCA, PSA and RCA-I. The known saccharide specificities and binding patterns of the lectins employed in this study allowed some conclusions about the nature and the distribution of the sugar residues in the oligosaccharide chains of renal glycoconjugates. The technique used in this report may be applicable to other studies such as evaluation of normal renal maturation, classification of renal cysts and pathogenesis of nephrotic syndrome. The observations herein reported may serve as a reference for these studies.     

Carbohydrate antigens of human megakaryocytes and platelet glycoproteins: a comparative study

Until now, carbohydrate antigens of human megakaryocytes have not been studied very extensively. For this reason, we investigated the staining pattern of 25 lectins and carbohydrate-specific monoclonal antibodies on paraffin-embedded trephine biopsies and acetone-fixed smears from patients with reactive and neoplastic bone marrow lesions. A biotin-streptavidin-alkaline phosphatase assay was used to visualize the binding of lectins or antibodies. Ulex europaeus agglutinin I (UEA-I) stained megakaryocytes in all cases tested. Monoclonal antibodies detecting fucosylated Lewis type 2 chain antigens (19-OLE, 12-4LE and LeuM1) were also reactive. Several lectins detecting backbone and core oligosaccharides [Helix pomatia agglutinin (HPA), peanut agglutinin (PNA), Erythrina cristagalli agglutinin (ECA), soybean agglutinin (SBA)] bound to megakaryocytes only after neuraminidase digestion. Moreover, we investigated human platelet lysates to gain some information about the carbohydrate residues of platelet glycoproteins which are synthesized by megakaryocytes. The carbohydrate expression of platelets showed striking similarities to that of megakaryocytes. Immunoblotting experiments revealed a strong binding of UEA-I, 19-OLE and 12-4LE to a band isographic to glycoprotein (gp) Ib. After desialylation of glycoproteins transblotted to nitrocellulose, ECA and PNA also reacted with a band of this molecular weight. Gp Ib is known to contain a mucin-like peptide core with a great number of potential O-glycosylation sites. Therefore, it is tempting to speculate that carbohydrate residues characterized in this study are involved in the complex biological interactions of gp Ib.     

Lectin histochemistry of mammalian Brunner's glands

Lectin histochemical study was performed on twenty-eight specimens of formalin-fixed paraffin embedded tissues of proximal duodenum from human, cat, dog and Rhesus (macaque) monkey to demonstrate the pattern of carbohydrate residues in submucosal glands of Brunner as compared to that of the duodenal absorptive and goblet cells. Ten different biotinylated lectins were used as probes, and avidin-biotin-peroxidase (ABC) or avidin-gold-silver (AGS) complexes were used as "visualants". Brunner's gland cells of the four species studied exhibited a similar lectin-binding pattern which differ from other duodenal cells. The epithelium of Brunner's gland stained intensely with Ricinus communis agglutinin-I (RCA-I), succinylated-WGA (S-WGA) and wheat-germ agglutinin (WGA), moderately with Bandeirea simplicifolia agglutinin-I (BS-I), Concanavalia ensiformis agglutinin (Con A) peanut agglutinin (PNA) and Ulex europaeus agglutinin-I (UEA-I) and occasionally with Dolichos biflorus agglutinin (DBA), Lens culinaris agglutinin (LCA) and soybean agglutinin (SBA). Desialylation with neuraminidase resulted in only a slight elevation in binding intensities of PNA, DBA and SBA, indicating that glycoconjugates of the Brunner's gland cells are rich in asialo-oligosaccharides, which differs from duodenal epithelial cells. In addition, these histochemical reagents were useful in localizing Brunner's gland elements in the duodenal mucosa.