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.     

Comparative immunochemical study of lectin-binding sites and cytoskeletal filaments in static and reactive mesothelium and adenocarcinoma

In cytological preparations, reactive mesothelial cells (RMC) in serous effusions are sometimes difficult to distinguish from adenocarcinoma cells (AC). RMC and AC can be distinguished by lectin-binding patterns, but the pattern of binding of lectins to normal mesothelium is not well defined. We investigated the expression of cytoskeletal filaments, cytokeratin (CK) and vimentin (VM), and the cell surface binding pattern of 10 lectins (HPA, SBA, ABA, DSA, PNA, RCA-I, UEA-I, LTA, WGA and ConA) in the serosa of 48 adenocarcinoma specimens. We also investigated the usefulness of six lectins (HPA, SBA, RCA-I, UEA-I, LTA and WGA) in identification of RMC and AC in 16 serous effusions. DSA reactivity was significantly higher (P < 0.05) in static mesothelial cells (SMC) than in RMC. Reactivity for LTA and ConA was significantly lower (P < 0.05) in SMC than in RMC. Anti-CK and anti-VM immunoreactivity was always positive in RMC and almost negative in SMC. In serous effusions, HPA, SBA and UEA-I binding was evident in 100, 88 and 81% of AC, respectively. Little to no binding of HPA, SBA or UEA-I was detected in RMC. Our results suggest that the morphological differences between SMC and RMC are likely to be due to differences in cytoskeletal composition, with accompanying changes in cell-surface lectin-binding patterns. HPA, SBA and UEA-I are likely to be useful markers for identification of RMC and AC in cytology.     

Comparative immunohistochemical investigation of markers for malignant histiocytes

The presence of lysozyme, alpha 1-antitrypsin (AT), alpha 1-antichymotrypsin (ACT), and cytoplasmic receptors for peanut and soy bean agglutinin and for concanavalin A (PNA, SBA, and ConA, respectively) was investigated in formalin-fixed, paraffin-embedded material from 16 cases of malignant histiocytosis. The tumors in these cases did not show phenotypic characteristics of T or B cells. Lysozyme and AT especially were found less frequently in tumor cells from malignant histiocytosis than in normal histiocytes, whereas ACT and binding sites for the lectins were maintained during malignancy. Specimens from 44 per cent of the cases were positive for lysozyme, 56 per cent for AT, 82 per cent for ACT, 88 per cent for PNA receptors, 94 per cent for SBA receptors, and 100 per cent for ConA receptors. Tumor cells from B- and T-cell lymphomas were negative for these markers. Plasma cells, granulocytes, and fibroblasts sometimes bound ConA, but not PNA or SBA. The cases of malignant histiocytosis were subdivided into three groups on the basis of grade of differentiation. The tumor cells from the cases in group 1 showed the highest degree of differentiation, those from group 2 an intermediate degree, and those from group 3 the lowest degree. Mitotic activity was present mainly in groups 1 and 2. Lysozyme was present most frequently in groups 1 and 3 and in cases with the least mitotic activity. Expression of AT was decreased in groups 2 and 3. The presence of phagocytosis, which is not obligatory for the diagnosis, was always correlated with ACT staining. The presence of binding sites for these lectins can be considered a useful marker for malignant histiocytes.     

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.     

Histochemical study of glycoconjugates in active and photoperiodically-regressed testis of hamster (Mesocricetus auratus)

The objective of the present study was to characterize glycoconjugates of hamster testis in gonadally-active and -inactive states by lectin histochemical methods. Thirteen HRP- or digoxigenin-labeled lectins were used in samples obtained from fertile and photoinhibited hamsters. In gonadally-active hamsters, spermatozoa tails were stained with Con-A, HPA, PNA, UEA-I, LTA, AAA, WGA and LFA and weakly with GNA and RCA-I. Spermatozoa acrosomes were labeled with HPA, SBA, WGA and PNA. Spermatid acrosomes were labeled with SBA, RCA-I, PNA, and WGA. Staining with GNA and Con-A was found in the Golgi phase and HPA staining was found in the Golgi phase and maturated spermatids. Cytoplasm of spermatocytes was labeled with Con-A, GNA, LTA, AAA, RCA-I, HPA, WGA and LFA, whereas spermatocyte membranes were stained with Con-A, LTA and AAA. Spermatogonia were strongly labeled with Con-A and moderately labeled with AAA, WGA and LFA. Sertoli cells were positive after staining with Con-A, AAA, WGA, and LFA. The lamina propria was positive after staining with UEA-I, LTA, AAA and LFA. Leydig cells showed strong labeling with SBA, Con-A, GNA, SNA and MAA, moderate labeling with WGA, weak labeling with RCA-I, AAA and LFA. In gonadally-inactive hamsters, spermatocytes showed increased staining with HPA, PNA and AAA, whereas staining with Con-A, GNA and LTA had disappeared. Spermatogonia showed an increased labeling with AAA and WGA, but labeling with Con-A and LFA had disappeared. Sertoli cells were strongly labeled with GNA. Con-A and GNA staining was decreased in Leydig cells of gonadally-inactive hamsters but PNA and HPA staining was increased. The lamina propria in regressed testes showed intense labeling with PNA. These results suggest that histological, morphological and hormonal changes occurring in hamster testis during exposure to a short photoperiod are reflected in altered patterns of expression and distribution of N- and O-linked glycans.     

Differences in lectin binding in tissue sections of human and murine malignant tumors and their metastases.

Lectin binding to tumor cells in tissue sections of 16 nonmetastatic and 24 metastatic human adenocarcinomas and 5 nonmetastatic and 5 metastatic murine Lewis lung carcinomas (LLCs) was assessed with an avidin-biotin peroxidase technique. In human tumors, Ulex europaeus agglutinin I (UEA I) showed no binding; whereas concanavalin A (Con A), Ricinus communis agglutinin I (RCA I), wheat germ agglutinin (WGA), soybean agglutinin (SBA), and Dolichos biflorus agglutinin (DBA) bound equally to primaries and metastases. However, peanut agglutinin (PNA) bound to less than 5% of cells in 37 of 40 primaries but to greater than 50% of cells in 18 of 24 metastases. In LLC tumors, UEA I and DBA showed no binding; whereas Con A, RCA I, and WGA bound equally to primaries and metastases. SBA bound to greater than 50% of cells in 5 metastases but not to the 5 primaries. There was less than 5% binding of PNA to 10 primary murine tumors after neuraminidase pretreatment of tissue sections but greater than 50% binding in 3 of 5 metastases. These studies indicate, in both human adenocarcinomas and an experimental tumor system, that most tumor cells which metastasize show preferential binding of PNA and SBA.     

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.     

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.     

外阴营养不良、外阴鳞状上皮细胞癌凝集素标记免疫组化分析

目的：探讨外阴营养不良增生型,硬化苔藓型表皮细胞和外阴鳞状上皮细胞癌等细胞膜结构与凝集素受体结合表达特征及它们三者之间的关系。方法：对慢性外阴营养不良表皮增生型,苔藓硬化型及外阴鳞状上皮细胞癌3种状态下的细胞进行了8种凝集素免疫组织化学标记,分析,比较。结果：外阴营养不良增生型表皮各层细胞细胞膜与刀豆凝集素（ConA),扁豆凝集素（LCA）,花生凝集素（PNA）,蓖麻凝集素（RCA－1）和大豆凝集素（SBA）结合强度弱,其表皮细胞细胞核膜与ConA,PNA和麦胚凝集素（WGA）有中等强度结合,外阴营养不良硬化苔藓型表皮各层细胞细胞膜与ConA,RCA-1 SBA和WGA结合强度弱,而与LCA不结合,其12例中的8例与荆豆凝集素（UEA－1）发生较弱的结合,外阴鳞状上皮细胞癌癌细胞与8种凝集素均结合,其12例中的7例其癌细胞膜与双花扁豆凝集素（DBA）弱结合,癌细胞膜与UEA－1强结合,但癌巢中央细胞团不与UEA－1结合,癌细胞细胞核膜与ConA,LCA,RCA-1呈强结合。结论：凝集素标记免疫组织化学染色可作为诊断,鉴别诊断外阴营养不良增生,硬化苔藓型和外阴鳞状上皮细胞癌新的指标,具有恶变潜能的增生型外阴营养不良与外阴鳞状上皮细胞癌,两者细胞核膜凝集素标记有相似之处,提示在外阴组织的癌变过程中,细胞核膜凝集素标记的异常表达是一个早期标识,糖基和糖蛋白代谢的异常可能是细胞发生癌变最早期的表现之一。     

Distribution and nature of membrane receptors for different plant lectins in the coelomocyte subpopulations of the Annelida Nereis diversicolor

Studies on membrane receptors have been performed on the Nereis coelomocytes using various lectins. In the agglutination assay, only LCA and WGA appeared nonreactive. Fluorescent lectins showed the poor reactivity of the eleocytes and the diversity of the receptors according to the granulocyte types. Types I-granulocytes reacted only with Con A. Type II-granulocyte membrane contained mannose and galactose receptors (reactivity with Con A, PNA and SBA). The type III-granulocyte membrane revealed the presence of mannose and fucose receptors (UEA, AAA). Electron microscope investigations with HRP-DAB or mannosyl labelled Con A, RCAI and LTA have confirmed the distribution of the membrane receptors.     

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)     

Lectin histochemistry for detection of the oligosaccharides in the testis of the chick embryo

The oligosaccharidic content, distribution and changes of the glycoconjugates in the testis of the chick embryo, from the 8th day of incubation to hatching, were studied using a battery of seven HRP-conjugated lectins (DBA, SBA, PNA, ConA, WGA, LTA, and UEA I). Our findings showed that ConA and WGA appeared to characterize the spermatogonia during their differentiation, maturation, migration and meiosis. In the Sertoli cells, a change of localization of staining with ConA and WGA was revealed during the differentiation and maturation of these cells. The basal membrane was characterized by the reactivity with ConA and WGA from the early stages of incubation. ConA, WGA and PNA reacted with the endothelial cells of the testis for the whole period of incubation considered. Moreover, the interstitial cells, since their appearance, showed reactivity with ConA, WGA and PNA at the plasma membrane and the cytoplasm.     

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.     

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.     

人及哺乳动物消化管中凝集素结合部位的形态观察

用三种辣根过氧化物酶标记的凝集素—WGA、SBA和PNA观察人及大小鼠的消化管各段中凝集素结合部位的分布。在各段消化管的粘膜上皮均有染色反应,但胃粘膜上皮细胞的核上区不被PNA着色。在胃底腺中,人的壁细胞只对WGA反应,主细胞对WGA和PNA都有反应,而大小鼠二种细胞对三种凝集素均有反应。杯状细胞对PNA不着色。肠腺反应与粘膜上皮相似。固有膜、平滑肌被WGA着色。神经元对WGA和PNA反应。由此提示糖蛋白分布的差异存在于各段消化管和同段消化管的不同区域并有种间差异。     

Lectin-binding in normal and fibrillated articular cartilage of human patellae

Summary Fluorescein-isothiocyanate (FITC) labeled lectins were used to study the distribution of specific binding-sites in histological sections of normal and fibrillated articular cartilage of human patellae.It has been shown that normal articular cartilage reveals lectin binding-sites for Concanavalin A (Con A) and wheat germ agglutinin (WGA), but not for soybean agglutinin (SBA), peanut agglutinin (PNA) and Ulex europaeus agglutinin (UEA).In fibrillated cartilage the distribution pattern of Con A and WGA is completely changed. SBA, PNA and UEA show a distinct staining pattern in particular in the fibrillated areas of degenerated cartilage. Lectin-staining of the extracellular matrix and the chondrocytes in both normal and fibrillated cartilage did not show any correlation with material that was either PAS- or Alcian blue-positive. In comparison with the conventional PAS- and Alcian blue reaction lectin-staining proved to be superior.Visualization of intra- and extracellular glycoconjugate-changes in normal and fibrillated cartilage in areas with no PAS and/or Alcian blue staining indicates that all layers of the cartilage are involved in the pathological process.It is evident that lectins can demonstrate minute differences between normal and arthrotic cartilage and we therefore conclude that lectins are sensitive and specific tools for the study of degenerative joint diseases.     

Lectin-binding patterns in the embryonic human paraxial mesenchyme

The paraxial mesenchyme in seven human embryos aged between Carnegie stages 12 and 17 was studied by lectin histochemistry with the lectins AIA, Con A, GSA II, LFA, LTA, PNA, RCA I, SBA, SNA, WGA. The paraxial mesenchyme was found to be segmented into sclerotomes by intersegmental vessels and from late stage 12 by intrasclerotomal clefts dividing each sclerotome into a cranial and caudal half. The lectins Con A, GSA II, LFA, LTA, SBA and SNA did not react at all in the paraxial mesenchyme. Staining for AIA, PNA, RCA I and WGA was found in the developing sclerotomes. However, no differences in the staining pattern between the two sclerotomal halves could be seen. It was striking that in contrast to the chick embryo no differences in binding for PNA between the cranial and caudal sclerotomal parts was observed. These findings reveal that PNA-binding sites do not play the same functional role in segmented axonal outgrowth and neural crest immigration into cranial sclerotomal halves in the human embryo, as found in chick embryonic development. Beginning with the stage 16-embryo, the already condensed caudal sclerotomal halves express Con A-, RCA- and PNA-binding sites. The staining for PNA in particular marked the differentiation of chondrogenous structures developing in this half. From the late stage 12 or stage 13, the walls of intersegmental and other vessels showed binding sites for AIA, PNA, RCA I, SNA and WGA.     

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 to serous ovarian tumours.

Sections of normal ovarian surface epithelium, benign serous cystadenomas, borderline serous cystadenomas and serous cyst-adenocarcinomas were stained with a pattern of lectins (Con A, WGA, SBA, DBA, UEA I, PNA and RCA I) to determine the different glycoproteins and their cellular changes. The epithelial cells stained with Con A, WGA, UEA I and RCA, although the intensity of the staining was generally higher in the malignant tumours. PNA stained only the malignant cells of the cystadenocarcinoma and DBA only the benign epithelial cells. These findings show that ovarian epithelial cells contain different glycoconjugates and that malignant transformation is accompanied by changes in the composition of these glycoconjugates.     

Lectin binding patterns in benign and malignant lesions of the breast.

The binding patterns of a panel of eight lectins were studied in twenty eight breast lesions, consisting of ten cases of fibroadenoma, three cases of cystosarcoma phyllodes, five cases of fibrocystic disease and ten cases of infiltrating duct carcinoma by light microscopy. The eight lectins viz. PNA, WGA, RCA, SBA, UEA I, LTA, LCA and Con A were tested on paraffin sections using the Avidin Biotin Peroxidase Complex technique. PNA, RCA and UEA I showed a consistent positivity in benign and malignant lesions. The binding was localised mainly along the apices of mammary ductal epithelial cells in the benign lesions. In contrast, the malignant cells showed a considerable variation in staining patterns like diffuse cytoplasmic, membranous, and vacuolar. No definite correlation was seen between the intensity of binding and the histological grade in infiltrating duct carcinoma except in the case of Con A which was seen to bind more intensely to poorly differentiated tumours. The diagnostic significance of these patterns have been discussed.