UEA-1 Binding Research Articles

An investigation using lectins of glycocomponents of mouse spermatozoa during capacitation and sperm-zona binding.

Ten different lectins conjugated to fluorescein isothiocyanate (FITC) were used to study the distribution of surface carbohydrates on mouse spermatozoa, and to monitor the possible changes of their distribution during capacitation in vitro and sperm-egg interaction. Most of the lectins gave a restricted pattern of binding to fixed or unfixed epididymal spermatozoa. Binding was highly specific because no staining occurred in the presence of appropriate monosaccharides. Binding of UEA I, DBA and Con A was unaffected by the type of fixative used, but it was influenced by mild centrifugation. While unwashed spermatozoa showed binding mainly over the acrosomal cap and equatorial or postacrosomal regions, spermatozoa washed by mild centrifugation showed a change in the staining of the equatorial segment. Binding of 5 different lectins to spermatozoa did not change during capacitation in vitro. In contrast, capacitated spermatozoa bound to the zona pellucida exhibited a UEA I binding pattern which was strikingly different from that of the capacitated but unbound spermatozoa. We conclude that glycocomponents of specific regions of mouse spermatozoa do not change dramatically during capacitation, but do alter significantly during binding to the zona pellucida.

Lectin-binding affinities of the epithelium in the respiratory tract. A light microscopical study of ciliated epithelium in rat, guinea pig, and hamstor

Complex carbohydrate components of surface coat and secretory granules were investigated in the laryngo-tracheo-bronchial epithelium of 3 laboratory animals (rat, guinea pig, and Syrian hamster). 2 groups of epithelial cells were distinguished in the light microscope: ciliated cells and non-ciliated cells. The latter mainly represent secretory cells and are subdivided into serous and mucous secretory cells. Apical glycocalix: In the rat, ciliated cells possess a significant number of Con A, RCA I, and WGA receptors, and a smaller number of UEA I binding sites. In hamsters and in guinea pigs additional binding sites for HPA could be demonstrated. The apical glycocalix of the non-ciliated cells in the rat evince marked staining with RCA I, WGA, and HPA, and less intensive binding of UEA I. In guinea pigs and in hamsters, the presence of additional Con A receptors was noted. Basolateral glycocalix: The basolateral surface coat of ciliated and non-ciliated cells shows identical lectin binding affinities. In the rat, the basolateral glycocalix binds RCA I; in the guinea pig, in addition, positive staining with UEA I and HPA is observed; in the hamster, the basolateral surface coat is outlined by RCA I and HPA receptors. Secretory products: Secretory granules of mucous cells in the rat react with Con A, UEA I and HPA lectins. In guinea pigs, these substances also bind RCA I and WGA lectins. Mucous granules in the secretory cells of the hamster are positive for Con A, RCA I, and HPA lectins. Granules of non-ciliated serous cells of rats bind Con A, UEA I, and HPA lectins. In the guinea pig, this reaction is weaker for UEA I lectin but comparable for Con A and HPA binding. A positive reaction with RCA I lectin only is found in the serous secretory granules of the hamster.

Identification of vascular system in experimental carcinoma for cryosurgery—Histochemical observations of lectin UEA-1 and alkaline phosphatase activity in vascular endothelium

Histopathologic and histochemical changes in experimental carcinomas following cryotreatment were observed to detect alkaline phosphatase (ALP) activity and UEA-1 lectin binding. Experimental carcinomas were induced in the hamster cheek pouch by topical application of 0.5% DMBA acetone solution twice a week. The cryoprobe at −60 °C was directly attached to the tumor surface for 90 sec. Histochemically, the tumor tissue following cryotreatment was completely destroyed in the surace area by the direct freezing and such cryonecrotic tumor tissue lacks stainability. Soon after cryotreatment and before cryonecrosis takes place, it has been observed that there is an intense dilatation of capillary vessels. Histochemically, high ALP activity was limited to capillary endothelium and to inflammatory cells. Lectin UEA-1 staining was usually found in both normal and neoplastic epithelial cells which were confined to capillary vessels. At 1 to 3 hr after cryotreatment. lectin UEA-1 binding was also positive in dilated endothelial cells of the frozen tissue as well as viable remaining neoplastic epithelia by freezing. ALP activity and UEA-1 binding disappeared in capillaries of crynecrotic area in tumor tissues. Those findings suggest that biologic membrane changes in capillary endothelium of tumor stroma occur following cryotreatment.

The histopathological and immunopathological diagnosis of angiosarcoma of the face and scalp

Angiosarcoma of the face and scalp (AS) may be associated with a better prognosis if the lesions are detected early in their development. However, the diagnosis of AS is hindered by its variable histopathology. We have examined cutaneous biopsies from 71 patients with AS to identify the most characteristic histological features. In addition, immunoperoxidase labelling was performed on selected cases for UEA-I binding. Factor VIII RA, laminin, vimentin and two antigens recognised by the monoclonal antibodies 4E6 (supplied by Dr Spry, Hammersmith Hospital) and PAL-E (Schlingeman et al., 1985). All the tumours showed areas recognizable as vascular channels, with atypical endothelial linings, but various degrees of differentiation were seen. The majority of tumours showed well-differentiated areas of collagen dissection (75%) and tumour giant cells (80%). Half the cases showed solid patches of poorly differentiated spindle cell or carcinoma-like change and in some this represented the major change. The three predominant histological patterns were examined for the presence of endothelial markers. Well-differentiated areas of collagen dissection showed uniform positive labelling by all markers except Factor VIIIRA, which gave patchy positivity and PAL-E which highlighted only normal vessels. Reduced positivity was seen in areas of luminal proliferation of tumour cells and labelling was generally absent in poorly differentiated solid areas. Our studies demonstrate the range of histopathological and immunopathological appearances in AS. However, loss of normal endothelial cell markers from well-differentiated vascular channels may represent the earliest stage of malignant change.

ConA and WGA receptors in rat skeletal muscles: Changes in density, distribution and composition following denervation

The differential binding of fluorescein-labeled ConA, WGA and UEA to cryostatic sections of control and of 8 days denervated muscles is described. Receptor sites for ConA and WGA appear to be very abundant in skeletal muscles and their abundance seems to increase following denervation. In contrast, concentration of receptor sites for UEA is below the sensitivity of the method. Differences in the distribution of the binding sites for ConA and WGA, apparent in untreated sections, were further analysed following predigestions by collagenase, hyaluronidase or neuraminidase. The most important difference among lectins appeared to be the preferential binding of ConA to the surface of muscle fibres and of WGA to connective tissue. By comparing results in control and denervated muscles a clear change of the effects of neuraminidase on WGA binding was evident following denervation. The binding of fluorescein-labeled ConA and WGA to untreated and to predigested cryostatic sections of skeletal muscle is a sensitive and simple histochemical method which can disclose precocious changes in composition of glycoconjugates following denervation and, what might be useful, in other experimental or pathological conditions.

Lectin-binding in premalignant lesions during submandibular gland carcinogenesis.

Complex carbohydrates in premalignant lesions of mouse submandibular gland tumors were examined by the lectin-peroxidase conjugate method. Peroxidase-conjugated lectins of PNA, RCA-1, DBA, SBA, UEA-1 and WGA were used to detect specific sugar residues of complex carbohydrates in premalignant lesions during experimental carcinogenesis. Marked reduction of PNA and SBA bindings occurred in duct-like structures and cystic lesions which were transformed from granular convoluted tubule cells. Premalignant lesions bound slightly to PNA, RCA-1, DBA, SBA and WGA and manifested increased UEA-1 binding. Squamous metaplastic epithelia of premalignant lesions manifested increased binding to PNA, RCA-1 and SBA as compared to those of duct-like structure and cystic epithelia.

Altered binding of Ulex europaeus I lectin to psoriatic epidermis.

We have used Ulex europaeus I (UEA I) lectin, specific for alpha-L-fucose-containing glycoconjugates, in fluorescence microscopy to stain cryostat sections of human skin from normal persons and patients with psoriasis and lichen simplex. In normal skin the upper layers of the stratum spinosum and the stratum granulosum were strongly reactive with UEA I, whereas the lower layers of the epidermis did not react. The staining intensity of the upper epidermis was similar to that of the endothelium of dermal blood vessels. Biopsies of the lesional skin of lichen simplex showed an intense UEA I-specific staining throughout the whole epidermis, similar in intensity to that seen in the upper epidermis of normal skin. In psoriatic lesions positive UEA I-specific fluorescence was seen throughout the whole epidermis, but the fluorescence was more faint and often granular. In uninvolved skin of psoriatic patients the whole epidermis showed a diffuse UEA I-specific fluorescence, differing in this respect from normal skin. In normal skin UEA I binds to epidermal cells which are at a certain state of differentiation. The results with psoriatic epidermis confirm that both uninvolved and lesional epidermis have a defect in epidermal maturation, as shown by the altered binding of UEA I lectin.

Cellular localization of lectin-affinity in tissue sections of normal human duodenum.

Peroxidase (HRP) conjugates of Arachis hypogaea agglutinin (PNA), Dolichos biflorus agglutinin (DBA), Ulex europaeus agglutinin I (UEA I) and Bandeiraea simplicifolia agglutinin I (BSA I) were used to detect the expression of carbohydrate moieties in glyco-conjugates of normal human duodenal mucosa. Lectin histology was performed on sections from paraffin embedded specimens of donor blood groups A, B, AB and 0. While PNA, DBA and UEA I staining appeared to be independent of the donor blood groups, BSA I affinity was restricted to the blood groups B and AB. Neither striated columnar cells nor goblet cells stained with PNA-HRP conjugates. Glyco-conjugates of goblet cell mucins reacted with DBA and UEA I, but staining intensities varied in crypts and villi: positive goblet cells occurred preferentially in upper parts of the crypts and in villi. Striated columnar cells also exhibited variation in staining intensities, with binding of DBA and UEA I observed in the upper half of crypts and in villi, occurring predominantly along the brush border and in apical parts of the cells. Glyco-conjugates synthesized by Brunner's gland cells possessed a great variety of lectin reactivity with the lectins employed. Within a given histological section positive gland areas with different staining intensities beside negative cell populations might reflect different functional states.

Expression of factor VIII-related antigen and ulex lectin binding sites in endothelial cells during long-term culture

The expression of factor VIII-related antigen (VIIIR:Ag) and the binding of Ulex Europaeus I lectin, a newly introduced endothelial marker, were studied upon repeated subculture of human umbilical vein endothelial cells. In primary culture, all cells showed a characteristic, finely granular cytoplasmic VIIIR:Ag-specific staining and binding of UEA I both to cell surface membrane and to a cytoplasmic reticular juxtanuclear structure representing the Golgi apparatus. After subculture, the number of VIIIR:Ag-positive cytoplasmic granules decreased and gradually up to 50 % of the cells became negative for this antigen, while still showing a uniform surface binding of UEA I lectin. In surface staining, VIIIR:Ag did not show any membrane-like localization but was distinctly associated with fibronectin-containing pericellular matrix fibers at all culture stages. UEA I lectin showed only a homogenous cell membrane staining.