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Peanut agglutinin affinity chromatography of Trypanosoma cruzi glycoproteins.

Glycoproteins from Trypanosoma cruzi epimastigotes have been extracted by diiodosalycilic acid and lithium salts, and phenol-water biphasic partition. Peanut agglutinin has been used in a one step preparative method for fractionating the total extract in order to separate the so-called galactose-terminal glycoproteins. The different fractions have been studied by SDS electrophoresis, ultracentrifugation and immunoelectrophoresis techniques. The experimental immunogenicity, antigenicity and specificity of the PNA affinity fractions has been evaluated.

Animals↗

Characterisation of the peanut lectin-binding glycoproteins of human epidermal keratinocytes.

We have previously shown that peanut lectin (PNA) binding is a useful marker of keratinocyte terminal differentiation and have identified two PNA-binding glycoproteins with electrophoretic mobilities of approximately 250 kDa and 110 kDa [11]. We now report that in epidermis and stratified cultures of keratinocytes the binding patterns of PNA and the sialic acid-specific lectin Limax flavus agglutinin (LFA) are complementary, with LFA showing specificity for cells in the basal layer. LFA bound to the 250-kDa glycoprotein immunoprecipitated with an antiserum raised against the PNA-binding glycoproteins (anti PNA-gp), but not to the 110-kDa glycoprotein; it also bound additional high-molecular-weight material. These data suggest that the 250-kDa glycoprotein is expressed in the basal layer in a form with terminal sialic acid residues and suprabasally in a form with terminal galactose. LFA and anti-PNA-gp stained all cells in a range of cultured epithelial lines tested, whereas PNA stained only cells that had lost contact with the culture substratum, raising the possibility that loss of sialic acid residues is associated with stratification. Anti PNA-gp recognized glycoproteins of differing mobilities in these lines. Anti PNA-gp also stained epithelial cells in all tissues tested. In keratinocytes the PNA-binding glycoproteins were localised to the cell surface by immunoelectron microscopy; they were abundant on the microvilli and absent from desmosomal junctions. In conclusion, we have obtained further information about the nature of the PNA-binding glycoproteins in keratinocytes and related glycoproteins in other epithelial cell types.

Cells, Cultured↗

Separation of normozoospermic human spermatozoa into subpopulations by selective agglutination with peanut agglutinin.

Incubation of human spermatozoa of normozoospermic origin with the galactose specific lectin peanut agglutinin (PNA) resulted in agglutination of the majority of sperm. This finding enabled separation of sperm into two subpopulations. The major one, accounting for 87.0 +/- 12.7 (SD)% consisted of agglutinating sperm (PNA+), while the minor subpopulation (PNA-) did not bind the lectin. The correlation between the percentages of PNA- sperm and acrosome-damaged sperm, as detected by light microscopy prior to separation, was analysed and an overlapping has been found. Light and electron microscopy examination revealed that the PNA- cells were either acrosomeless or possessed severely damaged acrosomes while the PNA+ sperm were mostly free of such pathologies. Following treatment of sperm with fluorescin-conjugated PNA the single cells lacked any labeling while the agglutinates exhibited fluorescence. However, the binding of the lectin to sperm was non-uniform and differences in fluorescence intensity at various parts of the head have been observed. The sialic acid content in PNA+ sperm was found to be significantly higher (7.5 +/- 2.2 micrograms/10(8) sperm) as compared to PNA- sperm (2.1 +/- 0.6 micrograms/10(8) sperm). It was suggested that sialic acid content could be a biochemical indicator of acrosomal integrity. Separation of sperm by selective PNA agglutination might be valuable for elimination of sperm affected by acrosomal pathologies from the ejaculate.

Galactose↗

Separation of sub-populations of sperm with higher fertility potential from normal and pathological semen by peanut agglutinin.

Incubation of human sperm from semen with counts below 20 x 10(6)/ml with peanut agglutinin (PNA) resulted in agglutination of about 70% of sperm. An inverse correlation was found between non-agglutinating (PNA) sperm and sperm density (r = 0.48, p less than 0.01) and a direct correlation with acrosome-damaged sperm (r = 0.83, p less than 0.001). Binding of 125I-PNA to sperm revealed high, and possibly also low affinity binding sites on sperm from both normozoospermic and oligozoospermic origins. Quantitative transmission electron microscopy analysis revealed that agglutinated, PNA+, sperm had lower frequency of acrosomeless spermatozoa than PNA(-)-sperm (44% versus 77%) and higher fertility score (+0.18 +/- 0.1 and -1.5 +/- 0.87 respectively, p less than 0.01). Removal of PNA- sperm from oligozoospermic semen may increase the fertility score of the remaining sperm.

Cell Separation↗

Histochemical comparison of specificity of three bowel carcinoma-reactive lectins, Griffonia simplicifolia agglutinin-II, peanut agglutinin and Ulex europaeus agglutinin-I.

A comparison of the histochemical affinities of three lectins reputedly specific to human large bowel carcinoma, namely Griffonia simplicifolia agglutinin-II (GSA-II), peanut agglutinin (PNA) and Ulex europaeus agglutinin-I (UEA-I), was done using 28 specimens in which normal mucosa, adenoma and carcinoma tissue were present and in contact with each other. In the normal mucosa, GSA-II and PNA revealed only weak affinity to the Golgi region of epithelial cells, whereas UEA-I showed binding to the apical surface of columnar cells and goblet cell mucins, especially in the right colon. Adenoma was characterized by relatively intense reactivity of the Golgi regions of epithelial cells for GSA-II and PNA as well as reactivity of the apical surface of the columnar cells for UEA-I. In carcinomas the apical surface of columnar cell-type tumor cells was stained most intensely with UEA-I, and then in descending order with GSA-II and PNA. GSA-II- and PNA-reactive carcinoma cells occurred more frequently in invasive carcinoma than in intramucosal carcinoma. Goblet cell-type tumor cells retained the properties of their normal counterparts. Staining with these lectins, especially GSA-II-horseradish peroxidase, might be helpful in the identification of carcinoma cells and for analysis of carcinoma-associated antigens.

Adenocarcinoma↗

Lectin binding in tissues from hydatidiform mole, invasive mole and choriocarcinoma to concanavalin-A, wheat germ agglutinin and peanut agglutinin.

A light microscopic analysis of lectin receptors in normal placenta and trophoblastic disease was performed utilizing biotinylated Concanavalin-A (Con-A), wheat germ agglutinin (WGA), and peanut agglutinin (PNA), in conjunction with an avidin-biotin peroxidase complex. Hydatidiform mole, invasive mole and choriocarcinoma exhibited increased receptors to Con-A and WGA compared to normal placenta. Increased reactivity to Con-A and WGA was associated merely with increased growth and proliferation of trophoblasts rather than a malignant transformation. Normal placenta, partial and complete mole generally showed moderate to strong binding with PNA after neuraminidase treatment, while invasive mole and choriocarcinoma (11 of 15 cases) generally showed minimal to absent reaction with PNA. Heterogeneity of PNA binding in choriocarcinoma was manifested by the presence of PNA reactivity in the trophoblast membrane in 2 cases wherein no prior neuraminidase treatment was given. This suggests that in some malignant trophoblasts, there is absence of sialic acid in the terminal cell surface carbohydrate groups resulting in the exposure of N-acetylgalactoseamine.

Choriocarcinoma↗

Cell surface carbohydrates in proliferative epidermal lesions. II. Masking of peanut agglutinin (PNA) binding sites in solar keratoses, Bowen's disease, and squamous cell carcinoma by neuraminic acid.

Seventy-six skin biopsies of proliferative lesions were studied by using 4 different lectins and an avidin-biotin-peroxidase complex. In solar keratosis, Bowen's disease and squamous cell carcinoma, malignant-appearing keratinocytes exhibited loss of membrane staining with Concanavalia ensiformis agglutinin (Con A), but revealed cytoplasmic staining. When incubated with peanut agglutinin (PNA), the malignant keratinocytes did not stain. However, the PNA binding sites were not absent, but masked by sialic acid. Following cleavage of the sialic acid with neuraminidase, free PNA binding sites could be demonstrated in the plasma membranes. In contrast, the keratinocytes in keratoacanthomas showed membrane staining with Con A and also contained free PNA binding sites. These histochemical findings confirm and extend our earlier observations regarding cell surface carbohydrates in premalignant and malignant epidermal lesions.

ABO Blood-Group System↗

Peanut agglutinin immunohistochemistry of basal cell carcinoma.

103 biopsies of basal cell carcinomas (BCCs) were studied using peanut agglutinin (PNA), PNA antibody and the peroxidase-antiperoxidase technique; 53 specimens of various skin tumors were examined as controls; 96% of the BCCs showed a band-like peritumorous reaction not seen in any other tumor except for the Pinkus' fibroepithelioma. The peritumorous PNA-binding was continuous in 51% of the BCCs studied and discontinuous in 45%; only 4% were completely negative. Both fibroepitheliomas revealed a discontinuous PNA-positive band. A narrow basement membrane-like positivity was seen around some small hair follicles situated within 2 neurofibromas and under one seborrhoeic keratosis. The PNA-binding band is apparently neither fibronectin, laminin, Type IV or Type V collagen and is not a constituent of normal epidermal, adnexal and vascular basement membranes.

Basement Membrane↗

Histochemical study of the influence of transplanted teeth with periodontal ligament of the binding of peanut agglutinin in rat dorsal skin.

Our previous study showed that the expression of carbohydrate residues in junctional epithelium (JE) after resection is closely related to attachment and stratification along the dental root surface. However, the influence of the periodontal ligament on carbohydrate expression has still not been clarified. In this study we examined the relationship between the presence of periodontal ligament and the expression of carbohydrate residues on epithelium regenerating along root surfaces. We transplanted extracted rat molars with or without periodontal ligament tissue, repeatedly frozen and thawed teeth with ligament and demineralized teeth without ligament into the dorsal skin of rats. After 2, 3, 5, 7, 10, 14 or 21 d, dorsal cutaneous tissues containing transplanted teeth were resected, fixed, decalcified and embedded in paraffin. Serial sections were stained histochemically with the HRP-conjugated lectin, peanut agglutinin (PNA) to observe the expression of carbohydrate residues in regenerating epithelium. Histochemical observation revealed that lectin binding reactions were changed from the characteristics of skin to those of JE when the regenerating epithelium was attached and stratified along the tooth with unfrozen or frozen tissue. These results suggested that the structural formation and expression of PNA in regenerating epithelium around the root surface were influenced by not only the tooth but also by the periodontal ligament.

Animals↗

In vitro influence of Phaseolus vulgaris, Griffonia simplicifolia, concanavalin A, wheat germ, and peanut agglutinins on HCT-15, LoVo, and SW837 human colorectal cancer cell growth.

BACKGROUND/AIMS: Compared with normal colonic mucosa, lectin receptor expression is increased in hyperplastic and neoplastic tissues; some lectins have been shown to influence human colonic epithelial cell proliferation. The aim was to assess further the influence of five lectins (Phaseolus vulgaris (PNA), Griffonia simplicifolia (GSA), concanavalin A (Con A), wheat germ (WGA), and peanut (PHA-L) agglutinins) on cellular growth in three human colorectal cancer cell lines (LoVo, HCT-15 and SW837). METHODS: Cells were cultured in four lectin concentrations (0.1, 1.0, 10, and 100 micrograms/ml) and growth assessed at days 2, 3, 5, and 7. The experiments were performed in media supplemented with either 1% or 10% fetal calf serum (FCS). Growth was assessed using the MTT (3-(4,5)-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) colorimetric assay. RESULTS: Growth in each cell line was greatly affected by at least two of the lectins tested. There was some variation in the effect of a given lectin on different cell lines. Lectin effects showed a dose-response and the greatest effects generally resulted from the highest concentrations at the longest culture time. WGA and Con A induced large effects in all cell lines; the effects of Con A were partly blocked by the higher concentration of FCS. PNA had modest and uniform stimulatory effects overall. The effects of GSA and PHA-L varied between cell lines. CONCLUSIONS: The lectins studied all have the potential to affect colonic cancer growth in vitro. Many dietary lectins are resistant to digestion and may have important effects in vitro but the definition of their role in human colonic cancer biology must take into account the variability in lectin response.

Cell Division↗

Binding of peanut lectin to specific epithelial cell types in kidney.

The binding of peanut agglutinin (PNA) to epithelial membranes of the rabbit kidney was evaluated at the light- and electron-microscope level using PNA conjugated to horseradish peroxidase. In the renal cortex and outer stripe of the medulla PNA appears to bind exclusively to the luminal membrane of intercalated cells in connecting tubules and collecting ducts. PNA also binds to the thin descending limb of the loop of Henle in the inner stripe and inner zone of the medulla. This very specific affinity of PNA should be useful in the isolation and characterization of specific cell types in cytologically heterogeneous epithelia.

Animals↗

Peanut lectin binds to a subpopulation of mitochondria-rich cells in the rainbow trout gill epithelium.

Fluorescently labeled peanut lectin agglutinin (PNA-FITC) was used to identify a subtype of mitochondria-rich (MR) cells in the gills of freshwater rainbow trout. In situ binding of PNA-FITC was visualized by inverted fluorescence microscopy and found to bind to cells on the trailing edge of the filament epithelium as demonstrated by differential interference contrast optics. The amount of PNA-FITC binding on the filament epithelium increased with cortisol pretreatment concomitant with an increased chloride cell fractional area as demonstrated by scanning electron microscopy. Dispersed gill cells were isolated by trypsinization and separated using a discontinuous Percoll density gradient. Cells migrating to the 1.06-1.09 g/ml interface were found to be MR as demonstrated by staining with the vital mitochondrial dye 4-(4-(dimethylamino)styryl)-N-methylpyridinium iodide and transmission electron microscopy (TEM). However, only approximately 40% of the MR cells were found to bind PNA-FITC. Cortisol pretreatment increased the relative numbers of MR cells isolated from the dispersed gill cell population, but the relative proportions of PNA binding cells remained unchanged. Ultrastructural analysis of isolated cells in the TEM demonstrated that the MR cell fraction was comprised of a mixed population of chloride cells and pavement cells.

Animals↗

Postnatal maturation of rabbit renal collecting duct. III. Peanut lectin-binding intercalated cells.

Measurements of transepithelial HCO3 transport in the rabbit cortical collecting duct (CCD) indicate that net HCO3 secretion becomes apparent only after the first month of life [F. M. Mehrgut, L. M. Satlin, and G. J. Schwartz, Am. J. Physiol. 259 (Renal Fluid Electrolyte Physiol. 28): F801-F808, 1990]. We used fluorescent probes and immunocytochemistry to trace the postnatal functional development of the beta-intercalated cell, the HCO3-secreting cell of the fully differentiated CCD. Throughout maturation, the beta-intercalated cell was empirically identified by its selective uptake of the pH-sensitive dye 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein, an alkaline cell pH, apical binding to peanut agglutinin (PNA) and monoclonal antibody B63, and by its functional capacity for apical Cl-HCO3 exchange as manifested by Cl-dependent extrusion of an intracellular alkali load. Compared with the mature segment, the neonatal mid-CCD exhibited fewer intercalated cells, which were characterized by a less alkaline cell pH, reduced apical Cl-HCO3 exchange activity, and shorter apical binding profiles for PNA. There was evidence for basolateral Cl conductance and similar buffering capacity at all ages. In the neonatal outer cortex there was little or no binding to PNA or to B63. As soon as cell surface antigens characteristic of the fully differentiated beta-cell were detected, functional studies indicated the presence, albeit reduced, of apical Cl-HCO3 exchange. Thus there is postnatal proliferation and maturation of HCO3-secreting intercalated cells in the rabbit kidney; the origin of these cells remains to be determined.

Animals↗

Inhibition of bicarbonate transport in peanut lectin-positive intercalated cells by a monoclonal antibody.

Intercalated cells (ICC) of the collecting duct are believed to secrete acid (alpha-type) or HCO3 (beta-type). Although these two types of ICC are functionally mirror images of each other, several components in their cell membranes are clearly unique. As a first step in defining the molecular composition of beta-ICC membranes, we raised cell-specific monoclonal antibodies (MAb) against surface antigens. One of these MAb, designated B63, reacts with the apical membrane of peanut lectin agglutinin (PNA)-positive cells of the kidney cortex. B63-positive cells do not react with antibodies against band 3 (the basolateral C1/HCO3 exchanger) or ST.48, markers for alpha-ICC and principal cells, respectively. Despite a significant positive correlation between PNA and B63 staining intensities, determined by flow cytometry, these markers react with separate antigens, as indicated by competition studies and the different distribution of the two antigens. In addition to renal beta-ICC, B63 antigen is present in tissues that are involved in HCO3 secretion, such as the pancreas, salivary glands, and the small intestine, suggesting that it might play a role in HCO3 secretion. To test this hypothesis more directly, we tested the effect of MAb B63 on HCO3 secretion and on changes in intracellular pH (pHi) in isolated perfused cortical collecting ducts. Luminal Cl removal in the presence of luminal 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid resulted in a reversible increase in pHi. Luminal application of MAb B63 prevented this change in pHi. MAb B63 also significantly inhibited (by 37.7 +/- 7.3%) HCO3 secretion by isolated perfused tubules, whereas another MAb (MAb 601), which reacts with a separate antigen on beta-ICC, did not alter HCO3 secretion or pHi. These results indicate that B63 antigen plays an important role in HCO3 secretion: it might be either the apical anion exchanger of beta-ICC or an associated regulatory protein.

Animals↗

Changes in the fatty acid patterns of brain phospholipids during development of rats fed peanut or rapeseed oil, taking into account differences between milk and maternal food.

The nature and amount of essential fatty acids in dietary fat play a leading part in the repartition of brain polyunsaturated fatty acids (n-3 and n-6). In order to determine precisely the respective roles of linolenic and linoleic acids in the diet on rat brain development, we used two diets in which the percentage of linolenic acid (18:3 n-3) was different. The animals were fed peanut oil (group A) or rapeseed oil (group B) during pregnancy and throughout lactation. The study of the fatty acid composition of gastric milk showed that the levels of linoleic acid (18:2 n-6) and more so linolenic acid (18:3 n-3) were much lower than in dietary fats. In group B, the 18:3 n-3 level of gastric content was about four times lower (2.4%) than in the maternal diet (8.5%) at the beginning of the suckling period and significantly increased until weaning. Analysis of the fatty acid composition of ethanolamine phosphoglycerides showed that docosapentaenoic acid delta 7-10-13-16-19 (22:5 n-3) and docosahexaenoic acid delta 4-7-10-13-16-19 (22:6 n-3) levels increased in group B in relation to group A and, on the other hand, the docosapentaenoic acid delta 4-7-10-13-16 (22:5 n-6) level decreased in group B. The sum of (n-3 + n-6) fatty acids did not change in either group B or group A. In our experimental conditions, we found no marked effect of diet composition upon conversion of linoleic acid to arachidonic acid. In summary, linolenic acid can be utilized in the brain (rather than linoleic acid) to provide long-chain polyunsaturated fatty acids and the amount of n-3 fatty acids would correlate with the desaturation activity of docosatetraenoic acid delta 7-10-13-16 (22:4 n-6) to docosapentaenoic acid delta 4-7-10-13-16 (22:5 n-6).

Animals↗

Assessment of UDP-galactosyl-transferase activity in gastric mucosa of patients with chronic liver disease using an enzyme-linked peanut agglutinin binding assay.

Gastric mucin plays an important role in protecting mucosa from irritants such as acids and pepsin, and UDP-galactosyltransferase is a key enzyme in mucin synthesis. In order to study the synthesis of gastric mucin in patients with chronic liver disease, we developed a new assay using a peanut agglutinin lectin to measure this enzyme in human gastric mucosa obtained by endoscopic biopsy. Enzyme activity correlated well with that determined with a previous method using radiolabeled galactose. The enzyme activity in gastric mucosa of cirrhotic patients was significantly lower than in patients with chronic hepatitis or in normal controls and correlated with the amount of mucin in surface epithelial cells. Our findings suggest that the synthesis of gastric mucin is impaired in patients with liver cirrhosis.

Adult↗

Peanut agglutinin inhibits proliferation of cultured breast cancer cells.

Cultured breast cancer cells express on their surface glycoproteins which are recognized by the peanut lectin (PNA). The proliferation of these cells (ZR-75.1 and 734-B) was inhibited by PNA. A mammary carcinoma cell line (BT-20) which does not react with PNA was not affected by this lectin. The combination of PNA with either retinoic acid or 4-hydroxy-tamoxifen led to an additive amplification of the antiproliferative activity. Also interferon-gamma showed in combination with PNA an improved growth-inhibitory action.

Asialoglycoproteins↗

Lectin binding in human breast cancer: clinical and pathologic correlations with fluorescein-conjugated peanut, wheat germ and concanavalin A binding.

Cell surface glycoconjugates of human breast cancer tissue were investigated using FITC peanut (PNA), wheat germ (WGA) and jackbean (concanavalin A; Con A) agglutinins. Although PNA and WGA binding patterns differed when normal and malignant breast tissues were compared, the specificity of this finding was poor and neither PNA nor WGA binding correlated with oestrogen receptor status or clinical outcome. Con A binding on the other hand was not seen in normal breast tissue. The percentage of Con-A-positive (Con A+) tumours increased progressively with advancing stage (16% Con A+ in stage I, 40% Con A+ in stage III) and there was a trend towards longer disease-free survival of patients with Con A- as compared to those with Con A+ tumours. However, in a multivariate analysis it was found that these differences were explained by the association with the stage of the disease.

Breast Neoplasms↗