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Mannose-binding Lectin (mannose-binding + lectin)

Distribution by Scientific Domains

Medical Sciences	60%
Life Sciences	20%

Distribution within Medical Sciences

Immunology	33%
Allergy & Clinical Immunology	16%

Selected Abstracts

Photoprotein aequorin as a novel reporter for SNP genotyping by primer extension,application to the variants of mannose-binding lectin gene,

HUMAN MUTATION, Issue 3 2006
Panayotis G. Zerefos
Abstract Mannose-binding lectin (MBL) is a key component of the innate immune system, and its deficiency is associated with increased susceptibility to various infections and autoimmune disorders. Since several nucleotide variations in the mannose-binding lectin 2 gene (MBL2) have been associated with the functional deficiency of MBL, there is a growing need to screen its allelic variants and develop genotyping methods for MBL2. In this context we propose a rapid, robust, cost-efficient, and automatable method for detecting all known allelic variants of MBL2. This report introduces for the first time the photoprotein aequorin as a reporter in genotyping by primer extension (PEXT) reactions. The method involves a single PCR amplification of a genomic region that spans all six variant nucleotide sites, i.e., three structural mutations in exon 1 (c.154C>T, pArg52Cys; c.161A>G, p.Gly54Asp; and c.170A>G, p.Gly57Glu), two single nucleotide polymorphisms (SNPs) at positions c.,619G>C and c.,290G>C (promoter region), and one SNP at position c.,66C>T of the 5, untranslated region. PCR is followed by PEXT reactions for each site. Biotin-dUTP is incorporated in the extended primer. The genotyping primers contain a poly(dA) segment at their 5, end. The products are captured by hybridization on the surface of microtiter wells that are coated with a poly(dT)-albumin. The extended primers only are detected by reaction with a streptavidin-aequorin conjugate. The bound photoprotein aequorin is measured within 3,sec by simply adding Ca2+. We carried out extensive optimization studies of the PEXT reaction and genotyped the six nucleotide variant sites using blood specimens from 27 normal DNA samples. The results of the proposed method agreed entirely with the sequencing data. Hum Mutat 27(3), 279,285, 2006. © 2006 Wiley-Liss, Inc. [source]

The lectin-complement pathway , its role in innate immunity and evolution

IMMUNOLOGICAL REVIEWS, Issue 1 2004
Teizo Fujita
Summary:, Innate immunity was formerly thought to be a non-specific immune response characterized by phagocytosis. However, innate immunity has considerable specificity and is capable of discriminating between pathogens and self. Recognition of pathogens is mediated by a set of pattern recognition receptors, which recognize conserved pathogen-associated molecular patterns (PAMPs) shared by broad classes of microorganisms, thereby successfully defending invertebrates and vertebrates against infection. Lectins, carbohydrate-binding proteins, play an important role in innate immunity by recognizing a wide range of pathogens. Mannose-binding lectin (MBL) and ficolin are lectins composed of a lectin domain attached to collagenous region. However, they use a different lectin domain: a carbohydrate recognition domain (CRD) is responsible for MBL and a fibrinogen-like domain for ficolin. These two collagenous lectins are pattern recognition receptors, and upon recognition of the infectious agent, they trigger the activation of the lectin-complement pathway through attached serine proteases, MBL-associated serine proteases (MASPs). A similar lectin-based complement system, consisting of the lectin,protease complex and C3, is present in ascidians, our closest invertebrate relatives, and functions in an opsonic manner. We isolated several lectins homologous to MBLs and ficolins and several MASPs in invertebrates and lower vertebrates, and herein we discuss the molecular evolution of these molecules. Based on these findings, it seems likely that the complement system played a pivotal role in innate immunity before the evolution of an acquired immune system in jawed vertebrates. [source]

Prognosis in pediatric hematologic malignancies is associated with serum concentration of mannose-binding lectin-associated serine protease-2 (MASP-2)

PEDIATRIC BLOOD & CANCER, Issue 1 2009
Aina Zehnder MD
Abstract Background Mannose-binding lectin (MBL) and MBL-associated serine protease-2 (MASP-2) are key components of the lectin pathway of complement activation. Their serum concentrations show a wide interindividual variability. This study investigated whether the concentration of MBL and MASP-2 is associated with prognosis in pediatric patients with cancer. Methods In this retrospective multicenter study, MBL and MASP-2 were measured by commercially available ELISA in frozen remnants of serum taken at diagnosis. Associations of overall survival (OS) and event-free survival (EFS) with MBL and MASP-2 were assessed by multivariate Cox regression accounting for prognostically relevant clinical variables. Results In the 372 patients studied, median serum concentration of MBL was 2,808 µg/L (range, 2,10,060) and 391 µg/L (46,2,771) for MASP-2. The estimated 4-year EFS was 0.60 (OS, 0.78). In the entire, heterogeneous sample, MBL and MASP-2 were not significantly associated with OS or EFS. In patients with hematologic malignancies, however, higher MASP-2 was associated with better EFS in a significant and clinically relevant way (hazard ratio per tenfold increase (HR), 0.22; 95% CI, 0.09,0.54; P,=,0.001). This was due to patients with lymphoma (HR, 0.11; 95% CI, 0.03,0.47; P,=,0.003), but less for those with acute leukemia (HR, 0.35; 95% CI, 0.11,1.15; P,=,0.083). Conclusion In this study, higher MASP-2 was associated with better EFS in pediatric patients with hematologic malignancies, especially lymphoma. Whether MASP-2 is an independent prognostic factor affecting risk stratification and anticancer therapy needs to be assessed in prospective, disease-specific studies. Pediatr Blood Cancer 2009;53:53,57. © 2009 Wiley-Liss, Inc. [source]

Crystallization and initial X-ray diffraction analysis of a mannose-binding lectin from champedak

ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 5 2010
Mads Gabrielsen
Mannose-binding lectin from champedak (Artocarpus integer) is a homotetramer with a single-monomer molecular weight of 16,800,Da. Previous work has shown it to bind IgE and IgM, as well as being a mitogen of T cells in humans. Champedak mannose-binding lectin has successfully been used to detect altered glycosylation states of serum proteins. The protein was crystallized at 293,K in space group P212121 (unit-cell parameters a = 76.89, b = 86.22, c = 95.37,Å) and the crystals diffracted to 2.0,Å resolution. [source]

Mannose binding lectin gene polymorphisms and asthma

CLINICAL & EXPERIMENTAL ALLERGY, Issue 9 2007
X. Wang
Summary Background Bronchial asthma is a chronic inflammatory disorder of the airways. Recently, it has been suggested that complement plays significant roles in asthma. Mannose-binding lectin (MBL) is one of the key molecules in complement activation pathways that are associated with several infectious and immune disorders. Subjects and method To investigate whether MBL plays roles in asthma, we analysed MBL2 polymorphisms (allele B, H/L and Y/X) and plasma MBL levels in a Japanese adult population including 232 healthy controls and 579 asthmatics. Results Although there was linkage disequilibrium among the three polymorphisms, each polymorphism significantly affects serum MBL levels independently. However, there were no significant differences between asthmatics and controls in MBL2 genotype distribution and in MBL concentrations [1.47±0.07(SE) mg/L for asthmatics and 1.66±0.14 mg/L for controls, P=0.2]. MBL levels and genotype have no significant relationship with serum IgE, pulmonary functions, and the severity of asthma. Conclusion Although plasma MBL levels depend on the MBL2 polymorphisms, these polymorphisms and plasma MBL levels are not associated with the asthma phenotype. [source]

Complement Activation in Emergency Department Patients With Severe Sepsis

ACADEMIC EMERGENCY MEDICINE, Issue 4 2010
John G. Younger
Abstract Objectives:, This study assessed the extent and mechanism of complement activation in community-acquired sepsis at presentation to the emergency department (ED) and following 24 hours of quantitative resuscitation. Methods:, A prospective pilot study of patients with severe sepsis and healthy controls was conducted among individuals presenting to a tertiary care ED. Resuscitation, including antibiotics and therapies to normalize central venous and mean arterial pressure (MAP) and central venous oxygenation, was performed on all patients. Serum levels of Factor Bb (alternative pathway), C4d (classical and mannose-binding lectin [MBL] pathway), C3, C3a, and C5a were determined at presentation and 24 hours later among patients. Results:, Twenty patients and 10 healthy volunteer controls were enrolled. Compared to volunteers, all proteins measured were abnormally higher among septic patients (C4d 3.5-fold; Factor Bb 6.1-fold; C3 0.8-fold; C3a 11.6-fold; C5a 1.8-fold). Elevations in C5a were most strongly correlated with alternative pathway activation. Surprisingly, a slight but significant inverse relationship between illness severity (by sequential organ failure assessment [SOFA] score) and C5a levels at presentation was noted. Twenty-four hours of structured resuscitation did not, on average, affect any of the mediators studied. Conclusions:, Patients with community-acquired sepsis have extensive complement activation, particularly of the alternative pathway, at the time of presentation that was not significantly reversed by 24 hours of aggressive resuscitation. ACADEMIC EMERGENCY MEDICINE,2010; 17:353,359 © 2010 by the Society for Academic Emergency Medicine [source]

Photoprotein aequorin as a novel reporter for SNP genotyping by primer extension,application to the variants of mannose-binding lectin gene,

Inhibition of DC-SIGN-mediated trans infection of T cells by mannose-binding lectin

IMMUNOLOGY, Issue 1 2003
Gregory T. Spear
Summary Some dendritic cells (DC) express a cell-surface lectin called ,dendritic cell-specific intracellular adhesion molecule 3 (ICAM-3)-grabbing non-integrin' (DC-SIGN). DC-SIGN has been shown to mediate a type of infection called ,trans' infection, where DC bind human immunodeficiency virus (HIV) and efficiently transfer the virus to T cells. We investigated the possibility that mannose-binding lectin (MBL), a soluble lectin that functions as a recognition molecule in innate immunity and that binds to HIV, could block trans infection mediated by DC-SIGN. Binding studies with glycoprotein (gp)120/gp41-positive and -negative virus preparations suggested that DC-SIGN and MBL bind primarily to glycans on gp120/gp41, as opposed to glycans on host-cell-derived proteins, indicating a close overlap in the binding site of the two lectins and supporting the notion that MBL could prevent binding of HIV to DC-SIGN. Preincubation of X4, R5 or dual-tropic HIV strains with MBL prevented DC-SIGN-mediated trans infection of T cells. The mechanism of MBL blocking trans infection of T cells was at least partly caused by blocking of virus binding to DC-SIGN positive cells. This study shows that MBL prevents DC-SIGN-mediated trans infection of T cells in vitro and suggests that in infected persons, MBL may inhibit DC-SIGN-mediated uptake and spread of HIV. [source]

Mannose-binding lectin gene polymorphisms in relation to periodontitis

JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 11 2008
Anna Louropoulou
Abstract Aim: To investigate the correlation of six functional polymorphisms in the MBL gene with MBL plasma levels in relation to periodontitis. Material and Methods: A total of 92 periodontitis patients and 70 controls, all of Caucasian origin, were included. Patients and controls were genotyped for the L/H, X/Y, P/Q, A/D, A/B and A/C polymorphisms. Distributions of genotypes, rate of allele carriage and allele frequencies were compared between patients and controls. Patients and controls were subdivided in groups of genotypes. Plasma MBL levels were compared between different genotype groups. Results: On the basis of genotyping, three phenotypes with regard to mannose-binding lectin (MBL) production were distinguished: high-producers, low-producers and deficient subjects. No differences in the genotype frequencies were observed between patients and controls. Within patients and controls, subjects with the high-producing genotypes had significantly higher MBL plasma levels than low-producers and deficient subjects (p<0.001). Plasma MBL was higher in low-producer patients compared with low-producer controls (padjusted=0.021). Conclusion: No association could be observed between MBL gene polymorphisms and susceptibility to periodontitis in Caucasians. However, now that genotyping could distinguish the low producing and deficient subjects from the high-producers, it was observed, for the first time, that MBL acts as a weak acute-phase protein in periodontitis. [source]

Mannose-binding lectin cord blood levels and respiratory symptoms during infancy: a prospective birth cohort study

PEDIATRIC ALLERGY AND IMMUNOLOGY, Issue 3 2009
Luregn Jan Schlapbach
Respiratory infections cause considerable morbidity during infancy. The impact of innate immunity mechanisms, such as mannose-binding lectin (MBL), on respiratory symptoms remains unclear. The aims of this study were to investigate whether cord blood MBL levels are associated with respiratory symptoms during infancy and to determine the relative contribution of MBL when compared with known risk factors. This is a prospective birth cohort study including 185 healthy term infants. MBL was measured in cord blood and categorized into tertiles. Frequency and severity of respiratory symptoms were assessed weekly until age one. Association with MBL levels was analysed using multivariable random effects Poisson regression. We observed a trend towards an increased incidence rate of severe respiratory symptoms in infants in the low MBL tertile when compared with infants in the middle MBL tertile [incidence rate ratio (IRR) = 1.59; 95% confidence interval (CI): 0.95,2.66; p = 0.076]. Surprisingly, infants in the high MBL tertile suffered significantly more from severe and total respiratory symptoms than infants in the middle MBL tertile (IRR = 1.97; 95% CI: 1.20,3.25; p = 0.008). This association was pronounced in infants of parents with asthma (IRR = 3.64; 95% CI: 1.47,9.02; p = 0.005). The relative risk associated with high MBL was similar to the risk associated with well-known risk factors such as maternal smoking or childcare. In conclusion the association between low MBL levels and increased susceptibility to common respiratory infections during infancy was weaker than that previously reported. Instead, high cord blood MBL levels may represent a so far unrecognized risk factor for respiratory morbidity in infants of asthmatic parents. [source]

Recombinant C1 inhibitor in brain ischemic injury,

ANNALS OF NEUROLOGY, Issue 3 2009
Raffaella Gesuete BD
Objective C1 inhibitor (C1-INH) is an endogenous inhibitor of complement and kinin systems. We have explored the efficacy and the therapeutic window of the recently available human recombinant (rh) C1-INH on ischemic brain injury and investigated its mechanism of action in comparison with that of plasma-derived (pd) C1-INH. Methods rhC1-INH was administered intravenously to C57Bl/6 mice undergoing transient or permanent ischemia, and its protective effects were evaluated by measuring infarct volume and neurodegeneration. The binding profiles of rhC1-INH and pdC1-INH were assessed in vitro using surface plasmon resonance. Their localization in the ischemic brain tissue was determined by immunohistochemistry and confocal analysis. The functional consequences of rhC1-INH and pdC1-INH administration on complement activation were analyzed by enzyme-linked immunosorbent assay on plasma samples. Results rhC1-INH markedly reduced cerebral damage when administered up to 18 hours after transient ischemia and up to 6 hours after permanent ischemia, thus showing a surprisingly wide therapeutic window. In vitro rhC1-INH bound mannose-binding lectin (MBL), a key protein in the lectin complement pathway, with high affinity, whereas pdC1-INH, which has a different glycosylation pattern, did not. In the ischemic brain, rhC1-INH was confined to cerebral vessels, where it colocalized with MBL, whereas pdC1-INH diffused into the brain parenchyma. In addition, rhC1-INH was more active than pdC1-INH in inhibiting MBL-induced complement activation. Interpretation rhC1-INH showed a surprisingly wider time window of efficacy compared with the corresponding plasmatic protein. We propose that the superiority of rhC1-INH is due to its selective binding to MBL, which emerged as a novel target for stroke treatment. Ann Neurol 2009;66:332,342 [source]

Distal intestinal gene expression in Atlantic salmon (Salmo salar L.) fed genetically modified maize

AQUACULTURE NUTRITION, Issue 1 2009
M.K. FRØYSTAD-SAUGEN
Abstract In the current experiment, RNA was isolated from the distal intestine (DI) of Atlantic salmon-fed fishmeal-based diets containing either genetically modified (GM) maize (Bt maize, Mon810®, Monsanto Company, St. Louis, Missouri, USA) or its conventional near-isogenic parental line (non-GM) for 82 days, both at 300 g kg,1 inclusion. From a suppression subtractive hybridization (SSH) cDNA library, 192 clones with similarity to both known and novel Atlantic salmon sequences were identified. Real-time PCR was used to study the differential expression of 10 clones between the dietary groups. Expression of a clone showing high protein similarity to proton-dependent high-affinity oligopeptide transporter was significantly upregulated in fish-fed GM maize compared with fish-fed non-GM maize. No significant differences in expression were observed for the nine other clones showing similarity to the following proteins: heat shock protein 90B, procathepsin B, interferon gamma-inducible protein 30, ferritin heavy subunit, serum lectin isoform/C-type mannose-binding lectin, fatty acid-binding protein/gastrotropin, ATP synthase [H+ transporting, mitochondrial F0 complex, subunit c (ATPSYNT)], sonic hedgehog and translationally controlled tumour protein. In conclusion, only minor differences in DI transcriptional gene expression was observed between fish fed the GM and non-GM maize diets. [source]

Systemic lupus erythematosus in a multiethnic US cohort: XXXIV.

ARTHRITIS & RHEUMATISM, Issue 6 2006
Deficient mannose-binding lectin exon 1 polymorphisms are associated with cerebrovascular but not with other arterial thrombotic events
Objective To study the association between deficient mannose-binding lectin (MBL) genotypes and arterial thrombotic events in systemic lupus erythematosus (SLE). Methods Patients with SLE of Hispanic, African American, and Caucasian ethnicity from LUMINA (LUpus in MInorities, NAture versus nurture), a multiethnic, longitudinal study of outcome, were studied. Arterial thrombotic events (myocardial infarction, angina, coronary artery bypass graft surgery, stroke, claudication, gangrene, or tissue loss and/or peripheral arterial thrombosis) that occurred after diagnosis were recorded. Genotyping for MBL gene polymorphisms was performed and their distribution was compared between patients who did and did not have thrombotic events. Results There were 58 events (21 cardiovascular, 27 cerebrovascular, and 10 peripheral vascular) in 48 patients. Patients who had thrombotic events were older and were more likely to be smokers, to have more severe disease, and to have accrued more damage overall. Also, a larger proportion of these patients had C-reactive protein values in the highest quintile of distribution. No significant difference in arterial thrombotic events was found in patients homozygous for MBL-deficient alleles compared with others. Similar results were seen within ethnic groups. Caucasians who developed potential thrombotic events exhibited a higher frequency of MBL-deficient alleles, but the difference was not statistically significant for all events together or for cardiovascular and cerebrovascular events combined. However, when only the cerebrovascular events were considered, the difference became statistically significant. Conclusion Age, smoking, and measures of activity and damage were associated with arterial thrombotic events in patients with SLE, but MBL-deficient genotypes were not, with cerebrovascular events in Caucasians being the exception. The relationship between MBL-variant alleles and arterial thrombotic events may exist only within select ethnic groups and event types. [source]

Crystallization and initial X-ray diffraction analysis of a mannose-binding lectin from champedak

Anti-endothelial cell antibodies in rheumatic heart disease

CLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 3 2010
V. Scalzi
Summary To evaluate the anti-endothelial cell antibodies (AECA), anti-cardiolipin antibodies (aCL) and serum mannose-binding lectin (MBL) profiles of a large cohort of Yemeni patients with rheumatic heart disease (RHD) and to correlate these findings with clinical features of the disease. Patients (n = 140) were recruited from Al-Thawra Hospital in Sana'a, Yemen. All had RHD diagnosed according to modified Jones' criteria. We also studied 140 sex- and age-matched healthy blood donors from the same area. Echocardiography was performed according to the recommendations of the American Society of Echocardiography. Solid phase enzyme-linked immunosorbent assays (ELISAs) were used to measure AECA and aCL titres and serum MBL levels. Forty per cent of the patients were AECA-positive, but only 7·8% were positive for aCL antibodies. Serum MBL levels were significantly lower in the RHD group (median 4221 ng/ml versus 5166 ng/ml in healthy controls). AECA titres were correlated positively with patient age, duration of RHD and the severity of aortic stenosis, as determined by echocardiographic findings. In several autoimmune rheumatic diseases, such as systemic lupus erythematosus, vasculitis and scleroderma, AECA have been shown to play pathogenic roles by producing proinflammatory and procoagulant effects (increased expression of adhesion molecules and tissue factors, increased cytokine release) in endothelial cells. In RHD, these autoantibodies might represent a pathological link between activation of the valvular endothelium and valvular damage. [source]

Design of a complement mannose-binding lectin pathway-specific activation system applicable at low serum dilutions

CLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 3 2006
M. Harboe
Summary Recently we showed that alternative pathway (AP) amplification was responsible for more than 80% of specific classical pathway-induced terminal pathway activation under physiological conditions. The present study aimed to design a system for specific lectin pathway (LP) activation applicable at low serum dilutions with a fully functional AP. Comparison between activation of normal human serum (NHS), a mannose-binding lectin (MBL) homozygous D/D -deficient serum, and sera deficient in C1q and C2, all diluted 1 : 2, was essential to document optimal conditions for LP specificity. Mannan on the solid phase of enzyme-linked immunosorbent assay (ELISA) plates was used for activation, showing 0·5 µg mannan/well to give optimal conditions because at this concentration a good signal was preserved for C4 and TCC deposition in NHS, whereas the C3 deposition observed in C2-deficient serum at higher mannan concentrations reached nadir at 0·5 µg/well, indicating a lack of direct AP activation under these conditions. Pooled NHS and C1q-deficient serum gave the same degree of C4 and terminal complement complex (TCC) deposition, whereas deposition of these products was not obtained with MBL-deficient serum. Reconstitution with purified MBL, however, restored the depositions. A blocking anti-MBL monoclonal antibody (mAb) completely abolished the complement deposition, in contrast to a non-inhibiting anti-MBL mAb. Activation of C2-deficient serum induced C4 deposition similar to NHS, but negligible deposition of C3 and TCC, confirming the lack of direct activation of AP. Thus, this assay is unique in being LP-specific at low serum dilution and thus particularly suitable to study LP activation mechanisms and the role of AP amplification under physiological conditions. [source]

C4d deposition on peritubular capillary (PTC) in the protocol biopsy of ABO-incompatible kidney transplantation under the treatment with anti-CD20 antibody and without splenectomy

CLINICAL TRANSPLANTATION, Issue 2007
Naofumi Imai
Abstract:, For the desensitization of A/B antigens, we had developed and reported a new potent immunosuppressive treatment, which is the pre-prescription of anti-CD20 monoclonal antibody with mycophenolate mofetil and low-dose steroid. Using this kind of desensitization therapy, splenectomy is not required at the kidney transplantation. Complement C4d deposition on peritubular capillary (PTC) in graft biopsy has been reported as a relatively reliable marker for humoral rejection. However, the C4d deposition was often observed in the graft biopsy of ABO-incompatible kidney transplantation even with no rejection findings. The aim of this study was to examine the effect of this treatment on C4d deposition on PTC. Baseline and protocol graft biopsies obtained from 12 recipients of ABO incompatible kidney transplants were evaluated by light and immunofluorescence microscopy. To elucidate the involvement of classical and/or lectin pathway of complement cascades in C4d deposition, we examined the deposition of the initial activating proteins on PTC, IgG and IgM in the classical pathway and mannose-binding lectin (MBL), H-ficolin, L-ficolin, MBL-associated serine protease (MASP)-1 and MASP-2 in the lectin pathway. Three out of nine available baseline biopsy specimens showed diffuse C4d and IgM deposition on PTC. In the protocol biopsy, nine of 12 specimens revealed diffuse C4d deposition on PTC. Five of them had positive deposition of IgM and H-ficolin on PTC, whereas the other initial proteins were not detected in all specimens. Apart from one case, the histological findings of the protocol biopsies were normal or borderline changes. Our study suggested that although the new treatment with anti-CD20 antibody treatment and without splenectomy was clinically effective, it did not perfectly inhibit C4d deposition on PTC. It also confirmed the dual activation of both classical and lectin pathways in the process of C4d deposition on PTC in ABO-incompatible transplantation. [source]

Histochemical Analysis of Glycoconjugates in the Skin of a Catfish (Arius Tenuispinis, Day)

ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 1 2010
A. Al-Banaw
Summary A histochemical study using conventional carbohydrate histochemistry (periodic-acid staining including diastase controls, alcian blue staining at pH 1 and 2.5) as well as using a battery of 14 fluorescein isothiocyanate (FITC)-labelled lectins to identify glycoconjugates present in 10 different areas of the skin of a catfish (Arius tenuispinis) was carried out. The lectins used were: mannose-binding lectins (Con A, LCA and PSA), galactose-binding lectins (PNA, RCA), N -acetylgalactosamine-binding lectins (DBA, SBA, SJA and GSL I), N -acetylglucosamine-binding lectins (WGA and WGAs), fucose-binding lectins (UEA) and lectins which bind to complex carbohydrate configurations (PHA E, PHA L). Conventional glycoconjugate staining (PAS staining, alcian blue at pH 1 and 2.5) showed that the mucous goblet cells contain a considerable amount of glycoconjugates in all locations of the skin, whereas the other unicellular gland type, the club cells, lacked these glycoconjugates. The glycoproteins found in goblet cells are neutral and therefore stain magenta when subjected to PAS staining. Alcian blue staining indicating acid glycoproteins was distinctly positive at pH 1, but gave only a comparable staining at pH 2.5. The mucus of the goblet cells therefore also contains acid glycoproteins rich in sulphate groups. Using FITC-labelled lectins, the carbohydrate composition of the glycoproteins of goblet cells could be more fully characterized. A distinct staining of the mucus of goblet cells was found with the mannose-binding lectins LCA and PSA; the galactosamine-binding lectins DBA, SBA and GLS I; the glucosamine-binding lectin WGA; and PHA E which stains glycoproteins with complex carbohydrate configurations. No reaction occurred with the fucose-binding lectin UEA and the sialic acid-specific lectin SNA. In addition, the galactose-binding lectins PNA and RCA showed only a weak or completely negative staining of the mucus in the goblet cells. The specificity of the lectin staining could be proved by inhibiting binding of the lectins by competitive inhibition with the corresponding sugars. From these data, we can conclude that the mucus produced by the epidermal goblet cells of A. tenuispinis is rich in mannose, N -acetylgalactosamine and N -acetylglucosamine residues. [source]

Histochemical Detection of Glycoconjugates in the Canine Epididymis

ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 2 2009
B. Schick
Summary A histochemical study using fluorescein isothiocyanate (FITC)-labelled lectins to identify glycoconjugates present in the efferent ductules and the three segments of the ductus epididymis (initial, middle and terminal segment) of dogs was carried out. The lectins used were: mannose-binding lectins (Con A, LCA and PSA), galactose-binding lectins (PNA, RCA), N -acetylgalactosamine-binding lectins (DBA, SBA, SJA and GSL I), N -acetylglucosamine-binding lectins (WGA and WGAs), fucose-binding lectins (UEA) and lectins which bind to complex carbohydrate configurations (PHA E and PHA L). The lectin-binding pattern in the canine epididymis presents similarities and differences to those observed in other mammalian species. The ductuli efferentes distinctly stained with most of the lectins used, whereas in the ductus epididymis a segment specific staining pattern was observed. Whereas principal cells of the ductus epididymis stained clearly with several FITC-labelled lectins (WGA, UEA and PHA-L), basal cells showed only a significant binding of Con A. [source]