Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P17931 (galectin-3)
 2,860 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

epsilon BP (for epsilon binding protein) is a M(r) 31,000 S-type animal lectin that binds to IgE and has been identified as the homologue of Mac-2, a macrophage cell-surface marker, as well as the lectins RL-29, CBP35, and L-34. The protein is composed of two domains with the amino-terminal portion containing tandem repeats of nine amino acids and the carboxyl-terminal half containing consensus sequences shared by S-type animal lectins. We determined the genomic map in both rat and mouse and isolated overlapping genomic clones that contain the 5' two-thirds of the murine gene. The remaining portion of the gene was obtained by polymerase chain reaction (PCR) amplification of genomic murine DNA followed by subcloning into plasmid vectors. The epsilon BP gene is composed of six exons separated by five introns. The entire amino-terminal repetitive sequence is contained in exon III, and the carboxyl-terminal domain is encoded by the three succeeding exons (IV, V, VI). The latter three exons correspond well in size and share sequence homology with three exons coding for 14-kDa S-type lectins. The sequence in exon I offers an explanation for the generation of two mRNAs differing only in their 5' untranslated sequences, previously reported in Mac-2 cDNA clones. Using cDNA synthesis and PCR amplification, we determined that two alternative splice sites are used in many different types of cells. This alternative splicing results in different 5' untranslated regions of the murine epsilon BP mRNA.
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PMID:Genomic cloning of the gene for an IgE-binding lectin reveals unusual utilization of 5' untranslated regions. 139 Jul 36

Dot immunoblotting of crude extracts of various aerial parts of birch trees, using patient serum rich in birch pollen IgE, showed IgE-binding activity in leaves, buds, twigs, seeds, bark, and old male catkins. Seed extracts analysed by SDS-PAGE, electroblotting to nitrocellulose and immune detection using isotope-conjugated anti-IgE verified the presence in seeds of an IgE-binding protein of an approximate molecular weight of 12 kD, distinct from the major allergen (molecular weight 17 kD) of Betula verrucosa pollen. The allergen of birch seeds was readily leachable from the seeds. Many of the birch plant part extracts were active in RAST inhibition using birch pollen RAST discs, but showed low potency relative to the allergenicity of birch pollen allergens.
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PMID:Expression of birch pollen-specific IgE-binding activity in seeds and other plant parts of birch trees (Betula verrucosa Ehrh.). 142 64

The demonstration of IgE-bearing epidermal Langerhans cells (LC) opened up new perspectives in the pathophysiology of atopic eczema. IgE receptors on LC have now been identified and characterized: all three IgE-binding structures so far known to be present in the human immune system have been demonstrated on LC, i.e. the low-affinity receptor for IgE (Fc epsilon RII/CD23), the so-called IgE-binding protein (epsilon BP) and the high-affinity receptor for IgE (Fc epsilon RI), which had hitherto been considered to be expressed exclusively on mast cells and basophils. Functionally, there is some evidence that these structures may be involved in the release of cytokines and/or IgE-mediated antigen focusing. Considering the specificity of IgE for environmental allergens and the particular place of LC in primary and secondary immune responses, it can be speculated that LC in the skin and mucosae play a major role in mechanisms of sensitization to such allergens and in the genesis of IgE-mediated diseases. Finally, IgE receptors on LC may provide targets for new therapeutic approaches in atopic diathesis.
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PMID:[IgE receptors in Langerhans cells. A link between the environment and the immune system?]. 147 69

We have recently demonstrated that normal human Langerhans cells are able to bind IgE. The study of IgE-binding molecules on normal LC led to the characterization of three distinct structures able to bind IgE, viz. the low affinity receptor for IgE, Fc epsilon R2/CD23, the so-called IgE-binding protein epsilon BP which is the human homologous of the murine Mac-2 antigen, and finally the high affinity receptor for IgE, Fc epsilon RI. In this review, we summarize the most recent data on these structures and their putative physiological relevance is discussed with regard to the atopic disease.
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PMID:IgE-binding molecules on human Langerhans cells. 147 37

Human epidermal Langerhans cells (LC) bearing IgE are found in disease states associated with hyperimmunoglobulinemia E. When studying the mechanism(s) underlying this phenomenon, immunohistology revealed that a majority of epidermal LC from normal skin of healthy individuals can specifically bind monomeric IgE. IgE binding to LC could neither be prevented by preincubation of the tissue with monoclonal antibodies (mAb) against either Fc epsilon RII/CD23 or Fc gamma RII/CD32, nor by the addition of lactose. However, binding could be entirely abrogated by preincubation with the anti-Fc epsilon RI alpha mAb 15-1, which interferes with IgE binding to Fc epsilon RI alpha gamma transfectants. These observations indicated that IgE binding to epidermal LC is mediated by Fc epsilon RI rather than by CD23, CD32, or the D-galactose-specific IgE-binding protein. This assumption gained support from our additional findings that: (a) the majority of LC exhibited distinct surface immunolabeling with the anti-Fc epsilon RI alpha mAbs 15-1 and 19-1, but not with any of eight different anti-Fc epsilon RII/CD23 mAbs; and (b) transcripts for the alpha, beta, and gamma chains of Fc epsilon RI could be amplified by polymerase chain reaction from RNA preparations of LC-enriched, but not of LC-depleted, epidermal cell suspensions. In view of the preeminent role of Fc epsilon RI crosslinking on mast cells and basophils in triggering the synthesis and release of mediators of allergic reactions, the demonstration of this receptor on epidermal LC may have important implications for our understanding of allergic reactions after epicutaneous contact with allergens.
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PMID:Epidermal Langerhans cells from normal human skin bind monomeric IgE via Fc epsilon RI. 153 43

Aspergillus fumigatus secretes an 18-kDa nonglycosylated IgE-binding protein. This protein was previously shown to be a ribotoxin, like alpha-sarcin and mitogillin. A 686-bp long A. fumigatus cDNA encoding an 18-kDa ribotoxin was cloned and expressed in Escherichia coli as a fusion protein with six adjacent histidines (rAsp f I/a). rAsp f I/a was purified to homogeneity by Ni(2+)-chelate affinity chromatography and refolded. The recombinant protein was enzymatically active resulting in the cleavage of 28S rRNA within a universally conserved region. rAsp f I/a was cytotoxic for EBV immortalized or PHA stimulated human PBMC. Furthermore, rAsp f I/a was recognized by murine mAb made against an 18-kDa ribotoxin. IgE of individuals allergic to A. fumigatus bound to rAsp f I/a as shown by ELISA, dot blots, and Western blots. rAsp f I/a elicited positive immediate type I skin reactions in individuals allergic to A. fumigatus but not in healthy control individuals. The results show that rAsp f I/a has similar functional characteristics when compared to the native 18-kDa ribotoxin. rAsp f I/a expressed in E. coli can therefore be used as a standardized Ag/allergen for serologic and clinical diagnosis of A. fumigatus-associated diseases.
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PMID:Cloning and expression of recombinant Aspergillus fumigatus allergen I/a (rAsp f I/a) with IgE binding and type I skin test activity. 162 93

IgE-binding protein (epsilon BP) was originally identified by virtue of its affinity for IgE. It is now known to be a beta-galactoside-binding lectin with the characteristic of an S-type carbohydrate recognition domain. The protein is composed of two domains: the amino-terminal domain consisting of tandem repeats and the carboxyl-terminal domain containing sequences shared by other S-type carbohydrate recognition domains. The amino-terminal domain also contains a number of potential recognition sites for collagenase cleavage. In this study, human epsilon BP was first expressed in Escherichia coli, and the carboxyl-terminal domain (epsilon BP-C) was then generated by collagenase digestion of epsilon BP. By equilibrium dialysis, the association constants of epsilon BP and epsilon BP-C for lactose were found to be similar (6.0 +/- 0.70) x 10(4) M-1 and (4.7 +/- 0.27) x 10(4) M-1, respectively. Both polypeptides contain only one lactose-binding site/molecule. By an assay involving binding of 125I-labeled epsilon BP or epsilon BP-C to solid phase IgE, and inhibition of this binding by saccharides, it was determined that epsilon BP-C retains the saccharide specificity of epsilon BP. Importantly, although unlabeled epsilon BP-C inhibited the binding of the radiolabeled epsilon BP to IgE, unlabeled epsilon BP caused increased binding to IgE, suggesting self-association among epsilon BP molecules. Oligomeric structures resulting from self-association of epsilon BP were confirmed by chemical cross-linking studies. Furthermore, epsilon BP possesses hemagglutination activity on rabbit erythrocytes, whereas epsilon BP-C lacks such activity. Based on these results, we propose a structural model for multivalency of epsilon BP: dimerization or oligomerization of epsilon BP occurs through intermolecular interaction involving the amino-terminal domain.
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PMID:Biochemical and biophysical characterization of human recombinant IgE-binding protein, an S-type animal lectin. 162 16

IgE-binding protein (epsilon BP) is a galactoside-specific lectin containing an S-type carbohydrate-recognition domain. It was originally identified in rat basophilic leukemia cells and is now known to be identical to a macrophage surface Ag, Mac-2, and lectins designated as CBP 35/L-34/RL-29. It has also been related to a nonintegrin laminin-binding protein isolated from mouse macrophages. In this report we have shown the following: epsilon BP is present in variable amounts in several mast cell lines, and the surface expression of epsilon BP in these cell lines is quite variable and does not correlate with the total amount of epsilon BP in the cell. epsilon BP is displayed on the cell surface in a manner that is reversible by lactose, most likely through attachment to yet unidentified glycoconjugates. The putative epsilon BP binding sites on the cell surface can be readily demonstrated by using radiolabeled epsilon BP, and the sites are present in comparable amounts in various cell lines. Expression of epsilon BP on the cell surface can be regulated; the most notable example is the upregulation of surface epsilon BP on RBL cells activated through the high-affinity IgE receptor by IgE immune complexes. Cell-surface epsilon BP is functional as measured by its ability to promote adhesion of trypsinized rabbit erythrocytes to mast cells and macrophages. On the basis of these results and reported properties of related lectins, we propose that the lectin represented by epsilon BP is a new class of cell-adhesion protein.
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PMID:Surface expression of functional IgE binding protein, an endogenous lectin, on mast cells and macrophages. 173 Aug 78

A number of lactose-binding lectins have recently been identified in the rat and mouse intestine, one of which corresponds to the C-terminal domain of IgE-binding proteins, originally identified in rat basophilic leukemia (RBL) cells and mouse 3T3 fibroblasts. In the present report, we describe the affinity purification of a rat intestinal lactose-specific lectin which binds murine IgE antibodies. This binding most likely occurs via the immunoglobulin carbohydrate chains, as it is inhibited by lactose. This intestinal lectin molecule is also immunologically related to the previously described IgE-binding protein (epsilon BP) isolated from RBL cells, since it is recognized by antibodies raised against recombinant epsilon BP. This intestinal form of epsilon BP has a molecular mass of 17.5 kDa, which is much lower than that of its RBL cell analogue (31 kDa). The attachment of IgE to the mouse intestinal epithelium was demonstrated by immunohistochemistry, along with the presence of a corresponding mouse intestinal epsilon BP. The carbohydrate-dependent nature of this attachment was established by demonstrating that IgE binding to mouse epithelium was specifically abolished by lactose (4 mM) and by a blood-group-A-active tetrasaccharide (0.2 mM), but not by mannose (10 mM). Finally, the association of IgE with the mouse intestinal epithelium was prevented by competition with the purified IgE-binding lectin isolated from rat intestine. Although the physiological function of this intestinal protein is still unknown, the finding that IgE binds to a lectin in the intestinal epithelium pinpoints a possible novel mechanism for the regulation of IgE-mediated disorders, such as food allergy.
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PMID:An intestinal galactose-specific lectin mediates the binding of murine IgE to mouse intestinal epithelial cells. 173 27

IgE is highly glycosylated, but the function of the oligosaccharide side chains is largely unknown. The previous discovery of an animal lectin, IgE-binding protein (epsilon BP), affords an opportunity to study potential carbohydrate-dependent effector functions of IgE. epsilon BP is a beta-galactoside-specific lectin with binding affinity for IgE and is now known to be equivalent to carbohydrate-binding protein 35 and the Mac-2 Ag; thus, it may have multiple functions in addition to IgE binding. We have previously shown that rat r epsilon BP recognizes sialidase-treated human myeloma IgE to a much greater extent than the untreated IgE. In contrast, human epsilon BP binds essentially equivalently to a monoclonal murine IgE with or without sialidase pretreatment. To validate a possible role for epsilon BP in the IgE system, we investigated the pattern of recognition of epsilon BP for various polyclonal human IgE samples. We show that polyclonal IgE derived from four individuals with hyper-IgE syndrome or atopic dermatitis recognizes epsilon BP and that there is individual variation in the proportion of IgE recognized by epsilon BP, ranging from greater than 60% for one sample to almost undetectable levels in another. We conclude that epsilon BP does indeed recognize polyclonal IgE and that this recognition is modulated by sialylation of IgE oligosaccharides. Furthermore, there exist different IgE glycoforms, varying in the degree of sialylation, and these are distributed in a distinct manner in different individuals.
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PMID:Heterogeneous IgE glycoforms characterized by differential recognition of an endogenous lectin (IgE-binding protein). 191 4


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