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)

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

The binding of a membrane proteoglycan from a non-encapsulated strain of Klebsiella pneumoniae (Kp-MPG) and four derivatives thereof, to human leukocytes, was investigated by indirect immunofluorescence using biotinylated F(ab')2 fragments of anti-Kp-MPG antibodies and the streptavidin-phycoerythrin amplification system in flow cytometry. Four Kp-MPG derivatives were studied: 1/ an acylpoly(1,3)galactoside (APG), 2/ an APG preparation submitted to acid hydrolysis which removed all fatty acids, but left intact the galactose chain of APG (GC-APG), 3/ a preparation obtained by mild alkaline hydrolysis, containing additional ester-linked C14 and C16 fatty acids bound to the APG molecule (EFA-APG) and 4/ a polymer of the latter compound (APG pol). Kp-MPG, APG and EFA-APG were shown to bind exclusively to monocytes at the lowest concentrations (from 0.15 to 3 microM APG). At higher concentrations, these compounds interacted with polymorphonuclear leukocytes, and with lymphocyte subsets in the following decreasing order: B cells, NK cells, CD8+ and CD4+ lymphocytes. Neither APG pol or GC-APG nor K. pneumoniae smooth LPS showed significant binding to leukocytes. However Kp-LPS treated by drastic alkaline hydrolysis displayed binding properties similar to those of APG. Removal of the ester-linked C14 and C16 fatty acids from EFA-APG did not affect the binding of the molecule. The capacity of cells from the myelomonocytic lineage to bind Kp-MPG and APG was very low in phenotypically immature cell lines (HL60 and U937) as compared with monocytes or polymorphonuclear cells. Treatment of U937 cells with interferon-gamma up-regulated their APG binding capacity along with the expression of the integrin CD 11 b and the CD 14 molecule, whereas monocytes exposed to interferon-gamma showed an increased binding of APG associated with an elevated expression of the galactose specific lectin Mac-2. The data demonstrate a preferential binding of Kp-MPG and APG to cells of the monocyte/macrophage lineage. APG binding does not involve the poly (1,3) galactose chain and the ester-linked C14 and C16 fatty acids but requires the presence of the hydrophobic part of the molecule.
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PMID:Binding of a membrane proteoglycan from Klebsiella pneumoniae and its derivatives to human leukocytes. 149 Jul 26

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

Phenotypic and functional changes associated with tumor-bearing host (TBH) macrophages (M phi) are partly responsible for immunosuppression during tumor growth. Flow cytofluorometric analyses revealed differences in cell-cycle kinetics between normal host (NH) and TBH M phi that were stimulated at specific receptors. Receptor-ligand interactions were induced by antibodies against Mac-1, -2, -3, and Ia receptors and changes in DNA synthesis were measured over a 12-h time course by incorporation of propidium iodide. TBH M phi showed higher DNA synthesis than NH M phi over this time course irrespective of the receptor induced. NH M phi stimulated at the Mac-1 receptor demonstrated higher DNA synthesis than control NH M phi although TBH M phi stimulated at this receptor and control TBH M phi failed to show any differences. Both NH and TBH M phi exhibited small, short-term decreases in DNA synthesis when stimulated at the Mac-2 receptor. TBH M phi that were stimulated at the Mac-3 receptor demonstrated higher DNA synthesis than their control counterparts while NH M phi stimulated at this receptor and control NH M phi showed identical levels of DNA synthesis. No differences in DNA synthesis were found among normal or TBH M phi that were stimulated through Ia. Differences in DNA synthesis did not appear to be attributable to differences in receptor expression. Further analysis of Mac-1 and Mac-3 stimulated cells revealed that DNA synthesis in NH M phi stimulated at the Mac-1 receptor returned to control levels at 48 h.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Macrophages stimulated by receptor-ligand interactions exhibit differences in cell-cycle kinetics during tumor growth: stimulation at Mac-1 and Mac-3 receptors alters DNA synthesis. 154 36

Ricin B chain is an N-glycosylated galactose-specific lectin. Examination of the amino acid sequence of the protein has shown it to be the product of a series of gene duplication events based on an original galactose binding peptide. The X-ray crystallographic structure of the protein reveals that it consists of two globular domains, each composed of three smaller subdomains. In each globular domain only one of the three subdomains has retained its ability to bind galactose. Through DNA manipulation we have created a series of fusions of portions of ricin B chain, each carrying only one galactose binding site, to the ricin signal sequence. Transcripts synthesized in vitro using SP6 RNA polymerase were injected into Xenopus oocytes where the recombinant proteins were produced in a mature form. The products were shown to be N-glycosylated and produced in a soluble stable form. Also, they retained the ability to bind galactose. Preliminary experiments on the reassociation of these ricin B chain fragments with ricin A chain to create a modified holotoxin were also carried out.
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PMID:Recombinant ricin B chain fragments containing a single galactose binding site retain lectin activity. 155 Mar 53

Mouse macrophage clones were generated from liver, bone marrow, spleen, thymus and brain by in vitro immortalization of primary cultures with VN11 recombinant retroviruses, transducing an avian v-myc oncogene. Tissue macrophages from eight different strains of mice were immortalized. All macrophage clones obtained thus far constitutively expressed F4/80, Mac-1, Mac-2 and Fc receptors. Class II MHC molecules were induced with IFN gamma. Constitutive and inducible functional activities of macrophages were retained in most of the clones; phagocytosis, chemotaxis, adhesion properties, cytokine production, MHC expression, cytotoxicity and toxic reactive nitrogen intermediate synthesis were all preserved. A model for studying macrophage differentiation in vitro using cloned cells is presented.
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PMID:New tools for investigating macrophage differentiation. 156 38

Changes in the expression of specific cell surface antigens on preimplantation mouse embryos were examined by immunocytochemistry. Embryos were recovered at various times during the preimplantation phase of normal pregnancy, and from pregnancies with experimentally induced delayed implantation, and were probed with a panel of monoclonal antibodies against murine leukocyte antigens. Antibodies directed against certain macrophage surface glycoproteins (i.e., Mac-2 and Mac-3) and those against lysosome-associated membrane glycoproteins (i.e., LAMP-1 and LAMP-2) reacted specifically with cell surface determinants on the embryos. Differences in the spatiotemporal patterns of antibody binding during normal and delayed implantation indicate that expression of the antigenic determinants recognized by these antibodies is regulated individually in response to intrinsic as well as extrinsic signals at the time of implantation, and thus they may be important for the process of embryo implantation.
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PMID:Changes in surface antigens on preimplantation mouse embryos. 159 37

The binding of a 34-kDa (mol. wt.) acylpoly(1,3)galactoside (APG) extracted from a membrane proteoglycan of Klebsiella pneumoniae to human blood leucocytes was investigated. APG is made of a long poly(1,3)galactose chain, a core-like region and a lipid moiety which comprises two glucosamine residues bound to a phosphate group and two beta OH myristic acids. Fluoresceinated APG was shown to bind preferentially to monocytes and to a lesser extent to polymorphonuclear neutrophils, as determined by flow cytometry. Binding of fluoresceinated APG was inhibited by unlabelled APG; it was concentration dependent, but not saturable, with rapid kinetics. It occurred at +4 degrees C but was markedly increased at 37 degrees C. It involved trypsin-sensitive molecules on the membrane of monocytes. Neither the parent proteoglycan nor lipopolysaccharide from K. pneumoniae or Salmonella minnesota competed for APG binding. A minor non-specific binding to lymphocytes, occurring predominantly on B cells, was observed. Unlike that of lipopolysaccharide, the APG binding was not blocked by polymyxin B sulphate. Interaction between the galactose chain of APG and the galactose receptor does not account for the binding of APG to monocytes because the galactose receptor (Mac-2) is expressed at high density on activated macrophages but not on monocytes. Despite its strong binding to human blood monocytes, APG displayed a much weaker activity than K. pneumoniae membrane proteoglycan with respect to induction of monocyte cytokine synthesis. When administered as a Technetium 99 conjugate, APG was shown to label inflammatory foci in experimental animals, and its property as a marker of macrophages is currently being evaluated in clinical trials.
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PMID:Binding of a bacterial acylpoly(1,3)galactoside to human blood leucocytes. 161 80

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


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