Search results for "Lectin"
showing 10 items of 495 documents
High Bacterial Agglutination Activity in a Single-CRD C-Type Lectin from <em>Spodoptera exigua</em> (Lepidoptera: Noctuidae)
2017
Lectins are carbohydrate-interacting proteins that play a pivotal role in multiple physiological and developmental aspects of all organisms. They can specifically interact with different bacterial and viral pathogens through carbohydrate-recognition domains (CRD). In addition, lectins are also of biotechnological interest because of their potential use as biosensors for capturing and identifying bacterial species. In this work, three C-type lectins from the Lepidoptera Spodoptera exigua were produced as recombinant proteins and their bacterial agglutination properties were characterized. The lowest protein concentration producing bacterial agglutination against a panel of different Gram+ an…
TLR2, TLR4 and Dectin-1 signalling in hematopoietic stem and progenitor cells determines the antifungal phenotype of the macrophages they produce
2016
TLRs represent an attractive target for the stimulation of myeloid cell production by HSPCs. We have previously demonstrated that HSPCs use TLR2 to sense Candida albicans in vivo and induce the production of macrophages. In this work, we used an in vitro model of HSPCs differentiation to investigate the functional consequences for macrophages of exposure of HSPCs to various PAMPs and C. albicans cells. Mouse HSPCs (Lin(-) cells) were cultured with M-CSF to induce macrophage differentiation, in the presence or absence of the following PRR agonists: Pam3CSK4 (TLR2 ligand), LPS (TLR4 ligand), depleted zymosan (which only activates Dectin-1), or C. albicans yeasts (which activate several PRRs, …
In Vitro Expression of the Endothelial Phenotype: Comparative Study of Primary Isolated Cells and Cell Lines, Including the Novel Cell Line HPMEC-ST1…
2002
Endothelial cell lines are commonly used in in vitro studies to avoid problems associated with the use of primary endothelial cells such as the presence of contaminating cells, the difficulty in obtaining larger numbers of cells, as well as the progressive loss of cell viability and expression of endothelial markers in the course of in vitro propagation. We have analyzed the characteristics defining distinctive endothelial phenotypes in the cell lines EA.hy926, ECV304, EVLC2, HAEND, HMEC-1, ISO-HAS-1 and a cell line recently generated in our laboratory, HPMEC-ST1.6R, and have compared these phenotypes with those found in primary human endothelial cells isolated from umbilical vein (HUVEC), …
Isolation and expression of a novel MBL-like collectin cDNA enhanced by LPS injection in the body wall of the ascidian Ciona intestinalis
2009
Collectins are a family of calcium-dependent lectins that are characterized by their collagen-like domains. Considerable interest has been focused on this class of proteins because of their ability to interact with components of the complement system activating a cascade of events responsible for the activation of the innate immune system. A differential screening between LPS-challenged and naïve Ciona intestinalis has been performed allowing the isolation of a full length cDNA encoding for a 221 AA protein. In silico analysis has shown that this polypeptide displays protein domains with similarities to mannose-binding lectins. A phylogenetic analysis suggested that C. intestinalis MBL has …
New functional ligands for ficolin-3 among lipopolysaccharides of Hafnia alvei.
2011
Ficolin-1 (M), ficolin-2 (L), ficolin-3 (H) and mannan-binding lectin (MBL) activate the complement system and have opsonic activity. The specificity of ficolin-3 is poorly characterized and currently limited to a few ligands only. We present new specific targets for human ficolin-3, identified among lipopolysaccharides (LPSs, endotoxin) of Hafnia alvei. The interaction was restricted to LPSs of four strains: 23, Polish Collection of Microorganisms (PCM) 1200, PCM 1203 and PCM 1205 and limited to their O-specific polysaccharides (O-specific PSs) composed of different numbers of oligosaccharide (OS) repeating units (RUs). Moreover, these LPS/ficolin-3 complexes activated the lectin pathway o…
COMPLEMENT-DEPENDENT B-CELL ACTIVATION BY COBRA VENOM FACTOR AND OTHER MITOGENS?
1974
It has been proposed that two distinct signals are required for the triggering of the precursors of antibody-forming bone marrow-derived cells (B cells): (a) the binding of antigen or of a mitogen to the corresponding receptor sites on B-cell membranes and (b) the interaction of activated C3 with the C3 receptor of B lymphocytes. There is growing evidence that B-cell mitogens and T (thymus-derived cell)-independent antigens are capable of activating the alternate pathway of the complement system (bypass). Therefore, the effect of another potent bypass inducer was investigated with regard to B-cell activation and the role of C3. Purified, pyrogen-free cobra venom factor was mitogenic for bot…
Inducible lectins with galectin properties and human IL1alpha epitopes opsonize yeast during the inflammatory response of the ascidian Ciona intestin…
2007
Studies on inducible ascidian lectins may shed light on the evolutionary emergence of cytokine functions. Here, we show that the levels of opsonins, with IL1alpha-epitopes, increase in Ciona intestinalis hemolymph as a response to an inflammatory stimulus and, in particular, to intratunic injection of lipopolysaccharide (LPS). The inflammatory agent promptly (within 4 h) enhances Ca(2+)-independent serum hemagglutinating and opsonizing activities, which are both inhibited by D-galactose and D-galactosides (alpha-lactose, N-acetyl-D-lactosamine, thio-digalactoside), suggesting that anti-rabbit erythrocyte lectins with galectin properties are involved as opsonins. Inducible galectin molecules…
T cell proliferation in the mixed lymphocyte culture does not necessarily result in the generation of cytotoxic T effector cells.
1975
It was tested whether T lymphocytes, when stimulated in vitro by M locus-coded lymphocyte activating determinants (LAD), are able to mediate cytotoxic effector functions. The assay for cytotoxicity included both the use of purified appropriate target cells (i.e. purified lipopolysaccharide blasts) as well as the use of phytohemagglutinin dependent cytolysis as a model for detecting cytotoxic T lymphocytes (CTL). Although strong proliferative responses were obtained in the mixed lymphocyte culture, the T cell blast generated did not display any detectable cytotoxic effector function. Thus, it is concluded that LAD, at least in the M locus-dependenet system, do have the capacity to induce T c…
Time Response of Oxidative/Nitrosative Stress and Inflammation in LPS-Induced Endotoxaemia—A Comparative Study of Mice and Rats
2017
Sepsis is a severe and multifactorial disease with a high mortality rate. It represents a strong inflammatory response to an infection and is associated with vascular inflammation and oxidative/nitrosative stress. Here, we studied the underlying time responses in the widely used lipopolysaccharide (LPS)-induced endotoxaemia model in mice and rats. LPS (10 mg/kg; from Salmonella Typhosa) was intraperitoneally injected into mice and rats. Animals of every species were divided into five groups and sacrificed at specific points in time (0, 3, 6, 9, 12 h). White blood cells (WBC) decreased significantly in both species after 3 h and partially recovered with time, whereas platelet decrease did no…
Inducible galectins are expressed in the inflamed pharynx of the ascidian Ciona intestinalis
2011
Although ascidians belong to a key group in chordate phylogenesis, amino acid sequences of Ciona intestinalis galectin-CRDs (CiLgals-a and -b) have been retained too divergent from vertebrate galectins. In the present paper, to contribute in disclosing Bi-CRD galectin evolution a novel attempt was carried out on CiLgals-a and -b CRDs phylogenetic analysis, and their involvement in ascidian inflammatory responses was shown. CiLgals resulted aligned with Bi-CRD galectins from vertebrates (Xenopus tropicalis, Gallus gallus, Mus musculus, Homo sapiens), cephalochordates (Branchiostoma floridae), echinoderms (Strongylocentrotus purpuratus) and a mono-CRD galectin from the ascidian Clavelina pict…