Search results for "Concanavalin A"
showing 10 items of 94 documents
Back to the oligomeric state: pH-induced dissolution of concanavalin A amyloid-like fibrils into non-native oligomers
2016
The subtle interplay between long range electrostatic forces, hydrophobic interactions and short range protein-protein interactions regulates the onset/evolution of protein aggregation processes as well as the stability of protein supramolecular structures. Using a combination of FTIR spectroscopy, light scattering and advanced imaging, we present evidence on the main role of electrostatic forces in the formation and stability of amyloid-like fibrils formed from concanavalin A (ConA), a protein showing structural homology with the human serum amyloid protein. At high protein concentration, where protein-protein interactions cannot be neglected, we highlight a thermal-induced aggregation pat…
The Galactose-Specific Lectin from the Sponge Chondrilla Nucula Displays Anti-Human Immunodeficiency Virus Activity in vitro via Stimulation of the (…
1990
A new lectin has been isolated from the sponge Chondrilla nucula. The purified CN lectin is a protein composed of four polypeptide chains with a molecular weight (MW) of 15600. The isoelectric point is 4.5 and the amino acid composition is rich in aspartic and glutamic acid. The lectin precipitates erythrocytes from humans (A, B, O) with a titre between 25 and 210. The CN lectin is d-galactose-specific and displays a moderate mitogenic effect on spleen lymphocytes from mice and on CD4-positive human H9 cells. An interesting feature of this lectin is its ability to stimulate the (2′-5′)oligoriboadenylate [(2′-5′)A] metabolic pathway in non-infected and human immunodeficiency virus (HIV-1)-i…
Immunomodulatory Therapy of Inflammatory Liver Disease Using Selectin-Binding Glycopolymers
2017
Immunotherapies have the potential to significantly advance treatment of inflammatory disease and cancer, which are in large part driven by immune cells. Selectins control the first step in immune cell adhesion and extravasation, thereby guiding leukocyte trafficking to tissue lesions. We analyzed four different highly specific selectin-binding glycopolymers, based on linear poly(2-hydroxypropyl)-methacrylamide (PHPMA) polymers. These glycopolymers contain either the tetrasaccharide sialyl-LewisX (SLeX) or the individual carbohydrates fucose, galactose, and sialic acids mimicking the complex SLeX binding motive. The glycopolymers strongly bind to primary human macrophages, without activatin…
Detecting Protein Aggregation on Cells Surface: Concanavalin A Oligomers Formation
2009
A number of neurodegenerative diseases involve protein aggregation and amyloid formation. Recently evidence has emerged indicating small-transient prefibrillar oligomers as the primary pathogenic agents. Noteworthy, strict analogies exist between the behaviour of cells in culture treated with misfolded non-pathogenic proteins and in pathologic conditions, this instance together with the observation that the oligomers and fibrils are characterised by common structural features suggest that common mechanisms for cytotoxicity could exists and have to be perused in common interactions involved in aggregation.We here report an experimental study on ConcanavalinA (ConA) aggregation and its effect…
Release of transforming growth factor-beta (TGF-β) and fibronectin by alveolar macrophages in airway diseases
1996
Abstract Asthma and chronic bronchitis are associated with airway remodelling, and airway macrophages are present in bronchial inflammation. TGF-β and fibronectin released by alveolar macrophages possess a fibrogenic potency. The potential role of alveolar macrophages in airway remodelling was studied in asthma and chronic bronchitis by the release of TGF-β and fibronectin. Alveolar macrophages were isolated by bronchoalveolar lavage in 14 control subjects, 14 asthmatics and 14 chronic bronchitics. The spontaneous and lipopolysaccharide (LPS)- or concanavalin A (Con A)-induced release of TGF-β and fibronectin was measured by ELISA. Alveolar macrophages from chronic bronchitics spontaneously…
Impaired cellular immune responses in chronic renal failure: Evidence for a T cell defect
1986
Impaired cellular immune responses in chronic renal failure: Evidence for a T cell defect. Cellular immune responses in vitro were studied in 24 patients on chronic hemodialysis and 16 healthy volunteers with normal kidney function. Patients on maintenance hemodialysis had lymphopenia with diminished numbers of both T4 + and T8 + T-lymphocytes. The T4/T8 ratios were within the normal range. Peripheral blood lymphocytes (PBL) showed a diminished proliferative response upon stimulation with concanavalin A, phytohemagglutinin and poke weed mitogen. When cell surface antigens were used for stimulation (mixed lymphocyte culture) uremic lymphocytes also showed a lower proliferation rate. Although…
Chronic T cell leukemia with unusual cellular characteristics in ataxia telangiectasia
1986
Abstract A 27-year-old male patient with ataxia telangiectasia (AT) developed atypical chronic lymphocytic leukemia with increasing bone marrow infiltration in the absence of organomegaly. One-third of the leukemia cells expressed a mature suppressor/cytotoxic T cell phenotype (T3+ T4- T6- T8+ T10-), two-thirds demonstrated additional helper/inducer T cell- associated antigens (T3+ T4+ T6- T8+ T10-), and a small fraction reacted with a natural killer (NK) cell-specific monoclonal antibody (Leu 11+). The proliferative response to stimulation in vitro with lectins and various monoclonal antibodies resembled the proliferation pattern of mature thymocytes: The cells responded to phytohemaggluti…
Stimulus-Dependent Increased Generation of Oxygen Intermediates in Monocytes and Polymorphonuclear Leukocytes in Psoriasis
1985
Based on recent findings indicating increased respiratory burst activity of monocytes (M phi) and polymorphonuclear leukocytes (PMN) in psoriasis upon stimulation with zymosan particles, we examined the question of whether incubation with various stimuli always results in augmented oxidative metabolism in psoriatic phagocytes. We compared M phi and PMN isolated from the peripheral blood of 12 patients with psoriasis and 12 control individuals. We measured the generation of oxygen intermediates of resting and stimulated M phi and PMN by luminol-enhanced chemiluminescence. The stimulants applied were: (1) aggregated immunoglobulin (aggIg), (2) zymosan, (3) zymosan opsonized with autologous se…
Activation of T‐Lymphocytes by LDL‐Cholesterol
2008
Native LDL-cholesterol can be mechanically stressed by strong vortexing. According to one hypothesis, mechanical shear stress within the vessel can lead to an aggregation of LDL-cholesterol and subsequently to activation of CD4 and CD8 T-lymphocytes. The goal of this study was to determine the proportion of activated CD4 and CD8 T-lymphocytes that is induced by adding unstressed and mechanically stressed LDL-cholesterol to whole blood samples. Whole blood was taken from 12 healthy subjects. All probands fasted for at least 12 h before blood withdrawal. In each case, 1 ml of whole blood from each subject was incubated for 16 h at 32 degrees C (89.3 degrees F) with concanavalin A (A), without…
Binding of concanavalin A to the surface of unfertilized and fertilized ascidian eggs.
1973
STUDIES with certain carbohydrate-binding proteins of plant origin (as concanavalin A and wheat germ agglutinin) have indicated that some surface properties of embryonic1,2 and of virally transformed cells3–6 are different from those of adult cells. The interpretation of the differences in terms of structural organization of the cell surface is, however, still controversial (see for example refs. 7 and 8).