Search results for "Opsonin"
showing 10 items of 24 documents
Essential role of surface-bound chemoattractant in leukocyte migration
1977
MANY chemotactic factors, usually proteins or peptides, have been isolated and studied, but little is known about the basic mechanism of leukocyte migration. This movement is termed chemotaxis if its direction is determined by substances in the cells' environment1. The chemotactic agent is assumed to convey information to the leukocytes by interaction with receptors. The subsequent sequence of events thus triggered in the cells is unknown but metabolic changes such as activation of an esterase have been reported as occurring as the cells move forward (for review see ref. 2). A role for surface-bound chemoattractant in cell locomotion was suggested by the observation that mouse fibroblasts m…
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…
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…
TNFα Primes Polymorphonuclear Leukocytes for an Enhanced Respiratory Burst to a Similar Extent As Bacterial Lipopolysaccharide
1990
We examined whether preincubating polymorphonuclear leukocytes (PMN) with TNF alpha would result in an enhanced respiratory burst upon subsequent stimulation by various agents. Bacterial lipopolysaccharide (LPS), a known primer of PMN, was used as control. We found that both LPS (0.01 to 10.0 microgram/ml) and recombinant TNF alpha (0.001 to 1.0 microgram/ml) act as direct stimulants of PMN as measured by chemiluminescence. Sixty minutes of preincubation of PMN with 1 microgram/ml TNF alpha or 10 micrograms/ml LPS resulted in similar priming for the respiratory burst elicited by opsonized zymosan, phorbol myristate acetate, zymosan, zymosan-activated serum, aggregated immunoglobulin, and f-…
Biomaterial Surface Hydrophobicity-Mediated Serum Protein Adsorption and Immune Responses.
2019
The nature of the protein corona forming on biomaterial surfaces can affect the performance of implanted devices. This study investigated the role of surface chemistry and wettability on human serum-derived protein corona formation on biomaterial surfaces and the subsequent effects on the cellular innate immune response. Plasma polymerization, a substrate-independent technique, was employed to create nanothin coatings with four specific chemical functionalities and a spectrum of surface charges and wettability. The amount and type of protein adsorbed was strongly influenced by surface chemistry and wettability but did not show any dependence on surface charge. An enhanced adsorption of the …
Prediction of pneumococcal conjugate vaccine effectiveness against invasive pneumococcal disease using opsonophagocytic activity and antibody concent…
2011
ABSTRACT We compared the abilities of two serological readouts, antipolysaccharide IgG antibody concentrations and opsonophagocytic activity (OPA) titers, to predict the clinical effectiveness of the 7-valent pneumococcal conjugate vaccine (7vCRM) against invasive pneumococcal disease (IPD). We also assessed the accuracy of the previously established thresholds for GlaxoSmithKline's enzyme-linked immunosorbent assay with 22F adsorption (22F-ELISA) (≥0.2 μg/ml) and OPA assay (titer, ≥8) in predicting effectiveness. We showed that following a 3-dose 7vCRM primary vaccination, the serological response rates as determined using thresholds of ≥0.2 μg/ml IgG and an OPA titer of ≥8 corresponded we…
Induction of immunologic memory following primary vaccination with the 10-valent pneumococcal nontypeable Haemophilus influenzae protein D conjugate …
2011
Background Induction of immunologic memory was assessed following primary vaccination with 10-valent pneumococcal nontypeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV). Methods Infants were randomized (1:1) to receive 3 doses of PHiD-CV or 7vCRM (7-valent CRM197-conjugated pneumococcal conjugate vaccine [PCV]) at 2, 3, and 4 months of age followed by 23-valent pneumococcal polysaccharide vaccine (23vPS) booster dose at 11 to 14 months of age. Pneumococcal geometric mean antibody concentrations (GMCs) and opsonophagocytic activity (OPA) geometric mean titers were measured. Results Postprimary immune responses were consistent with those in previous PHiD-CV and 7vCRM studies…
Flow cytometric assay for quantifying opsonophagocytosis and killing of Staphylococcus aureus by peripheral blood leukocytes.
1992
We describe a novel flow cytometric method for quantifying opsonophagocytosis and killing of Staphylococcus aureus in cell-rich plasma obtained after dextran sedimentation of erythrocytes. To analyze opsonophagocytosis, phagocytes were labeled with a phycoerythrin-conjugated monoclonal antibody and were incubated with viable staphylococci containing carboxyfluorescein as a vital fluorescent dye. Phagocytosing cells assumed a dual, orange-green fluorescence. The relative numbers of bacteria associating with phagocytes could be determined by quantifying the decrease of free green fluorescent particles. A parallel incubation of fluorescent bacteria with unlabeled cell-rich plasma was performed…
F-type lectin from serum of the Antarctic teleost fish Trematomus bernacchii (Boulenger, 1902): Purification, structural characterization, and bacter…
2021
Abstract The increasing availability of sequenced genomes has enabled a deeper understanding of the complexity of fish lectin repertoires involved in early development and immune recognition. The teleost fucose-type lectin (FTL) family includes proteins that preferentially bind fucose and display tandemly arrayed carbohydrate-recognition domains (CRDs) or are found in mosaic combinations with other domains. They function as opsonins, promoting phagocytosis and the clearance of microbial pathogens. The Antarctic fish Trematomus bernacchii is a Perciforme living at extremely low temperatures (−1.68 °C) which is considered a model for studying adaptability to the variability of environmental w…
Primary structure and opsonic activity of an F-lectin from serum of the gilt head breamSparus aurata(Pisces, Sparidae)
2012
Abstract The recently described fucose-binding agglutinin from the European eel revealed a novel lectin fold (the ‘F-type’ fold) that is shared with other carbohydrate-binding proteins and proteins from prokaryotes to vertebrates clustered under the newly established F-type lectin (FTL) family. We previously reported the purification and biochemical characterization of a fucose-binding protein (FBP) isolated from serum of the gilt head bream (Sparus aurata, SauFBP). In the present article, the complete coding sequence of SauFBP revealed that it is a member of the FTL family, consisting of two tandem carbohydrate recognition domains (CRD) that display the F-type sequence motif. In vitro opso…