Search results for "Opsonin Proteins"
showing 10 items of 11 documents
Quantitative analysis of opsonophagocytosis and of killing of Candida albicans by human peripheral blood leukocytes by using flow cytometry
1991
We describe a simple, rapid, automated procedure for measuring opsonophagocytosis and killing of Candida albicans by human peripheral blood leukocytes. Yeast cells are labelled by allowing uptake and cleavage of membrane-permeable bis-carboxyethyl-carboxyfluorescein pentaacetoxymethylester to its membrane-impermeable fluorescent derivative bis-carboxyethyl-carboxyfluorescein. The yeast cells are added to cell-rich plasma obtained after dextran sedimentation of erythrocytes. Opsonophagocytosis and killing are quantified by using automated fluorescent cell analysis, and the following parameters can be obtained: (i) relative percentage of phagocytes that participate in opsonophagocytosis, (ii)…
Quantitative contributions of IgG, IgM and C3 to erythrophagocytosis and rosette formation by peritoneal macrophages, and anti-opsonin activity of de…
1976
In vitro phagocytosis by guinea pig peritoneal macrophages of immune complexes (EA) was shown to be dependent on IgG antibody in a dose-dependent fashion. C3b enhanced phagocytosis of EA at limited IgG antibody concentrations only. When IgM antibody was used for sensitization of sheep red blood cells (SRBC), phagocytosis and rosette formation did not occur in the absence of bound C3. The polyanion, dextran sulfate 500 (DS), was shown to depress both rosette formation and phagocytosis of EAIgG, C1423 and EAIgMC1423, as well as immune adherence of human group 0 erythrocytes and hemolytic activity of C3. This effect of DS was seen only when it was actually present in the incubation medium.
Structural and functional diversity of the lectin repertoire in teleost fish: Relevance to innate and adaptive immunity
2011
Protein–carbohydrate interactions mediated by lectins have been recognized as key components of innate immunity in vertebrates and invertebrates, not only for recognition of potential pathogens, but also for participating in downstream effector functions, such as their agglutination, immobilization, and complement-mediated opsonization and killing. More recently, lectins have been identified as critical regulators of mammalian adaptive immune responses. Fish are endowed with virtually all components of the mammalian adaptive immunity, and are equipped with a complex lectin repertoire. In this review, we discuss evidence suggesting that: (a) lectin repertoires in teleost fish are highly dive…
Opsonizing activities of IgG, IgM antibodies and the C3b inactivator-cleaved third component of complement in macrophage phagocytosis
1976
Phagocytosis of SRBC by guinea-pig peritoneal macrophages is enhanced by opsonizing IgG antibody alone. IgM antibody requires the presence of bound C3. Treatment of C3b coated SRBC with purified C3b inactivator (yielding EAIgM C1423d) does not reduce attachment to, and phagocytosis by, peritoneal macrophages. This finding suggests the existence of a C3d receptor on peritoneal macrophages. EC43b intermediates which have been produced by removing IgM antibody by mercaptoethanol treatment and by subsequent removal of C1 and C2, are phagocytosed despite the absence of IgM antibody. Furthermore, treatment of EC43b with C3b inactivator does not change phagocytosis. Thus, IgM antibody does not app…
Alpha-1-antitrypsin-induced inhibition of complement-dependent phagocytosis.
1981
Abstract In a previous investigation, inhibition of complement-dependent rosette formation by alpha1-antitrypsin (α1-AT) was observed, and it was demonstrated that α1-AT interacts through its carbohydrate portion with C3 and its fragments. In the present study, the effect of α1-AT on the complement-receptor-mediated phagocytosis by human peripheral blood monocytes was examined. Purified α1-AT inhibited in a dose-dependent manner phagocytosis of C3-carrying yeast particles. Inhibition was selective, concerned only C3-receptor-mediated phagocytosis, neither Fc-receptor-mediated phagocytosis nor uptake of untreated yeast particles was blocked by α1-AT. It was demonstrated that α1-AT exerted it…
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…
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 the sea bass (Dicentrarchus labrax): purification, cDNA cloning, tissue expression and localization, and opsonic activity.
2009
Recently described biochemical and structural aspects of fucose-binding lectins from the European eel (Anguilla anguilla) and striped bass (Morone saxatilis) led to the identification of a novel lectin family ("F-type" lectins) characterized by a unique sequence motif and a characteristic structural fold. The F-type fold is shared not only with other members of this lectin family, but also with apparently unrelated proteins ranging from prokaryotes to vertebrates. Here we describe the purification, biochemical and molecular properties, and the opsonic activity of an F-type lectin (DlFBL) isolated from sea bass (Dicentrarchus labrax) serum. DlFBL exhibits two tandemly arranged carbohydrate-r…