immune complexes

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Application of fluorescent monocytes for probing immune complexes on antigen microarrays.

Application of fluorescent monocytes for probing immune complexes on antigen microarrays.

Detection of antigen specific antibody is an important step of diagnostic processes where alteration of the humoral immunity is presumed. Measurement of the quality of antigen specific antibody in addition to its quantity may improve diagnostic accuracy as different antibody isotypes and glycoforms can induce dissimilar effector functions. Several examples have already been published on how measurement of various Ig isotypes in different patholog- ical states in an antigen microarray format can be used to identify and differentiate between control and affected serum samples [2]. Another approach, which might be more relevant for certain pathological conditions, is when not the antibody level but the induced effector function is determined. Antibody effector functions are diverse: neutralization, opsonization, complement activation, antibody-dependent cellular cytotoxicity, and induction of phagocytosis. Our group earlier developed a microarray based method for the measurement of immune complex-induced complement activation [21] and its application to follow immu- nization [22] and to characterize antibody repertoir and complement activation in autoimmune diseases [23]. Now we focused on the cellular side of effector functions. Here we present a microarray system where immune complexes formed on antigen microarrays are probed with monocytoid cells.
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Platelet Activation and Thrombus Formation over IgG Immune Complexes Requires Integrin αIIbβ3 and Lyn Kinase.

Platelet Activation and Thrombus Formation over IgG Immune Complexes Requires Integrin αIIbβ3 and Lyn Kinase.

IgG immune complexes contribute to the etiology and pathogenesis of numerous autoim- mune disorders, including heparin-induced thrombocytopenia, systemic lupus erythemato- sus, rheumatoid- and collagen-induced arthritis, and chronic glomerulonephritis. Patients suffering from immune complex-related disorders are known to be susceptible to platelet- mediated thrombotic events. Though the role of the Fc receptor, FcγRIIa, in initiating platelet activation is well understood, the role of the major platelet adhesion receptor, integrin αIIbβ3, in amplifying platelet activation and mediating adhesion and aggregation down- stream of encountering IgG immune complexes is poorly understood. The goal of this inves- tigation was to gain a better understanding of the relative roles of these two receptor systems in immune complex-mediated thrombotic complications. Human platelets, and mouse platelets genetically engineered to differentially express FcγRIIa and αIIbβ3, were allowed to interact with IgG-coated surfaces under both static and flow conditions, and their ability to spread and form thrombi evaluated in the presence and absence of clinically-used fibrinogen receptor antagonists. Although binding of IgG immune complexes to FcγRIIa was sufficient for platelet adhesion and initial signal transduction events, platelet spreading and thrombus formation over IgG-coated surfaces showed an absolute requirement for αIIbβ3 and its ligands. Tyrosine kinases Lyn and Syk were found to play key roles in IgG- induced platelet activation events. Taken together, our data suggest a complex functional interplay between FcγRIIa, Lyn, and αIIbβ3 in immune complex-induced platelet activation. Future studies may be warranted to determine whether patients suffering from immune complex disorders might benefit from treatment with anti-αIIbβ3-directed therapeutics. a11111
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The role of complement in the modulation by fluid-phase IgG of the production of reactive oxygen species by polymorphonuclear leukocytes stimulated with IgG immune complexes

The role of complement in the modulation by fluid-phase IgG of the production of reactive oxygen species by polymorphonuclear leukocytes stimulated with IgG immune complexes

We have shown that the presence of complement components in the immune com- plexes of IgG appreciably increases the ca- pacity of ROS production by PMN. Also, when complement is present in the immune complexes, fluid-phase IgG has no effect on the induction of ROS production. Comple- ment receptors would not be affected by the occupation of Fcγ receptors by fluid-phase IgG, so that the ICIgG-C can by-pass the competitive inhibition that is observed with ICIgG. In this case, the interaction mediated by complement receptors may increase the binding of immune complexes to the cells or may by itself also stimulate ROS generation. One possibility we should consider is that the immune complex could be partially solubilized upon the addition of serum for the preparation of ICIgG-C, as previously reported (19,20). In our experiments this was improbable since the relation between serum volume and the ICIgG mass used by us was much smaller than that needed to solubilize the immune complexes. Compared to the volume used by the cited investigators with IgG antibody and BSA, we used a se-
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Circulating immune complexes, immunoglobulin G, salivary proteins and salivary immunoglobulin A in patients with Sjögren's syndrome

Circulating immune complexes, immunoglobulin G, salivary proteins and salivary immunoglobulin A in patients with Sjögren's syndrome

Objective The aim of this study was to evaluate serum concen- trations of circulating immune complexes (CIC) and immuno- globulin G (IgG), and salivary proteins (SP) and salivary immu-[r]

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Role of Immune Complexes from Pacients with Different Clinical Forms of Schistosomiasis in the Modulation of In Vitro Granuloma Reaction

Role of Immune Complexes from Pacients with Different Clinical Forms of Schistosomiasis in the Modulation of In Vitro Granuloma Reaction

Schistosomiasis is a disease whose pathology is strongly related to the granulomatous reaction formed around parasite eggs trapped in host tissues. Studies have shown that the chronic intestinal form (INT) of this infection is associated with a variety of immunoregulatory mechanisms which lead to a dimin- ished granulomatous reaction. Using an in vitro model of granuloma reaction, we show that immune complexes (IC) isolated from sera of INT patients are able to reduce granulomatous reaction developed by peripheral blood mononuclear cells (PBMC) from acute (AC), INT and hepatosplenic (HE) patients to soluble egg antigen (SEA)-conjugated polyacrylamide beads (PB-SEA). This inhibitory activity is also observed in cell proliferation assay of PBMC from INT and HE patients stimulated with SEA and adult worm antigen (SWAP). Furthermore, IC isolated from sera of patients with different clinical forms of the disease are also able to suppress INT patients PBMC reactivity. Therefore, our results show that circulating IC present in sera of patients with different clinical forms of schistosomiasis may down- regulate PBMC reactivity to parasite antigens resulting in a diminished granuloma reaction to parasite eggs.
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Role of Immune Complexes from Pacients with Different Clinical Forms of Schistosomiasis in the Modulation of In Vitro Granuloma Reaction

Role of Immune Complexes from Pacients with Different Clinical Forms of Schistosomiasis in the Modulation of In Vitro Granuloma Reaction

Schistosomiasis is a disease whose pathology is strongly related to the granulomatous reaction formed around parasite eggs trapped in host tissues. Studies have shown that the chronic intestinal form (INT) of this infection is associated with a variety of immunoregulatory mechanisms which lead to a dimin- ished granulomatous reaction. Using an in vitro model of granuloma reaction, we show that immune complexes (IC) isolated from sera of INT patients are able to reduce granulomatous reaction developed by peripheral blood mononuclear cells (PBMC) from acute (AC), INT and hepatosplenic (HE) patients to soluble egg antigen (SEA)-conjugated polyacrylamide beads (PB-SEA). This inhibitory activity is also observed in cell proliferation assay of PBMC from INT and HE patients stimulated with SEA and adult worm antigen (SWAP). Furthermore, IC isolated from sera of patients with different clinical forms of the disease are also able to suppress INT patients PBMC reactivity. Therefore, our results show that circulating IC present in sera of patients with different clinical forms of schistosomiasis may down- regulate PBMC reactivity to parasite antigens resulting in a diminished granuloma reaction to parasite eggs.
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Precipitated immune complexes of IgM induce the generation of reactive oxygen species by rabbit polymorphonuclear leucocytes

Precipitated immune complexes of IgM induce the generation of reactive oxygen species by rabbit polymorphonuclear leucocytes

consumption and formation of superoxide; according to the type of stimulus, different signal transduction pathways may be in- volved (14,15). With regard to immune com- plexes, most studies have been done with the IgG class (4); from the available data (11,16) it appears that the kinetics of chemilumines- cence is variable depending on the form in which the immune complexes (or the aggre- gated immunoglobulins) are presented to the cells (soluble, precipitated or adsorbed on surfaces). With precipitated ICIgG from the equivalence zone we observed a chemilumi- nescence effect which was limited in time, with a sharp peak around 5 min, in agree- ment with results reported for human neutro- phils (16). Our observations that precipi- tated ICIgM can also be an effective stimu- lus for chemiluminescence generation and thus for O 2 - production reveal a new func-
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Down modulation of MHC surface molecules on B cells by suppressive immune complexes obtained from chronic intestinal schistosomiasis patients

Down modulation of MHC surface molecules on B cells by suppressive immune complexes obtained from chronic intestinal schistosomiasis patients

Granulomatous inflammation around parasite eggs is the prominent lesion in human schistosomiasis. Studies have suggested the involvement of a series of suppressive mechanisms in the control of this reaction, such as macrophages, cytokines, idiotipic interactions and immune complexes (IC). The studies examine the role of IC obtained from chronic intestinal schistosomiasis patients (ISP) in the reactivity of peripheral blood mononuclear cells (PBMC). The results have shown that these immune complexes are able to suppress cell reactivity by inducing an increase in the production of soluble mediators such as prostaglandins and IL-10. To gain a better understanding of how this suppression occurs the present study examines the phenotypic pattern of PBMC after immune complex treatment in cell proliferation assays. These data show that cultures including immune complex present a higher percentage of B lymphocytes in which a lower expression of a MHC-class II gene product, HLA-DR was detected. This altered expression of the HLA-DR molecule on B lymphocytes after IC treatment suggests a novel mechanism for the suppression observed, that is, IC might decrease the antigen-presenting function of B lymphocytes. © 1998 Elsevier Science B.V. All rights reserved.
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CONCENTRATION OF CIRCULATING IMMUNE COMPLEXES IN EXPERIMENTAL GENERALIZED INFLAMMATORY PROCESS IN ANIMALS OF DIFFERENT AGE UNDER ACTION OF IMMUNOMODULATORS

CONCENTRATION OF CIRCULATING IMMUNE COMPLEXES IN EXPERIMENTAL GENERALIZED INFLAMMATORY PROCESS IN ANIMALS OF DIFFERENT AGE UNDER ACTION OF IMMUNOMODULATORS

Kovalenko T.I., Klimova Ye.M., Minukhin V.V. Under physiological conditions a formation and a presence of the CEC in liquids is one of the manifestations of the immune response to receipt of antigens and an important factor, which provides immunity. Circulating immune complexes act as agents involved in the regulation of immune response and maintaining communication between the immune system and other regulatory systems of the body and direction to his defense. The intensity of the

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Interleukin-33 primes mast cells for activation by IgG immune complexes.

Interleukin-33 primes mast cells for activation by IgG immune complexes.

Mast cells (MCs) are heterogeneous cells whose phenotype is modulated by signals received from the local microenvironment. Recent studies have identified the mesenchymal-derived cytokine IL-33 as a potent direct activator of MCs, as well as regulator of their effector phenotype, and have implicated this activity in the ability of mast cells to contribute to murine experimental arthritis. We explored the hypothesis that IL-33 enables participation of synovial MCs in murine K/BxN arthritis by promoting their activation by IgG immune complexes. Compared to wild-type (WT) control mice, transgenic animals lacking the IL-33 receptor ST2 exhibited impaired MC-dependent immune complex-induced vascular permeability (flare) and attenuated K/BxN arthritis. Whereas participation of MCs in this model is mediated by the activating IgG receptor FccRIII, we pre-incubated bone marrow-derived MCs with IL-33 and found not only direct induction of cytokine release but also a marked increase in FccRIII-driven production of critical arthritogenic mediators including IL-1b and CXCL2. This ‘‘priming’’ effect was associated with mRNA accumulation rather than altered expression of Fcc receptors, could be mimicked by co-culture of WT but not ST2 2/2 MCs with synovial fibroblasts, and was blocked by antibodies against IL-33. In
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Kidney involvement in malaria : an update

Kidney involvement in malaria : an update

and these events are probable contributing factors for kidney injury, in association with hemodynamic instability, including hypovolemia and shock. Endothelial activation leads to the release of several cytokines, including thromboxane, catecholamines, endothelin and other inflammatory mediators that are also implicated in the pathogenesis of malaria-associated kidney injury. Immune system activation in malaria can go through Th1 and Th2 response. When Th2 response prevails in the infection by P. malariae, complement activation occurs, with deposits of immune complexes leading to glomerulonephritis. Hemodynamic instability due to intense erythrocyte parasitism leads to acute tubular necrosis, as seen in the infection by P. falciparum. When Th1 response prevails, acute interstitial nephritis and acute glomerulonephritis can be seen. Cortical necrosis has also been described in malaria, characterizing a more severe kidney injury and generally associated with non-recovery of renal function and consequently development of end-stage kidney disease 8 .
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Autoantibody production in chronic idiopathic urticaria is not associated with Helicobacter pylori infection

Autoantibody production in chronic idiopathic urticaria is not associated with Helicobacter pylori infection

Chronic idiopathic urticaria (CIU) is a dermatological syndrome, characterized by raised erythematous skin lesions, that affects 20% of the general population and has been associated with autoimmunity. However, some reports have also suggested a close relationship between CIU and Helicobacter pylori infection, which is endemic in developing countries and associated with chronic gastritis, peptic ulcer disease, and gastric carcinoma. In the present study, we investi- gated the occurrence of autoantibodies in sera from 23 CIU subjects infected with H. pylori and from 23 CIU subjects without this infec- tion. The presence of anti-thyroid antibodies was determined by indirect hemagglutination assay and the presence of autoantibodies to IgE and C1INH was determined by ELISA. Antibodies to thyroid antigens were detected at low titers from 100 to 400 in three of 23 (13%) CIU-infected subjects and in four of 23 (17%) CIU-noninfected subjects. The titers of anti-IgE autoantibodies were similar in these CIU groups, presenting absorbances of 1.16 ± 0.09 and 1.07 ± 0.16, respectively, while a titer of 1.14 ± 0.15 was detected in the healthy control group. The concentration of anti-C1INH autoantibodies was the same in the CIU-infected and -noninfected subjects (7.28 ± 1.31 and 7.91 ± 2.45 ng/ml, respectively), and was 7.20 ± 2.25 ng/ml in the healthy control group. However, the serum levels of complexed anti- C1INH antibodies were increased in CIU-infected subjects compared to CIU-noninfected subjects and healthy controls with an absorbance of 1.51 ± 0.21 vs 1.36 ± 0.16 and 1.26 ± 0.23, respectively (P < 0.05), indicating an impaired clearance of immune complexes in CIU- infected patients. In conclusion, no correlation was observed between H. pylori infection and autoantibody production in CIU patients consistent with reports of clinical studies.
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IgA testing for diagnosis of retroviral infections in the Caribbean

IgA testing for diagnosis of retroviral infections in the Caribbean

First, all IgG and IgG immune complexes are removed by protein G treatment, and then IgA enzyme-linked immunosorbent assay (ELISA) and the Western blot test are [r]

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REPOSITORIO INSTITUCIONAL DA UFOP: Nitric oxide-mediated immune complex-induced prostaglandin E2 production by peripheral blood mononuclear cells of humans infected with Schistosoma mansoni.

REPOSITORIO INSTITUCIONAL DA UFOP: Nitric oxide-mediated immune complex-induced prostaglandin E2 production by peripheral blood mononuclear cells of humans infected with Schistosoma mansoni.

Granuloma reaction around Schistosoma mansoni eggs is the prominent lesion in human schistosomia- sis. Studies have suggested the involvement of a series of suppressive mechanisms in the control of this reac- tion. Using an in vitro model of granuloma formation, we have shown that immune complexes (IC) isolated from sera of chronic intestinal schistosomiasis pa- tients were able to reduce granulomatous reaction de- veloped against soluble egg antigen-conjugated poly- acrylamide beads. In this system, the role of the L -

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Porcine D-amino acid oxidase: production of the biologically active enzyme in Escherichia coli

Porcine D-amino acid oxidase: production of the biologically active enzyme in Escherichia coli

peroxidase-labelled oat anti rabbit serum and the appropriate Immune complexes were detected chromogenic with substrate (see Metho s). Denominations of[r]

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Quím. Nova  vol.25 número4

Quím. Nova vol.25 número4

In this paper, we report the synthesis and characterization of a new series of oxovanadium(IV) dithiocarbamates complexes with pyridine, which also form complexes of the general formula [VO(L) 2 ].py, noted as adducts, and alternating complexes of the ge- neral formula [VO(OH)(L)(py) 2 ]OH.H 2 O, that are soluble in water and noted as derivatives.

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Uveal melanoma cells utilize a novel route for transendothelial migration.

Uveal melanoma cells utilize a novel route for transendothelial migration.

UM Transmigration is Regulated by Cell Adhesion Molecules We asked whether UM cells initiated and maintained contact with ECs through known cell adhesion receptors. When immune cells perform TEM, they bind to ICAM1 on the surface of activated ECs [13]. For UM cell TEM, ECs are not expected to be activated in the metastatic tissue target; therefore, the EC monolayers were not treated with inflammatory activators in our system. However, ICAM1 and VCAM are expressed constitutively on ECs, albeit at lower levels than on activated ECs. In addition, ECs use VE-cadherin to adhere to each other at cell junctions. UM cells express E-cadherin and N-cadherin [25], and VE-cadherin has been observed on cutaneous melanoma cells [26].
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Immune recovery vitritis

Immune recovery vitritis

3. Postelmans L, Payen MC, De Wit S, Caspers-Velu L. Neo vascular- isation of the optic disc after highly active antiretroviral ther- apy in an AIDS patient with cytomegalovirus retinitis. A new immune recovery-related ocular disorder? Ocular Immunology and Inflammation 1999; 7(3-4):237-40.

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Protein-protein docking with F(2)Dock 2.0 and GB-rerank.

Protein-protein docking with F(2)Dock 2.0 and GB-rerank.

2.8.1 Automated detection of complex types. Since F 2 Dock 2.0’s parameters are optimized separately for antibody- antigens and enzyme-inhibitors/enzyme-substrates, and a general set of parameters are used for all other types of complexes, the user only needs to specify the complex type to ensure the set of optimized parameters are applied. If the type is unknown, F 2 Dock 2.0 tries to determine which set of parameters to use as follows. If F 2 Dock 2.0 locates the six CDR loops (L1, L2, L3, H1, H2 and H3) in the protein sequence using the algorithm in [49], it identifies it as an antibody and uses the corresponding parameter set. Otherwise, if neither molecule is identified as an antibody and at least one of the molecules has at least 200 residues and at least 8% of its surface residues are Glycines then F 2 Dock 2.0 uses the enzyme complex parameter set. Finally, if both tests fail, a set of parameters for the general case is used. Among the complexes in the Zlab benchmark 2.0, F 2 Dock 2.0 fails to identify only one antibody (1KXQ) and three enzymes (1AY7, 1UDI and 2MTA). See Supplement S1 for details.
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Respiratory chain complexes in dynamic mitochondria display a patchy distribution in life cells.

Respiratory chain complexes in dynamic mitochondria display a patchy distribution in life cells.

Figure 5. Hybrid mitochondria following mitochondrial fusion display a patterned distribution of RC complexes. Ongoing fusion and fission of mitochondria subsequent to cell fusion caused the generation of hybrid mitochondria with a mixed population of RC complexes. A. Appearance of mitochondria with CIII-R and CII-g 5d after coexpression. Lower part: Line plot of CIII-R and CII-G fluorescence intensities along the longitudinal axis of a single mitochondrion, indicated with a white arrow head in A. The corresponding Pearson’s cross correlation coefficient is 0.89 calculated from the fluorescence distribution in a single mitochondrion as depicted in the lower part. B. CV-R and CV-G distribution in hybrid mitochondria 5 h after cell fusion. The corresponding Pearson coefficient is 0.49 calculated from the line plot in the lower part. C. CV-R and CIII-G fusion and analysis 4 h later. Lower part: Line plot of CIII-G and CV-R fluorescence intensities along the longitudinal axis of a single mitochondrion, indicated with a white arrow head in C. The corresponding Pearson’s cross correlation coefficient is 0.38. D. CI-G and CV-R in mitochondria 4.5 h after cell fusion. Lower part: Line plot of CI-G and CV-R fluorescence intensities along the longitudinal axis of a single mitochondrion, indicated with a white arrow. The corresponding Pearson’s cross correlation coefficient is 0.49. Some fragmented mitochondria display only CV-R fluorescence, because they did not fuse with CI-G-mitochondria (arrow). E. CI-G and CIII-R fluorescence distribution in mitochondria 5 h after fusion. The calculated Pearson for the correlation of the fluorescence distribution is 0.62. F. CI-G and mtDsRed fluorescence distribution in mitochondria in cells co- expressing both plasmids. The corresponding Pearson’s cross correlation coefficient is 0.66. Scales bars 1 mm = 30240 pixel (A, C, D E), 1 mm = 108 pixel (B), 1 mm = 134 pixel (F). After recording z-stacks, the images were deconvolved by
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