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Query: UMLS:C0024141 (systemic lupus erythematosus)
 44,322 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In vitro, collagen and collagen-like material in GBM, were demonstrated to have a particular high affinity for any DNA tested (mammalian, bacterial, viral, and plant). GBM fixed DNA 40-80 times more than HGG and BSA and 10-40 times more than bacterial LPS. GBM has a higher affinity for SSDNA than for DSDNA. This binding was inhibited at low pH, low ionic strength, and in the presence of anionic detergents, indicating that the highly negatively charged DNA may interact with the basic site on collagen or GBM by electrostatic forces. This interaction was competitively interfered with by DNA-binding proteins such as Clq. Complexes formed of DNA and anti-DNA antibodies did not exhibit the same binding property as free DNA. However, DNA which was already bound to GBM or to collagen could very efficiently bind anti-DNA antibodies and form immune complexes which would remain on these structures. The biological significance of the binding of DNA to GBM or to collagen should be particularly considered in relation to the pathogenesis of SLE. It is possible that DNA released from disrupted or degenerating cells would bind to surrounding collagen fibers or to basement membranes and then act as an immunoabsorbant for circulating anti-DNA antibodies. Some evidence for an in vivo binding of SSDNA to renal structures was obtained in mice treated with bacterial LPS 2 days before the injection of SSDNA.
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PMID:In vitro demonstration of a particular affinity of glomerular basement membrane and collagen for DNA. A possible basis for a local formation of DNA-anti-DNA complexes in systemic lupus erythematosus. 0 78

Administration of thymosin fraction V to NZB/NZW F1 mice, an animal model for human SLE, accelerated the appearance of proteinuria and anti-nDNA antibodies, increased deposition of immunoglobulins in kidneys, and significantly shortened survivals. Although the addition of thymosin to in vitro cultures of spleen and lymph node cells from thymosin-treated mice increased DNA synthesis in response to stimulation with Con A, in vivo treatment with thymosin did not affect the Con A response. There was no effect on in vitro responses to PHA or LPS, or on IgM antibody formation to SRBC (T cell dependent) or SSS III (T cell independent) immunizations. Antibodies to thymosin or contamination of our thymosin preparations with nucleic acids could not be demonstrated. The acceleration of autoimmune disease produced by thymosin treatment could not be explained by alteration of the T and B cell functions studied.
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PMID:Effect of altered lymphocyte function on immunologic disorders in NZB/NZW mice. III. Acceleration of disease by thymosin. 30 81

The 125I-Clq binding test was modified in order to allow for the detection of immune complexes in native unheated human serum. Indeed, heat-inactivation (56 degrees, 30 min) was found to reduce the Clq-binding activity of immune complexes mixed with native serum. This effect was not observed when EDTA was added to the native serum before mixing the immune complexes. The modified 125I-Clq binding test was performed in two steps: first, the tested native serum sample was incubated for 30 min at 37 degrees C with 0.13 M EDTA in order to prevent the integration of 125I-Clq into the intrinsic Clqrs complex, second, 125I-Clq and polyethylene glycol (final concentration 2.5%) were added to this mixture, and further incubated for 1 hr at 4 degrees C. Under these conditions, free Clq remained soluble whereas Clq bound to macromolecular complexes was precipitated. The competitive effect of intrinsic Clq and the interference of other substances such as DNA or bacterial LPS were very limited. The modified Clq binding test was applied to the clinical investigation of 44 patients with systemic lupus erythematosus; and increased Clq binding activity (Clq-BA) was observed in 91% of the samples. The level of Clq-BA was found to be significantly correlated to the DNA-binding capacity and to the decrease of the level of some complement components.
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PMID:Detection of immune complexes in unheated sera by modified 125I-Clq binding test. Effect of heating on the binding of Clq by immune complexes and application of the test to systemic lupus erythematosus. 124 40

The effect of conditioned medium on the biosynthesis and glycosylation profile of acute phase proteins secreted by the human hepatoma cell line Hep G2 was studied. Conditioned medium was prepared from nonactivated [CM-LPS(-)] and ex vivo lipopolysaccharide activated [CM-LPS(+)] monocytes from eight patients with active rheumatoid arthritis (RA), five patients with active systemic lupus erythematosus (SLE), and seven healthy subjects. The biosynthesis of albumin, alpha 1-antichymotrypsin and alpha 1-proteinase inhibitor and the profile of glycosylation of proteinase inhibitor were analysed. CM-LPS(-) from patients with SLE had a similar effect to CM-LPS(-) from healthy subjects. In contrast, CM-LPS(-) from patients with RA had the same effect as CM-LPS(+) from healthy donors. A similar effect to that of CM-LPS(+) of healthy subjects was seen with CM-LPS(+) from patients with SLE and with CM-LPS(+) from patients with RA. The treatment of CM-LPS(+) with antibodies against interleukin 6 neutralised most of its ability to induce changes in the biosynthesis and glycosylation of acute phase proteins. Antibodies to interleukin 1 and tumour necrosis factor alpha had only a limited effect on the ability of CM-LPS(+) to induce changes of albumin and alpha 1-antichymotrypsin syntheses, whereas they had no effect on the biosynthesis and glycosylation of proteinase inhibitor. These results indicate that: (a) monocytes isolated from patients with active SLE and active RA have different capabilities of inducing alterations of acute phase proteins in vitro; (b) ex vivo activation of monocytes from patients with SLE leads to the full induction of its capabilities to change acute phase proteins, whereas the activation of monocytes from patients with RA has no additive effects; and (c) interleukin 6 seems to be a major cytokine involved in the regulation of the glycosylation pattern of acute phase proteins.
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PMID:Different capabilities of monocytes from patients with systemic lupus erythematosus and rheumatoid arthritis to induce glycosylation alterations of acute phase proteins in vitro. 137 63

The expression of cell surface nuclear Ag was studied by examining the binding of anti-histone mAb to viable human peripheral blood cells. Freshly isolated cells showed no binding of these mAb. However, in vitro culture in the presence of LPS induced a dose-dependent expression of cell surface nuclear Ag on monocytes (M3+ cells). The addition of IL-1 beta to cultures also induced expression of cell surface nuclear Ag, whereas IFN-gamma was without effect. Release of nuclear material into the supernatants over time was demonstrated by using a chromatin-specific sandwich ELISA. Analysis of the DNA in the released nuclear material demonstrated banding at multiples of 190 bp, suggesting the release of polynucleosomes. Although LPS was required for cell surface nuclear Ag expression, it did not affect the release of nuclear material into the supernatants. The ability of monocytes to bind exogenous chromatin was studied by adding biotinylated-chromatin to PBL and detection with FITC-avidin. Freshly isolated PBL bound no chromatin, but when PBL were cultured in the presence of LPS, monocytes bound chromatin in a saturable manner. The LPS induction of the capacity to bind exogenous chromatin was blocked by cycloheximide. These data suggest that monocyte activation is associated with the expression of a chromatin (?nucleosome)-binding receptor and that this receptor is capable of binding nuclear material released into the cellular milieu. Monocytes may thus provide an important mechanism for the removal of extracellular nuclear material at sites of cell death and/or inflammation. The binding of nuclear Ag to cell surfaces and potential abnormalities of this binding may play a role in the induction of antinuclear antibodies and/or tissue damage in diseases such as SLE.
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PMID:Regulation of nuclear antigen expression on the cell surface of human monocytes. 157 30

Autoimmune MRL-lpr/lpr and NZB/W mice spontaneously secrete large quantities of pathogenic IgG1 and IgG2a autoantibodies. NZB mice also produce autoantibodies but these tend to be of the IgM H chain class. This work examines whether differences in the isotype of autoantibody produced by lupus-prone mice reflects differences in the sensitivity of autoreactive B cells to lymphokine-mediated IgG secretion. Twenty-five percent of normal BALB/c B cells produced IgG1 when stimulated in vitro with IL-4 plus LPS. This was comparable with the effect of IL-4 on small resting B cells from MRL-lpr/lpr and NZB/W mice. In contrast, less than 8% of the resting B cells from NZB mice produced IgG1 under these conditions. LPS plus IFN-gamma induced 5% of BALB/c and NZB/W but only 1% of NZB B cells to secrete IgG2a. Because lymphocytes from both young and old NZB mice showed diminished IgG1 and IgG2a secretion after lymphokine treatment, B cells from this strain appeared to be intrinsically resistant to the effects of IL-4 and IFN-gamma. In contrast, a disproportionately large proportion (22%) of B cells from adult MRL-lpr/lpr mice produced IgG2a when treated with IFN-gamma in vitro. Only B cells from MRL-lpr/lpr mice with active disease responded with such high levels of IgG2a production: cells from animals that had not yet developed clinical disease produced normal levels of IgG2a. Within each strain, B cells producing antibodies against autoantigens such as DNA, bromelain-treated mouse RBC and Sm responded to treatment with IL-4 and IFN-gamma in a manner indistinguishable from B cells producing antibodies against conventional Ag such as TNP and ARS.
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PMID:IgG1 and IgG2a production by autoimmune B cells treated in vitro with IL-4 and IFN-gamma. 210 5

Systemic lupus erythematosus is a multifactorial systemic disease in which genetic, immunologic, hormonal, and environmental factors may contribute to disease pathogenesis. Bacterial products (eg, bacterial lipopolysaccharide [LPS]) induce a lupuslike disease in normal mice and trigger an early and accelerated form of lupus nephritis in NZB/W mice. To investigate whether the mechanism by which LPS accelerates nephritis in the NZB/W mice involves interference with processing of immune complexes (IC), we administered LPS to NZB/W mice for 5 weeks and probed the kinetics of removal, liver uptake, and organ localization of a subsaturating dose of radiolabeled IC (2.5 mg of bovine serum albumin-antibovine serum albumin). Control NZB/W mice received vehicle (saline) alone. In NZB/W exposed to LPS, features of polyclonal B-cell activation (PBA) were enhanced, anti-DNA antibodies were raised, and a proliferative glomerulonephritis developed that was associated with renal insufficiency and substantial proteinuria. This LPS-accelerated nephritis could not be attributed to altered complement concentration, to altered blood cell carrier function, to delayed removal of pathogenic (large-sized) ICs from the circulation, to impaired liver uptake of ICs, or to enhanced localization of ICs in kidney. The findings indicate that transformation of nephritis is probably the result of LPS-induced PBA, that defective processing of pathogenic IC is not a contributory factor to nephritis, and that mechanisms other than passive renal localization of circulating ICs must be operative.
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PMID:Bacterial lipopolysaccharide transforms mesangial into proliferative lupus nephritis without interfering with processing of pathogenic immune complexes in NZB/W mice. 222 Oct 21

TNF-alpha is a macrophage-derived cytokine with diverse biologic activities, including potent immunomodulatory effects. In vitro studies have implied that TNF-alpha has predominantly proinflammatory and immunostimulatory effects, but paradoxically in vivo studies have demonstrated that administration of TNF-alpha suppresses murine lupus. To assess the effects of TNF-alpha on immune function in normal mice, we treated C57BL/6 mice with recombinant murine TNF-alpha (10 micrograms i.p.) or PBS on alternate days for up to 8 wk. Administration of TNF-alpha decreased the percentage of splenic T and B cells and increased the percentage of splenic macrophages without significantly altering the total number of mononuclear cells. Administration of TNF-alpha also caused progressive inhibition of splenic lymphocyte function, out of proportion to the quantitative reduction in B and T cells. After 8 wk of therapy, the proliferative responses of splenic lymphocytes to Con A, PHA, and LPS were reduced by 100, 90, and 60%, respectively, in treated mice compared with control mice. The reduction in T cell proliferation was due primarily to alteration of accessory cell function rather than direct inhibition of T cell function. Treatment with TNF-alpha markedly inhibited T cell cytotoxicity induced by immunization with allogenic target cells, and it virtually ablated NK cell activity. Inhibition of these in vitro tests of lymphocyte function correlated with inhibition of delayed type hypersensitivity in vivo. In contrast, treatment with TNF-alpha did not impair humoral immunity. These findings imply that TNF-alpha may affect cell-mediated immunity more profoundly than humoral immunity. This observation may be relevant to the mechanism whereby TNF-alpha suppresses murine lupus.
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PMID:Effects of recombinant murine tumor necrosis factor-alpha on immune function. 230 39

The influence of dietary fat on autoimmunity in lupus-prone (NZB x NZW)F1 mice has been demonstrated. In defining further the effects of dietary lipid on the immune system of this strain, female weanling mice were placed on four diets differing in quantity and type of fat. Their immunologic response was then studied by a variety of tests at 4 and 7 mo of age. Few differences were seen among the four groups at 4 mo of age. At 7 mo of age, however, the mice receiving diets high in saturated and unsaturated fats had a reduced mitogenic response to T cell mitogens and an enhanced response to the B cell mitogen LPS. Immunoglobulin levels and delayed hypersensitivity responses did not show any consistent differences among the diet groups. At 7 mo, however, mice receiving diets high in unsaturated fat demonstrated hyperresponsiveness to injected sheep red blood cells as measured by the hemolytic plaque technique. In addition, peritoneal leukocytes from the same diet group exhibited an increased response to bromelain-treated autologous erythrocytes which was decreased after treatment with anti-Thy-1 antiserum and complement. Phagocytosis by peritoneal macrophages was significantly decreased in the animals fed high-fat diets, particular high saturated fat. Similarly, natural killer cell activity was markedly reduced in the mice with a high intake of saturated lipid, a finding which correlated with the in vitro production of interferon. These results indicate that diets high in fat influence immune responses and thus can affect the onset and severity of autoimmune disease. A low-fat diet can reduce the development of disease by maintaining normal immune responses. The data also suggest that unsaturated fat may influence T helper cell activity and therefore antibody production, whereas saturated fats may affect cellular immune responses which are dependent on membrane contact.
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PMID:Dietary fat and immune function. I. Antibody responses, lymphocyte and accessory cell function in (NZB x NZW)F1 mice. 241 89

Systemic lupus erythematosus (SLE) is characterized by multiple defects affecting B and T lymphocyte cell function. In view of the influence that monocytes may have on these functions, we have examined monocyte function in patients with SLE and normals. Monocytes were examined as to number, their ability to modulate IgG synthesis, phagocytose yeast particles, and acid phosphatase activity. Patients had more monocytes and mononuclear cells made more IgG, but these factors appear to be independent of each other. Monocytes from lupus patients are less phagocytic but show similar levels of acid phosphatase activity to normal controls. Normal, but not lupus monocytes, show enhanced phagocytosis following treatment with LPS. The effect of monocyte stimulation on acid phosphatase activity is the same in lupus and normal monocytes. Taken together, these observations suggest that the increased numbers of monocytes in lupus patients and some subtle functional differences in these cells may be important in the progression of this disease.
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PMID:Monocyte function in systemic lupus erythematosus. 250 Feb 77


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