Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024141 (systemic lupus erythematosus)
 44,322 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study reports the effects in vitro and in vivo of L-canavanine (LCN), an amino acid found in commonly consumed legumes, on immune function in normal and autoimmune mice. L-Canavanine in high doses effectively blocks all DNA synthesis in vitro within 24 h. At lower doses, LCN affects B-cell function of autoimmune New Zealand Black/New Zealand White (NZB/NZW)F1 mice, inhibiting [3H]thymidine incorporation in response to B-cell mitogens, and pokeweed-induced intracytoplasmic immunoglobulin synthesis. LCN stimulates intracytoplasmic immunoglobulin (IgG greater than IgM). T-cell functions such as lymphoproliferation in response to concanavalin A or phytohemagglutinin and T-cell cytotoxicity are not affected. Suppression of the lipopolysaccharide response by LCN is removed by the addition of fresh B cells. Addition of the amino acid to mouse diet resulted in a decrease in the life-span of the autoimmune NZB and (NZB X NZW)F1 mice and abolished the protective effect of male sex on their survival. The decrease in survival in LCN-treated autoimmune mice correlated with an increase in spontaneous immunoglobulin-secreting cells (IgG greater than IgM) and antinuclear and double-stranded DNA antibodies. The histopathological analyses revealed increased glomerular damage and immunoglobulin deposition in the kidneys of the LCN-treated autoimmune and normal (DBA/2) mice. Ten percent of normal mice developed high titers of autoantibodies after 24 weeks of the diet. These data suggest a dietary amino acid, L-canavanine, affects B-cell function resulting in autoimmune phenomena and providing a new animal model of autoimmunity, a diet-induced systemic lupus erythematosus.
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PMID:Effects of L-canavanine on immune function in normal and autoimmune mice: disordered B-cell function by a dietary amino acid in the immunoregulation of autoimmune disease. 387 46

A lupus-like disease characterized by a severe immune complex glomerulonephritis and IgG autoantibody production was induced in (C57BL/6 X DBA/2)F1 mice by injection of parental DBA/2 lymphoid cells. The ensuing graft-vs-host (GVH) reaction resulted in a 10- and a 100-fold increase in serum IgG antibody levels to denatured DNA and total histones, respectively, compared with that in F1----F1 control mice. The level of anti-DNA antibodies peaked 2 wk after injection of DBA/2 cells and preceded peak anti-histone levels by approximately 2 wk. Anti-histone antibodies were generated predominantly to histones H1, H2A, and H2B, a profile different from that observed in NZB/NZW and MRL-lpr/lpr mice. The marked increase in IgG antinuclear antibodies did not correlate with increases in total IgG serum levels and was not associated with comparable increases in antibodies to transferrin, hemoglobin, fibrinogen, or thyroglobulin. Selective autoantibody production was also observed in vitro, wherein GVH spleen cells produced high levels of IgG antibodies to total histones and denatured DNA but not to these non-nuclear protein antigens. In contrast, spleen cells stimulated in vitro with lipopolysaccharide produced equivalent amounts of antibodies to all antigens tested. Our results are in agreement with those of other investigators and collectively suggest that IgG autoantibodies in GVH disease, and possibly in spontaneous lupus-like disease, are not secondary to a generalized B cell activation, but may be selectively generated in response to self antigens with unique configurational properties.
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PMID:Autoimmunization in murine graft-vs-host disease. I. Selective production of antibodies to histones and DNA. 387 58

The present data demonstrate the induction of antisingle-stranded (SS) DNA and antidouble-stranded DNA antibodies in various strains of mice, including athymic C57BL/6 nude mice, after the injection of bacterial lipopolysaccharide (LPS). This anti-DNA response is dose dependent and varies quantitatively according to the strain of the injected mice. It is not correlated to the H-2 histocompatibility locus nor to the immune response to LPS. The lipid A fraction appears to be the active part of the LPS molecule for this particular effect. In addition, it was found that DNA is released in circulating blood a few hours after the injection of LPS. Most of the DNA released has physicochemical and immunochemical characteristics of SS DNA. Therefore, the anti-DNA response induced by injections of LPS may be the result of a release of DNA in a particularly immunogenic form at a time when the immune system, in particular the B lymphocytes, is rendered capable by LPS of developing an immune response to such a soluble antigen. These effects of LPS may account for the triggering or the exacerbation of ante-DNA antibodies during infections with gram-negative bacteria, and a similar mechanism may be involved in the pathogenesis of systemic lupus erythematosus.
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PMID:Release of DNA in circulating blood and induction of anti-DNA antibodies after injection of bacterial lipopolysaccharides. 460 9

Sera from patients with systemic lupus erythematosus and from mice spontaneously developing lupus were subjected to isoelectric focusing by a microsucrose gradient method. The spectrotypes of human antibodies to native DNA, denatured DNA, and polyriboadenylic acid (poly A) were compared. Antibodies to native DNA and denatured DNA focused into two regions whose boundaries were pH 5.0-7.0 and pH 8.5-10.0. Antinative DNA antibodies were more homogeneous than antidenatured DNA antibodies. Anti-DNA antibodies in cryoglobulins showed more restriction than those present in serum. There was no relationship between spectrotype and pattern of disease expression. Murine antibodies to native DNA were more heterogeneous than human anti-DNA antibodies. The spectrotypes of antidenatured DNA antibodies from patients with systemic lupus erythematosus or drug induced lupus, or from an immunized rabbit, were similar. Likewise, antibodies to poly A were similar in both human and murine lupus. In contrast to anti-DNA, antibodies to poly A were restricted and focused only in the alkaline range (pH 9.5-10.0). The spectrotype of antipoly A antibodies induced by lipopolysaccharide were comparable but had an additional small band at pH 6.2. Our results suggest unique antibody spectrotypes with varying degrees of restriction for different nucleic acid antigens. Furthermore, spontaneous and induced autoantibodies have similar spectrotypes. Thus, the B cell clones producing antinucleic acid antibodies may be similar whether they are activated spontaneously, following immunization, or as a consequence of polyclonal stimulation.
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PMID:Comparison of different antinucleic acid antibody spectrotypes in spontaneous, induced, and murine lupus. 616 39

Peripheral blood lymphocytes from 43 patients with systemic lupus erythematosus (SLE) and from age- and sex-matched normal controls were cultured with lipopolysaccharide (LPS) to examine the response to the polyclonal B-cell activator. Lymphocytes from active SLE patients incorporated 4840 +/- 471 (mean +/- SE) cpm in response to LPS, whereas lymphocytes from inactive SLE patients incorporated 6906 +/- 897 cpm. In contrast, lymphocytes from normal individuals incorporated 7452 +/- 1126 cpm. Ig synthesis of lymphocytes from active SLE in response to LPS stimulation was also less than that of normal individuals. The helper T-cell function of active SLE, as examined by co-culturing irradiated SLE lymphocytes with unirradiated normal lymphocytes, was normal. These results thus suggested that a defect of B lymphocytes exists in active SLE patients. This B-cell defect and T suppressor cells apparently play an important role in the pathogenesis of SLE.
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PMID:Mitogenic responses to lipopolysaccharide by B lymphocytes from patients with systemic lupus erythematosus. 621 30

Interleukin-1 (IL-1) is a monocyte product with diverse amplifying effects on immune cell reactions. We have studied 16 untreated SLE patients to determine the production of IL-1 by their monocytes under the stimulus of E. Coli lipopolysaccharide (LPS) or phorbol myristate acetate (PMA) and measured by the capacity of their supernatants to augment normal autologous mixed lymphocyte cultures (AMLR) or to replace accessory cells in Con A-induced proliferation of T lymphocytes. Concurrently, we studied the response of T lymphocytes from these same patients to IL-1 by its capacity to increase the percentage of stable E rosette forming cells and by the enhancement of T cell proliferation in AMLR. Monocytes from SLE patients produced significantly less IL-1 activity than those of age matched controls, regardless of the stimulus (LPS or PMA), as well as of the indicator system. All patients with active disease and seven of the 10 patients with inactive disease had decreased production of IL-1 activity as determined by at least one method. Response of T lymphocytes from SLE patients to IL-1 produced by normal monocytes was also found decreased as compared to normals. This defect was more marked in the T cells from patients with active than in those of patients with inactive disease. These findings indicate that the immunoregulatory disturbance that SLE patients have encompasses monocytes as well as T and B lymphocytes and suggest that the defect is either multicentric or originates in the stem cell.
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PMID:Defective monocyte production of, and T lymphocyte response to, interleukin-1 in the peripheral blood of patients with systemic lupus erythematosus. 622 71

In vivo, prolonged polyclonal activation of B cells by the nonantigenic but potent mitogenic lipid A portion of lipopolysaccharide (LPS-R595) resulted in acceleration of the late life systemic lupus erythematosus disease of female MRL/n, BXSB, and NZW mice, mimicking the time, form, and histopathological features characteristic of their early life disease counterparts, i.e., MRL/l females, BXSB males, and (NZB X NZW)F1 females. Similar polyclonal B cell activation of "immunologically normal" mice has less effect and led to a limited expression of autoimmune disease. This R595-induced autoimmunity and immune complex-mediated disease seemed to be the direct result of activation of the immune system and not from other effects of endotoxin since C3H/HeJ, a strain lacking lymphocyte receptors for LPS-R595, had neither serological nor histological evidence of autoimmune disease despite identical treatment.
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PMID:Induction of murine autoimmune disease by chronic polyclonal B cell activation. 633 69

B cell hyperactivity, a feature common to all lupus-prone murine strains, may be caused by hyperresponsiveness to, overproduction of, or bypassing of certain signals required for B cell activation, proliferation, and differentiation. In this study, we have compared the responses of B cells from three lupus-prone strains of mice (BXSB males, MRL and NZB/W females) and normal strains in a number of assays for which two or more signals are required to obtain a response. In medium to low density cultures of B cells from BXSB and NZB/W but not MRL/l lupus mice, the cells' proliferation induced by bacterial lipopolysaccharide (LPS) or anti-mu antibody was much higher than that of B cells from normal controls. At low B cell density, polyclonal activation by these substances and subsequent Ig secretion were dependent on accessory signals present in supernatants of concanavalin A-treated normal lymphocytes (CAS) or on the MRL/l proliferating T cell-derived B cell differentiation factor (L-BCDF) in both lupus-prone and immunologically normal mice. However, the responses of B cells from BXSB and NZB/W, but not MRL/l, mice to these accessory signals were higher than those of normal mice. Ig synthesis by fresh B cells of BXSB and NZB/W mice cultured in the absence of mitogens but in the presence of CAS or L-BCDF was higher than by similar cells from other strains, suggesting an increased frequency of B cells activated in vivo in these two autoimmune strains of mice. The patterns of IgG subclass secretion in response to LPS (without added CAS or L-BCDF) were abnormal in all lupus strains, with a predominance of IgG2b and/or IgG2a and low levels of IgG3, contrary to normal B cells for which IgG3 synthesis predominated. However, IgG1 synthesis in vitro by autoimmune and normal B cells alike was highly dependent on T cell-derived soluble mediators. Antigen-specific responses to SRBC in vitro of B cells from all lupus strains, like those of B cells from normal strains, required a minimum of three signals (antigen, LPS, T cell-derived antigen nonspecific helper factors). Yet, once triggered, B cells of BXSB and NZB/W mice gave higher responses than those of the other strains. We conclude that B cells of lupus mice have signal requirements similar to those of normal mice. Nevertheless, B cells of BXSB and NZB/W, but not MRL/l, lupus mice hyperrespond or process some accessory signals abnormally.
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PMID:B cell dependence on and response to accessory signals in murine lupus strains. 640 39

Lymph node and spleen cells of the autoimmune MRL/Mp-lpr/lpr mouse strain spontaneously produce (in the absence of mitogenic stimulation) a factor(s) that induces B cell differentiation. This factor is not produced by the congenic MRL/n mouse strain that lacks the lpr gene or by normal mouse strains. However, lymphoid cells of the B6-lpr/lpr (B6/1) strain also produce a B cell differentiation factor. Although the factor acts on resting B cells, its effect is greatly magnified by activating the B cells with anti-mu or lipopolysaccharide. MRL/l mice begin producing the factor as early as 1 mo of age but levels increase with age and appearance of lymphoproliferation. Cell depletion studies reveal that this factor is produced by T cells of the Lyt-1+2-phenotype. Because of its association with the lpr/lpr genotype, we term this B cell differentiation factor L-BCDF. Functional analysis of L-BCDF reveals that it acts regardless of cell density in culture and in the absence of interleukin 2 (IL-2). In fact, the increase in the production of L-BCDF by MRL/1 T cells with aging occurs concomitantly with a marked decrease in their ability to produce IL-2. No T cell replacing factor activity or B cell growth factor-like activity can be detected in MRL/l-derived supernatants. L-BCDF induces both IgM and IgG synthesis in lipopolysaccharide-activated B cells; however, it has a greater effect on IgG secretion. In particular, the production of IgG1, IgG2a, and IgG2b are markedly enhanced in the presence of L-BCDF. The spontaneous production of L-BCDF by T cells of SLE mice of lpr/lpr genotype suggests an association of this factor with autoimmunity.
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PMID:Identification of a B cell differentiation factor(s) spontaneously produced by proliferating T cells in murine lupus strains of the lpr/lpr genotype. 660 Apr 90

Palmerston North (PN) mice, a newly recognized model of systemic lupus erythematosus, were compared with autoimmune hybrid NZB/NZW mice in a study designed to examine spleen cell responsiveness to T-cell and B-cell mitogens. Modest reductions of responses to phytohemagglutinin (PHA) and concanavalin A (Con A) were noted in PN females after 24 weeks of age; these responses were reduced significantly in NZB/NZW females. In contrast, male PN and NZB/NZW mice responded actively to PHA and Con A throughout the first year of life. Responses to lipopolysaccharide were not affected by age or sex. Anti-DNA antibody levels, blood urea nitrogen, and glomerular histology were analyzed to determine if autoantibody production or renal failure correlated with suppressed mitogenic responsiveness. These factors, examined singly and together, were not as important as age. In this system, age and sex did not influence spleen cell responses to mitogens in normal CD-1 mice. Age and sex were of minimal importance in determining responses to T-cell mitogens in the recently defined PN model of autoimmunity. In contrast, age and sex exerted strong influences upon responses to PHA and Con A in the NZB/NZW model of lupus.
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PMID:Responses to T-cell and B-cell mitogens in autoimmune Palmerston North and NZB/NZW mice. 660 3


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