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)

The gene responsible for the lpr mutation in MRL mice that are prone to systemic lupus erythematosus has been shown to encode the apoptosis-inducing Fas antigen, thus pointing to control of apoptosis as a major regulatory mechanism in autoimmunity. In the non-obese diabetic mouse model for insulin-dependent diabetes, four non-MHC-linked loci have been localized in the murine genome that were found to be associated with successive stages of the disease. These findings should soon have a major impact on our understanding of human autoimmune diseases.
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PMID:Non-MHC-linked genes in autoimmune diseases. 128 39

Fas antigen is a cell-surface protein that mediates apoptosis. It is expressed in various tissues including the thymus and has structural homology with a number of cell-surface receptors, including tumour necrosis factor receptor and nerve growth factor receptor. Mice carrying the lymphoproliferation (lpr) mutation have defects in the Fas antigen gene. The lpr mice develop lymphadenopathy and suffer from a systemic lupus erythematosus-like autoimmune disease, indicating an important role for Fas antigen in the negative selection of autoreactive T cells in the thymus.
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PMID:Lymphoproliferation disorder in mice explained by defects in Fas antigen that mediates apoptosis. 137 94

Studies indicate that autoimmune phenomena might be caused by a failure to eliminate autoreactive lymphocytes. Therefore, we examined Fas antigen and bcl-2 expression and function in lymphocytes from human systemic lupus erythematosus (SLE) patients. Freshly isolated lymphocytes from patients with active SLE expressed more Fas antigen than did lymphocytes from patients with inactive SLE or from normal controls. They also showed characteristic DNA fragmentation after treatment with anti-Fas antibody. Expression of bcl-2 in T cells from active SLE patients was significantly higher than that in cells from inactive SLE patients and from normals. These data suggest that lymphocytes in patients with active SLE maintain an activated state in vivo. However, the role of Fas and bcl-2 expression in the regulation of lymphocyte survival in SLE is still unclear and further investigations concerning the role of these molecules in autoimmune phenomenon in SLE are needed.
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PMID:Expression and function of Fas antigen and bcl-2 in human systemic lupus erythematosus lymphocytes. 752 11

Cells of the immune system are, most likely, programmed to die unless recruited into an immune response. An active cell death program may also be induced by a variety of soluble and surface signals, many of which have only recently been recognized. The importance of these pathways in maintaining tolerance is highlighted by the development of lupus-like diseases in three different mouse strains that have spontaneous mutations in the Fas/APO-1 receptor or its ligand. The known function of Fas/APO-1 in signalling apoptosis explains the persistence of self reactive cells in lpr mice although it is unclear, at present, whether Fas defects effect both central and peripheral tolerance. Whereas Fas/APO-1 receptor expression appears to be normal in humans with SLE, other defects in the Fas/APO-1 pathway or other key molecules in the cell death survival require further study.
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PMID:Apoptosis in SLE--too little or too much? 753 Nov 24

Fas antigen (CD95) is a membrane-associated molecule that mediates apoptotic cell death and may play a role in the induction and maintenance of T cell tolerance. To elucidate the involvement of Fas antigen in human autoimmune diseases, we analysed Fas antigen expression by peripheral T cells from patients with SLE and rheumatoid arthritis (RA), using three-colour flow cytometry. Both CD4+ and CD8+ T cells from SLE patients expressed Fas antigen in a higher density than did these cells from healthy donors and from RA patients. Enhancement of Fas antigen density was noted in Fas+CD45RO+ memory T cells from SLE patients. More remarkably, a significant expression of Fas antigen was observed in CD45RO- naive T cells from SLE patients. CD4+CD45RO- T cells from SLE patients co-expressed Fas antigen and early to intermediate activation antigens such as CD25 and CD71, and late activation antigen HLA-DR in only FashiCD4+ naive T cells. Such up-regulation of Fas antigen expression in SLE patients seems to be clinically meaningful, because mean fluorescence intensity (MFI) of Fas antigen on CD4+ T cell subsets inversely correlates with the absolute size of CD4+ T cell subsets in peripheral blood of SLE patients. These results suggest that T cells with increased Fas antigen expression may be highly susceptible to apoptotic cell death, in vivo. A putative mechanism for lymphopenia in SLE patients is discussed.
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PMID:Up-regulated expression of Fas antigen (CD95) by peripheral naive and memory T cell subsets in patients with systemic lupus erythematosus (SLE): a possible mechanism for lymphopenia. 753 28

The Fas/APO-1 (Fas) antigen is a cell surface protein that mediates apoptosis and belongs to the tumor necrosis factor receptor family. The lymphoproliferative (lpr) anomaly in mice results from a retroviral disruption within the fas gene. Mice that are homozygous for the lpr mutation accumulate large numbers of T lymphocytes and exhibit an autoimmune syndrome resembling systemic lupus erythematosus. A possible explanation for this process is that in the absence of Fas antigen, lpr T cells may be resistant to normal peripheral deletional signals. The bacterial superantigen staphylococcal enterotoxin B (SEB) rapidly induces anergy and deletion by apoptosis of reactive T lymphocytes in normal mice. Administration of SEB to adult lpr mice results in the delayed induction of both unresponsiveness and deletion of V beta 8+ lymph node cells. This is not due merely to an increased thymic output in lpr mice; the delayed induction of tolerance and elimination of reactive lpr T cells by superantigens are intrinsic properties of the cells. The progressive lymphadenopathy in lpr mice may reflect a process of lymphoaccumulation rather than lymphoproliferation. A delay in tolerance induction and elimination of self-reactive T cells could have profound influence on the autoimmune diathesis of lpr mice.
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PMID:Delayed kinetics of T lymphocyte anergy and deletion in lpr mice. 753 79

The recessive mouse mutations lpr and gld create deficiencies in an interacting pair of cell surface molecules, CD95 (Fas/APO-1) and Fas-ligand (FasL), respectively, resulting in autoantibody production resembling human systemic lupus erythematosus. The mechanisms of self-tolerance affected by deficiency in either molecule are not established, but CD95 deficiency both in B cells and in CD4+ T cells recognizing major histocompatibility complex (MHC) class II molecules is required for autoimmunity in lpr mice. Here we track the outcome of in vivo interactions between B cells and CD4+ T cells that recognize a transgene-encoded autoantigen, hen egg lysozyme (HEL), using cells from mice transgenic for immunoglobulin and T-cell receptor (TCR) genes. B cells that had not previously encountered HEL autoantigen (naive cells) were triggered into proliferation and antibody production upon interaction with antigen and HEL-specific CD4+ T cells. By contrast, B cells that had been chronically exposed to HEL during their development and carried desensitized surface immunoglobulin (sIg) antigen receptors (anergic cells) did not produce antibody but instead were eliminated in the presence of HEL-specific CD4+ T cells. CD95-deficient anergic B cells, however, were not eliminated by CD4+ T cells and were triggered to proliferate. These findings identify a novel regulatory step for eliminating autoreactive B cells that seems unique in its dependence on CD95.
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PMID:CD95 (Fas)-dependent elimination of self-reactive B cells upon interaction with CD4+ T cells. 760 71

The BXSB Y chromosome-linked mutant gene, Yaa, accelerates the progression of a lupus-like autoimmune syndrome only in mice that are predisposed to autoimmune diseases. Unlike the lpr gene, which causes the defects in the Fas antigen-mediating apoptosis, the autoimmune enhancing activity of the Yaa gene is selective, depending on autoantigens, and varies among lupus-prone mice. To obtain a better definition of the role of the Yaa gene in the acceleration of autoimmune disease, we have investigated immune responses to several foreign antigens to determine whether the Yaa gene is able to potentiate immune responses to foreign antigens in a selective manner. We report here that the Yaa gene potentiated immune responses against foreign antigens only in mice which are genetically (H-2-linked) low responding, but not high or non-responding. Moreover, studies on Yaa(+)-Yaa- double bone marrow chimeric mice revealed that B cells from Yaa+ mice were selectively stimulated to produce antibodies to low-responding antigen, human IgG, while both B cell populations similarly responded to high-responding antigen, ovalbumin. Our results suggest that first, the selective immune enhancing activity of the Yaa gene may be related to differences in the capacity of T helper cells specific for given self or foreign antigens; and second, a specific cognate interaction of T helper cells with Yaa+ B cells is apparently responsible for the selective enhancement of immune responses to antigens, to which mice are genetically low responding.
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PMID:Selective enhancing effect of the Yaa gene on immune responses against self and foreign antigens. 784 28

The BXSB/MpJ (BXSB) murine strain (H-2b) spontaneously develops an autoimmune syndrome with features of systemic lupus erythematosus (SLE) that affects males much earlier than females. A mutant gene located on the BXSB Y chromosome, designated Yaa (Y chromosome-linked autoimmune acceleration), is responsible for the acceleration of the disease observed in male BXSB mice. Studies on H-2 congenic and I-E transgenic mice have clearly demonstrated that the MHC class II genes play a crucial role in the development or protection of SLE. However, the MHC effect can be completely masked by the presence of the Yaa gene in mice with certain genetic backgrounds. It is intriguing that the Yaa gene effect is selective on autoimmune responses, varying in different lupus-prone mice. Studies on immune responses against foreign antigens have shown that the Yaa gene potentiates immune responses only against antigens to which mice are genetically (H-2-linked) low-responding, but not high-responding. Thus, the selective immune enhancing activity of the Yaa gene may be related to differences in the capacity of T helper cells specific for given antigens. Moreover, studies on Yaa(+)-Yaa- bone marrow cell chimeric mice have suggested that a specific cognate interaction of T helper cells with Yaa+ B cells is responsible for a selective enhancing effect of immune responses to foreign antigens as well as autoantigens. It is significant that unlike the lpr mutation, whose abnormality is associated with the capacity of the Fas antigen to mediate apoptosis, the Yaa gene by itself is unable to induce significant autoimmune responses in mice without apparent SLE background. This suggests that the molecular defect of the Yaa gene is likely to differ from that of the lpr gene, and that the Yaa gene effect requires the abnormal autosomal genome present in lupus-prone mice. Based on these findings, a possible molecular nature of the Yaa gene abnormality will be discussed.
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PMID:The role of the Yaa gene in lupus syndrome. 793 Aug 46

MRL/Mp-lpr/lpr (MRL-lpr) mice have been used for a model of human systemic lupus erythematosus. This strain of mice homozygous for an autosomal recessive mutation, lpr (lymphoproliferation), develops massive lymphadenopathy with the expansion of CD4-CD8- (double negative; DN) T cells. Recently it was demonstrated that lpr mice have defects in the gene of Fas antigen which mediates apoptosis, indicating a possibility of defect in negative selection of autoreactive T cells in the thymus of lpr mice. However, the mechanisms that control the accumulation of DN T cells in lymph nodes, and the involvement of DN T cells in the clinical manifestation of disease, have not been well understood. In this study, the expression of various cell adhesion molecules on lymphocytes from MRL-lpr mice was examined. The strong expression of CD44 antigen as well as heat stable antigen (HSA) on abnormal DN T cells of lymph nodes was characteristic in MRL-lpr mice. Furthermore, the accumulation of DN T cells in lymph nodes might result from augmented binding of lymphocytes to endothelial cell surface of lymph nodes, possibly due to the failure of Mel-14 antigen shedding from DN T cell surface. In addition, it was found that monoclonal antibodies reactive with cell adhesion molecules such as CD44, Mel-14, CD45R and HSA expressed on DN T cells, could trigger the lytic activity of DN T cells and redirected DN T cell-mediated lysis of Fc-receptor-positive target cells (EL-4). In contrast to T cell receptor (TCR)-mediated cytotoxicity, this redirected cytotoxicity was not inhibited by anti-lymphocyte function associated antigen-1 (LFA-1) antibody. Thus, cell adhesion molecules may play a major role in delivering the transmembrane signal to DN T cells of MRL-lpr mice that trigger the lytic activity. It is likely that DN T cells of MRL-lpr mice induce tissue damages by the interaction with ligand on vascular endothelium or extracellular matrix in vivo.
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PMID:[Functional studies of adhesion molecules on CD4-CD8- double negative T cells of autoimmune MRL/Mp-lpr/mice]. 822 81


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