Differential gene expression in autoimmune mice.
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Animals↗
Biomedical subjects
J D Mountz
Publications and source records attributed to J D Mountz.
Antinucleic acid antibodies, gene expression, and autoimmune mice.
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Animals↗
Oncogene expression in autoimmune mice.
Systemic autoimmune disease states are known to be associated with abnormal cell growth or differentiation. In the murine models of systemic lupus erythematosus (SLE), specific genotypes result in dysregulated growth of certain lymphocyte subpopulations. Although genes underlying autoimmune syndromes have been characterized by mendelian genetics, it has not yet been possible to characterize them at the molecular level. Recently, it has become clear that cellular proto-oncogenes can regulate cell growth and differentiation. Therefore, we have studied the expression of five different proto-oncogenes; myc, myb, abl, bas, and raf, in organs and cells of various autoimmune strains. These genes were selected because each has previously been associated with abnormal hemopoietic cell growth, and because each has been at least partially characterized at the molecular and functional level. We have found selective abnormal proto-oncogene expression associated with the characteristic abnormal cell growth or differentiation of lymphocytes of autoimmune mice. The lymph nodes of MRL-lpr/lpr mice are packed with unusual T cells. These had a marked increase in myb expression. There was a 20-40-fold increase in myb RNA in lymph nodes of lpr/lpr mice on several different genetic backgrounds. The gld/gld mouse has a very similar unusual T cell in the lymph nodes: it also had a comparable increase in myb RNA in the nodes. In contrast, myb expression was not elevated in the other autoimmune mouse strains lacking these abnormal T cells. Whereas such lpr/lpr mice had increased myb expression in the lymph nodes and splenic T cells, they had markedly subnormal myb expression in the thymus, an organ with high myb in normal and in the other autoimmune strains. These results suggest that one phase of intrathymic differentiation in other mice occurs in the periphery of lpr/lpr mice. The spleens of NZB and male BXSB mice had increased myc expression which was found to be associated with B cells upon cell separation. Similarly, increased bas and abl expression was associated with autoimmune B cells. The xid gene, which retards or prevents the expression of murine lupus by retarding B cell maturation, was associated in BXSB.xid, NZB.xid, and MRL-lpr/lpr.xid congenic mice with marked reduction in expression of myc, bas, and abl in the spleens containing B cells, but not of myb in the lpr/lpr.xid nodes containing primarily the unusual T cells. Raf expression was found to be associated in lpr/lpr and gld/gld mice with both the unusual T cells and splenic B cells.(ABSTRACT TRUNCATED AT 400 WORDS)
Animals↗
Unusual expression of IL 2 receptors and both the c-myb and c-raf oncogenes in T cell lines and clones derived from autoimmune MRL-lpr/lpr mice.
Concomitant with their disease, autoimmune MRL-lpr/lpr mice develop a profound lymphadenopathy composed of an unusual dull Lyt-1+ population of T cells. To examine the unusual growth properties and origin of these T cells, as well as their potential role in disease, very rapidly growing T cell lines and clones have been developed from cultures of MRL-lpr/lpr spleen and LN cells. These were studied for growth receptors, oncogene expression, and surface markers. The results further demonstrate the unique nature of lpr-derived T cells and show that i) all lines and clones exhibit greatly elevated expression of both the c-myb and the c-raf oncogenes, ii) despite the reported defect in IL 2 receptor expression of mitogen-activated fresh MRL-lpr/lpr T cells, all long-term lines or clones bear large numbers of IL 2 receptors continuously and without stimulation, although iii) unlike slower growing IL 2-dependent lines from MRL-lpr/lpr mice, these rapidly growing lines and clones are poorly inhibited by anti-IL 2 receptor antibody. Such IL 2 receptor-bearing, nontransformed T cells that are easily maintained have been useful in growth factor studies.
Animals↗
Modulation of c-myb transcription in autoimmune disease by cyclophosphamide.
This study explores the relationship between autoimmunity and the myb proto-oncogene, a gene important for T cell development. The lpr/lpr mice had very large amounts of myb RNA in the lymph node (LN) cells; but unexpectedly, they had abnormally low levels of myb RNA in the thymus, an organ normally rich in myb RNA. Mice with the gld/gld genotype had high myb RNA levels in peripheral LN, similar to lpr/lpr mice, but had normal thymic myb RNA levels. Both lpr/lpr and gld/gld mice and an AILD patient with lymphadenopathy and high myb RNA in peripheral blood cells were treated with cyclophosphamide (CY). In all cases, the CY eliminated the lymphadenopathy and corrected the abnormal myb expression. However, there were significant differences in the clinical and cellular responses to this drug. A single large dose of CY led to marked regression of the lymphadenopathy of gld/gld mice and long-term amelioration of their autoimmune syndrome. In contrast, similar treatment of lpr/lpr mice failed to alter either the lymphadenopathy or the disease process. Consistent with these clinical findings, LN myb was normalized in gld/gld mice by a single injection of CY, whereas there was no effect on myb expression in lpr/lpr mice. The AILD patient reacted much like the gld/gld mice in that myb RNA levels in the peripheral blood, and bone marrow returned to normal after only three doses of CY. The lymphadenopathy and high levels of LN myb mRNA of the lpr/lpr mice could be normalized; this occurred only after long-term treatment with CY. These events were accompanied by an increase in thymic myb mRNA from low levels. These studies have combined a molecular probe with CY therapy to provide insights into the cellular bases for lymphoproliferative autoimmune diseases.
Animals↗
Autoimmunity and increased c-myb transcription.
A single recessive gene, lpr, induces an autoimmune-lymphoproliferative syndrome in several strains of mice. The lymphoid organs of lpr/lpr mice contained cells with increased amounts of myb RNA, which codes for a protein found in the nucleus. A similar human lymphoproliferative disorder also had an increase in c-myb expression. Mouse T cells induced by mitogens to proliferate did not express large amounts of myb RNA, indicating that marked myb expression is not a general feature of lymphocyte activation and proliferation.
Animals↗
Rheumatoid arthritis and small airways function. Effects of disease activity, smoking, and alpha 1-antitrypsin deficiency.
The sensitive pulmonary function tests of change in maximum expiratory flow (delta Vmax 50) and volume of isoflow were used to determine the effects of rheumatoid arthritis (RA), smoking, and alpha 1-antitrypsin deficiency phenotypes on peripheral airways. Patients were prospectively divided into 4 groups: 14 smokers with RA, 12 nonsmokers with RA, 11 smokers without RA, and 13 nonsmokers without RA. delta Vmax 50 was the most discriminating variable and demonstrated significant small airway obstructive disease in the first 3 groups, with an additive effect in the group of smokers with RA. An increased incidence of the alpha 1-antitrypsin-deficient MS phenotype was seen in the RA smoker group, and this phenotype was associated with severe pulmonary disease.
Arthritis, Rheumatoid↗
Studies of immune defective RIII/AnN mice.
The present study advances our knowledge of the newly described immunodeficient RIII/AnN mouse. This strain was found to have markedly reduced spleen size and low serum levels of IgM, IgA, IgG1, IgG2 alpha, and IgG2 beta. Studies of F2 and backcross mice demonstrated that the defective immunoglobulin production was due to multiple genes: a dominant gene for low IgA and recessive genes for the others. RIII mice, like xid-bearing mice, had a markedly reduced splenic plaque-forming cell (PFC) response to Type III pneumococcal polysaccharide; however, unlike xid-bearing mice, the RIII/AnN mice produced substantial serum antibody responses to pneumococcal polysaccharide, polyriboinosinic . polyribocytidylic acid, and trinitrophenyl--Ficoll. In addition, spleen cells from RIII/AnN mice proliferated normally when stimulated with anti-mu, whereas those from xid mice did not. Thus, RIII/AnN mice represent a model of hypogammaglobulinemia and restricted immunodeficiency. They differ from other immunodeficient mice, and should assist in the analysis of immunodeficiency, autoimmunity, and regulation of class-specific immunoglobulin production.
Agammaglobulinemia↗
Neutrophil migration in response to chemotactic factors: effects of generation conditions and chemotherapeutic agents.
The effects of various chemotactic factor generation conditions and several chemotherapeutic agents on neutrophil migration were determined using in vitro assay systems designed as models for inflammatory processes occurring in the synovial cavities of patients with rheumatoid arthritis. The microtubule-promoting agent concanavalin A and the microfilament-disrupting agent cytochalasin B were shown in these systems to inhibit neutrophil migration towards zymosan-activated serum-derived chemotactic factors. Neutrophils, immunoglobulin G aggregates, and serum were required for maximum generation of comparable chemotactic factors. Insoluble immunoglobulin G aggregates with or without rheumatoid factor produced more chemotactic factor activity on interaction with neutrophils than soluble immunoglobulin G aggregates. Exposure of neutrophils to supratherapeutic levels of the nonsteroidal antiinflammatory agent aspirin decreased neutrophil response to chemotactic factors while exposure to the slow-acting or immunomodulating agents gold, D-penicillamine, or azathioprine had no effect on this neutrophil function. In vitro systems employing neutrophils, insoluble aggregates, and serum may offer useful means for assaying drug effects on important functional components of the rheumatoid inflammatory process.
Antigen-Antibody Complex↗
Bleomycin-induced cutaneous toxicity in the rat: analysis of histopathology and ultrastructure compared with progressive systemic sclerosis (scleroderma).
Rats injected with bleomycin over a 58-week period developed weight loss, alopecia, hyperpigmentation, skin thickening and skin tautness when compared with saline-injected control animals. The only significant abnormality in laboratory blood tests was an increased sedimentation rate in the bleomycin-treated rats compared with controls. Histological examination of dorsal skin showed atrophied sebaceous glands and increased collagen fibres, with diameters ranging from 37.5 to 75 nm as compared with 72.5 to 100 nm in control animals. Chronic bleomycin exposure produces clinical, histological and ultrastructural skin changes similar to those found in human progressive systemic sclerosis (scleroderma).
Animals↗
Ethambutol-induced toxic epidermal necrolysis.
Toxic epidermal necrolysis (TEN) is a severe cutaneous reaction that most commonly is related to drug exposure and that clinically can be confused with other bullous dermatoses, particularly staphylococcal scalded skin syndrome (SSSS) and erythema multiforme major (the Stevens-Johnson syndrome). We report the first case, to our knowledge, of TEN associated with ethambutol hydrochloride administration. Toxic epidermal necrolysis can be partially differentiated from other bullous dermatoses by history and clinical presentation. Microbiological results (eg, the isolation of Staphylococcus aureus in SSSS) and immunological studies (eg, the demonstration of immune complexes in the Stevens-Johnson syndrome) may aid in differentiation, but ultimately the diagnosis depends on histopathological examination of involved skin.
Aged↗
Bilayer lipid membranes (BLM) study of antigen-antibody interactions.
Previous work of del Castillo and co-workers has shown that bilayer lipid membranes (BLM) can be used as transducers for detection of antigen-antibody reactions. The present experiments extend the previous work by incorporating complement into the BLM system. The results indicate that the antigen-antibody complex or the complement has no ability to affect the BLM system separately, but when carefully combined they will destabilize the BLM as a tool for investigating immunological reactions is suggested.
Antibodies↗
Construction of a recombinant adenovirus vector encoding Fas ligand with a CRE/Loxp inducible system.
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Actins↗
Clinical features associated with correction of T-cell senescence: increased acute-phase response, amyloidosis and arthritis.
Two prominent features associated with immunosenescence are thymic involution and altered T-cell phenotype and responsiveness. We have shown previously that in CD2-fas transgenic mice, in which the Fas apoptosis molecule is constituatively expressed on T cells, T-cell senescence is greatly reduced. Using a different experimental approach, the relationship between T-cell senescence and apoptosis was analyzed on human PBMCs. The results indicate that there was increased apoptosis of CD45RO- (CD45RA+) T cells upon activation. We propose that this could account for the increase in CD45RO+ 'memory' T cells with aging in humans. Together these results are consistent with the notion that T-cell senescence is associated with altered apoptosis and decreased T-cell responsiveness. T-cell responsiveness remained high in CD2-fas transgenic aged mice, but there was no increase in overall life span of the mice. Increased T-cell responsiveness was associated with an increased acute-phase response and amyloid A deposition in the glomerulus of these mice. These data suggest that restoration of the T-cell immune function in aged individuals must be carried out in concert with correction of other immune factors that down modulate the acute-phase response to prevent undesirable side-effects.
Acute-Phase Reaction↗
Genetic dissection of age-related changes of immune function in mice.
Understanding of the genetic basis of normal and abnormal development of the immune response is an enormous undertaking. The immune response, at the most minimal level, involves interactions of antigen presenting cells (APCs), T and B cells. Each of these cells produce cell surface and soluble factors (cytokines) that affect both autocrine and paracrine functions. A second level of complexity needs to consider the development of the macrophage/monocyte lineage as well as the production of the common lymphoid precursor which undergoes distinct maturation steps in the thymus and periphery to form mature T cells as well as in BM (BM) and lymphoid organs to form mature B cells. A third level of complexity involves the immune response to infectious agents including viruses and also the response to tumour antigens. In addition, there are imbalances that predispose to decreased responses (immunodeficiencies) or increased responses (autoimmunity). A fourth level of complexity involves attempts to understand the differences in the immune response that occurs at a very young age, in adults, and at a very old age. This review will focus on the use of C57BL/6 J X DBA/2 J (BXD) recombinant inbred (RI) strains of mice to map genetic loci associated with the production of lymphoid precursors in the BM, development of T cells in the thymus, and T-cell responses to stimulation in the peripheral lymphoid organs in adult and in aged mice. Strategies to improve the power and precision in which complex traits such as the age-related immune response can be mapped is limited with the current set of 35 strains of BXD mice. Strategies to increase these strains by generating recombinant intercross (RIX) strains of mice are being developed to enable this large set of lines to detect quantitative trait loci (QTLs) with a much higher consistency and statistical power. More importantly, the resolution with which these QTLs can be mapped would be greatly improved and, in many cases, adequate to carry out direct identification of candidate genes. It is likely that, given the complexity of the immune system development, the number of cells involved in an immune response, and especially the changes in the immune system with ageing, mapping hundreds of genes will be required to fully understand age-related changes in the immune response. This review outlines ongoing and future strategies that will enable the mapping and identification of these genes.
Aging↗
Decreased T cell stimulatory capacity of monocyte-derived human macrophages following herpes simplex virus type 1 infection.
Macrophages play a central role in establishing a specific immune response by acting as professional antigen presenting cells (APC) for T cells leading to a vigorous immune response. In order to analyze if Herpes simplex Virus (HSV) type 1 infection might affect the macrophage APC-function, monocyte-derived human macrophages were infected with HSV-1 strain F in vitro. Cocultures with allogeneic T cells revealed a strongly impaired stimulatory capacity of HSV-infected macrophages compared to uninfected controls which was not owing to a productive viral infection in macrophages. An increased expression of Fas ligand (FasL/CD95L) was detected in HSV-infected macrophages by FACS analysis. Although the majority of the macrophages expressed high levels of Fas (CD95/Apo-1), the HSV-induced upregulation of FasL did not result in an increased autocrine apoptosis of macrophages which might be related to endogenous expression of the apoptosis inhibitor FLICE inhibitory protein (FLIP). However, substantial apoptosis occurred in peripheral T cells as well as Fas-sensitive Jurkat T cells when cocultured with HSV-infected macrophages. These findings suggest that the paracrine killing of activated T cells by FasL expressing APC might be a novel strategy of immune evasion by HSV.
Apoptosis↗
Defective clearance of adenovirus in IRF-1 mice associated with defects in NK and T cells but not macrophages.
A replication-defective adenovirus-LacZ recombinant virus (AdLacZ) was injected intravenously into IRF-1(-/-) mice and wild-type mice to characterize the contribution of IRF-1 to the immune-mediated clearance of Ad vector. Compared with wild-type mice, IRF-1(-/-) mice expressed higher levels of the LacZ gene product in the liver. After infusion of the AdLacZ, the expression of IRF-1 mRNA was upregulated in the liver of wild-type mice, but not in IRF-1(-/-) mice. Both spleen and liver mononuclear cells from IRF-1(-/-) mice initially exhibited a markedly lower number of NK, NK-T and CD8 T cells. At day 7 after the administration of AdLacZ, there was a significantly increased population of NK, NK-T and CD8 T cells in both spleen and liver, and also CD11b(+) cells in liver of IRF-1(-/-) mice, compared with the increased in wild-type mice. As IRF-1 is an important signal for production of IFN-gamma by CD8 T and NK cells as well as production of IL-12 by CD11b(+) cells, we determined whether there were lower levels of these cytokines in IRF-1(-/-) mice after Ad challenge. Surprisingly, there were lower levels of IL-12, but higher levels of IFN-gamma and IL-18 in IRF-1(-/-) compared with wild-type mice at day 7 after administration with AdLacZ. These results indicate that delayed clearance of Ad is associated with partial correction of defects of the NK, NK-T and CD8 T cells and increased production of IFN-gamma and IL-18 in IRF-1(-/-) mice.
Adenoviridae↗
Persistent expression of a soluble form of Fas/APO1 in continuously activated T cells from a patient with SLE.
OBJECTIVE: To report a patient with SLE whose T cells expressed disproportionally increased amounts of an alternatively spliced form of Fas/APO1 transcript and secreted a soluble form of Fas. METHODS: We established continuously activated, short-term T cell lines from 16 patients with SLE and from 6 normal controls. The structure, expression and function of Fas was examined using RT-PCR and sequencing, flow cytometry (surface expression of Fas), ELISA (measurement of soluble Fas) and a PI-based cytotoxicity assay (functional analysis). RESULTS: A soluble form of Fas which originates from an alternatively spliced transcript and lacks the transmembrane domain of the original molecule was the dominant product of the Fas-gene in one line (S18B) derived from a patient with very active SLE. Compared to a control line, the S18B cells displayed decreased surface Fas expression but increased accumulation of Fas inside the cell. The amount of soluble Fas in the culture supernatant of S18B was found to be 1.8 times higher than that of a control line. Culture supernatants from S18B cells inhibited anti-Fas mAb-medicated T cell death. CONCLUSION: Continuously activated T cells from one patient with SLE displayed increased amounts of soluble Fas that inhibits anti-Fas mediated cell death. Although the frequency of this abnormality among patients with SLE and other diseases is unknown, increased production of soluble Fas may have contributed to the pathogenesis of SLE in the patient presented here.
Adolescent↗