Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0153470 (Spleen)
 4,015 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Spleen cells from rats that have recovered from experimental autoimmune encephalomyelitis (EAE) suppress the production of IFN-gamma by effector T cells of EAE in an Ag-specific manner. These postrecovery suppressor cells also inhibit EAE in vivo. Fractionation of the postrecovery suppressor spleen cells on nylon wool and OX-8 coated plates yields a nylon wool-adherent CD4+ suppressor cell population that, when cocultured with effector T cells, suppresses IFN-gamma production by these effector cells. In contrast, the nylon wool-adherent, CD4+ postrecovery suppressor cell population fails to inhibit the production of IL-2 by the effector T cells. In further experiments, the effector T cell population was depleted of CD8+ cells and cocultured with the nylon wool-adherent, CD4+ postrecovery suppressor cells, and the supernatants were assayed for IFN-gamma and IL-2. IFN-gamma production was inhibited in these cultures but IL-2 production was not inhibited. Irradiated effector T cells were cocultured with CD4+ postrecovery suppressor cells, without myelin basic protein, in an effort to determine whether the mechanism of differential lymphokine suppression involved an anti-idiotypic response against effector T cells. No IL-2 was produced, indicating that there was no CD4+ suppressor cell mediated anti-idiotypic response against effector T cells. These studies suggest that the suppressor cell is a nylon wool adherent, CD4+ T cell that functions to down-regulate EAE effector T cells by differential inhibition of lymphokine production.
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PMID:CD4+ suppressor cells differentially affect the production of IFN-gamma by effector cells of experimental autoimmune encephalomyelitis. 257 35

Previous efforts from our laboratory have investigated the mechanisms responsible for dimethylnitrosamine (DMN)-induced suppression of T cell responses. These studies suggested that such changes in T cell activity were most likely to be due to alterations in the down-regulatory signals controlling T cell activation. Accordingly, the production of PGE2, a potent inhibitor of T cell activation, was examined in macrophages obtained from animals exposed to either DMN or vehicle in vivo. The production of PGE2 was determined in macrophages representing various stages of activation (responsive, primed and fully activated) and various stages of differentiation (CSF-1-derived or GM-CSF-derived macrophages). All peritoneal macrophages obtained from DMN-exposed animals demonstrated enhanced production of PGE2 following stimulation with either endotoxin or IFN-gamma as compared to macrophages obtained from vehicle-exposed macrophages. Moreover, the enhanced levels of PGE2 were due to increased PGE2 production rather than to shifts in the kinetics of PGE2 production and utilization. CSF-1- and GM-CSF-induced bone-marrow-derived macrophages (BMDM) produced minimal levels of PGE2, regardless of the in vitro stimulation of cells obtained from either vehicle or DMN treatment groups. Spleen cells obtained from DMN-exposed animals produced significantly higher amounts of PGE2 following endotoxin stimulation compared to control splenocytes. Splenocytes from DMN-exposed animals also demonstrated a suppressed proliferative response to the mitogen Con A. However, when splenocytes from DMN-exposed animals were co-cultured with indomethacin they demonstrated Con A-stimulated proliferative responses similar to the responses of vehicle control splenocytes. These results demonstrate that DMN exposure results in increased PGE2 production by macrophages and that this increase in PGE2 production may be responsible for suppressed T cell responses observed in DMN-exposed animals.
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PMID:Augmented macrophage PGE2 production following exposure to dimethylnitrosamine in vivo: relevance to suppressed T cell responses. 280 73

Mice infected with LP-BM5 murine leukemia viruses (MuLV) develop a syndrome with many features in common with AIDS including lymphadenopathy and profound immunodeficiency associated with enhanced susceptibility to infection and terminal B cell lymphomas. To evaluate cellular defects that may predispose infected mice to these sequelae, we studied the regulation of IFN gene expression. Spleen cells from mice infected with LP-BM5 MuLV expressed high levels of IFN-gamma mRNA by 1 wk post-inoculation and throughout the course of disease. By comparison, transcripts of IFN-alpha/beta genes were not detected in spleen cells at any time after infection. In uninfected mice, expression of IFN-alpha/beta genes is induced rapidly after infection with New-castle disease virus, but mice inoculated with LP-BM5 MuLV were unable to induce these genes by 4 wk after retroviral infection. Inhibition of IFN-alpha/beta induction due to LP-BM5 MuLV infection also occurred in nude mice, indicating this effect was not mediated by activated T cells. Furthermore, low levels of IFN-gamma transcripts were detected in spleens of nude infected mice, suggesting that cells other than T cells can express this gene. These results suggest that the normal contributions of IFN to control of microbial spread, immune surveillance, and lymphoid interactions are disrupted by infection with LP-BM5 MuLV.
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PMID:Abnormal regulation of IFN-alpha, -beta, and -gamma expression in MAIDS, a murine retrovirus-induced immunodeficiency syndrome. 284 90

Effects of carrageenan (CAR) treatment on the response of interferon (IFN) production in vivo and in vitro after stimulation with an IFN-gamma inducer, staphylococcal enterotoxin A (SEA), was investigated. The IFN-gamma production in mice stimulated with SEA was impaired after i.v. administration of a 20 mg/kg dose of CAR. Spleen cells (SC) from CAR-treated mice had decreased ability to produce IFN in vitro after stimulation with the same inducer. SC obtained from mice during the suppressive state inhibited IFN-gamma production when they were co-cultured with mononuclear cells prepared from spleens of untreated control mice. This suppressor cell activity could be removed from SC by an adherence technique to plastic surface. The SC with suppressor activity were not inactivated by treatments with monoclonal anti-Thy-1.2 antibody, anti-asialo GM1 antisera and anti-mouse immunoglobulin antisera followed by complement. The suppressive activity was detected in cell-free culture fluids of macrophage fractions containing suppressor cell activity. These results suggest that the decrease in IFN-gamma production in mice pretreated with CAR may associate with the presence of suppressor cells characterized to the monocyte/macrophage lineage.
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PMID:Suppression of interferon gamma production in mice treated with carrageenan. 293 70

Natural suppressor (NS) cell activity is the ability of apparently unprimed "null" cells to nonspecifically suppress immune responses. Previously we have shown that NS cell activity from the spleens of mice undergoing chronic graft-vs-host disease (GVHD) is enhanced in vitro by activated T cell signals (e.g., Con A supernatant [CAS]). Here we asked if the naturally occurring suppressor activity found in the neonatal mouse spleen is caused by NS cells, and if so whether this NS activity is also responsive to T cell signals. Finally, we wanted to identify the material in the CAS to which the NS cells respond. Spleen cells from (BALB/c X B10.D2)F1 neonates contain potent, genetically unrestricted suppressor activity toward normal mitogen responses. The cells responsible for this suppression are nonadherent, Thy-, Ig- and are thus by definition NS cells. Neonatal spleen NS cells suppress the indicator Con A response of all mouse strains tested, but their behavior with regard to LPS responses is different. They significantly inhibit the indicator LPS response of allogeneic strains, but are less inhibitory of LPS-stimulated syngeneic (BALB/c X B10.D2)F1 and parental strains. However, the addition of CAS to these latter cultures enhances the NS inhibition of the LPS response to the level of suppression seen with a Con A response. Two lymphokines were able to replace the CAS. Recombinant interferon-gamma (rIFN-gamma) closely mimics the activity found with whole CAS, with low concentrations (1 U/well) being capable of enhancing the neonatal NS activity to near-maximal levels. Recombinant interleukin 2 (rIL 2) is also capable of stimulating the neonatal NS activity to near maximum. However, the rIL 2 must be added at much higher concentrations, taking greater than 50 U/well to get maximum activation of NS suppression. The addition of anti-IFN-gamma antiserum to these LPS suppression assays removes the ability of CAS to activate the neonatal NS cells. Anti-IFN-gamma antiserum also removes the ability of rIL 2 as well as rIFN-gamma to activate the NS cells. It thus appears that the rIL 2 is working by its ability to stimulate IFN-gamma production. Anti-IFN-gamma also removes the ability of the neonatal NS cells to suppress a Con A response. Therefore, it appears that neonatal splenic NS cells respond to, and are activated by, IFN-gamma to carry out their suppressive activity.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Natural suppressor (NS) activity from murine neonatal spleen is responsive to IFN-gamma. 295 98

Infection of mice with Mycobacterium bovis BCG sensitizes them for immune induction of interferon (IFN)-gamma by specific antigen. These mice were found also to respond to lipopolysaccharide (LPS) and concanavalin A (Con A) with high level production of IFN-gamma in the circulation, which was not observed in control mice. In this study, we compared the IFN-gamma response to LPS with that to Con A in an attempt to clarify the cellular mechanisms responsible for in vivo LPS-induced IFN-gamma production. Consequently, (i) the responses to LPS and Con A differed in the kinetics, that to LPS having a longer lag period. (ii) Spleen cells taken from infected mice produced little IFN-gamma in response to LPS, but they showed a higher IFN-gamma response to Con A than those from control mice. (iii) By treating infected mice with immunosuppressive drugs or antibodies to T and natural killer cells before challenge with the inducers, it was indicated that different cellular systems are involved in the IFN-gamma responses to LPS and to Con A.
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PMID:Cellular mechanisms in in vivo production of gamma interferon induced by lipopolysaccharide in mice infected with Mycobacterium bovis BCG. 299 37

As a model for the study of human atypical mycobacterial disease, we explored the basis for the prolonged mycobacteriosis in mice infected with Mycobacterium intracellulare. Two weeks after i.v. injection of mycobacteria, peritoneal macrophages were found to be activated, as indicated by their capacity to produce large amounts of superoxide anion (O2-) in response to phorbol myristate acetate (PMA) or viable M. intracellulare. However, 4 wk after infection, despite the continued presence of large numbers of mycobacteria in the spleen, macrophages from infected animals produced low amounts of O2-. Unfractionated spleen cells from mice infected 4 wk earlier produced increased amounts of interleukin 2 and interferon (IFN) when stimulated with the mitogen concanavalin A, but less of these lymphokines than unstimulated cells when exposed to antigens derived from M. intracellulare, suggesting production of an inhibitory factor. Spleen cells from infected mice were not stimulated to incorporate [3H]thymidine by exposure to mycobacterial antigens; but this unresponsiveness could be reversed by addition of indomethacin to the cultures. Additional investigation showed that macrophages from infected animals produced large amounts of prostaglandin E2 (PGE2) when stimulated by mycobacterial antigens. In vitro, such concentrations of PGE2 inhibited uptake of [3H]thymidine by stimulated spleen lymphocytes from infected animals. Thus, it seemed likely that in infected animals, macrophage-derived PG suppressed production of IFN-gamma by lymphocytes, which in turn prevented activation of the macrophages to full microbicidal activity. To test this hypothesis, we administered either indomethacin, IFN-gamma, or muramyl dipeptide to infected mice. Mice treated with each of these agents showed decreased spleen and lung weights, and decreased numbers of viable mycobacteria in these organs. These results support the concept that interaction between the host and M. intracellulare is modulated profoundly by PG and suggest that administration of agents that directly promote macrophage activation can enhance resistance to infection by this organism.
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PMID:Chronic infection due to Mycobacterium intracellulare in mice: association with macrophage release of prostaglandin E2 and reversal by injection of indomethacin, muramyl dipeptide, or interferon-gamma. 300

Lyt-2+ T cell clones were established from Listeria monocytogenes-infected mice. The clones secreted IFN-gamma after stimulation with spleen cells from L. monocytogenes-infected mice plus IL-2. Spleen cells from normal mice were not stimulatory. Furthermore, cloned T cells lysed L. monocytogenes-infected macrophages. Cytolysis was antigen-specific and H-2K-restricted. These findings suggest a role for specific cytotoxic T cells in the immune response to intracellular bacteria.
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PMID:Listeria monocytogenes-reactive T lymphocyte clones with cytolytic activity against infected target cells. 308 1

Macrophage synthesis of nitrite and nitrate after activation by BCG infection or by treatment in vitro with both T cell-derived (lymphokines (LK) or recombinant murine interferon-gamma (IFN-gamma] and bacterial (lipopolysaccharide (LPS) and heat-killed bacillus Calmette-Guerin (hk BCG] agents was studied by using macrophages from C3H/He and C3H/HeJ mice. Spleen and peritoneal macrophages isolated from BCG-infected donors that were producing nitrate continued to synthesize nitrite and nitrate in culture. LPS treatment in vitro (25 or 50 micrograms/ml) additionally increased this nitrite/nitrate synthesis. Thioglycolate-elicited macrophages from non-infected C3H/HeJ mice treated with LK also produced nitrite/nitrate, and concurrent LPS (0.1 to 50 micrograms/ml) treatment resulted in enhanced synthesis. Recombinant IFN-gamma also stimulated nitrite/nitrate synthesis by C3H/He and CeH/HeJ macrophages as did LPS (C3H/He only) and hk BCG. When given concurrently with either LPS or hk BCG, IFN-gamma enhanced C3H/He and C3H/HeJ macrophage nitrite/nitrate synthesis over that produced by macrophages treated with either LPS or hk BCG alone. Macrophages activated in vitro exhibited a 4 to 12 hr lag time before engaging in nitrite/nitrate synthesis, which then proceeded for 36 to 42 hr at linear rates. Daily medium renewal did not alter the synthesis kinetics but increased the total amount of nitrite/nitrate produced. Nitrate and nitrite were stable under the conditions of culture and when added did not influence additional macrophage synthesis. Taken together, these results indicate that T cell lymphokines and IFN-gamma are powerful modulators of macrophage nitrite/nitrate synthesis during BCG infection and in vitro, and nitrite/nitrate synthesis appears to be common property of both primed and fully activated macrophage populations.
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PMID:Induction of nitrite/nitrate synthesis in murine macrophages by BCG infection, lymphokines, or interferon-gamma. 311 Feb 73

Immunosuppression is a well-characterized consequence of chronic graft-versus-host disease (GVHD). We have previously shown that interferon (IFN) is produced in high levels during acute GVHD. Our objective in this study was to determine if IFN, as a cytokine with known immunosuppressive qualities, could be detected in mice experiencing chronic GVHD-induced immunosuppression. Two different experimental models were used to induce chronic GVHD. The first model involved the injection of parental strain spleen cells into adult F1 hybrids (AJ----B6AF1), while the second model utilized GVHD induced across minor histocompatibility barriers (B10.D2----BALB/c). Results indicated that significant levels of serum IFN-alpha/beta are present in mice undergoing chronic GVHD. Spleen cells from chronic GVHD mice were also shown to produce significant levels of IFN-alpha/beta upon in vitro culture in medium only. This IFN-alpha/beta production was greatly increased when GVHD spleen cells were cultured with either concanavalin A (Con A) or IL-2. In contrast, IFN-gamma production was undetectable in these Con A- or IL-2-containing cultures. Additionally, these same spleen cells which produced high levels of IFN-alpha/beta were immunosuppressed as measured by mitogen-induced cell proliferation. These results suggest that IFN-gamma production is defective in GVHD spleen cells, and that the presence of high IFN-alpha/beta production by GVHD mice may contribute to the immunosuppression associated with chronic GVHD.
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PMID:Enhanced interferon-alpha/beta (IFN-alpha/beta) and defective IFN-gamma production in chronic graft versus host disease: a potential mechanism for immunosuppression. 311 28


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