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Query: UMLS:C0021051 (immunodeficiency)
 71,517 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Polymorphonuclear granulocytes (PMN; or neutrophils) from uninfected or human immunodeficiency virus-infected subjects were tested for their ability to inhibit growth of Candida albicans and produce interleukin-1 beta (IL-1 beta) and IL-6 in vitro. It was seen that PMN from AIDS (Centers for Disease Control stage IV) patients expressed equal if not greater anticandidal activity compared with the activity expressed by neutrophils from all other subjects examined. On exposure to granulocyte macrophage-colony-stimulating factor or to a mannoprotein constituent (MP-F2) from C. albicans itself, PMN from AIDS patients showed enhanced antifungal activity and production of remarkable quantities of IL-1 beta and IL-6. These findings suggest that the functional abilities of PMN to inhibit Candida growth and secrete relevant proinflammatory and immunomodulatory cytokines are intrinsically preserved in AIDS patients.
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PMID:Anticandidal activity and interleukin-1 beta and interleukin-6 production by polymorphonuclear leukocytes are preserved in subjects with AIDS. 850 Dec 41

Most studies of apoptosis on T lymphocytes have examined the effects of various stimuli on immature T cells from the thymus. Previous work has indicated that apoptosis of mature memory T cells may be an important pathophysiologic mechanism in diseases such as AIDS, cancer, and autoimmunity. The effect of IL-2 on apoptosis of T cells is not clear. Therefore, we studied the ability of IL-2 to rescue Ag-specific T cells from apoptosis. We found that IL-2, in a dose-dependent manner, prevented T cells from entering apoptosis induced by gamma-irradiation, mitomycin C, or dexamethasone. This effect was specific for IL-2; IL-1 beta, IL-6, or IFN-gamma could not reproduce it. In contrast to Ag-specific T cells, immature T cells and naive mature peripheral T cells could not be rescued by IL-2 from radiation-induced apoptosis. Apoptosis rescue by IL-2 was associated with the induction of bcl-2 mRNA and protein. This induction could not be attributed to the effects of IL-2 on the cell cycle, as T cells that were prevented from cell cycle progression by irradiation showed a similar induction of bcl-2. Rescued cells retained their Ag-specific proliferative capacity and in vivo functions. These findings demonstrate that the apoptotic death of Ag-specific T cell lines, cells which can be regarded as a model for memory T cells, can be prevented with IL-2. This effect may have important therapeutic implications for patients receiving chemotherapy or radiotherapy, and for patients with AIDS who develop immunodeficiency primarily as a result of loss of Ag-specific memory T cells.
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PMID:IL-2 rescues antigen-specific T cells from radiation or dexamethasone-induced apoptosis. Correlation with induction of Bcl-2. 854 1

Microglia are the major target for human immunodeficiency virus (HIV) infection within the central nervous system. Because only a few cells are productively infected, it has been suggested that an aberrant cytokine production by this cell population may be an indirect mechanism leading to the development of neurological disorders in HIV-infected patients. Therefore we decided to study the secretion pattern of several interleukins (IL) by microglial cells and peripheral blood macrophages isolated from uninfected and simian immunodeficiency virus (SIV)-infected Rhesus monkeys. We found that uninfected, unstimulated primate microglia produce more IL-6 and less TNF alpha than peripheral blood macrophages, but generate comparable levels of IL-1 beta and IL-8. After infection with SIV in vitro, synthesis of all cytokines tested is increased compared to uninfected cultures and to peripheral blood macrophages. Microglia isolated from infected animals produce more IL-8 and TNF alpha than the uninfected cultures and display a strongly increased capacity to secrete TNF alpha upon stimulation with lipopolysaccharide. In addition, production of IL-6 by in vivo-infected microglia increases with time in culture to very high levels despite the fact that only a few cells contained replicating virus. These findings clearly show that the cytokine production of microglia is impaired after SIV infection both in vitro and in vivo and that a low level of viral replication is sufficient for these alterations to occur. In conclusion, the results of this study further support a possible role of cytokines in the pathogenesis of neuro-AIDS.
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PMID:The effect of simian immunodeficiency virus infection in vitro and in vivo on the cytokine production of isolated microglia and peripheral macrophages from rhesus monkey. 866 83

Once infected by obligate intracellular pathogens, monocytes/macrophages release cytokines that activate natural killer (NK) cells. NK cells in turn produce and secrete monocyte/macrophage activating factors such as interferongamma (IFN-gamma), which are important in the early control of these infections. Here we demonstrate that human NK cells are potent producers of another monocyte/macrophage-activating factor, macrophage inflammatory protein-1 alpha (MIP-1 alpha). Fresh NK cells produce negligible amounts of MIP-1 alpha after stimulation with the monocyte-derived cytokines IL-12, TNF-alpha, IL-1 beta, or IL-10, while stimulation with IL-15 alone results in modest MIP-1 alpha production. Abundant NK cell production MIP-1 alpha is seen after costimulation with IL-12 and IL-15, and is dose-dependent. Combinations of IL-12, with TNF-alpha, IL-1 beta, or IL-10 are substantially less effective inducers of MIP-1 alpha production by NK cells. NK cell MIP-1 alpha mRNA transcripts were detectable within 1 h after costimulation with IL-12 plus IL-15 and steadily increased over 24 h, with a concomitant increase in protein production detectable at 12 h. Resting NK cells constitutively express mRNA transcript for a MIP-1 alpha receptor, and costimulation with IL-12 and IL-15 upregulates its level of expression. Equilibrium binding studies with radioiodinated MIP-1 alpha were consistent with the induction of a single class of high affinity MIP-1 alpha receptors on NK cells costimulated with IL-12 and IL-15. Addition of exogenous MIP-1 alpha to resting NK cells did not enhance cytokine production, but did increase NK cytotoxic activity. The requirement for IL-15 as a critical cofactor for NK cell production MIP-1 alpha suggests a potentially unique role for this monocyte-derived cytokine in combination with IL-12. As MIP-1 alpha is known to potentiate the action of IFN-gamma on monocytes and to suppress human immunodeficiency virus replication, the NK cell's production of MIP-1 alpha may be important during the innate immune response to infection.
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PMID:Human natural killer cells produce abundant macrophage inflammatory protein-1 alpha in response to monocyte-derived cytokines. 867 82

Proinflammatory cytokines are important mediators during endotoxemia. In experimental models, injection of lipopolysaccharide (LPS) activates macrophages leading to excessive secretion of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1 beta and IL-6; infusion of high dose of these mediators results in organ failure and death. Natural infection may be different, because it persists over days or even weeks, with repeated endotoxin challenge to macrophages. Little is known about the capacity of peripheral blood mononuclear cells (PBMCs) to release proinflammatory cytokines under these conditions. Therefore, as an ex vivo model of sepsis, the expression of proinflammatory cytokines after stimulation of whole blood with LPS was studied. A high LPS dose (1 microgram/ml) maximally increased TNF-alpha, IL-1 beta and IL-6 secretion in controls, but a marked depression was observed in septic patients (p < 0.01; 15 patients with severe sepsis versus 20 control patients without infection). This reduction persisted for up to 10 days after diagnosis of sepsis. The release of TNF-alpha, IL-1 beta and IL-6 was markedly decreased in the septic group even when a lower and physiologically more relevant LPS concentration (1 ng/ml) was used. IL-1 beta mRNA was similar to controls, but a down-regulation was observed in TNF-alpha and IL-6 transcript levels in PBMCs from the blood of septic patients. This was at least in part due to a marked reduction in TNF and IL-6 mRNA half-life. These results indicate that different mechanisms down-regulate proinflammatory cytokine release in the whole blood of septic patients. Although excessive secretion is known to be deleterious, low concentrations of these cytokines are involved in regulating essential cellular and humoral immune functions. Thus, the reduced capacity to express and release adequate amounts of proinflammatory cytokines after exposure to endotoxin, as observed in whole-blood PBMCs from septic patients, may contribute to the development of immunodeficiency.
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PMID:Interleukin-1, -6 and tumor necrosis factor-alpha release is down-regulated in whole blood from septic patients. 867 54

Among immunological abnormalities present in human immunodeficiency virus type 1 (HIV-1)-infected individuals are dysregulation of cytokine production and CD4 down-regulation in both T-helper cells and monocytes/macrophages. The HIV-1 envelope glycoprotein 120 (gp120) has the ability to induce different cytokines in peripheral blood mononuclear cells and in monocytes/macrophages in vitro which in some instances have been reported to down-regulate macrophage CD4 expression. This study provides evidence that HIV-1 recombinant gp120 (rgp120) down-regulates both surface and total CD4 expression in primary tissue culture-differentiated macrophages (TCDM) at the level of transcription. The CD4 down-regulation observed in TCDM occurred between 6 and 12 hr after rgp120 treatment preceded by a peak of endogenous tumour necrosis factor-alpha (TNF-alpha) observed at 3-6 hr post-treatment. We demonstrate that the TCDM CD4 down-regulation observed after rgp120 treatment was inhibited by the use of an anti-huTNF-alpha monoclonal antibody (mAb), but not by mAb directed against other cytokines induced by rgp120, such as interleukin-1 beta (IL-1 beta) and interferon-alpha (IFN-alpha). The present findings roughly parallel those observed both in the sera of patients and in the monocytes/macrophages isolated from HIV-positive individuals, suggesting that gp120 by stimulating endogenous TNF-alpha production could be a good candidate for the CD4 down-regulation observed in the monocytes/macrophages of HIV-1-infected individuals. In contrast to CD4 down-regulation in HIV-infected lymphocytes, which results from a direct effect of viral genes on CD4 expression, soluble factors such as cytokines induced during HIV infection might explain the monocyte/macrophage CD4 dysregulation observed in acquired immune deficiency syndrome.
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PMID:HIV-1 envelope glycoprotein gp120 down-regulates CD4 expression in primary human macrophages through induction of endogenous tumour necrosis factor-alpha. 870 50

Nitric oxide (NO) is a newly discovered gas that plays an important role in cell communication and host resistance to infection. The production of NO was examined in the sera of seven children infected with human immunodeficiency virus type 1 (HIV-1) and in the sera of 14 children who became seronegative for HIV-1 during the first year of life. In addition, we determined serum levels of various cytokines, such as interleukin (IL)-1 beta, tumor necrosis factor (TNF)-alpha, and gamma interferon (IFN-gamma), inasmuch as these cytokines are potent inducers of NO production. Production of NO, detected as circulating serum levels of nitrite, was measured with use of the Griess reagent. Serum levels of cytokines were determined by enzyme immunoassay. Increased serum levels of nitrite were observed in children with HIV-1 infection (0.4 +/- 0.2 mumol/L; P = .013), and in those who became seronegative for HIV-1 during the first year of life (0.5 +/- 0.3 mumol/L; P = .04). Furthermore, serum levels of IL-1 beta and TNF-alpha were significantly elevated in children with HIV-1 infection (37.5 +/- 23.6 pg/mL and 91.2 +/- 45.1 pg/mL, respectively). Prophylactic administration of intravenous immune globulin provoked a significant decrease of circulating levels of nitrite in children with HIV-1 infection. In conclusion, NO may play a role as a cytostatic or cytotoxic factor for invading microorganisms, and thus it is probably involved in limiting and/or eradicating infection.
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PMID:Increased levels of nitrite in the sera of children infected with human immunodeficiency virus type 1. 872 4

The human immunodeficiency virus (HIV) is neuroinvasive and commonly causes cognitive and motor deficits during the later stages of viral infection. (referred to as HIV dementia). The mechanism(s) for disease revolves around secretory products produced from immune-activated brain macrophages/microglia. Recently, we developed an animal model system for HIV dementia that contains xenografts of HIV-1-infected cells inoculated into brains of mice with severe combined immunodeficiency (SCID). This animal system was used to quantitatively evaluate HIV-induced neuropathology. Xenografts of HIV-1-infected human monocytes (placed into the putamen and cortex of SCID mice) remained viable for 5 weeks. HIV-1 p24 antigen expression in mouse brain was persistent. Progressive inflammatory responses (including astrogliosis and cytokine production), which began at 3 days, peaked at day 12. The range of astrocyte proliferative reactions exceeded the inoculation site by > 1000 microns. Brains with virus-infected monocytes showed a > or = 1.6-fold increase in glial fibrillary acidic protein (staining distribution and intensity) as compared with similarly inoculated brains with uninfected control monocytes. These findings paralleled the accumulation and activation of murine microglia (increased branching of cell processes, formation of microglial nodules, interleukin (IL)-1 beta and IL-6 expression). An inflammatory reaction of human monocytes (as defined by HLA-DR, IL-1 beta, IL-6, and tumor necrosis factor-alpha expression) and neuronal injury (apoptosis) also developed after virus-infected monocyte xenograft placement into mouse brain tissue. These data, taken together, demonstrate that this SCID mouse model of HIV-1 neuropathogenesis can reproduce key aspects of disease (virus-infected macrophages, astrocytosis, microglial activation, and neuronal damage). This model may serve as an important means for therapeutic development directed toward improving mental function in HIV-infected subjects with cognitive and motor dysfunction.
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PMID:Human immunodeficiency virus encephalitis in SCID mice. 878 Mar 78

Infection of human CD4-positive T lymphocytes by human immunodeficiency virus type 1 (HIV-1) is thought to lead to death of infected cells by apoptosis, although one recent report questions this conclusion. Here we demonstrate that HIV-1-induced apoptosis of the H9 human T cell line is blocked by peptide inhibitors of IL-1 beta converting enzyme (ICE)-family proteases, but not by the antagonistic M3 anti-Fas Ab. Apoptosis occurred in all phases of the cell cycle, not selectively in G2 as a consequence of vpr-mediated cell cycle arrest. We conclude that apoptosis accounts for all cell death related to HIV-1 infection of the human CD4-positive cell line H9, requires an ICE-like protease but is not Fas mediated, and occurs in all phases of the cell cycle.
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PMID:Apoptosis induced by HIV infection in H9 T cells is blocked by ICE-family protease inhibition but not by a Fas(CD95) antagonist. 881 76

The human immunodeficiency virus 1 (HIV-1) Tat protein is known to be capable of suppressing antigen- and CD3-induced activation of human T cells. Previously, it was shown that Tat can bind to the dipeptidyl peptidase IV (DP IV, CD26) and inhibit the degradation of the chromogenic substrate Gly-Pro-p-nitroanilide. Using the method of free zone capillary electrophoresis, here we have shown that the DP IV-catalyzed hydrolysis of the NH2-X-Pro-containing cytokine peptides IL-2(1-12), IL-1 beta(1-6), and IL-6(1-12) was also significantly inhibited by the Tat protein. Moreover, HIV-1 Tat at a concentration of 10 micrograms/ml was found to have a strong suppressive effect on DNA synthesis and IL-1 beta production, but stimulates secretion of IL-1 receptor antagonist (IL-1RA) and TNF-alpha of CD26-expressing U937-H cells. It did not impair neither DNA synthesis nor cytokine production of low CD26-expressing U937-L cells. Similar results have been found with synthetic DP IV/CD26 inhibitors (Immunobiol., 1994, vol. 192, pp. 121-136). These data strongly suggest that Tat protein is a potent "natural" inhibitor of DP IV/CD26, and they support the hypothesis that DPIV plays a role in Tat's immunosuppressive activity.
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PMID:CD26 mediates the action of HIV-1 Tat protein on DNA synthesis and cytokine production in U937 cells. 885 5


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