Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human promonocytic cells chronically infected with human immunodeficiency virus-1 (HIV-1) (clone U1.1.5) were grown in the presence of media conditioned by primary rat cortical astrocytes and HIV-1 expression was assessed by measuring reverse transcriptase activity. Media conditioned by non-stimulated and lipopolysaccharide (LPS)-stimulated astrocytes induced the expression of HIV-1 2.1-fold and 4.1-fold, respectively. LPS alone, media conditioned by the uninfected parental cell line of U1.1.5 (U937), and culture media from four other cell lines, had no effect on viral expression. The magnitude of induction was time- and dose-dependent. Tumor necrosis factor alpha (TNF-alpha) was detected in LPS-stimulated astrocyte-conditioned medium and the HIV-inducing capability of the medium was neutralized, in part, by an antibody to recombinant murine TNF-alpha. These results suggest a role for astrocytes in the induction of HIV expression and thus in the pathogenesis of HIV-1 infection in brain.
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PMID:Astrocyte-conditioned medium stimulates HIV-1 expression in a chronically infected promonocyte clone. 222 7

Interleukin-6 (IL-6/B cell stimulatory factor 2) has been found to drive activated human B-lymphocytes through the final stages of differentiation to become immunoglobulin-producing cells. Most patients with common variable immunodeficiency (CVI) have B-lymphocytes that fail to differentiate into high-rate immunoglobulin-secreting cells in vivo and in vitro. In view of (1) the known effects of IL-6 to promote B-lymphocyte terminal differentiation and (2) the defect in differentiation in B-lymphocytes of patients with CVI, we believed that it was important to analyze the role of this cytokine in patients with CVI. Using an IL-6-dependent murine hybridoma cell line in a bioassay, serum IL-6 levels were determined in 17 patients with CVI and in eight normal control subjects. Thirteen of the 17 patients with CVI exhibited serum IL-6 levels that were twofold to 18-fold higher than the range (mean, +2 SD) of normal control subjects. Spontaneous IL-6 production by peripheral blood mononuclear cells (PBMC) of patients with CVI was significantly higher than that from normal control subjects, whereas lipopolysaccharide maximally stimulated IL-6 production by PBMCs of patients with CVI or PBMCs of normal control subjects was equivalent. A substance inhibitory of IL-6 bioactivity was found in equivalent amounts in sera of both patients and normal control subjects. Sera from patients with CVI with high IL-6 bioactivity were found to have saturated this IL-6 inhibitory substance, thus resulting in large amounts of free IL-6 in the sera. These studies suggest that the failure of B cells from patients with CVI to terminally differentiate into high-rate immunoglobulin-secreting cells cannot be attributed to a decrease in the serum levels of IL-6 and that the increased circulating IL-6 levels in patients with CVI result from hyperproduction rather than decreased use of IL-6. The persistently elevated levels of IL-6 observed in some patients with CVI may secondarily result in the induction of the neoplastic and autoimmune phenomena associated with this disease.
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PMID:Elevated serum interleukin-6 associated with a failure in B cell differentiation in common variable immunodeficiency. 222 13

A promonocytic cell model was used to investigate cytokine gene transcription in U937 and U9-IIIB cells chronically infected with human immunodeficiency virus type 1 (HIV-1). The production of interferon (alpha-1 interferon [IFN-alpha 1], IFN-alpha 2, and IFN-beta), interleukin (interleukin 1 alpha [IL-1 alpha], IL-1 beta, and IL-6), and tumor necrosis factor alpha (TNF-alpha) mRNA was characterized by quantitative polymerase chain reaction mRNA phenotyping in U937 and U9-IIIB cells following coinfection with Sendai paramyxovirus or stimulation with lipopolysaccharide (LPS). Chronic HIV-1 infection of U9-IIIB cells resulted in a low constitutive level of transcription of TNF and IL-1 genes but not IFN genes; however, when the cells were coinfected with Sendai virus, 10- to 20-fold higher levels of IFN-beta, IL-1 beta, IL-6, and TNF-alpha mRNA were observed in U9-IIIB cells than in similarly induced U937 cells. The enhanced levels of cytokine RNA in virus-infected U9-IIIB cells were also accompanied by higher levels of IFN antiviral activity and TNF secretion than in U937 cells. Transcript levels for IFN-alpha 1 and IFN-alpha 2 were equivalently induced in virus-infected U937 and U9-IIIB cells, indicating that a generalized derepression of cytokine gene expression did not occur as a consequence of HIV-1 infection. When LPS was used as an inducer, a distinct pattern of cytokine gene expression was detected in U9-IIIB cells. TNF-alpha and IL-1 beta but not IFN-alpha or IFN-beta transcripts were induced by LPS. These results suggest that HIV-1 infection of promonocytic cells may prime or sensitize cells such that subsequent antigenic challenge leads to coordinate enhancement of cytokine gene expression.
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PMID:Coordinate enhancement of cytokine gene expression in human immunodeficiency virus type 1-infected promonocytic cells. 224 88

Peripheral blood monocytes from human immunodeficiency virus (HIV)-infected individuals or AIDS-related complex/AIDS patients ex vivo exhibit distinct alterations in some but not all immune functions. In studies presented here, monocytes from healthy donors were infected with HIV 1 in vitro and co-cultures with autologous uninfected T lymphocytes were set up. The monocyte/macrophage (M phi)-dependent T cell function was determined by measurement of proliferative and secretory [interleukin (IL)2, interferon-gamma] responses to lectin (phytohemagglutinin), mitogen (anti-CD3 monoclonal antibody), or recall antigen (tetanus toxoid, tuberculin). Accessory function of M phi was normal after HIV infection when optimal amounts (10%-20%) were added to the T lymphocytes. However, HIV infection of M phi significantly decreased T cell proliferative responses and secretion of IL2 when supplemented at limited dilution (0.5%-5%), although interferon-gamma production was not affected. Whereas the lipopolysaccharide-triggered M phi production of IL1 was not impaired by HIV 1 infection, there was a significant decrease in this response when anti-CD3 monoclonal antibody or tetanus toxoid were used to trigger the peripheral blood mononuclear cells. The impairment of proliferation of T lymphocytes in the presence of HIV 1-infected M phi could be overcome by addition of exogenous IL 1. Taken together, these data clearly show that the mononuclear phagocyte-dependent enhancement of stimulated T cell proliferation and lymphokine secretion is decreased when the restricted numbers of monocytes/M phi are HIV 1 infected. There are, therefore, two possible roles of M phi in HIV infection and progression to disease. First, as a reservoir and vehicle for dissemination of the virus, and second, as an immune cell whose essential functions are impaired by infection.
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PMID:Decreased accessory cell function of macrophages after infection with human immunodeficiency virus type 1 in vitro. 225 85

Seven strains of inbred mice were compared for their susceptibility to the lethal effects of Shiga-like toxin II (SLT II). A/J mice, which are unable to produce the C5 component of complement, did not differ from C5 normal mice in susceptibility to SLT II. CBA/NJ mice (hemizygous for X-linked immunodeficiency) did not differ from the B-cell sufficient CBA/J strain. C3H/HeJ mice, defective in macrophage response to lipopolysaccharide (Lpsd), showed a consistently and significantly longer mean time to death than did the normally responsive C3H/HeN strain. C57BL/10ScN mice, which also carry the Lpsd allele, showed a similar but smaller difference in mean time to death compared with the C57BL/10SnJ strain. Production of tumor necrosis factor could be induced in vitro by SLT II treatment of C3H/HeN, but not C3H/HeJ macrophages. These results imply that antibody and complement production do not modulate SLT II lethality in mice, but that the macrophage may contribute to SLT II-induced injury.
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PMID:Evidence for participation of the macrophage in Shiga-like toxin II-induced lethality in mice. 227 89

Expression of tumor necrosis factor (TNF alpha), tissue factor (TF), and interleukin 1-beta (IL-1 beta) mRNA was evaluated in monocytes isolated from patients infected with human immunodeficiency virus (HIV). There was a significant depression (66%) of the induced level of TF mRNA expression in response to lipopolysaccharide. Conversely, the response of TNF alpha and IL-1 beta, following LPS induction, was "normal." TF mRNA reduction was also observed to a lesser degree in AIDS-related complex patients (20%) but not in asymptomatic seropositives. TF is necessary for initiation of the coagulation protease cascade, leading to thrombin production and fibrin deposition, which play a role in inflammatory responses. Its selective reduction may be a factor in the diminished resistance to secondary infections observed in AIDS. Further, since the TF defect increases as patients progress toward AIDS, it may serve as a marker for disease progression.
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PMID:A selective defect in tissue factor mRNA expression in monocytes from AIDS patients. 229 2

The production of interleukin-1 beta (IL-1 beta), IL-6, and tumor necrosis factor alpha (TNF-alpha) by fresh peripheral blood mononuclear cells was evaluated after exposure to human immunodeficiency virus (HIV) or purified recombinant HIV-1 envelope glycoprotein (rgp120). To exclude the role of contaminating endotoxin in this study, all media were subjected to ultrafiltration and reagents contained less than 25 pg of endotoxin per ml by Limulus assay. Under endotoxin-free conditions, no increases in IL-1 beta, IL-6, or TNF-alpha mRNA or protein were detectable in cell cultures exposed to HIV-1, HIV-2, or rgp120 (0.1 to 10 micrograms/ml), as compared with cytokine levels in mock-exposed cultures. However, concentrations of endotoxin (lipopolysaccharide) as low as 0.5 ng/ml induced significant production of mRNA and protein for these three cytokines. Preincubation of mononuclear cells with "shake" HIV-1 preparations and also mock-infected shake preparations prior to lipopolysaccharide stimulation resulted in a two- to threefold increase in IL-1 beta and TNF-alpha production. This priming effect was not observed with rgp120 (0.1 to 10 micrograms/ml) or standard HIV-1 or mock-infected supernatants, suggesting the presence of biologically active material independent of virus in the shake preparations. Our studies indicate that, in the absence of endotoxin, HIV-1, HIV-2, and HIV gp120 do not induce production of IL-1 beta, IL-6, or TNF-alpha by peripheral blood mononuclear cells.
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PMID:Human immunodeficiency virus does not induce interleukin-1, interleukin-6, or tumor necrosis factor in mononuclear cells. 233 21

The production of tumor necrosis factor alpha (TNF alpha) and interleukin 1 (IL-1) was measured in supernatants of cultured peripheral blood monocytes that were obtained from patients with human immunodeficiency virus type 1 (HIV 1) infection and that were purified by counterflow centrifugal elutriation (86-92% purity). TNF alpha levels were significantly higher in monocytes isolated from symptomatic HIV 1-infected patients as compared to normal controls. Although IL-1 levels were also elevated in this group of symptomatic patients they did not reach statistical significance. The production of the two monokines was intermediate in asymptomatic HIV 1-infected individuals. The increase of TNF alpha was observed in the absence of in vitro stimulation as well as in the presence of interferon-gamma plus lipopolysaccharide. TNF alpha and IL-1 were measured by radioimmunoassay and by bioassay, the results of the two methods being highly correlated for both cytokines. The levels of TNF alpha and IL-1 were also positively correlated. These data suggest that IL-1 and TNF alpha may be involved in the pathogenesis of HIV 1 infection.
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PMID:Purified blood monocytes from HIV 1-infected patients produce high levels of TNF alpha and IL-1. 249 10

Synovial fluid from patients with rheumatoid arthritis (RA-SF) contains a biological activity which can replace T cells for activation of antibody secretion in human blood lymphoid cells and which can also induce the selective differentiation of IgG2b-secreting cells in lipopolysaccharide (LPS)-pre-activated mouse spleen cells. The B-cell activity of this factor was studied in CBA/N mice which have an X-linked B-cell immunodeficiency which manifests itself as a defective humoral response to certain thymus-independent antigens (TI-2). RA-SF has now been shown to reconstitute partly the B-cell deficiency in CBA/N splenic B cells in vitro. Addition of RA-SF to LPS-pretreated cell cultures results in IgG2b secretion in CBA/N spleen cells as well. In contrast to cells from normal CBA mice, cells from CBA/N mice cannot respond to interleukin 4 (IL-4) after addition of LPS with production of IgG1 antibodies in vitro. However, the addition of RA-SF completely restores a normal IL-4-induced IgG1 response. No other biologically active factors have been shown to allow the production of IgG antibody producing cells in CBA/N splenic B cells. It is postulated that the xid immunodeficiency could be the result of a deficient production of a biological activity which is abundant in RA-SF.
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PMID:Rheumatoid synovial fluid reconstitutes the B-cell defect in CBA/N mice. 260 14

In an attempt to assess the role of immune cytotoxic activity in the sequence of events leading to the acquired immunodeficiency syndrome (AIDS), natural cytotoxic activity was studied in 17 asymptomatic homosexual males, seropositive for anti-human immunodeficiency virus (HIV) antibodies, as compared to 16 of their seronegative counterparts and to 14 control healthy heterosexual individuals. Cell (contact)-mediated cytotoxicity (CMC) as well as cytotoxin (CTX) production by lipopolysaccharide (LPS)-stimulated, phytohemagglutinin (PHA)-stimulated, HeLa tumor cell-stimulated, and unstimulated peripheral blood mononuclear cells (PBMC) were determined using HeLa cell monolayer cultures, sensitized with cycloheximide, as targets. The CMC was markedly enhanced in the seropositive group (28 +/- 21 (mean +/- SD) lytic units/10(6) PBMC) as compared to the seronegative group (17 +/- 7; P less than 0.005) and to the heterosexual group (13 +/- 6; P less than 0.05). Likewise, CTX production by unstimulated PBMC from seropositive homosexuals (19 +/- 26 units/ml) was higher than that observed in the other groups (both 4 +/- 4 units/ml; P less than 0.05). CTX production by PHA-stimulated, LPS-stimulated, and HeLa cell-stimulated PBMC was significantly enhanced in both the seropositive and seronegative groups in comparison to the normal heterosexual controls. These results suggest that increased cytotoxic activity may be present in homosexuals prior to their exposure to HIV, and may be further enhanced after HIV infection.
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PMID:Possible role of natural cytotoxic activity in the pathogenesis of AIDS. 278 1


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