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Query: UMLS:C0019693 (HIV)
 170,526 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cytokine responses are dramatically affected when HIV-1 infected cells are activated with certain antigenic stimuli. We report the effects of HIV-1 tat gene in cytokine modulation, using HIV-1 tat transfected T (Jurkat) and B (Raji) cell lines. Studying the effect of tat and/or PMA + PHA on mRNA expression of 14 cytokines (IL-1 alpha, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12, TNF-alpha, TNF-beta, GM-CSF, TGF-beta, IFN-gamma and MIP-1 alpha) illustrated differential effects. In addition to the varied effects of tat on the steady state levels of cytokine mRNAs, tat induced the secretion of TNF-beta preferentially in both B and T cell lines, either by itself as in Raji B cell line or synergistically upon PMA + PHA stimulation as in Jurkat T cell line.
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PMID:Differential expression of cytokine genes in HIV-1 tat transfected T and B cell lines. 769 26

Previous studies demonstrated that mucosal HIV p24 antigen content varied during the progression of HIV infection. In this study, expression of HIV RNA and mRNA of selected cytokines was examined in rectal mucosa from HIV-infected individuals. Rectal biopsies from 27 subjects were studied: 7 with CD4 counts > 500/mm3 (early), 11 with CD4 < 500 (intermediate), and 9 with AIDS (late), plus 4 HIV-seronegative controls. RNA in situ hybridization was performed using 35S-labeled riboprobes of HIV, TNF-alpha, IL-1 beta, IL-2, IL-4, IL-5, IL-6, IL-10, INF-alpha, IFN-gamma, and TGF-beta. HIV RNA was detected more frequently in the intermediate group than in the other groups (p < 0.005). Cytokine mRNA expression also varied during disease progression. The expression of IFN-alpha, IFN-gamma, and TGF-beta mRNA was most prevalent early in the disease; peak expression of IL-4, IL-5, IL-6, and IL-10 was seen during the intermediate stage, and peak expression of TNF-alpha and IL-1 beta mRNA were seen in AIDS patients. HIV RNA and cytokine mRNA expression vary during HIV disease progression. HIV RNA expression is greatest in the intermediate stage of the disease. The pattern of cytokine mRNA expression suggests predominant cell-mediated immunity under basal conditions and early in the disease, generalized cytokine activation in its middle phase, and proinflammatory cytokine activation in AIDS patients. Cytokine modulation of HIV expression in rectal mucosa in vivo may occur and have pathogenic importance.
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PMID:Variation in the expression of human immunodeficiency virus RNA and cytokine mRNA in rectal mucosa during the progression of infection. 770 12

A decrease in natural killer (NK) cell function has been related to the progression of human immunodeficiency virus (HIV) infection. In the present study, we assessed the ability of a streptococcus-derived biologic response modifier, OK-432, to augment NK lysis of uninfected K562 and U937 cells and HIV-infected U937 cells by peripheral blood mononuclear cells (PBMC) from HIV-seropositive homosexual men. Optimal two- to fourfold increases in lysis of the three targets were observed after pretreatment of PBMC from HIV-negative subjects for 4 h with 2 micrograms of OK-432 per ml. This effect was related primarily to gamma interferon (IFN-gamma) production induced by OK-432 and was not linked to production of tumor necrosis factors alpha and beta or to monocytes in the cultures. The enhancing effect of OK-432 on NK cell function was diminished but still evident in PBMC from subjects with relatively early-phase (< 3-year) HIV infection and high CD4+ cell counts and was lower in subjects with longer-term HIV infection (> 3 years), in association with reduced production of IFN-gamma. Augmentation of NK cell activity in HIV-infected men by OK-432 was comparable to that induced by treatment of cells with 1,000 U of IFN-alpha or interleukin 2 per ml. The data suggest that the NK cell-enhancing effects of OK-432 are at least in part mediated by IFN-gamma and that OK-432 may be effective in treatment of patients with early-phase HIV infection.
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PMID:Enhancement of natural killer cell activity in human immunodeficiency virus-infected subjects by in vitro treatment with biologic response modifier OK-432. 771 19

Cryptococcus neoformans is responsible for pulmonary and meningal infections in HIV patients. The lack of effective cellular cooperation caused by the low level of CD4+ cells, and the resistance of C. neoformans to phagocytosis allows growth and persistence of the yeast in the host. We describe here an in-vitro model of intracellular replication of C. neoformans inside J774-A.1 macrophages, and the determination of the intracellular antifungal activity of amphotericin B and fluconazole alone or in association with IFN-gamma. The maximum inhibitory effect was observed with one MIC of amphotericin B and 100 or 1000 IU/mL of IFN-gamma. amphotericin B alone (at 1 x MIC), or either 1 x or 50 x MIC of fluconazole in normal or IFN-gamma activated macrophages, did not eradicate the ingested yeast. A potential underlying mechanism of the synergy of amphotericin B in IFN-gamma primed macrophages was investigated by measurement of nitrite level and by use of the NO synthase competitive inhibitor, NG-monomethyl L-arginine (NMMA). One MIC of amphotericin B was able to activate the synthesis of nitrogen reactive intermediates in IFN gamma-primed macrophages. NMMA treated infected macrophages responded less well to IFN-gamma priming, resulting in a moderate inhibition in subsequent amphotericin B exposure.
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PMID:Synergic inhibitory activity of amphotericin-B and gamma interferon against intracellular Cryptococcus neoformans in murine macrophages. 773 Feb 21

The susceptibility of patients with AIDS to certain opportunistic infections is due to defective cell-mediated immunity. The contribution of direct infection of macrophages with HIV-1 to this defect is unknown. To address this issue, we infected normal human monocyte-derived macrophages with a monocytotropic strain of HIV-1 and examined their ability to phagocytose and kill the opportunistic pathogen, Toxoplasma gondii. Phagocytosis of heat-killed T. gondii was reduced in HIV-infected macrophages compared with mock-infected controls. Opsonization of heat-killed T. gondii increased phagocytosis by both mock- and HIV-infected macrophages, but phagocytosis in HIV-infected cultures remained lower than in controls. Internalization of live T. gondii by macrophages was unaffected by HIV infection. Intracellular replication of live T. gondii was enhanced by HIV infection, as shown in four experiments, each using monocyte-derived macrophages from a different donor. Treatment of HIV-infected macrophages with IFN-gamma decreased parasite replication but not to control levels. These findings suggest that infection of macrophages by HIV may be a contributing factor to the reactivation of T. gondii infection in patients with AIDS.
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PMID:HIV-1 infection of human macrophages impairs phagocytosis and killing of Toxoplasma gondii. 775 54

In vitro experiments using purified rat CD4+ T cells in primary and secondary mixed leukocyte cultures (MLC) have been carried out to explore the mechanism of inhibition of cell-mediated autoimmune disease in the rat by a nondepleting monoclonal antibody (mAb) to CD4. Previous work has shown that W3/25, a mouse anti-rat CD4 mAb of immunoglobulin G1 isotype, completely prevents the development of the paralysis associated with experimental allergic encephalomyelitis (EAE) in Lewis rats, but does so without eliminating the encephalitogenic T cells. The in vitro experiments described in this study have shown that when CD4+ T cells were activated in the presence of the anti-CD4 mAb in a primary MLC, the synthesis of interferon (IFN) gamma, but not interleukin (IL) 2, was completely inhibited. After secondary stimulation, now in the absence of the mAb, the synthesis of IL-4 and IL-13 mRNA was greatly enhanced compared with that observed from CD4+ T cells derived from primary cultures in which the mAb was omitted. As IL-4 and IL-13 are known to antagonize cell-mediated immune reactions, and as EAE is cell-mediated disease, the data suggest that the W3/25 mAb controls EAE by modifying the cytokine repertoire of T cells that respond to the encephalitogen. The capacity for the mAb to suppress IFN-gamma synthesis provides, in part, an explanation for this change in cytokine production. These findings are discussed in terms of what is known of the factors that determine which cytokine genes are expressed on T cell activation. Possible implications for the evolution of T cell responses in human immunodeficiency virus infection are also discussed.
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PMID:Activation of CD4+ T cells in the presence of a nondepleting monoclonal antibody to CD4 induces a Th2-type response in vitro. 779 Aug 23

The objective of this study was to assess the ability of HIV-1 to establish an in vitro infection of primary human umbilical vein endothelial cells (HUVEC). The HUVEC and colon carcinoma cell lines were inoculated with different isolates of HIV-1 (HIV-1SF2, HIV-1Mck and HIV-1LAI) and productive viral infection was assessed by both the detection of p24 core antigen in the culture supernatants and the presence of specific spliced HIV mRNA. The infection which was detected in the inoculated HUVEC and all the colon carcinoma cell lines could not be blocked using an antibody targeted against the CD4 receptor. Furthermore, the HIV-inoculated HUVEC secreted elevated levels of IL-6 and this increase was found to be proportional to the size of the viral inoculum. No changes in the production of IL-1 beta, TNF-alpha, IFN-alpha and IFN-gamma were detected following HIV infection. The colon carcinoma cells, however, did not secrete increased levels of these cytokines following HIV-1 inoculation. These results confirm that non-CD4 expressing cells, such as endothelial cells and certain colon epithelial cells, serve as targets and reservoirs for HIV. Moreover, the production of IL-6 by HIV-infected endothelial cells may be a contributing factor to the aberrant immunoregulation associated with HIV infection in vivo.
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PMID:Productive in vitro infection of human umbilical vein endothelial cells and three colon carcinoma cell lines with HIV-1. 779 33

Phenotype and release of IL1 alpha, IL6 and TNF alpha were examined in monocytes derived from 14 healthy donors and 24 tumour patients in a long-term culture using immunohistochemical, RNA in situ hybridization and ELISA techniques. After stimulation with LPS and IFN-gamma, blood monocytes and resulting macrophages showed an overall decrease in cytokine release from the 6th to the 48th day of culture, both with and without HIV infection. HIV infection provided a strong stimulus for IL6 production and a weak stimulus for IL1 alpha production, whereas TNF alpha release decreased after HIV infection. Non-HIV-infected monocytes/macrophages from patients with malignancies showed significantly reduced cytokine production after stimulation, in comparison with monocytes/macrophages from healthy subjects. In vitro HIV infection of monocytes from tumour patients caused severe depression of cytokine production during the whole time of observation. In all experiments a parallel was observed between the extent of cytokine release and the presence of young/early inflammatory macrophages as identified by the antibody MAC387/27E10 in situ. In contrast, cytokine expression assessed semiquantitatively by immunohistochemical staining in situ showed discordant development, since it increased during long-term culture, while supernatant concentrations of cytokines declined. Simultaneously, significant cytokine RNA levels could be found in macrophages from the 6th to the 24th day of culture, as detected by in situ hybridization. After 48 days of culture, no more cytokine RNA was detectable, while macrophages continued to exhibit distinct immunohistochemical positivity for cytokine antibodies. From these results, it is concluded that macrophages kept in culture for a long period become inhibited in their secretion. HIV has an ambivalent effect on cytokine production in Mo/Mac, resulting in an increase in IL6 and IL1 as well as a decrease in TNF alpha production. Mo/Mac of non-HIV-infected tumour patients show significantly reduced cytokine production in comparison with Mo/Mac from healthy subjects. The sum of the HIV infection in vitro and the tumour burden results in a dramatic reduction in cytokine release in Mo/Mac. This finding may provide a possible explanation for the specific aggressive behaviour of non-Hodgkin's lymphoma and Hodgkin's disease in AIDS.
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PMID:In vitro analysis of HIV- and non-HIV-infected monocytes/macrophages from healthy subjects and patients with malignant tumours. 780 Sep 44

Approximately a third of adults and half of children with acquired immunodeficiency syndrome (AIDS) eventually suffer from neurological manifestations, including dysfunction of cognition, movement, and sensation. Among the various pathologies reported in the brain of patients with AIDS is neuronal injury and loss. A paradox arises, however, because neurons themselves are for all intents and purposes not infected by human immunodeficiency virus type 1 (HIV-1). This paper reviews evidence suggesting that at least part of the neuronal injury observed in the brain of AIDS patients is related to excessive influx of Ca2+. There is growing support for the existence of HIV- or immune-related toxins that lead indirectly to the injury or death of neurons via a potentially complex web of interactions between macrophages (or microglia), astrocytes, and neurons. Human immunodeficiency virus-infected monocytoid cells (macrophages, microglia, or monocytes), especially after interacting with astrocytes, secrete substances that potentially contribute to neurotoxicity. Not all of these substances are yet known, but they may include eicosanoids, that is, arachidonic acid and its metabolites, as well as platelet-activating factor. Macrophages activated by HIV-1 envelope protein gp120 also appear to release arachidonic acid and its metabolites. These factors can lead to increased glutamate release or decreased glutamate reuptake. In addition, gamma interferon (IFN-gamma) stimulation of macrophages induce release of the glutamate-like agonist quinolinate. Human immunodeficiency virus-infected or gp120-stimulated macrophages also produce cytokines, including tumor necrosis factor-alpha and interleukin-1 beta, which contribute to astrogliosis. A final common pathway for neuronal susceptibility appears to be operative, similar to that observed in stroke, trauma, epilepsy, neuropathic pain, and several neurodegenerative diseases, possibly including Huntington's disease, Parkinson's disease, and amyotrophic lateral sclerosis. This mechanism involves the activation of voltage-dependent Ca2+ channels and N-methyl-D-aspartate (NMDA) receptor-operated channels, and therefore offers hope for future pharmacological intervention. This review focuses on clinically tolerated calcium channel antagonists and NMDA antagonists with the potential for trials in humans with AIDS dementia in the near future.
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PMID:AIDS-related dementia and calcium homeostasis. 784 72

Replication of HIV is regulated by virus-encoded regulatory proteins, as well as by a variety of cellular factors including cytokines. In the present study, we have investigated the autocrine/paracrine effects of endogenous cytokines on HIV replication in primary PBMCs of healthy HIV seronegative individuals. Addition of rIL-2 to cultures between 0 and 72 h after isolation of PBMCs allowed the replication of primary HIV isolates and laboratory-adapted HIV strains to levels comparable with or greater than those obtained in parallel cultures of autologous PHA-blasts. In this regard, both major cellular targets of HIV infection, CD4+ T lymphocytes and mononuclear phagocytes, were maintained for several weeks in IL-2-stimulated PBMC cultures and virion production was observed in both cell lineages. The kinetics of secretion of several cytokines (such as TNF-alpha, IL-1 beta, IL-6, and IFN-gamma), as well as expression of cellular activation markers, paralleled HIV replication in IL-2-stimulated PBMCs. Endogenous pro-inflammatory cytokines and IFN-gamma played a major role in the regulation of HIV replication in IL-2-stimulated PBMCs, as determined by the ability of several anti-cytokine Abs or antagonists to suppress HIV production; this was not the case in parallel cultures of autologous PHA-blasts. Thus, IL-2-stimulated PBMCs may represent a more physiologic in vitro system than PHA-blasts for the study of HIV infection and replication, and should prove useful in investigating the role of cytokines and other host factors in the regulation of HIV production.
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PMID:HIV replication in IL-2-stimulated peripheral blood mononuclear cells is driven in an autocrine/paracrine manner by endogenous cytokines. 786 11


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