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Query: UMLS:C0001175 (AIDS)
 120,706 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The ability of the human immunodeficiency virus (HIV) to replicate in CD+ T lymphocytes and mononuclear phagocytes(MP) is strongly influenced by immunoregulatory cytokines. In the T cell system, interleukin-2 (IL-2) provides a mitogenic signal leading to both cell proliferation and virus replication. Among other HIV-inductive cytokines, only tumor necrosis factor-alpha or -beta (TNF-alpha/-beta) have been shown thus far to trigger virus expression both in T cells and MP. The mechanism of action of TNF involves the activation of the cellular transcription factor NF-kB which binds to specific consensus sequences present in the enhancer region of the HIV proviral LTR. In addition, several other cytokines (including colony stimulating factors, IL-1, IL-3, and IL-6) have demonstrated upregulatory effects on HIV production in MP, whereas nonimmune interferons (INF-alpha/-beta) have been shown to suppress HIV replication in T cells and MP by acting at different phases in the virus life cycle. Finally, cytokines such as TGF-beta, IFN-gamma, and IL-4 have demonstrated either upregulatory or suppressive effects on virus expression depending on the experimental conditions. This scenario indicates that HIV expression is under the control of a complex network of immunoregulatory cytokines, in addition to its own endogenous regulatory proteins, suggesting that new pharmacologic strategies may be aimed at either mimicking or interrupting cytokine-dependent virus expression. In this regard, a number of different physiologic and pharmacologic agents capable of interfering with cytokine-mediated events, including glucocorticoids, anti-oxidants, such as N-Acetyl-L-Cysteine (NAC), and retinoic acid (RA) have already been shown to profoundly affect HIV replication in vitro.
AIDS Res Hum Retroviruses 1992 Feb
PMID:The effect of cytokines and pharmacologic agents on chronic HIV infection. 154 Apr 7

Viral genes capable of inducing vascular tumors in the skin of transgenic mice are the tat gene of HIV-1 and polyoma virus' middle T antigen gene. Instead of vascular tumors, the tat gene of HTLV-I causes thymic atrophy and mesenchymal tumors in transgenic mice. No proof exists that any of these genes contribute to the induction of KS but HIV-1 tat is a strong suspect. The gene product K-FGF of the oncogene K-fgf/hst (int) uses bFGF receptors, is homologous with bFGF and acts as a mitogen for fibroblasts, endothelial cells and melanocytes. The overexpression of the K-fgf gene in KS is not proven unequivocally; some doubts exist suggesting the activation of this gene during the laboratory procedure of transfection with KS cell heavy DNA. Growth factor(s) not well identified (IL-6?) are released from HTLV-I- or II, or HIV-1- or 2-infected T4 lymphocytes and in particular from HIV-1-infected macrophages. This growth factor(s) promote(s) the continuous proliferation of endothelial cells and KS cells. AIDS-KS cells release other growth factors identical with or closely related to basic FGF, a major inducer of angioneogenesis. In addition, acidic FGF, IL-1 alpha and -beta, GM-CSF, PDGF-B and TGF-beta are released from AIDS-KS cells. The release of GM-CSF is induced by IL-1. GM-CSF promotes granulocytic, monocytic and endothelial cell proliferation. TGF-beta is known to suppress lymphocyte-mediated cytotoxicity and may act as a local immunosuppressive factor together with interferon inactivators. We theorize that when TGF-beta production ceases, TNF-beta (lymphotoxin) production switches on leading to programmed cell death (apoptosis) of KS cells resulting in regression of these lesions. The newly discovered angiogenesis factors VEGF/VPF may emerge as protooncogene-oncogene products analogous to PDGF and c-sis activation. AIDS-KS heavy DNA transfects NIH3T3 cells. NIH3T3 cells carrying this gene induced angiosarcomas when implanted in mice. An as yet unidentified large virus (mycoplasma?) was derived from these cells during passages in culture. No causative relationship between this agent and Kaposi sarcoma has as yet been established. Even though IFN-alpha exerts antiretroviral effects in AIDS, we propose that the therapeutic effect of IFN-alpha in AIDS-KS is based on antiangiogenesis activity by suppressing protooncogenes-oncogenes of the FGF family.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Kaposi's sarcoma: its 'oncogenes' and growth factors. 165 29

CD8+CD57+ T cells, expanded in peripheral blood lymphocytes of AIDS patients, inhibit the effector phase of HLA-specific cytotoxic T lymphocytes, natural killer and lymphocyte-activated killer cells in a 4-h chromium-release assay. This inhibitory activity present in supernatants of purified sorted CD8+CD57+ cells is mediated by a non-antigen-specific inhibitory factor which is distinct from prostaglandin E2, T cell growth factor (TGF)-beta, latent-TGF-beta, tumor necrosis factor (TNF)-alpha and TNF-beta. Partial biochemical characterization demonstrates that the CD8+CD57+ inhibitory activity (a) is heat, trypsin and acid resistant, (b) binds to concanavalin A columns, indicating its glycosylation state and (c) is mediated by a 20-30-kDa soluble molecule.
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PMID:A lectin-binding soluble factor released by CD8+CD57+ lymphocytes from AIDS patients inhibits T cell cytotoxicity. 170 6

Dysmorphic marrow morphology and bone marrow failure are common in AIDS patients, but the mechanism of HIV-1 effects on blood cell production is unclear. Experiments to test the susceptibility of hematopoietic progenitor cells to HIV-1 infection have led to conflicting results. We found that hematopoietic colony formation by burst-forming units-erythroid and CFU-GM was equivalently inhibited by both active and heat-inactivated, noninfectious virus. Inhibition was dependent on the presence of macrophages and was not observed in cultures derived from highly enriched CD34+ cells. We hypothesized that TNF-alpha, produced by mononuclear phagocytes after contact with HIV-1 or gp120 and itself a potent suppressor of hematopoiesis, might mediate this effect. The addition of anti-TNF-alpha neutralizing Abs to marrow cultures abrogated inhibition by gp120 or virus. In contrast, neutralizing Abs to Il-4, IFN-alpha, and TGF-beta failed to improve colony formation. TNF-alpha was released from blood monocytes and marrow mononuclear cells stimulated by gp120. TNF-alpha is increased in the blood of patients with late stage AIDS and may mediate many of the symptoms of the disease. Our data do not support a requirement of direct infection of hematopoietic progenitor cells by HIV-1 for the inhibition of hematopoiesis in vitro. We propose instead an indirect mechanism of viral suppression of hematopoiesis as a result of TNF-alpha induction by virus or viral envelope glycoprotein. The importance of local TNF-alpha production in patients' marrow is amenable to clinical testing.
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PMID:HIV-1 suppression of hematopoiesis in vitro mediated by envelope glycoprotein and TNF-alpha. 752 21

Cytokines represent the major factors involved in the communication between T cells, macrophages and other immune cells in the course of an immune response to antigens and infectious agents. A number of studies on mouse and human T helper (Th) clones have recently provided extensive evidence for the existence of different activities exhibited by Th cells (called Th1 and Th2), which was apparently inferred from the profile of cytokine secretion. The Th1-type immune response is generally associated with IgG2a production and the development of cellular immunity, the Th2-type response with IgE production, eosinophils and mast cell production. This review focuses on the role of different cytokines produced by macrophages (especially interferons (IFNs), TNF-alpha, IL-10 and IL-12) or T cells (IFNs, IL-2, IL-4, IL-10, IL-13 and TGF-beta) in macrophage-T cell interactions and the cytokine relevance in the differentiation of Th cells towards the Th1 or Th2 type of immune response. Th1-derived cytokines (IFN-gamma, IL-2, TNF-alpha) favor macrophage activation, whereas the Th2 cytokines (IL-4, IL-10, IL-13) exhibit suppressive activities on macrophage functions. A key role in the differentiation towards the Th1-type response is now attributed to IL-12, a recently described cytokine produced mainly by macrophages. Its production can be upregulated by IFN-gamma and is inhibited by IL-10 and IL-4. All this emphasizes the importance of macrophage-cytokine interactions in determining the type of immune response. This article also aims to review recent data concerning the roles of IFNs alpha/beta (type I) and IFN-gamma (type II) in the regulation of the immune response. While there is much information on the regulatory effects of IFN-gamma (also called "immune IFN") on the immune response, little is so far known of the role of type I IFNs. These cytokines, originally described as simple antiviral substances, are now taken to be important regulators of the immune response. Recent data indicate that these molecules (especially IFNs-alpha) specifically promote the differentiation towards the Th1-type response. The stimulatory effects of IFN-alpha on the generation of the Th1-type response may be involved in its therapeutic effects in some human diseases, including early AIDS, hypereosinophilia and certain tumors.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Role of interferons and other cytokines in the regulation of the immune response. 753 71

HIV-1 expression in monocytes/macrophages can be controlled by transforming growth factor-beta 1 (TGF-beta 1). TGF-beta 1 is present in astrocytes surrounding HIV-1-infected monocyte/macrophages in brain tissue from patients with AIDS but not from seronegative, normal individuals. We sought to determine whether or not production of TGF-beta 1 can be directly stimulated by HIV-1 in astrocytes. Astrocytes from neonatal rat cortex grown in primary culture were exposed to HIV-1 virions for 24 h. One day later, TGF-beta 1 was measured in culture supernatants by a biological assay. HIV-1 caused 1.7-2.1-fold increase in extracellular concentration of TGF-beta 1. TGF beta 1 production also was stimulated by recombinant HIV-1 proteins gp120, p66 and p24. Gp120 labeled with fluorescein was visualized inside astrocytes and its stimulatory effect was not blocked by antibodies against rat CD4. The effect was not specific to HIV-1 and its proteins, because non-opsonized Latex particles and leucine methyl ester (LME) (known to be phagocytosed and endocytosed, respectively, by astrocytes) also stimulated TGF-beta 1 production. The effect was inhibited by two inhibitors of the phago/endocytotic pathway, chloroquine and leupeptin. These results may be relevant to the neuropathogenesis of HIV-1 infection.
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PMID:HIV-1 non-specifically stimulates production of transforming growth factor-beta 1 transfer in primary astrocytes. 764 40

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

This study characterizes the effect of transforming growth factor (TGF) beta 1 on clusterin expression in rat brain cells. 24 h after an acute unilateral intracerebroventricular infusion of TGF-beta 1, clusterin mRNA prevalence was increased in astrocytes that contained immunoreactive (IR) glial fibrillary acidic protein (GFAP). TGF-beta 1 selectively induced clusterin mRNA in astrocytes, as no clusterin mRNA was detected in neurons, oligodendrocytes, or microglia. TGF-beta 1 induced a bilateral increase in clusterin mRNA per astrocyte. Astrocyte hypertrophy (GFAP-IR area) was only increased on the ipsilateral side. In pure astrocyte cultures, TGF-beta 1 (200 pM) decreased clusterin mRNA levels and the rate of clusterin RNA transcription. However, in cultures of astrocytes that contained microglia and oligodendrocytes (mixed glia cultures), TGF-beta 1 caused a dose-dependent increase in astrocytic clusterin mRNA levels. The astrocytes that responded to TGF-beta 1 included two GFAP-IR subtypes, type 1 and 2. TGF-beta 1 increased clusterin protein in the conditioned medium from cultured glia, in either monotypic or mixed glial cultures. Thus, TGF-beta 1 and heterotypic cell interactions influence clusterin expression by astrocytes and may be important to the role of clusterin in multiple sclerosis, AIDS, and Alzheimer's disease.
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PMID:Clusterin expression by astrocytes is influenced by transforming growth factor beta 1 and heterotypic cell interactions. 773 Apr 44

Immunohistochemical localization of transforming growth factor beta 1 (TGF-beta 1) was studied in Kaposi's sarcoma (KS) tissues obtained from autopsy and biopsy materials of patients with and without acquired immunodeficiency syndrome (AIDS) or human immunodeficiency virus (HIV) infection. There was no difference in the localization and distribution of TGF-beta 1 in KS tissues regardless of the HIV-1 status of the patients. Rabbit polyclonal antibodies to synthetic peptides, corresponding to the first 30 amino acids of mature TGF-beta 1, anti-LC(1-30), and anti-CC(1-30), were used for localization of intracellular and extracellular TGF-beta 1. An antibody to a peptide corresponding to amino acids 266 to 278 of the TGF-beta 1 precursor sequence anti-Pre(266 to 278) was used to detect the TGF-beta 1 precursor and the latency-associated peptide. Intracellular mature TGF-beta 1 was demonstrated in mononuclear cells, presumably macrophages, within KS tumors but not in spindle-shaped KS cells. Extracellular mature TGF-beta 1 was localized in the basement membranes of blood vessels and fibrous capsules of KS tumors. Intracellular reactivity to anti-Pre was localized in vascular smooth muscle cells and pericytes within the tumor, in variable proportions of spindle-shaped KS cells, and also in macrophage-like cells. These cells appear to be the production sites of TGF-beta 1, which may exert paracrine as well as autocrine proliferative effects.
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PMID:Immunohistochemical localization of transforming growth factor-beta 1 in Kaposi's sarcoma. 775 Sep 30

The Mycobacterium avium complex comprises intracellular bacteria associated with disseminated infection in patients with acquired immune deficiency syndrome (AIDS). Immune defects that lead to infection are unknown but cytokines appear to play an important role in the immunomodulation of host defence mechanisms. We evaluated the cytokine profiles seen temporally after murine M. avium infection. Spleen cells were obtained from M. avium-infected C57BL/6 mice and uninfected mice at weeks 1, 2, 3, 4 and 5. Cells were cultured in vitro and subsequently pulsed with killed M. avium. Supernatants were collected from the cultured splenic cells and the concentrations of interleukin-6 (IL-6), transforming growth factor-beta 1 (TGF-beta 1) and tumour necrosis factor-alpha (TNF-alpha) were measured. TGF-beta 1 was detected at week 1, followed by IL-6 production at week 2. Elevated TNF-alpha levels were observed at week 3. The addition of polyclonal anti-TGF-beta 1 antibody to M. avium-infected peritoneal macrophages in the presence of splenic cell supernatants from weeks 1, 3 and 5 led to decreased bacterial counts compared to controls. Anti-IL-6 antibody did not have any effect on macrophage anti-mycobacterial activity. Concurrently, we observed decreased expression of TNF-alpha receptors on infected macrophages. We propose that the early elevated levels of TGF-beta 1, a known suppressor of macrophage function, in conjunction with down-regulation of TNF-alpha receptors may help explain the suboptimal macrophage response to TNF-alpha, leading to impaired anti-mycobacterial activity.
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PMID:Production of TNF-alpha, IL-6 and TGF-beta, and expression of receptors for TNF-alpha and IL-6, during murine Mycobacterium avium infection. 779 28


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