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

The small intestine is a major target in HIV infection. Chronic diarrhoeal disease associated with malabsorption is the principal clinical manifestation of such infection. Reduced intestinal immunity and opportunistic enteric infections play a major role in clinical disease, but an enteropathy induced by HIV per se has also been implicated. The immunopathology of reduced intestinal immunity and its progression during HIV infection is poorly understood. HIV genome and proteins have been detected reproducibly in cells of the lamina propria resembling macrophages, but direct epithelial infection with HIV is controversial. Another factor which may contribute to diarrhoea is autonomic neuropathy within the jejunum. Small intestinal disease causes malabsorption of fat and disaccharides and may contribute to the weight loss seen in advancing HIV infection. However, malnutrition seen in HIV infection is multifactorial and may occur as a constitutional sign of infection in the absence of overt intestinal disease. Reduced food intake does not appear to be a causative factor in the weight loss in constitutionally well stage IV patients and there is some evidence that release of cytokines (TNF alpha/cachectin) into plasma or locally into tissue may mediate such events. The response of HIV-infected individuals to nutritional support is variable, but it is becoming increasingly apparent that the response is limited by the presence of severe systemic infection. However, aggressive nutrition is an important therapeutic mode which should be offered to all HIV-infected patients.
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PMID:Malabsorption, malnutrition and HIV disease. 228 81

In order to assess the role of alveolar macrophages and their products in the control of Pneumocystis carinii pneumonia (PCP) and other infections in AIDS, bronchoalveolar lavage cells and peripheral blood mononuclear cells from HIV-positive AIDS/ARC patients (with and without PCP) and HIV-negative patients were counted and cultured in vitro; spontaneous and LPS-induced tumour necrosis factor-alpha (TNF-alpha) production was measured. Markedly increased spontaneous TNF-alpha production by alveolar macrophages and, to a lesser extent, peripheral blood monocytes was found in HIV-positive patients with active PCP but not in patients without the infection. Higher TNF production was associated with lower counts of Pneumocystis in the bronchoalveolar lavage fluid. These results suggest that TNF-alpha production by macrophages may play an important role in the control of Pn. carinii infection in AIDS.
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PMID:Alveolar macrophages in AIDS patients: increased spontaneous tumour necrosis factor-alpha production in Pneumocystis carinii pneumonia. 235 41

To determine the effects of immunomodulatory agents upon HIV replication in macrophages, cultured monocyte-derived macrophages were treated with various substances and then infected with a macrophage-tropic strain of HIV-1. Pretreatment with rIFN-alpha, IFN-beta, and IFN-gamma, or bacterial LPS prevented viral replication in macrophages. In treated cultures, little or no infectious HIV or p24 core antigen was released into the supernatant, no virions were seen by electron microscopy, no viral RNA or DNA was detectable in the cell lysates, and no cytopathology (as determined by multinucleated giant cell formation) occurred. In contrast, pretreatment with a wide dose range of recombinant IL-1 beta, IL-2, IL-4, IL-6, M-CSF, TNF, or lymphotoxin failed to protect macrophages from productive infection by HIV. A consistent effect of granulocyte/macrophage-CSF on HIV replication in macrophages was not observed. In dose response studies, pretreatment with approximately 100 U/ml of IFN-alpha, approximately 10 U/ml of IFN-beta, or approximately 100 U/ml of IFN-gamma was sufficient to prevent virion release maximally and to prevent cytopathology completely. In kinetic studies, IFN-alpha, IFN-gamma, or LPS were added to the macrophage cultures either before or after infection with HIV. Even when added 3 d after infection with a multiplicity of 1 50% tissue-culture infectious dose per cell, all three treatments markedly reduced virion release, suggesting that these agents act at a point in the viral life cycle beyond the early events of virus binding, penetration, and uncoating. These data indicate that HIV replication in previously uninfected macrophages may be regulated by an inducible host cell mechanism. These findings may explain the restricted replication of HIV in macrophages in vivo and suggest an antiviral role for interferons in the therapy of HIV infection.
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PMID:Interferons and bacterial lipopolysaccharide protect macrophages from productive infection by human immunodeficiency virus in vitro. 246 37

The production of tumor necrosis factor alpha (TNF alpha) and IL-1 beta by the monocytic cell line THP-1, productively infected with HIV-1, was investigated using specific RIA and Northern blot analysis. HIV-infected cells, like uninfected cells, did not constitutively produce any detectable amounts of protein or mRNA for TNF alpha or IL-1 beta. After stimulation with LPS or a combination of LPS plus IFN-gamma, TNF alpha and IL-1 beta were detected in tissue culture supernatants and cell lysates and transcripts for both cytokines were seen on Northern blots. No significant difference in production of these two cytokines was observed between uninfected and chronically infected cells. Acutely HIV-infected cells, however, showed phenotypic changes compatible with maturation and an increase in TNF alpha and IL-1 beta mRNA production, and released significantly higher levels of TNF alpha and IL-1 beta compared with chronically infected or uninfected cells. Furthermore, LPS stimulation of HIV-infected cells increased virus production. These results suggest that HIV-infected monocytic cells may produce increased amounts of TNF alpha and IL-1 beta in response to stimuli that could be present in vivo.
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PMID:Production of tumor necrosis factor alpha and interleukin 1 beta by monocytic cells infected with human immunodeficiency virus. 247 73

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

We have investigated the effect of TNF, a cytokine produced during most immunologic and inflammatory reactions, on HIV genome expression in human T lymphocytes. A CD4+ human T cell line (J.Jhan) was transfected with vectors permitting the expression of the chloramphenicol acetyl transferase (CAT) gene under the control of the long terminal repeat (LTR) of HIV-1. rTNF was found to induce HIV LTR transactivation as intensely as PHA or phorbol esters. PHA enhanced TNF receptor expression in J.Jhan cells and acted synergistically with TNF on HIV LTR induction. TNF was also shown to induce well expression of a whole HIV provirus genome transfected into J.Jhan cells. The use of various CAT constructs carrying fragments of the HIV LTR, combined with bandshift assays, showed that TNF stimulates HIV transcription by acting on the kB-like enhancer element of the LTR through induction and/or activation of an NF-kB-like protein factor. Such findings are compatible with the hypothesis that TNF production participates in the pathogenesis of AIDS by enhancing HIV replication in T lymphocytes.
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PMID:Tumor necrosis factor stimulates transcription of HIV-1 in human T lymphocytes, independently and synergistically with mitogens. 257 6

Human T cell lines Molt-4, Jurkat, and TLOm-1 were infected by HIV-1 in the presence of various concentrations of r-TNF. The infectivity of HIV-1 was monitored by an indirect immunofluorescence method using anti-HIV-1-positive human serum. We found that r-TNF enhanced the replication of HIV-1. HIV-1-induced giant cell formation between HIV-1 chronically infected Molt-4 cells and HIV-1-uninfected Molt-4 cells was accelerated by r-TNF. The median tissue culture infectious doses (TCID50) of HIV-1 determined in the presence of TNF revealed that TNF apparently accelerated the time of the appearance of CPE but did not affect final titer of HIV-1.
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PMID:Enhancement of HIV replication and giant cell formation by tumor necrosis factor. 278 93

Cytokines such as interleukin-1 (IL-1) and tumor necrosis factor alpha (TNF alpha) are important in normal immune processes. In this study, we demonstrate that human immunodeficiency virus type 1 (HIV-1) virions induce normal peripheral blood mononuclear phagocytes to produce both IL-1 and TNF within a few hours after their exposure to virus. The induction of these cytokines by HIV-1 does not require a productive infection. Blocking studies with soluble CD4 indicate that the effect is mediated through the CD4 molecule. In addition, the treatment of mononuclear phagocytes with OKT4A monoclonal antibody mimics the effects of HIV-1. Thus, these results indicate that induction of IL-1 and TNF alpha can occur via signals mediated through the CD4 molecule on mononuclear phagocytes. TNF has been shown by other investigators to induce HIV-1 expression. Therefore, TNF alpha may play a role in autocrine and paracrine regulation of HIV-1 expression. In addition, the induction of IL-1 and TNF by HIV-1 may also contribute to some of the neurologic and physiologic disorders associated with acquired immunodeficiency syndrome.
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PMID:Interleukin-1 and tumor necrosis factor alpha can be induced from mononuclear phagocytes by human immunodeficiency virus type 1 binding to the CD4 receptor. 278 93

We investigated the CD8+CD57+ alveolar cell functions and their immunoregulatory role in lungs from HIV-seropositive patients with the clinical presentation of lymphocytic alveolitis at different stages of human immunodeficiency virus (HIV) disease. We previously reported, at Stage IV of HIV infection, an expansion of CD8+CD57+ alveolar lymphocytes mirroring the decline of local anti-HIV cytotoxic T-lymphocyte (CTL) responses, and demonstrated that sorted CD8+CD57+ alveolar lymphocytes inhibited the effector phase of these HIV-specific CTL. In the present study, we show that the expansion of CD8+CD57+ alveolar T cells can also be detected at stages II and III of HIV disease, although at a lower degree than observed at Stage IV of HIV infection. When sorted, these CD8+CD57+ alveolar lymphocytes block effector killer cells such as allospecific CTL, natural killer (NK), and lymphokine-activated killer (LAK) cells. The mechanism of action of these inhibitory T-lymphocytes has been further studied and we demonstrated that: (1) cell-to-cell contact between inhibitor and killer is not required, (2) nonstimulated alveolar CD8+CD57+lymphocytes but not CD57- lymphocytes spontaneously release a solube inhibitor of cytolytic functions (ICF). This inhibitory activity of alveolar CD8+CD57+ cells is mediated by a glycosylated protein which is distinct from tumor necrosis factor-alpha (TNF alpha), TNF beta, transforming growth factor-beta 1 (TGF beta 1), TGF beta 2, interferon alpha (IFN alpha), interferon gamma (IFN gamma), and prostaglandins. The release of such an inhibitor of killer cell functions by CD8+CD57+ lymphocytes in the lungs, which are an important interface between the sterile body and the antigen-laden environment, may play a role in the local control of cell immunity.
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PMID:Alveolar CD8+CD57+ lymphocytes in human immunodeficiency virus infection produce an inhibitor of cytotoxic functions. 751 68

The HIV and visna lentiviruses induce an inflammatory reaction in the central nervous system (CNS) of the infected hosts leading to dysmyelination, demyelination, and neuronal loss. The basic domain of the transactivating Tat protein has been involved in CNS damage. Infusion of basic containing domain Tat peptides in the lateral ventricle (systemic injection) or in the grey matter, i.e., hippocampus and thalamus (local injection), induced an inflammatory process characterized by the formation of an edema and invasion of macrophage accompanied by reactive astrogliosis. Control peptides originating from either lentiviral proteins or irrelevant protein as ovalbumin did not lead to any inflammatory reaction or cell death. The inflammation led to the loss of ependymal cells in the lateral ventricles and neurons in the grey matter. RNA extracted from the Tat-injected hemisphere reacted with TNF-alpha, IL-1 alpha and beta, and IL-6 probes. The macrophage/microglia inducible nitric oxyde synthase was also expressed. Blockade of TNF-alpha by a pentoxifylline treatment led to the decrease of IL-1 and iNOS expression accompanied by a reduction of the volume of the lesions indicating that the Tat-induced lesions might be mediated by TNF production.
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PMID:The basic domain of the lentiviral Tat protein is responsible for damages in mouse brain: involvement of cytokines. 752 41


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