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

Interferons can suppress the replication of certain retroviruses, including oncogenic murine retroviruses. In recent studies of the Lentivirinae subfamily of Retroviridae, an endogenous, immunologically induced interferon was found to restrict the replication of visna in macrophages. Several studies have shown that the replication of a human lentivirus, the human immunodeficiency virus (HIV), is also susceptible to interferon control. Here we review the evidence that interferons can protect macrophages from HIV in vitro. Macrophages treated with interferons or bacterial lipopolysaccharide (LPS) become essentially nonpermissive for HIV replication. Using the polymerase chain reaction to amplify HIV proviral DNA, we now report that interferon and LPS act to restrict the formation of proviral DNA. Effects on any several steps in the HIV life cycle may explain this data, and single-cycle infection studies are needed to define the precise roles of these agents. Taken together, these findings may explain the restricted replication of HIV in macrophages in vivo and suggest an antiviral role for endogenously produced interferon in the maintenance of the prolonged asymptomatic period which typically follows HIV infection. Interferons are currently undergoing clinical trials to determine if they have antiviral effects in HIV-infected patients.
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PMID:The role of interferons in the control of HIV replication in macrophages. 168 22

The capacity of human monocytes/macrophages (M/M) infected with a human immunodeficiency virus-1 (HIV-1) isolate to produce several immunomodulating cytokines including interleukin-1 alpha (IL-1 alpha), IL-1 beta, tumor necrosis factor-alpha (TNF-alpha), IL-6, IL-8, and macrophage chemoattractant and activating factor (MCAF) was examined. Although HIV infection itself induced significant increases in the level of mRNAs for IL-1 beta, TNF-alpha, IL-6, and IL-8, the levels of lipopolysaccharide (LPS)-induced mRNAs for IL-1 alpha, IL-1 beta, TNF-alpha, IL-6, IL-8, and MCAF were decreased over those of uninfected LPS-stimulated cells. In addition, HIV-infected M/M produced lower amounts of IL-8 protein, as measured by radioimmunoassay over an 18-day culture period. These results suggest that HIV infection generally suppresses the LPS-inducible cytokine production in human M/M. The impact of the role of these cytokines in the immunity and pathogenesis of HIV-1 infection is discussed.
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PMID:Decrease in cytokine production by HIV-infected macrophages in response to LPS-mediated activation. 172 30

Human promonocyte cells chronically infected with human immunodeficiency virus type (HIV-1) (clone U1.1.5) were grown in the presence of media conditioned by human astrocytes and glioma cell lines U251 and 253. HIV-1 expression was assessed by measuring reverse transcriptase activity. All media conditioned by unstimulated and lipopolysaccharide (LPS) stimulated glial cells induced HIV-1 expression and contained detectable levels of interleukin-6 (IL-6) but not tumor necrosis factor-alpha (TNF-alpha). An antibody against IL-6, but not against TNF-alpha, reduced the induction of HIV-1 by the conditioned media in a concentration-dependent manner. The magnitude of HIV-1 induction by the conditioned media was proportional to the concentration of IL-6 in them. The data indicate that normal and transformed human astrocytes are capable of stimulating HIV-1 expression in chronically infected promonocytic cells by secreting IL-6. The results demonstrate that cytokines secreted by neural cells could play an important role in regulating HIV-1 expression in the brain.
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PMID:Human astrocytes stimulate HIV-1 expression in a chronically infected promonocyte clone via interleukin-6. 174 78

In view of its unique ability to stimulate human B cells, we have considered using Brucella abortus (BA) as a carrier for human vaccines. Recently we showed that HIV-1 coupled to BA, but not unconjugated HIV-1, was able to stimulate murine responses even in the relative absence of CD4+ T cells. This result suggested that HIV-BA may be useful in boosting the immunity of individuals infected with HIV-1 and who have impaired CD4+ T cell function. In order to refine this carrier we purified lipopolysaccharide (LPS) from BA and examined its effects on immune responses. Similar to LPS from E. coli (LPS-EC), LPS-BA was capable of stimulating mouse B cells to proliferate. In addition, LPS-BA could activate mouse spleen cells to secrete antibodies in vitro. Isotype analysis revealed that IgM and all the IgG subclasses were elicited. When comparing these responses to those of LPS-EC, LPS-BA induced a greater percentage of IgG2a and LPS-EC evoked more IgG3. IgG2a is probably important in protection against murine viral infection. LPS-BA was haptenated with trinitrophenol TNP-LPS (BA) and tested for carrier effect. Similar to TNP-BA and TNP-LPS (EC), TNP-LPS (BA) triggered anti-TNP antibody of the IgM and all IgG subclasses. In contrast, TNP-ficoll induced mainly IgM and only small amounts of IgG3. These results suggest that LPS-BA, like intact BA, behaves as a T-independent type 1 carrier, and as such may be advantageous as a carrier for human vaccines development.
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PMID:Immunogenicity of lipopolysaccharide derived from Brucella abortus: potential as a carrier in development of vaccines for AIDS. 180 68

Tumor necrosis factor-alpha (TNF) is a cytokine involved in the pathogenesis of shock and in granuloma formation, tissue necrosis, and fibrosis, in many organ systems, including the lung. It has been suggested that cells from patients infected by the human immunodeficiency virus (HIV + ve) are primed for TNF release. We postulated that TNF release from the alveolar macrophages (AM) of such patients with lung disease might lead to their observed pulmonary dysfunction. We present data confirming that peripheral blood monocytes (PBM) and demonstrating that AM from HIV + ve patients with pulmonary manifestations show significantly greater TNF production than those from HIV-negative (HIV - ve) subjects. In addition, we found sequentially significant increases in TNF production from AM and PBM of HIV + ve patients with no pathogens detected at bronchoscopy (NB), bacterial pneumonia (BP), and those with Pneumocystis carinii pneumonia (PCP). The overall TNF levels were greater from AM than PBM in all groups other than spontaneous production from HIV - ve subjects. Adherent populations of PBM and AM were incubated for 4 h with lipopolysaccharide (10 micrograms/ml) or control medium alone. Cell-free supernatants were examined for the presence of TNF using an immunoassay. The TNF levels (mean +/- SD) in IU/ml from stimulated PBM of the PCP, BP, NB, and control groups, respectively, were 186 +/- 36, 140 +/- 30, 95 +/- 18, and 55 +/- 10 and the spontaneous levels were 123 +/- 25, 100 +/- 22, 75 +/- 24, and 11 +/- 5.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Production of tumor necrosis factor-alpha by blood and lung mononuclear phagocytes from patients with human immunodeficiency virus-related lung disease. 189 44

Activation of T lymphocytes infected with the human immunodeficiency virus-1 (HIV-1) results in enhancement of viral replication mediated in part by activation of cellular NF kappa B capable of binding directly to sequences in the viral long terminal repeat, or LTR. Together with CD4+ T cells, macrophages constitute a major target for infection by HIV-1. Unlike lymphocytes, however, stimulation of mononuclear phagocytes is not associated with cell division and proliferation. Human monocyte-derived macrophages transfected with HIV-LTR-CAT constructs demonstrated down-regulation of CAT activity after stimulation with bacterial lipopolysaccharide (LPS) that mapped to a region distinct from NF kappa B binding sites. In contrast, fresh monocytes and the promonocytic U937 cell line both demonstrated up-regulation of HIV-LTR-CAT expression by LPS. Differentiation of U937 by PMA to establish a nondividing phenotype resulted in down-regulation of transfected HIV-LTR-CAT activity by LPS similar to that in mature macrophages. Human monocyte-derived macrophages infected with HIV-1 in vitro demonstrated a decrease in viral p24 release after incubation in LPS that was comparable to the negative regulation that occurred in the transient transfection assays. Factors controlling HIV replication may differ in dividing and nondividing hematopoietic cells and may contribute to restricted viral expression in nondividing cells.
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PMID:Activation of human monocyte--derived macrophages with lipopolysaccharide decreases human immunodeficiency virus replication in vitro at the level of gene expression. 190 15

We have investigated the effects of human immunodeficiency virus type-1 (HIV-1) infection on constitutive and lipopolysaccharide (LPS)-induced expression of interleukin-6 (IL-6) in cultured blood monocyte-derived macrophages. Highly productive and cytopathic infection of macrophages was established with the macrophage-tropic HIV-1 BaL strain. On Days 14-28 post infection, infected and mock-infected cells were activated with LPS or control medium for 6-24 hours before harvesting culture supernatants and cellular RNA. IL-6 bioactivity in culture supernatants was measured with the IL-6-dependent B9 cell line. IL-6 mRNA levels were quantitated by Northern blot analysis with scanning densitometry. In the absence of LPS activation, IL-6 activity was near or below the limit of detection in supernatants from both infected and uninfected cultures. Similarly, without LPS stimulation, IL-6 mRNA was not detectable in either infected or uninfected macrophages. After activation with LPS, marked increases in IL-6 mRNA levels and supernatant bioactivity were evident in both infected and uninfected cultures, but the response to LPS was consistently greater in infected macrophages. LPS-induced IL-6 mRNA levels and supernatant bioactivity were 7.4- and 4.4-fold higher, respectively, in infected compared with uninfected macrophages (n = 5, p less than .05). These studies demonstrate that highly productive HIV-1 infection does not increase constitutive IL-6 expression in macrophages, but does prime macrophages for an augmented IL-6 response to LPS. These findings may help define the mechanisms responsible for increased IL-6 production in patients with HIV-1 infection.
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PMID:Interleukin-6 expression in primary macrophages infected with human immunodeficiency virus-1 (HIV-1). 193 Dec 35

We have measured the production of interleukin 1 (IL 1), interleukin 6 (IL 6), and tumor necrosis factor alpha (TNF alpha) by unstimulated monocytes and monocytes stimulated with lipopolysaccharide (LPS) isolated from the peripheral blood of patients infected with human immunodeficiency virus 1 (HIV-1) and healthy controls. Spontaneous and LPS-induced cytokine production were not significantly different between patients and controls. Median lipopolysaccharide-stimulated cytokine secretion for patients and controls was 1.7 and 4.3 U/ml for IL 1, 475 and 625 U/ml for IL 6, and 468 and 580 pg/ml for TNF alpha. Cytokine levels were not related to stage of disease. We conclude that in vivo HIV infection itself does not alter peripheral blood monocyte cytokine secretion.
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PMID:Cytokine secretion by peripheral blood monocytes from human immunodeficiency virus-infected patients is normal. 193 24

Although monocytic cells can provide a reservoir for viral production in vivo, their regulation of human immunodeficiency virus type 1 (HIV-1) transcription can be either latent, restricted, or productive. These differences in gene expression have not been molecularly defined. In THP-1 cells with restricted HIV expression, there is an absence of DNA-protein binding complex formation with the HIV-1 promoter-enhancer associated with markedly less viral RNA production. This absence of binding was localized to the NF-kappa B region of the HIV-1 enhancer; the 65-kDa plus 50-kDa NF-kappa B heterodimer was preferentially lost. Adding purified NF-kappa B protein to nuclear extracts from cells with restricted expression overcomes this lack of binding. In addition, treatment of these nuclear extracts with sodium deoxycholate restored their ability to form the heterodimer, suggesting the presence of an inhibitor of NF-kappa B activity. Furthermore, treatment of nuclear extracts from these cells that had restricted expression with lipopolysaccharide increased viral production and NF-kappa B activity. Antiserum specific for NF-kappa B binding proteins, but not c-rel-specific antiserum, disrupted heterodimer complex formation. Thus, both NF-kappa B-binding complexes are needed for optimal viral transcription. Binding of the 65-kDa plus 50-kDa heterodimer to the HIV-1 enhancer can be negatively regulated in monocytes, providing one mechanism restricting HIV-1 gene expression.
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PMID:Negative regulation of human immunodeficiency virus type 1 expression in monocytes: role of the 65-kDa plus 50-kDa NF-kappa B dimer. 194 56

To assess the value of feline immunodeficiency virus (FIV) infection as a model for human immunodeficiency virus (HIV) infection in man, we studied the impairment of certain immunological functions following natural or experimental FIV infection. Proliferative responses of peripheral blood mononuclear cells (PBMC) from symptomatic and asymptomatic cats after naturally or experimentally acquired FIV infection, induced by activation with the mitogens concanavalin A, pokeweed mitogen, or lipopolysaccharide or by stimulation with human interleukin-2 (IL-2), were significantly lower than the proliferative responses found with PBMC from noninfected control cats. Also IL-2 production levels of mitogen-activated PBMC from naturally infected symptomatic cats were significantly reduced. These data confirm that the pathogenesis of FIV infection in the cat, like HIV infection in man, is characterized by a serious malfunction of the immune system.
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PMID:Feline immunodeficiency virus (FIV) infection in the cat as a model for HIV infection in man: FIV-induced impairment of immune function. 196 59


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