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

Cells from the human monocytic cell-line THP1 were incubated prior to activation with IFN-gamma or LPS with varying amounts of p24, the main product of the HIV gag gene and the major component of the virus core. The IFN-gamma-dependent increase of mRNA for HLA-DR and for the heavy chain of cytochrome b was markedly decreased by p24 but not by gp120. This effect was abrogated by anti-p24 antibodies. On the other hand, preincubation of THP1 cells with p24 did not affect the accumulation of the LPS-dependent mRNA for TNF alpha and IL1-beta. These results indicate that p24 at concentrations similar to those found in the serum of HIV-infected individuals specifically affects IFN-gamma-induced activation markers.
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PMID:The HIV core protein p24 inhibits interferon-gamma-induced increase of HLA-DR and cytochrome b heavy chain mRNA levels in the human monocyte-like cell line THP1. 190 83

We have evaluated the TNF production by alveolar macrophages (AM) in 43 HIV-infected subjects in relation with 1) their clinical and biologic status; 2) the presence of lung opportunistic infections (OI); and 3) the expression of HIV by AM. This production was assessed in a standard chromium release test, using monocytic U937 cells as targets. The spontaneous TNF production by AM from patients without lung OI was higher than that from seronegative controls (p less than 0.02). This production by AM was similar to that of blood monocytes, suggesting that it was not related, in these subjects, to any particular lung status. The extent of TNF release by AM was correlated to the presence of a lymphocytic alveolitis (p less than 0.05), and not to the patients' clinical presentation nor to their CD4 cell count. Finally, AM from these subjects could be normally stimulated in vitro by IFN-gamma. On the other hand, it appeared that the spontaneous TNF release by AM shown in vitro to express HIV (p24+ AM) was significantly higher than that by their p24- counterparts (p less than 0.05) and by controls (p less than 0.01). In addition, contrasting with the marked increase of TNF release by p24- AM after their stimulation with IFN-gamma (p less than 0.001), p24+ AM appeared to be refractory to any stimulation by IFN, arguing for their activation in vivo. Finally, the spontaneous TNF release by AM was significantly increased during lung OI, compared with controls (p less than 0.01) as well as with AIDS patients without OI (p less than 0.01). In addition, the production of TNF by AM in these subjects was higher than that by the corresponding blood monocytes (p less than 0.02), suggesting a compartmentalization of this response within the lungs. In conclusion, it appears that the TNF production by AM of seropositive patients is highly related to the presence of lung OI as well as to the expression of HIV by these cells. In the context of the up-regulation of HIV expression induced by TNF in vitro, our data could suggest that the in vivo release of TNF by AM could participate in viral dissemination. Moreover, we hypothesize that the generation of activated AM refractory to any further stimulation could in turn lead to the development of additional pulmonary infections.
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PMID:Tumor necrosis factor production in HIV-seropositive subjects. Relationship with lung opportunistic infections and HIV expression in alveolar macrophages. 190

Reduced tryptophan and increased kynurenine concentrations have been reported in patients with human immunodeficiency virus type 1 (HIV-1) infection. From in vitro data it appears that activated indoleamine 2,3-dioxygenase (IDO) is involved in this metabolic change. IDO is inducible by interferon-(IFN)-gamma. We compared serum concentrations of IFN-gamma and neopterin (the biosynthesis of which is also inducible by IFN-gamma) with serum, tryptophan and kynurenine of 42 patients with HIV-1 infection. IFN-gamma, neopterin and kynurenine levels were significantly increased compared to HIV-1 seronegative controls whereas tryptophan was significantly decreased. Various significant correlations were found between tryptophan, kynurenine, IFN-gamma and neopterin concentrations. Highest degree of correlation was found between neopterin, IFN-gamma and the kynurenine per tryptophan quotient which is the ratio between the product and the substrate concentration of IDO. The data indicate that decreased tryptophan in HIV-1 seropositives may result from chronic immune activation and can be referred to increased activation of IDO.
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PMID:Increased endogenous interferon-gamma and neopterin correlate with increased degradation of tryptophan in human immunodeficiency virus type 1 infection. 190 3

The hallmark of infection with HIV-1 is progressive depletion and qualitative dysfunction of the CD4+ Th cell population in infected individuals. Clinical trials of antiretroviral agents have shown that, despite suppression of virus replication, regeneration of the T cell pool does not occur. One proposed explanation for the defective regenerative capacity of the CD4+ T cell pool is infection of early T lymphocyte progenitors or stem cells. An additional explanation could be failure of cells of the intrathymic microenvironment (thymic epithelial (TE) cells) to carry out critical nurturing functions for developing thymocytes, i.e., secretion of thymocyte-trophic cytokines and expression of adhesion molecules. This study examines the effect of HIV on cultured TE cells and determines the role of TE cells in the regulation of viral expression in chronically HIV-infected cells. We found no evidence of infection of TE cells after exposure to HIV-1. However, normal human serum induced secretion of IL-6 by TE cells; induction of TE IL-6 was partially blocked by anti-IFN-gamma antibodies. Moreover, supernatants from TE cells maintained in normal human serum up-regulated HIV replication in chronically HIV-1-infected cells. Because intrathymic T cell precursors can be infected with HIV and T cell precursors come into close contact with TE cells in the thymus, IL-6 secreted by TE cells during normal intrathymic development may induce HIV expression in infected thymocytes in vivo and promote the intrathymic spread of HIV.
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PMID:Thymic microenvironment induces HIV expression. Physiologic secretion of IL-6 by thymic epithelial cells up-regulates virus expression in chronically infected cells. 191 77

The control of HIV-1 or SIV replication within macrophages is probably influenced by a variety of viral and cellular factors. Of the cellular factors, the authors have studied cytokine influence on SIV replication in vitro utilizing simian alveolar macrophages and uncloned SIVmacMTV, a macrophage-tropic variant. The approach allowed quantification of viral replication on a per-cell basis. As reported for HIV-1 replication in macrophages, TNF-alpha significantly increased SIV production in these macrophage cultures. GMCSF also resulted in marked increases in SIV gag protein in culture supernatants. However, after correcting for differences in total cell numbers and numbers of gag-containing cells in the treated and untreated cultures, GMCSF did not upregulate SIV production on a per-cell basis. IL-6 increased SIV replication little if at all but induced significantly greater cytopathic changes in the treated cultures compared with infected, untreated cultures. In contrast, IFN-gamma greatly decreased replication. Our results for GMCSF, IFN-gamma, and IL-6 are in contrast to previously published reports of cytokine control of HIV-1 growth in target cells, and they stress the importance of cell number analyses and the use of primary cultures in the study of lentiviral replication kinetics in macrophages.
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PMID:Cytokine influence on simian immunodeficiency virus replication within primary macrophages. TNF-alpha, but not GMCSF, enhances viral replication on a per-cell basis. 192 4

Monocytes/macrophages serve a number of immunologic functions and play a major role in the host defense against infection. Abnormal functions of monocytes have been reported in AIDS and HIV+ individuals. A recent report from our laboratory demonstrated that peripheral blood monocytes (PBM) derived from AIDS patients were de novo "activated" as assessed by direct cell-mediated cytotoxicity (CMC) and secretion of cytotoxic factors and tumor necrosis factor-alpha (TNF alpha). Thus, both the direct cytotoxicity as well as the antibody-dependent cellular cytotoxicity (ADCC) exerted by the monocytes may contribute to the destruction of HIV-infected/coated cells and the immunopathogenesis of AIDS. The present study investigated the ability of HIV+ PBM to mediate ADCC against antibody-coated target cells in an 18-hr 51Cr release assay. Initial studies examined ADCC using a macrophage resistant target Raji and rabbit anti-Raji serum. The results show that the majority of PBM from HIV+ individuals mediate ADCC activity while the majority of PBM from normal healthy controls was not cytotoxic. While activation of PBM with recombinant interferon-gamma (rIFN-gamma) enhances the ADCC activity of normal PBM, treatment of HIV+ PBM with IFN-gamma resulted in significant enhancement of ADCC. Both untreated and treated PBM from HIV+ individuals had significantly higher ADCC than PBM from normal individuals. Of interest, a significant ADCC activity was found by PBM derived from two HIV- high risk individuals whether untreated or treated with rIFN-gamma. The ADCC results with RAJI target cells prompted us to investigate whether ADCC can also be obtained using HIV-infected T4+ cells. We selected a macrophage and TNF resistant T4+ CEM cell line as target for ADCC. The target was coated with inactivated HIV and pooled human anti-HIV serum was used. Studies with a few HIV+ individuals demonstrate that significant ADCC is obtained with PBM from HIV+ individuals but little or no ADCC by normal PBM and the ADCC was specific for HIV. The ADCC was also significantly enhanced by treatment of PBM with rIFN-gamma. The results of this study clearly indicate that PBM from HIV+ individuals are endowed with the capacity to mediate ADCC against HIV-infected/coated cells and thus, we postulate that PBM may play a direct role in vivo in lysis or suppression of HIV-coated/infected cells and in the pathogenesis of AIDS.
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PMID:Peripheral blood monocytes derived from HIV+ individuals mediate antibody-dependent cellular cytotoxicity (ADCC). 210 87

We report that 11 human immunodeficiency virus 1 (HIV-1)-seropositive patients, including three AIDS patients, were able to generate a cellular immune response to the intradermal injection of low doses (2-10 micrograms) of recombinant interleukin 2 (rIL-2). A dose-dependent zone of induration appeared at the site of injection, peaked at 24 hr, and was accompanied by the local accumulation of T cells, monocytes, and Langerhans cells. Despite the reductions in the CD4+ T-cell counts in the peripheral blood of most patients, CD4+ T-cells could still be mobilized with rIL-2 injections into the skin. The total number of immigrant cells was equivalent to those in HIV-1-seronegative patients, although the CD4+/CD8+ ratio of the dermal population was reduced. In response to rIL-2, major histocompatibility complex (MHC) class II antigen was expressed on the surface of keratinocytes, Langerhans cells, lymphocytes, and macrophages. In addition, the gamma interferon (IFN-gamma)-induced protein IP-10 rapidly appeared in dermal inflammatory cells and keratinocytes. A majority of HIV-1-seropositive patients demonstrated low or absent responses to common skin-test antigens. Those with positive zones of induration were often defective in the cellular expression of the IFN-gamma-induced MHC class II antigen. The simultaneous administration of rIL-2 and soluble antigen at widely separated cutaneous sites led to an enhancement of skin-test antigen reactivity in seropositive patients. The results suggest that local administration of rIL-2 to seropositive patients may act systemically, stimulating cellular immunity to recall antigens, and thus may be of potential benefit in the defense against opportunistic pathogens encountered in HIV-1 infection.
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PMID:Cutaneous response to recombinant interleukin 2 in human immunodeficiency virus 1-seropositive individuals. 214 21

The ability of recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF) and gamma interferon (IFN-gamma) to modify human immunodeficiency virus (HIV; also called HTLV-III/LAV) infection in the monocytic cell line U-937 was examined. When added to persistently infected cell cultures, GM-CSF at 30-300 units per ml produced maximal reductions in reverse transcriptase activity of 37-55% 10-14 days after its addition, whereas IFN-gamma produced reductions of 64-68% 10-17 days after addition. When used prior to acute HIV infection and maintained in the cell culture system, these cytokines reduced reverse transcriptase activity 90-100% and nearly eliminated viral antigen expression but did not prevent return of productive infection after their removal. These results indicate that, in a monocyte model of HIV infection, GM-CSF and IFN-gamma substantially restrict HIV expression and that these cytokines deserve further evaluation as therapeutic alternatives in HIV-related disorders.
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PMID:In vitro modification of human immunodeficiency virus infection by granulocyte-macrophage colony-stimulating factor and gamma interferon. 243 Feb 98

Specific cellular immune responses to human immunodeficiency virus type 1 (HIV-1) were assessed in mononuclear leukocyte cultures from homosexual men with documented, early phase HIV-1 infection. Cell cultures from men with a mean duration of 1.3 yr (range, 0.3 to 2.2 yr) of HIV-1 infection were treated with UV-inactivated, whole, purified HIV-1 Ag together with various concentrations of rIL-2. Cell supernatants were harvested after 5-day incubation and assayed for IFN activity against encephalomyocarditis virus in human WISH cells. IFN subtypes were characterized by neutralization of antiviral activity with antiserum specific for human IFN-gamma and IFN-alpha. Results showed that cultures from 68% (17 of 25) of the HIV-1-seropositive subjects produced "immune" IFN-gamma in response to whole HIV-1 Ag plus rIL-2. IFN-gamma was induced in only 20% (5 of 25) of cultures treated with HIV-1 Ag alone. Enhancement of HIV-1-specific IFN-gamma production by rIL-2 was synergistic rather than additive in that titers induced by the mixture were consistently higher than the sum of IFN titers induced by HIV-1 or rIL-2 alone. This effect was not demonstrable in cultures from 18 HIV-1-seronegative men. Similarly, HIV-1-immune specific augmentation of IFN-gamma production by rIL-2 was noted for PENV9, a recombinant HIV-1 envelope glycoprotein gp41 and gp120 fragment. Production of IFN-gamma may be an important, HIV-1-immune specific parameter in the host response to this retrovirus.
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PMID:HIV-1-specific production of IFN-gamma and modulation by recombinant IL-2 during early HIV-1 infection. 245 86

The interferon (IFN) system, both serum IFN levels and the in vitro IFN production, was investigated in 38 clinically asymptomatic multitransfused hemophiliacs, half positive and half negative for HIV antibodies. In most patients, no circulating IFN was detected; similar levels of IFN-alpha were obtained after peripheral blood mononuclear cell (PBMC) stimulation with Sendai virus both in hemophiliacs and controls, while production of IFN-gamma following stimulation with phytohemagglutin (PHA) was diminished in a large number of patients irrespective of their HIV serology. These data indicate that the deficiency in IFN-gamma generation is not only related to HIV contamination but may be a direct consequence of the chronic antigenic stimulation through Factor VIII concentrates.
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PMID:Interferon production in severe hemophiliacs with and without HIV antibodies. 245 51


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