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

This review suggests that infections are potent immunomodulators by causing significant alterations in one or more mediators of homeostasis and that an effective antibiosis may be a potent immunomodulator, albeit indirectly. When large numbers of microorganisms are killed, their enzymes and toxins are rapidly released and activate the immune system. The septic syndrome and the potentially progressive states of septic shock, acute respiratory distress syndrome and multiple organ system failure illustrate the biological response modulating (BRM) activity of both infection and antibiotic. Enhancement of phagocytosis and intracellular killing would be a useful immunomodulatory activity for antibiotics. Equally useful would be the capacity of the antibiotic to bind or inactivate bacterial lipopolysaccharide (LPS) to diminish monocyte release of tumour-necrosing factor (TNF) at a rate equal to or faster than the killing effect of the antibiotic on bacteria. For other types of immune deficiencies, such as are observed in HIV-positive patients with secondary bacterial, fungal and viral infections, modulation of viral receptors including HIV-R on CD4 lymphocytes accompanied by their up-regulation, enhancement of interferon (IFN) and natural killer (NK) function and inhibition of CD8 suppressor activity would be important activities. The classic example of polymyxin as an immunomodulating, albeit toxic, antibiotic offers a rational and definitive basis for the concept. In-vitro data on cefodizime, a third generation cephalosporin that achieves good tissue levels, are presented and show the ability of the intact antibiotic, as well as its immunomodulating side-chain, to down-regulate TNF and interleukin 1 (IL-1) released from human monocytes by lectin-activated lymphocytes, LPS and IFN.
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PMID:Antibiotics as biological response modifiers. 207 50

The terminal carbohydrate residues of HIV I and II were detected by ferritin labeled lectins in electron microscopy. Different cell lines, which were infected with HIV I and II, expressed different terminal carbohydrate residues, which could also be detected on the viral envelope by electronmicroscopy. Especially N-Acetylgalactosamine residues were detected by Vicia villosa agglutinin only on Jurkat cells. This may have functional implications, since this lectin recognizes contrasuppressor T cells.
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PMID:Carbohydrate components of human immunodeficiency viruses type I and II. 209 Oct 51

Peripheral blood monocytes from human immunodeficiency virus (HIV)-infected individuals or AIDS-related complex/AIDS patients ex vivo exhibit distinct alterations in some but not all immune functions. In studies presented here, monocytes from healthy donors were infected with HIV 1 in vitro and co-cultures with autologous uninfected T lymphocytes were set up. The monocyte/macrophage (M phi)-dependent T cell function was determined by measurement of proliferative and secretory [interleukin (IL)2, interferon-gamma] responses to lectin (phytohemagglutinin), mitogen (anti-CD3 monoclonal antibody), or recall antigen (tetanus toxoid, tuberculin). Accessory function of M phi was normal after HIV infection when optimal amounts (10%-20%) were added to the T lymphocytes. However, HIV infection of M phi significantly decreased T cell proliferative responses and secretion of IL2 when supplemented at limited dilution (0.5%-5%), although interferon-gamma production was not affected. Whereas the lipopolysaccharide-triggered M phi production of IL1 was not impaired by HIV 1 infection, there was a significant decrease in this response when anti-CD3 monoclonal antibody or tetanus toxoid were used to trigger the peripheral blood mononuclear cells. The impairment of proliferation of T lymphocytes in the presence of HIV 1-infected M phi could be overcome by addition of exogenous IL 1. Taken together, these data clearly show that the mononuclear phagocyte-dependent enhancement of stimulated T cell proliferation and lymphokine secretion is decreased when the restricted numbers of monocytes/M phi are HIV 1 infected. There are, therefore, two possible roles of M phi in HIV infection and progression to disease. First, as a reservoir and vehicle for dissemination of the virus, and second, as an immune cell whose essential functions are impaired by infection.
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PMID:Decreased accessory cell function of macrophages after infection with human immunodeficiency virus type 1 in vitro. 225 85

The effect of N-(3-phenyl-2-propenyl)-1-deoxynojirimycin (ppDNM) on the lectin binding to HIV-1 glycoprotein was analyzed by using biotinylated lectins of various sugar specificities as probes. ppDNM potentially inhibited HIV-1-induced syncytium formation and viral infectivity of HIV-1 without cytotoxicity. The lectin binding assay showed that ppDNM treatment reduced Con A binding to gp120 of HIV-1.
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PMID:Effect of N-(3-phenyl-2-propenyl)-1-deoxynojirimycin on the lectin binding to HIV-1 glycoproteins. 228 26

To characterize the cytotoxic events taking place in the lung of patients with HIV-1 infection, we studied the cells recovered from the bronchoalveolar lavage (BAL) of nine patients with AIDS, seven patients with AIDS-related complex, and two patients with lymphadenopathy. Phenotypic analysis was coupled to a series of functional evaluations of nonspecific cytotoxic abilities performed on lung effectors, including their property to bind K-562 targets, to release natural killer cytotoxic factor (NKCF), and to become cytotoxic following in vitro activation with rIL-2. Our results demonstrated that lung cells bearing the NK-related CD16, CD56, and CD57 antigens were quantitatively increased, irrespective of the disease stage. The majority of the cells also coexpressed the CD3 molecule and the alpha/beta T cell receptor (TCR), notably the phenotype characterizing MHC-unrestricted cytotoxic T cells. From a functional point of view, a severe impairment of the spontaneous cytotoxic ability was demonstrated in most patients. Evaluation at the single cell level showed a normal percentage of the effector/target conjugates formed by HIV-1 lymphocytes. The release of NKCF was undetectable in patients with AIDS even following lectin stimulation, whereas BAL cells from patients with earlier infection produced and/or could be triggered to release discrete amounts of NKCF by incubation with PHA. Studies designed to activate lung cytotoxic cells with rIL-2 showed that in most patients the stimulation of effector cells with rIL-2 enhanced the spontaneous killing and elicited a lymphokine-activated killer (LAK) phenomenon.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Cytotoxic events taking place in the lung of patients with HIV-1 infection. Evidence of an intrinsic defect of the major histocompatibility complex-unrestricted killing partially restored by the incubation with rIL-2. 238 2

Cytotoxic cells appear to play an important role in host defense against viral infection. In HIV-1 infection there is an expansion of the Leu7-positive lymphocyte population which is associated with cytotoxic activity. Since a form of non-MHC-restricted T-cell cytotoxicity [lectin-dependent cell cytotoxicity (LDCC)] has been reported to be mediated by CD3+Leu7+ cells, we evaluated LDCC and Leu7-positive lymphocyte populations in HIV-1-infected subjects and healthy controls. Both LDCC and percentages of Leu7+CD3+ and Leu7+CD2+ cells were increased in HIV-1-infected individuals as compared to controls. However, the CD3+Leu7+ lymphocyte population was increased to a greater degree than the CD8+Leu7+ population and a minor Leu7+ cell population (Leu7+CD4+) was expanded in the early stages of infection. Lectin-dependent cell cytotoxicity was positively correlated with the percentages of Leu7+CD3+ cells. Thus T-cells with the capacity to mediate high levels of non-MHC-restricted cytotoxicity are present in increased proportions in HIV-1-infected individuals and persist in advanced disease. Further studies are required to see if these cells participate in HIV-specific cytotoxicity or reflect an aberrant, ineffective, or immunologically detrimental response to the virus.
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PMID:T cells expressing high levels of non-major histocompatibility complex (MHC)-restricted cytotoxicity are present in early and late clinical phases of human immunodeficiency virus 1 (HIV-1) infection. 252 2

In this study carbohydrate-mediated interactions of the envelope glycoprotein, gp120, of HIV-1 were investigated. Oligosaccharide probes (neoglycolipids), prepared from the N-glycosidically-linked chains of the natural and recombinant forms of gp120, were used in conjunction with the intact glycoprotein to investigate reactivities with a soluble carbohydrate-binding protein (lectin) known as mannose-binding protein in human serum. Evidence is presented that the high-mannose-type oligosaccharides with seven, eight and nine mannose residues from both forms of gp120 are recognized by the serum lectin, and that these reactivities are unrelated to CD4 recognition. Reactivities of the two forms of envelope glycoprotein with macrophages derived from human blood monocytes and with the mannose-specific macrophage endocytosis receptor isolated from human placental membranes were also investigated. Evidence is presented that both forms of gp120 bind to the macrophage surface by multiple interactions in addition to CD4 binding, and that among these interactions is a carbohydrate-mediated binding to the endocytosis receptor. We propose that such carbohydrate-mediated interactions could form the basis of viral attachment to a variety of healthy and diseased tissues.
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PMID:Oligosaccharide-mediated interactions of the envelope glycoprotein gp120 of HIV-1 that are independent of CD4 recognition. 256 Oct 54

The pathogenesis of cellular immune deficiency following human immunodeficiency virus (HIV) infection could result from quantitative and/or qualitative dysfunction of the CD4+ lymphocyte population. To better characterize the T-cell response to soluble antigen with HIV infection, we have isolated peripheral blood lymphocytes and purified populations of CD4+ lymphocytes from healthy HIV antibody-positive subjects, patients with acquired immunodeficiency syndrome (AIDS)-related complex (ARC), and healthy HIV antibody-negative controls. T-lymphocyte function was determined by proliferative response to lectin (phytohemagglutinin), phorbol 12-myristate 13-acetate (PMA), calcium ionophore, purified recombinant HIV envelope gp120, tetanus toxoid antigen, and tetanus toxoid antigen in the presence of recombinant gp120 or purified recombinant soluble CD4. PBLs and CD4+ lymphocytes from asymptomatic HIV-infected subjects responded equally well to lectin, PMA, and/or calcium ionophore and to tetanus toxoid as cells from uninfected control subjects. The cells that proliferated in response to a soluble antigenic stimulus did not respond to gp120. Cells from subjects with ARC had a selective antigen recognition defect independent of the number of CD4+ lymphocytes. Recombinant gp120 inhibited CD4+ lymphocyte proliferation to antigenic stimulus by 30-40%. Recombinant soluble CD4, a proposed therapeutic for HIV, had no effect on T-cell response to antigen. A selective antigen recognition response was not compromised early in HIV infection but was compromised in subjects with ARC. Inhibition of proliferation to tetanus toxoid by gp120 suggests that HIV may affect major histocompatibility complex II restricted antigen recognition independent of CD4+ cell loss.
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PMID:CD4+ lymphocyte function with early human immunodeficiency virus infection. 256 77

The neuropathologic findings of brains and spinal cords removed at autopsy from 26 infants and children with AIDS is described; in two cases, only the spinal cords were available. The most common finding in the brains was dystrophic calcification of blood vessels of all calibers in the basal ganglia and deep cerebral white matter (21 og 24 cases). The next most frequent finding was subacute encephalitis (SE) (15 of 24 cases) with microglial nodules and multinulceated giant cells. Immunocytochemical and in situ hybridization studies showed HIV antigen or genetic sequences only in the brains of cases with SE. Multinucleated giants cells (MGC) were the most frequent cells with reaction products. MGC were labeled with ricinus lectin (RCA), but not with leukocyte common antigen (LCA) or glial fibrillary acidic protein. Many cells in microglial nodules were labeled with RCA, but not LCA; cells in the perivascular compartment were labeled with LCA, but not RCA. Corticospinal tract degeneration was noted in 15 of 20 spinal cords. In six cases tract degeneration was consistent with delayed myelination, and the remaining cases had axonal injury consistent with Wallerian degeneration. Opportunistic infections were rare (three cases). Central nervous system lymphoma occurred in three children and was the most common mass lesion. In two cases lymphoma occurred in the setting of a systemic polyclonal immunoproliferation possibly related to Epstein-Barr virus infection. Cerebrovascular accidents were noted in seven cases. Two cases had hemorrhage associated with immune thrombocytopenia; one hemorrhage was catastrophic. Two children had large vessel arteriopathy with multiple encephalomalacias. Two children had a necrotizing encephalopathy with encephalomalacia and vascular changes suggestive of a mitochondrial cytopathy.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Central nervous system pathology in pediatric AIDS: an autopsy study. 273 40

A method for preparative isolation of human monoclonal antibody isoproteins is described in the present paper. A human monoclonal antibody directed against the transmembrane protein gp 41 from the human immunodeficiency virus (HIV-1) was used in this study. The antibody belongs to the IgG1 subtype and exhibits antibody dependent cellular cytotoxicity. The resolving power of conventional preparative protein separation techniques such as ion-exchange chromatography, chromatofocusing and lectin affinity chromatography is too poor for a complete separation of isoproteins. The more sophisticated technique of chromatofocusing on FPLC-based material (Mono P, Pharmacia) did not satisfy our expectation. With semipreparative IEF in immobilized pH gradients we were able to prepare the different isoproteins of a human monoclonal antibody in milligram amounts. No significant difference between the single isoproteins with respect to specificity and avidity to the recombinant antigen (rec gp 160) was detected. Therefore, we assume that the separation conditions did not influence the immunochemical nature of the antibody and significant denaturation and/or precipitation of the IgG did not occur. Furthermore the method affords preparative separation with resolution equivalent to analytical runs. Experiments for scale up and further characterization of isoproteins (carbohydrate composition, amino acid analysis, half life times etc.) are in progress.
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PMID:Isolation of human monoclonal antibody isoproteins by preparative isoelectric focusing in immobilized pH gradients. 277 64


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