Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: UMLS:C0021051 (immunodeficiency)
71,517 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Impaired polymorphonuclear neutrophil (PMN) function may contribute to the onset of certain life-threatening bacterial and fungal infections in human immunodeficiency virus (HIV)-infected patients. Published data on PMN functional activity in HIV infection are controversial, possibly because most studies have involved PMNs isolated from their blood environment by means of various procedures that may differently affect surface receptor expression and thereby alter cellular responses. We therefore used flow cytometry to study the expression of adhesion molecules at the PMN surface, actin polymerization, and the oxidative burst of whole-blood polymorphonuclear neutrophils in 42 HIV-infected patients at different stages of the disease. These PMNs were activated in vivo, as demonstrated by increased expression of the adhesion molecule CD11b/CD18, reduced L-selectin antigen expression, increased actin polymerization, and increased H2O2 production. The alterations were present in asymptomatic patients with CD4+ cell counts greater than 500/microL and did not increase with the progression of the disease. Stimulation by bacterial N-formyl peptides showed dysregulation of L-selectin shedding and decreased H2O2 production after ex vivo priming with tumor necrosis factor alpha or interleukin-8 (IL-8). These latter impairments, which correlated with the decrease in CD4+ lymphocyte numbers and with IL-8 and IL-6 plasma levels, could contribute to the increased susceptibility of HIV-infected patients to bacterial infections.
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PMID:Polymorphonuclear neutrophils from human immunodeficiency virus-infected patients show enhanced activation, diminished fMLP-induced L-selectin shedding, and an impaired oxidative burst after cytokine priming. 752 41

It has been recently reported that murine hematopoietic stem cells and progenitors express low levels of CD4. In this study, we have investigated by phenotypic and functional analysis whether the CD4 molecule was also present on human hematopoietic progenitors. Unfractionated marrow cells or immunomagnetic bead-purified CD34+ cells were analyzed by two-color fluorescence with an anti-CD4 and an anti-CD34 monoclonal antibody (MoAb). A large fraction (25% to 50%) of the CD34+ cells was weakly stained by anti-CD4 antibodies. Moreover, in further experiments analyzing the expression of CD4 in different subpopulations of CD34+ cells, we found that CD4 was predominantly expressed in phenotypically primitive cells (CD34+ CD38-/low CD71low Thy-1high, HLA-DR+/low). However, the presence of CD4 was not restricted to these primitive CD34+ cell subsets and was also detected in a smaller fraction of more mature CD34+ cells exhibiting differentiation markers. Among those, subsets with myelo-monocytic markers (CD13, CD33, CD14, and CD11b) have a higher CD4 expression than the erythroid or megakaryocytic subsets. In vitro functional analysis of the sorted CD34+ subsets in colony assays and long-term culture-initiating cell (LTC-IC) assays confirmed that clonogenic progenitors (colony-forming unit-granulocyte-macrophage, burst-forming unit-erythroid, and colony-forming unit-megakaryocyte) and LTC-IC were present in the CD4low population. However, most clonogenic progenitors were recovered in the CD4- subset, whereas the CD4low fraction was greatly enriched in LTC-IC. In addition, CD4low LTC-IC generated larger numbers of primitive clonogenic progenitors than did CD4- LTC-IC. These observations suggest that, in the progenitor compartment, the CD4 molecule is predominantly expressed on very early cells. The CD4 molecule present on CD34+ cells appeared identical to the T-cell molecule because it was recognized by three MoAbs recognizing different epitopes of the molecule. Furthermore, this CD4 molecule is also functional because the CD34+ CD4low cells are able to bind the human immunodeficiency virus (HIV) gp120. This observation might be relevant to the understanding of the mechanisms of HIV-induced cytopenias.
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PMID:Expression of CD4 by human hematopoietic progenitors. 754 75

The CD4 molecule serves as the principal cell surface receptor common to both the human and simian immunodeficiency viruses (HIV-1, HIV-2 and SIV). Since binding to CD4 is not sufficient to permit virus entry, HIV 'co-receptors' have been implicated in mediating the fusion of viral and cellular membranes necessary for completing the entry process. In order to identify candidate co-receptor molecules, a panel of monoclonal antibodies (MAbs) directed against adhesion molecules was tested for the ability of the MAbs to inhibit HIV-1-induced cell fusion (syncytium formation) and HIV-1 entry. Certain antibodies directed against CD18, CD11b and CD11c inhibited HIV-1-induced syncytium formation but not entry, in agreement with previous reports. Interestingly, certain antibodies to ICAM-3 (intercellular adhesion molecule 3) (CD50) significantly inhibited HIV-1-specific entry but not syncytium formation using human SupT1 cells. Only one antibody directed against ICAM-3 significantly inhibited HIV-1-induced syncytium formation, entry and infectivity. Our results suggest that certain epitopes of ICAM-3 may be involved in mediating HIV-1-specific entry into lymphoid and monocytoid cells.
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PMID:Intercellular adhesion molecule 3, a candidate human immunodeficiency virus type 1 co-receptor on lymphoid and monocytoid cells. 754 Jan 95

Leukocyte adherence deficiency (LAD) is an inherited immunodeficiency disease caused by defects in the CD18 leukocyte integrin subunit. Transduction of CD18 into hematopoietic cells from children with LAD represents a potential therapy for this disorder. In an attempt to maximize transfer and expression of CD18, we evaluated retroviral vectors with and without the neomycin selectable marker, with a modified tRNA primer binding site designed to prevent inhibition of gene expression, and with two different viral envelope proteins produced by using the amphotropic retrovirus packaging cell line PA317 or the gibbon ape leukemia virus packaging cell line PG13. The vectors were tested using transducing K562/CD11b cells and LAD Epstein-Barr virus (EBV) B cells and measuring levels of cell-surface CD11/CD18 expression by fluorescence-activated cell sorter analysis. The best results were obtained with vectors made using PG13 packaging cells, for which about 25% of the K562 cells exposed once to the vectors expressed surface CD11b/CD18 and about 25% of the LAD EBV B cells exposed three times over a 3-day period to the vectors expressed surface CD11a/CD18. In contrast, transduction of cells under similar conditions with retroviral vectors produced using PA317 producer cells yielded less than 2% of the K562 cells and less than 4% of the LAD EBV B cells expressing the CD11/CD18 heterodimer on the cell surface. The presence or absence of the neomycin resistance gene or the modified tRNA primer had no effect on CD18 gene transfer rate or expression level. The increase in transduction with PG13 vectors correlated with Northern blotting and reverse transcription-polymerase chain reaction studies that indicated that both K562 cells and the LAD EBV B cells express transcripts for the gibbon ape leukemia virus receptor at higher levels than for the amphotropic virus receptor. These findings indicate that the transduction efficiency of retroviral packaging cell lines correlates with receptor gene expression in the target cells and that vectors made using PG13 cells may be efficacious for gene therapy for LAD and other diseases in which gene transfer to hematopoietic cells is required.
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PMID:Improved transfer of the leukocyte integrin CD18 subunit into hematopoietic cell lines by using retroviral vectors having a gibbon ape leukemia virus envelope. 766 85

In this study we evaluated the phenotype of alveolar mononuclear phagocytes recovered from the bronchoalveolar lavage fluid of 24 patients with human immunodeficiency virus infection (AIDS-related complex 8 patients. AIDS 16 patients) and 8 healthy individuals by using a panel of monoclonal antibodies known to react with tissue macrophages, in combination with a flow cytometer. The results showed that 90% of patients with AIDS present a marked reduction in the expression of several antigenic determinants (in decreasing order: CD68, CD36, CR1, CD11c, HLA-DR). The levels of antigen expression by flow cytometry seem to decline with disease progression, showing the most dramatic perturbations in patients with full-blown AIDS associated with pulmonary infections (especially Pneumocystis carinii pneumonia) and lower peripheral CD4 lymphocyte counts. In contrast, patients with AIDS-related complex or AIDS without histological or cultural evidence of pulmonary involvement showed, respectively, only minimal or medium antigenic decreases. However, only a minor proportion (16%, 20%, 20%, 25%, and 25% respectively) of human immunodeficiency virus infected patients (mostly with AIDS) had a significant reduction of the levels of CD4, CD14, CD45R, CD11b, and CD16 antigens in the alveolar macrophages. Since macrophages play a central role in the pathogenesis of AIDS, it may be postulated that the loss of various phenotypic markers on alveolar mononuclear phagocytes (some of them known for their important immunoregulatory actions) could have an important part in the pathogenesis of human immunodeficiency virus induced immunosuppression, and thereby condition the abnormal susceptibility to pulmonary diseases typical of human immunodeficiency virus-infected patients.
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PMID:Reduced expression of macrophage-associated antigens on alveolar mononuclear phagocytes from acquired immunodeficiency syndrome. 769 Dec 71

Cellular differentiation is thought to play an important role in the susceptibility of monocytic lineage cells to human immunodeficiency virus (HIV) infection as well as in their ability to support virus replication. In addition, virus replication in monocytes/macrophages has been demonstrated in vitro to be strongly modulated by several cytokines such as tumor necrosis factor alpha and granulocyte-macrophage colony-stimulating factor. The purpose of the present study was to investigate the interaction between cellular differentiation and cytokines in the regulation of HIV expression from chronically infected monocytic lineage cells. U1, a persistently HIV-infected promonocytic cell line, is characterized by low levels of virus expression which can be modulated by several cytokines. 1 alpha,-25-Dihydroxyvitamin D3 (Vit.D3), a well-known differentiating agent for myelomonocytic cells which has been previously reported to modulate HIV replication in other in vitro systems, induced maturation of U1 cells toward a macrophage-like phenotype, as demonstrated by the induction of the differentiation-associated cell surface markers CD14 and CD11b. Vit.D3-induced differentiation did not result in induction of HIV expression; however, when U1 cells were stimulated with tumor necrosis factor alpha in the presence of Vit.D3, a synergistic induction of cell differentiation and viral expression was demonstrated. In contrast, Vit.D3 suppressed the induction of HIV expression in U1 cells stimulated with gamma interferon, interleukin-6, and granulocyte-macrophage colony-stimulating factor, although synergy between Vit.D3 and these cytokines was observed in terms of cellular differentiation. These data suggest that differentiation of monocytic cells does not necessarily correlate with increased HIV expression.
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PMID:Effect of cellular differentiation on cytokine-induced expression of human immunodeficiency virus in chronically infected promonocytic cells: dissociation of cellular differentiation and viral expression. 788 4

Cells of monocytic lineage (Mo) persistently infected with human immunodeficiency virus (HIV) have been suspected to be a major reservoir for in vivo transmission of virus to susceptible target cells. Cellular events and mechanisms that upregulate viral gene expression in such cells are important issues. Because the traffic of such cells is central to biodistribution of HIV, we have explored the impact of interaction of endothelium with HIV-1-infected U1 promonocytic cells. Coculturing of U1 with human umbilical endothelial cells (HUVEC) for 24 to 72 hours in the absence of stimulation induced HIV-1 p24 biosynthesis significantly. Antibody-blocking experiments indicated that CD11/CD18 integrins play a role in upregulation of HIV expression elicited by interaction with HUVEC. Engagement of CD11b/CD18 by adherence of U1 to surfaces coated with either the cognate ligand fibrinogen or monoclonal antibody specific for CD11b/CD18 also enhanced p24 biosynthesis. Furthermore, endothelial cells were found to constitutively synthesize and secrete soluble factors that enhanced HIV-1 synthesis. The enhancing factors, of estimated size 10 to 45 kD, were induced in HUVEC to high levels by monokines or by lipopolysaccharide, resulting in markedly enhanced HIV-1 expression by U1. These endothelial cell-derived HIV-1-enhancing factors consist of, among others, interleukin-6 (IL-6), IL-1 beta, and granulocyte-macrophage CSF (GM-CSF). Our results suggest that activation of HIV biosynthesis in infected Mo via interaction with endothelium may impact significantly on the tissue distribution and pathogenesis of HIV infections.
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PMID:Upregulation of human immunodeficiency virus-1 in chronically infected monocytic cell line by both contact with endothelial cells and cytokines. 791 48

We recently demonstrated that 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS) prevented the infection of T cells by human immunodeficiency virus type-1 (Cardin et al., J. Biol. Chem. 266, 13355, 1991). In the present study we have used a panel of monoclonal antibodies (mabs) against a variety of human leukocyte antigens to characterize the interaction of DIDS by flow cytometry with various T cell surface molecules. DIDS blocked the specific immunoreactivity of mabs OKT4A and Leu 3A with CD4 on human leukemic T cells (JM) and human mononuclear lymphocytes with an IC50 approximately 30 microM. The membrane distal (D1) and proximal (D3 and D4) domains of CD4 remained blocked for up to 5 hr of culture and returned to control levels of expression after 24 hr, reflecting the rate of membrane turnover of the CD4-DIDS complex. The binding frequencies (% positive) for anti-CD2, -CD3, -CD5, -CD6, -CD7, -CD8, -CD11a, -CD14, -CD18, -CD19, -CD45, -T cell receptor, and -HLA-DR were not significantly affected. However, there was a partial reduction in the antigen density of CD2, CD5, CD8, and CD11b. The selective interaction of DIDS with CD4 suggests that antagonism of the virus receptor may account in part for the antiviral properties of the stilbene disulfonate.
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PMID:Specific interaction of 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid with human cellular CD4. 795 38

Alveolar macrophages (AMs) harvested from 32 HIV-infected patients with respiratory problems (opportunistic pulmonary infections, n = 12; other lung disease, n = 20) and 13 healthy controls were stained with a panel of 15 monoclonal antibodies directed against surface antigens implicated in cell function. Antigen expression was quantified by flow cytometry and expressed as relative linear median fluorescence intensity (RLMFI). On AMs of patients, as compared with controls, there was a significant enhancement of HLA DP (12.1 +/- 1.5 vs 6.5 +/- 0.9, p = 0.01, M +/- SEM, RLMFI units), CD11b (3.4 +/- 0.5 vs 1.7 +/- 0.4, p = 0.014), CD11c (8.9 +/- 1.0 vs 4.8 +/- 0.8, p = 0.0046), CD14 (2.1 +/- 0.3 vs 1.0 +/- 0.2, p = 0.0009), and CD33 (1.7 +/- 0.1 vs 1.0 +/- 0.2, p = 0.0093). No significant differences could be established for HLA-DR (36.9 +/- 5.8 vs 30.9 +/- 7.5, NS), HLA-DQ (3.4 +/- 0.3 vs 3.1 +/- 0.6, NS), CD54 (1.9 +/- 0.3 vs 1.2 +/- 0.1, NS), CD13 (2.5 +/- 0.6 vs 1.5 +/- 0.3, NS), CD36 (1.4 +/- 0.2 vs 0.9 +/- 0.3, NS), CD71 (10.3 +/- 1.9 vs 8.9 +/- 1.8, NS), CD25 (0.8 +/- 0.0 vs 0.9 +/- 0.1, NS), 27E10 (1.1 +/- 0.1 vs 0.8 +/- 0.3, NS), RM3/1 (1.9 +/- 0.4 vs 1.5 +/- 0.4, NS), and CD4 (1.5 +/- 0.3 vs 1.0 +/- 0.0, NS). The expression of CD14 and CD11b, but not of HLA class II antigens and CD71, was increased in the smaller cell population compared with the larger, thus suggesting monocyte recruitment. The increased expression of HLA-DP, CD11c, CD14, and CD33 on the patients' AMs was independent of smoking habits. The degree of immunodeficiency as indicated by the absolute peripheral CD4 count, the character of HIV-related pulmonary disease, and the prophylactic use of pentamidine or zidovudine did not significantly modify the antigen expression pattern. It is concluded that HIV infection may lead, most probably indirectly, to enhanced expression of surface antigens by local upregulation and/or recruitment of monocytes from the peripheral circulation. The functional significance of enhanced marker expression requires further clarification.
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PMID:Expression of surface markers on alveolar macrophages from symptomatic patients with HIV infection as detected by flow cytometry. 818 14

Microglia, the resident tissue macrophages of the central nervous system, have a highly differentiated morphology and do not express many of the antigens typically associated with other tissue macrophages. Activation of microglia is associated with a change in morphology and an increase in their repertoire of antigen expression. Microglia become activated in many neuropathological conditions including chronic neurodegenerative diseases and human immunodeficiency virus neuropathology, yet little is known of the mechanisms involved. Here we demonstrate for the first time that microglia can be activated and induced to divide and/or undergo apoptosis via a beta 2-integrin (complement receptor type 3, CR3, Mac-1 or CD11b/CD18) using an anti-CR3 monoclonal antibody (McAb5C6). This antibody, which has been shown to block myelomonocytic recruitment during central nervous system inflammation, is unique in that it can cross the intact blood-brain barrier to activate microglia. Since CR3 not only binds the iC3b component of the alternative complement cascade but also denatured proteins this suggests a potential route for microglia activation in neuropathological conditions.
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PMID:Mitosis and apoptosis of microglia in vivo induced by an anti-CR3 antibody which crosses the blood-brain barrier. 825 20


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