Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0272170 (SDS)
 50,377 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Feline immunodeficiency virus (FIV) infection induces syncytium formation and cell death in primary feline astrocyte cultures but persistently and noncytopathically infects Crandell feline kidney cells (CrFK). Because viral envelope glycoproteins are implicated in cell fusion events we evaluated the astrocyte-produced FIV surface glycoprotein for properties that might distinguish it from that produced in CrFK cells. The surface glycoprotein from astrocytes migrated faster on SDS-PAGE and contained more Endo H-sensitive oligosaccharides than that from CrFK, although the precursor and deglycosylated envelope glycoproteins from both cells were the same size. Castanospermine treatment of infected astrocytes, which blocks glucose trimming from oligosaccharide side chains of glycoproteins, both obliterated the mobility difference between astrocyte- and CrFK-produced FIV surface glycoproteins and prevented syncytium in infected astrocyte cultures. These results demonstrate the importance of the infected cell type in viral envelope protein glycosylation and implicate cell type-specific carbohydrate structures on retroviral glycoproteins as mediators of cell fusion.
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PMID:Cell-specific envelope glycosylation distinguishes FIV glycoproteins produced in cytopathically and noncytopathically infected cells. 131 53

We analyzed platelet-associated antigens from a hemophilia B patient with human immunodeficiency virus type 1 (HIV-1)-related thrombocytopenia. Two bands appeared at 31,000 and 37,000 daltons in the platelet lysate after reaction with autologous serum in SDS-PAGE and Western blots. The band at 37,000 daltons was obtained using anti-herpes simplex type 1 (HSV-1) rabbit antiserum. Doublet bands at 36,000 and 37,000 daltons also appeared after reaction with HSV-1 seropositive human serum. The band at 31,000 daltons appeared after reaction with anti-HIV-1 rabbit serum. These results suggest that the platelet-associated antigens in this patient are components of both HSV-1 and HIV-1 antigens. In addition, acyclovir decreased his PAIgG level and increased his platelet count, and zidovudine increased his platelet count. Thus, we concluded that each of the platelet-associated antigens is partially responsible for the thrombocytopenia by causing deposition of immune complexes in this patient.
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PMID:Herpes simplex virus type 1 and human immunodeficiency virus type 1 antigens in platelets from a hemophilia B patient with human immunodeficiency virus type 1-related thrombocytopenia. 132 48

A method is described for the separation and purification of proteins from complex mixtures of foreign antigens in a form suitable for stimulating T cells in vitro. The technique involves electrophoretic separation of proteins followed by elution, concentration and adsorption of the polypeptide subunits to latex microspheres. Alternatively, where a specific antibody is available, proteins may be affinity-purified from a heterogeneous mixture of antigens, using antibody-coated latex microspheres. Nanogram quantities of protein coupled to latex were shown to be highly efficient stimulators of antigen-specific T cells as tested by in vitro proliferation and cytokine release assays. The utility of this technique was demonstrated using poliovirus capsid proteins separated by SDS-polyacrylamide gel electrophoresis (PAGE) and coupled to latex microspheres for specificity analysis of T cell clones. Antigen reactivity of the T cell clones was confirmed using recombinant baculoviruses expressing individual poliovirus proteins. Furthermore, recombinant proteins coupled to latex microspheres were used for efficient stimulation and in vitro propagation of T cell clones specific for the simian immunodeficiency virus (SIV) envelope (env) protein. Although the technique is illustrated in this report using viral antigens, it has also proved to be an efficient method for the separation of bacterial antigens in studies of polyclonal T cell responses to Bordetella pertussis antigens.
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PMID:Preparative separation of foreign antigens for highly efficient presentation to T cells in vitro. 133 64

Isotype and binding characteristics of T cell-reactive antilymphocyte antibodies (ALA) were investigated in 287 human immunodeficiency virus (HIV)+ sera from patients with CDC II to IVC clinical disease. Using purified soluble T-lymphoblast (CEM cell line) membranes and an ELISA method, 29 HIV+ sera showed significant reactions with this substrate and a selective expression of IgG-ALA was detected in 7 HIV+ sera. Subsequent microcytotoxicity assays, utilizing peripheral T lymphocytes and CEM cells as targets, demonstrated no significant cytotoxic capability in such sera, whereas 12 of 17 HIV+ serum samples with IgM-ALA ELISA reactivities showed a significant degree of killing in the Terasaki test. Further experiments of saturation of CD4 molecules on CEM extract by OKT4 monoclonal antibody (MoAb) induced a high inhibition of IgG-ALA binding to the T-cell membranes in only two IgG-ALA+ sera (No. 93, CDC III; No. 179, CDC II stage). Conversely, treatment of CEM membrane lysate with Leu3a MoAb, specific for the gp120 reactive domain of the HIV receptor, failed to prevent membrane binding in all seven of the IgG-ALA+ sera. Following the adsorption of serum 93 on a T-cell membrane antigen affinity column, SDS-PAGE analysis demonstrated that the predominant ALA material reacting with T-cell membranes was IgG with no detectable traces of IgM. These data provide evidence that ALA in HIV+ patients may be simultaneously or selectively expressed as IgG and/or IgM with different properties.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Differential isotype expression and binding properties of T cell-reactive antibodies in human immunodeficiency virus (HIV) infection. 137 49

The lymphocyte activation gene 3 (LAG-3), expressed in human activated T and natural killer (NK) cells, is closely related to CD4 at the gene and protein levels. We report here the initial characterization of the LAG-3-encoded protein. We have generated two monoclonal antibodies after immunization of mice with a 30-amino acid peptide that corresponds to an exposed extra loop region present in the LAG-3 immunoglobulin-like first domain. The reactivity of these reagents is directed against LAG-3 since they recognize both membrane-expressed and soluble recombinant LAG-3 molecules produced in a baculovirus expression system. The two antibodies are likely to react with the same or closely related epitope (termed LAG-3.1) exposed on the LAG-3 first domain extra loop, as assessed in competition experiments on LAG-3-expressing activated lymphocytes. Cellular distribution analysis indicated that the LAG-3.1 epitope is expressed on activated T (both CD4+ and CD8+ subsets) and NK cells, and not on activated B cells or monocytes. In immunoprecipitation experiments performed on activated T and NK cell lysates, a 70-kD protein was detected after SDS-PAGE analysis. 45-kD protein species were also immunoprecipitated. Both the 70- and 45-kD proteins were shown to be N-glycosylated. In Western blot analysis, only the former molecule was recognized by the anti-LAG-3 antibodies, demonstrating that it is LAG-3 encoded. These anti-LAG-3 antibodies were used to investigate whether the LAG-3 protein interacts with the CD4 ligands. By using a high-level expression cellular system based on COS-7 cell transfection with recombinant CDM8 vectors and a quantitative cellular adhesion assay, we demonstrate that rosette formation between LAG-3-transfected COS-7 cells and human leukocyte antigen (HLA) class II-bearing B lymphocytes is specifically dependent on LAG-3/HLA class II interaction. In contrast to CD4, LAG-3 does not bind the human immunodeficiency virus gp120. This initial characterization will guide further studies on the functions of this molecule, which may play an important role in immune responses mediated by T and NK lymphocytes.
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PMID:Characterization of the lymphocyte activation gene 3-encoded protein. A new ligand for human leukocyte antigen class II antigens. 138 59

We studied the expression of gamma delta T cell receptors (TCR) on T-cell lines and clones derived from peripheral blood lymphocytes (PBL) from certain patients with primary immunodeficiency disorders and normal donors. Immunoprecipitation with the anti-Leu 4, anti-gamma-chain and/or anti-delta-chain monoclonal antibodies followed by SDS-PAGE analysis revealed that 7 of 13 (54%) T-cell lines and clones developed from PBL of patients with primary immunodeficiency disorders expressed non-disulfide-linked gamma delta TCR, utilizing either the C gamma 2abc or the C gamma 2bc gamma-chain constant region gene segment. 5 of 13 (38%) T-cell lines/clones expressed disulfide-linked gamma delta TCR, whereas an additional T-cell line was comprised of T cells expressing either disulfide-linked (C gamma 1) or non-disulfide-linked (C gamma 2bc) gamma delta TCR. T-cell lines and clones developed from four of light patients with primary immunodeficiency disorders exhibited exclusively non-disulfide-linked gamma delta TCR utilizing either the C gamma 2abc or the C gamma 2bc gamma-chain segment. T-cell lines derived from a fifth patient exhibited primarily non-disulfide-linked gamma delta TCR, bringing to five of eight the numbers of patients that expressed exclusively or primarily non-disulfide-linked gamma delta TCR. T-cell lines/clones derived from the remaining three patients exhibited exclusively disulfide-linked gamma delta TCR. The age of these patients varied over a wide range and there was not an association between their age and the type of gamma delta TCR expressed on T-cell lines derived from their PBL. In contrast, to these findings 14 of 16 (87.5%) T-cell clones derived from PBL of normal donors expressed disulfide-linked gamma delta TCR, whereas only 2 of 16 (12.5% expressed non-disulfide linked gamma delta TCR. Among the T-cell clones from normal donors which express disulfide-linked gamma delta TCR two different types were identified. Those exhibiting under reducing conditions on SDS-PAGE two completely resolved polypeptide chains in the range of 37 kD to 44 kD, and those exhibiting under the same conditions indistinguishable overlapping gamma- and delta- chains in the range of 40-42 kD. Several T-cell lines and clones from normal donors or patients with primary immunodeficiency that expressed either disulfide- or non-disulfide-linked gamma delta TCR were delta TCS1+, demonstrating that the delta TCS1 determinant is expressed on both types of gamma delta TCR.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Disulfide-linked and non-disulfide-linked gamma/delta T-cell antigen receptors: differential expression on T-cell lines and clones derived from normal donors and patients with primary immunodeficiency disorders. 138 68

Ubiquitinated proteins are degraded by a 26 S ATP-dependent protease. SDS-polyacrylamide gel electrophoresis analysis of the purified 26 S enzyme reveals more than 20 polypeptides ranging in apparent molecular masses from 20 to 110 kDa. Although many of the subunits smaller than 30 kDa are members of the multicatalytic protease family, the identity and function of the larger polypeptides have remained unknown. We report here the cDNA sequence for subunit 4, a 51-kDa chain of the 26 S protease. Subunit 4 belongs to a recently identified eukaryotic ATPase family, which includes proteins involved in peroxisome formation, secretion, and human immunodeficiency virus gene expression. Subunit 4 also shows weak similarity to ClpA, the ATP-binding subunit of the Escherichia coli protease, Clp.
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PMID:Subunit 4 of the 26 S protease is a member of a novel eukaryotic ATPase family. 142 20

Soluble forms of a human cell-surface molecule expressed on T lymphocytes (CD4) neutralize diverse strains of both human (HIV) and simian (SIV) immunodeficiency viruses through the induction of envelope shedding and direct competition with cellular CD4 for virus binding. However, we have previously shown that sCD4 enhances infection of simian immunodeficiency viruses from African green monkeys (SIVagm) and have theorized that this enhancement is due to the induction of conformational changes leading to viral fusion (receptor-mediated activation). In this report, we compared the relative association of the envelope glycoproteins of SIVagm with HIV type 1 (HIV-1) in order to determine if a more stable association of SIVagm envelope glycoproteins might account for the differential effects of sCD4 on the infectious process. Monospecific antisera to each of the SIVagm glycoproteins were generated and used to detect stable heterodimers by radioimmunoprecipitation. Standard solubilization buffers containing both ionic and nonionic detergents or saturating concentrations of sCD4 failed to disrupt SIVagm gp120 interactions with the transmembrane protein, gp36, whereas HIV-1 heterodimers were easily dissociated. Higher concentrations of SDS (1%) were necessary to disrupt the SIVagm envelope complexes demonstrating the existence of strong noncovalent interactions between these membrane glycoproteins. In addition, morphometric analysis by electron microscopy revealed that the linear density of SIVagm spikes was stable and resisted shedding when virus was incubated with sCD4 whereas a significant decrease in linear spike density was noted for HIV-1. Based on our original hypothesis, the strong association of SIVagm glycoprotein spikes during soluble receptor binding may allow for highly stable conformational intermediates important for viral fusion, while neutralization of HIV-1 by sCD4 results from less stable envelope associations.
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PMID:Strong association of simian immunodeficiency virus (SIVagm) envelope glycoprotein heterodimers: possible role in receptor-mediated activation. 149 51

Vpu as a human-immunodeficiency-virus-type-1-encoded 81-amino-acid integral-membrane protein was expressed in Escherichia coli using the inducible ptrc promoter of an ATG fusion vector. Recombinant Vpu is associated with membranes of E. coli and could be partially solubilized by detergents. Recombinant Vpu was phosphorylated in vitro with purified porcine casein kinase II (CKII) as well as with a CKII-related protein kinase found in cytoplasmic extracts of human and hamster cells. Recombinant Vpu associated with E. coli membranes has turned out to be the best substrate for in vitro phosphorylation with CKII. This reaction can be inhibited by heparin and the ATP analogue 5,6-dichloro-1-(beta-D-ribofuranosyl)benzimidazole (DRB), both known to be potent inhibitors of CKII. Radiolabelled gamma ATP and gamma GTP were used as phosphate donors in vitro phosphorylation of recombinant Vpu. In vivo phosphorylation of Vpu in HIV-1-infected H9 cells was also inhibited by DRB. We concluded therefrom that the Vpu protein is phosphorylated by the ubiquitous CKII in HIV-1-infected human host cells. Two seryl residues in the sequence of Vpu (position 52 and 56) correspond to the consensus S/TXXD/E for CKII. These potential phosphorylation sites are located within a well-conserved dodecapeptide of Vpu (residues 47-58), which is found in different HIV-1 strains as well as in a Vpu-like protein of SIVCPZ. Monoclonal and polyclonal antibodies directed against two different epitopes of Vpu were used for immunoprecipitation of Vpu from HIV-1-infected cells and for detection of Vpu in Western blot analyses. Vpu from HIV-1-infected cells as well as recombinant Vpu expressed in E. coli were determined by SDS/PAGE using 6 M urea to be 9 kDa, which corresponds to the calculated molecular mass of Vpu.
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PMID:Human-immunodeficiency-virus-type-1-encoded Vpu protein is phosphorylated by casein kinase II. 154 Dec 98

Large amounts of histones, H1, H2A, H2B, H3, and H4, were observed in total extracts of T4 lymphocytes and derived cell lines infected with the human immunodeficiency virus (HIV) type 1 or type 2. These histones were simply detectable by analysis of crude cellular extracts by polyacrylamide gel electrophoresis in SDS and staining the proteins with Coomassie blue or by immunoblot assays using specific polyclonal antibodies. The histones were found to be localized in the nucleoplasm, bound to low molecular weight (LMW) DNA in the form of nucleosomes. The mechanism responsible for the accumulation of nucleosomes during HIV infection was found to be due to fragmentation of cellular DNA, a mechanism referred to as apoptosis or programmed cell death in which a nuclear endonuclease becomes activated and cleaves DNA at internucleosomal regions. Accordingly, the LMW DNA accumulated in the course of infection was found to have a characteristic pattern of nucleosomal ladder and its accumulation was reduced in the presence of zinc, a known inhibitor of the endonuclease. Routinely in acute HIV infections, the accumulation of nucleosomes was observed at least 24 hr before lysis of infected cells. In a particular HIV-1 infection, in which the first signals of the cytopathic effect (vacuolization of cells and appearance of syncytia) was observed at Days 6-7 whereas maximal virus production occurred at Days 10-17, the accumulation of nucleosomes was at its maximal level already on Day 6 postinfection. In the nucleoplasm of chronically infected cells producing virus but not manifesting a cytopathic effect, no LMW DNA or histones were detectable. These observations indicate that the cytopathic effect of HIV infection is associated with apoptosis. The detection of histones and oligonucleosomal DNA fragments in the nucleoplasm can be used as a convenient marker for chromatin fragmentation during this process.
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PMID:The cytopathic effect of HIV is associated with apoptosis. 168 28


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