Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q07644 (polypeptide)
 72,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Serologic testing for human immunodeficiency virus type 1 (HIV-1) is currently based on enzyme linked immunosorbent assay (ELISA) as screening method. Positive ELISA-results have to be confirmed by at least one second procedure such as Western blotting or immunofluorescence. To obtain new diagnostic reagents for confirmatory testing, we expressed viral antigens in procaryotic systems. Peptides representing epitopes of structural core (gag)- and envelope (env)-proteins of HIV were produced in E. coli as stable immunogenic beta-galactosidase fusion proteins. Recombinant proteins were taken for immunoblot-assays. The results of Western blotting with those fusion proteins were in general comparable with conventional ELISA, immunofluorescence, immunoblot with cell-culture derived virus and commercially available ELISA tests based on recombinant proteins. Immunoblots using recombinant transmembrane protein (gp41) derived polypeptide were more sensitive than the conventional procedure with purified virion proteins. Western blotting with recombinant fusionproteins provide reliable and inexpensive serodiagnostics without handling of infectious cell cultures.
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PMID:[Serologic AIDS diagnosis with polypeptides obtained by genetic technics of the human immunodeficiency virus (HIV-1)]. 332 45

Electron microscopy of human immunodeficiency virus (HIV) has provided evidence for a virion model which when sectioned, consists of a circular envelope surrounding an inner conical core. When sections are perpendicular to the core axis, the envelope is still circular, but the tapered core appears as a dot near the center of the envelope. An observation inconsistent with the present model is the frequent finding of an electron-lucent "polygonal window" associated with the virion envelope. Here, we provide evidence for a new model of HIV. This model, which accounts for the polygonal windows and the shape of the envelope, places the conical core inside a regular polyhedron that lies just under the envelope. We tested the validity of various polyhedrons with three-dimensional computer graphics which emulate thin section electron microscopy. With this technique, about 2000 computer-generated "thin sections" of HIV-models were compared with electron micrographs of HIV. A structure consistent with the computer-generated data reveals a detailed model for HIV with the following features; (a) the conical core is inside an envelope-associated capsid having icosadeltahedral symmetry. This envelope-associated capsid is 60-sided and contains 32 vertices, 20 of which have hexagonal symmetry and 12 of which have pentagonal symmetry, (b) the inner rodlike core abuts the inside of any 2 opposing hexagonal vertices, (c) the pentagonal vertices do not support the inner core. A comparison of these results with that of Gelderblom et al. (Gelderblom HR, Hausmann EHS, Ozel M, Pauli G, Koch MA: Fine structure of HIV and immunolocalization of structural proteins. Virology 156: 171, 1987), suggests that the p17 polypeptide is a component of the envelope-associated icosadeltahedral capsid. This computer emulation technique provides a thorough test of this model of HIV, but does not constitute proof. Additional testing methods such as bidirectional metal shadowing and freeze etching will be needed to confirm this new virion structure. Additionally, this computer technique may be useful for testing the proposed morphology for cell organelles.
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PMID:Computer emulation of thin section electron microscopy predicts an envelope-associated icosadeltahedral capsid for human immunodeficiency virus. 333 3

A rat spleen cDNA library was screened for clones carrying the cDNAs for prothymosin alpha and parathymosin. Sequence analysis of a clone carrying the entire coding region for prothymosin alpha confirmed and completed the amino acid sequence for this polypeptide and established the number of amino acid residues as 111. Rat prothymosin alpha differs from human prothymosin alpha at six positions, including four substitutions and two insertions. The nucleotide sequences of the cDNAs for the rat and human polypeptides are more than 90% identical in the open reading frames, with significant homology extending into the 5' and 3' flanking regions. From the same library, we also isolated a clone carrying 80% of the coding region for rat parathymosin. The number of amino acid residues in rat parathymosin is 101, based on the sequence deduced from the cDNA insert and earlier information on the sequence in the amino-terminal portion of this polypeptide. Despite their similarity in size and amino acid composition, rat prothymosin alpha and rat parathymosin show only limited sequence homology, primarily in the segment including residues 14 through 25, where 10 of 12 positions are identical in the two polypeptides. this is also the region of significant sequence similarity to a 12-amino-acid segment in the p17 protein of the human immunodeficiency disease associated virus (HTLV-IIIB).
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PMID:Prothymosin alpha and parathymosin: amino acid sequences deduced from the cloned rat spleen cDNAs. 337 5

In a program screening civilian applicants for U.S. military service for human immunodeficiency virus (HIV) infection, we studied the frequency of false positive diagnoses retrospectively among applicants seropositive for HIV in a subpopulation with a very low prevalence of infection. That subpopulation was defined as consisting of all applicants tested between October 16, 1985, and June 30, 1987, who were young (17 or 18 years of age) and resided in a rural county in a state with a low incidence of reported acquired immunodeficiency syndrome (n = 135,187). Serum specimens from 15 applicants positive for HIV in this low-prevalence subpopulation were retrieved from a serum bank and retested by two Western blot methods, radioimmunoprecipitation, and an immunoassay constructed from a molecularly cloned and expressed viral envelope polypeptide. Fourteen of the 15 samples were unequivocally positive on all retest assays, and 1 was negative. Thus, the measured rate of false positive diagnoses in this program was 1 in 135,187 persons tested. Factors important in achieving a low false positive rate were redundant, multistep testing algorithm, conservative criteria for interpreting Western blots, the requirement that a second, newly drawn serum specimen be tested for verification before a diagnosis of HIV was considered established, and tight quality control of laboratory testing procedures. We conclude that a screening program for HIV infection in a low-prevalence population can have an acceptably low false positive rate.
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PMID:Measurement of the false positive rate in a screening program for human immunodeficiency virus infections. 341 77

T-cell lymphocyte subpopulations were successfully converted by means of thymus polypeptide factor in a 17-year-old boy with chronic mucocutaneous candidiasis and combined immunodeficiency. It was demonstrated that the injections caused normalization of the peripheral T-lymphocytes subpopulations and a better state of general health. Normalization was due to a minimal increase in total peripheral T-lymphocytes and T-helper cells and a significant decrease in T-suppressor cells.
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PMID:[Clinical and immunologic studies of the use of thymus polypeptide factor (thymostimulin) in chronic mucocutaneous candidiasis]. 348 76

A 240-bp DNA fragment encoding a peptide, designated ENV(80), homologous to a conserved part of the gp41 transmembrane glycoprotein of human immunodeficiency virus (HIV) was chemically synthesized and inserted into different plasmid expression vectors. Escherichia coli transformants containing these plasmid constructs produced upon induction high amounts of either an ENV(80) peptide of relative molecular mass (Mr) of 10,000 or the same ENV(80) peptide N-terminally fused to E. coli chloramphenicol acetyltransferase (CAT) or to mouse dihydrofolate reductase (DHFR) having Mr of 36,000 and 31,000 respectively. All polypeptides containing the ENV(80) sequences were strongly reactive with antibodies present in sera from AIDS virus-infected individuals, but not with control sera. The strategy of gene assembly allowed the expression of ENV(80) subfragments fused to DHFR. The serodiagnosis of 15 positive sera by Western blot analysis using these bacterially synthesized ENV(80) subfragments revealed the presence of several immunoreactive epitopes on the 80-amino acid polypeptide which were recognized differently by the various patients.
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PMID:Subregions of a conserved part of the HIV gp41 transmembrane protein are differentially recognized by antibodies of infected individuals. 349 55

Screening tests for antibodies to the human immunodeficiency virus (HIV), based on the indirect ELISA principle using viral preparations as antigen, yield a substantial number of false-positive and false-negative results. These failures are due to the lack of certain viral polypeptides or contaminating cellular polypeptides in viral preparations. Therefore, the accuracy of the screening tests should be improved by using highly purified, synthetic viral antigens. With establishment of such an ELISA antigen in mind, we examined a bacterially synthesized polypeptide [ENV(80)] that corresponds to 80 conserved amino acids of the HIV gp41 transmembrane glycoprotein. ENV(80) was expressed as a DHFR fusion protein in Escherichia coli. Results obtained by HIV ELISA and immunoprecipitation with 497 serum samples from various groups at risk of AIDS were compared with those obtained with the ENV(80) ELISA. The ENV(80) ELISA was found to be superior to the H9/HTLV-III ELISA with respect to sensitivity and specificity and is almost equivalent in accuracy to immunoprecipitation.
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PMID:A new ELISA test for HIV antibodies using a bacterially produced viral env gene product. 354 57

To detect human immunodeficiency virus (HIV) antibodies in a simple enzyme-linked immunoassay (CBre3-EIA), we used an Escherichia coli-expressed polypeptide antigen, representing the carboxy-terminal third of the external membrane glycoprotein gene fused with the amino-terminal half of the transmembrane glycoprotein gene. Over a 3-month period, 2707 consecutive serum samples referred for confirmatory testing for human T-lymphotrophic virus type III (HTLV-III) antibodies were evaluated by both Western blot and CBre3-EIA. On a single determination for each sample, the CBre3-EIA was found to have an estimated sensitivity (99.9%) and specificity (99.1%) similar or superior to the more cumbersome Western blot method. This study shows that all HIV-seropositive subjects have antibodies to the virus envelope protein; no other virus antigens are required for construction of highly sensitive immunoassays.
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PMID:Diagnosis of human immunodeficiency virus infection by immunoassay using a molecularly cloned and expressed virus envelope polypeptide. Comparison to Western blot on 2707 consecutive serum samples. 355 11

The capacity to neutralize the human immunodeficiency virus (HIV) in vitro was examined in 52 sera obtained from 23 seropositive individuals in addition to 7 negative control sera. Neutralization was measured as the activity of a serum to protect MT-4 cells against the cytopathic effect of HTLV-IIIB. Virus neutralization depended on HIV antibodies. Some sera had HIV neutralizing antibody titers of several thousands. All serum samples had been titrated in two ELISAs based either on disrupted HTLV-IIIB or on a bacterially synthesized polypeptide (ENV-80) of gp41 as a test antigen. The correlation of neutralizing activity of the sera with ELISA titers was low. A correlation of serum neutralizing titers with the stage of the disease could not be observed. However, in a longitudinal study with 6 patients over up to 22 months an increase in neutralizing antibodies seemed to protect against progression of the disease. The implications of these findings for antibody treatment and vaccine development are discussed.
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PMID:Neutralizing antibodies and the course of HIV-induced disease. 365 Jan

A five-amino-acid (TDNYT) sequence of vasoactive intestinal polypeptide (VIP) shares homology with the proposed attachment sequences of the human immunodeficiency virus (HIV). Synthetic peptides with these sequences have previously been shown to block viral envelope (gp120) binding and HIV infectivity and to serve as agonists of the CD4 (or T4) receptor. Utilizing an in vitro human monocyte chemotaxis bioassay we examined novel synthetic VIP and gp120 sequences and characterized their pharmacological activities on monocyte chemotaxis. CD4 receptor activity is primarily specified by N-terminal (VIP [1-12]) amino acids. The profound immunosuppression of AIDS is not easily explained solely by virus infection. Recently described immunological functions of VIP are similar to some of the immunological abnormalities shown by patients with AIDS. An overproduction of a VIP-like molecule from viral sources (e.g. gp120) could explain some of the immune system impairments which have been described in AIDS.
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PMID:Vasoactive intestinal peptide 1-12: a ligand for the CD4 (T4)/human immunodeficiency virus receptor. 368 24


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