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)

A new, modular Western blot (immunoblot) system for human immunodeficiency virus (HIV) antibodies (ABN WesPage; Wellcome) was compared with enzyme immunoassays (Wellcome, Behringwerke, and Abbott) and with a U.S. Food and Drug Administration (FDA)-licensed Western blot (DuPont) in a multicenter study. A total of 649 serum samples from HIV patients at different stages of the disease, as well as from high-risk patients, from patients with conditions unrelated to AIDS, and from healthy blood donors, were used in the evaluation along with nine seroconversion panels. For evaluation of Western blot reactivity, both Centers for Disease Control (CDC) and FDA criteria were used. With the DuPont Western blot as the reference assay, the overall sensitivity and specificity of the ABN WesPage were 100 and 99.1%, respectively, when indeterminate results were not taken into account and when both tests were interpreted in accordance with CDC criteria. The DuPont Western blot detected significantly more antibodies to pol and gag gene products than the ABN WesPage. The ABN WesPage showed a higher positive rate of detection of viral envelope band gp160. When both Western blots were interpreted in accordance with CDC criteria, the ABN WesPage and the DuPont Western blot yielded 9.3 and 10.4% indeterminate results, respectively. When the DuPont Western blot was interpreted in accordance with the manufacturer's instructions (FDA criteria), 25.7% of the samples tested were regarded as indeterminate. The choice of interpretation criteria is of paramount importance for the evaluation of HIV Western blot patterns.
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PMID:Multicenter evaluation of the novel ABN Western blot (immunoblot) system in comparison with an enzyme-linked immunosorbent assay and a different Western blot. 155 87

Concordance between two primer pairs and the clinical sensitivity of a single primer pair-probe system were evaluated for a human immunodeficiency virus type 1 (HIV-1) polymerase chain reaction (PCR) assay. Six-hundred sixty-three clinically defined HIV-1 specimens were analyzed in a blind fashion for HIV-1 DNA using an optimized, well-characterized PCR assay. All samples were amplified in duplicate with each of two primer pairs targeting distinct, highly conserved regions within the HIV-1 gag genome. Amplified product was detected by oligomer hybridization using 32P-labeled probes. Correlation between PCR, culture, and serology data was achieved in 661 of 663 (99.7%) specimens. After initial analysis, discordant PCR results due to discrepancies between primer pairs were observed in 9 of 663 (1.4%) specimens. All nine specimens were resolved as negative on reevaluation. After retesting of discordant PCR results, concordance between the two primer pairs was achieved in 100% of samples. These data indicate that the two primer pair systems performed comparably and that good clinical sensitivity (100%) would be achieved using a single primer-probe system. Factors and procedures that influence the reproducibility and accuracy of this HIV-1 PCR assay are discussed.
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PMID:Detection of HIV-1 DNA by PCR: evaluation of primer pair concordance and sensitivity of a single primer pair. 156 Mar 39

Tat-dependent expression of an endogenous lethal or deleterious foreign gene might be useful for abrogating the production of human immunodeficiency virus (HIV) from cells. This type of HIV-induced cellular killing, as well as other approaches to gene therapy for HIV infection, would be facilitated by simple HIV vectors that express introduced genes in a Tat-inducible manner. As part of studies to examine the feasibility of this concept, we constructed HIV-1 vectors that express the hygromycin B phosphotransferase gene (Hygr) in a Tat-dependent manner. Comparison of the efficiency of propagation of each vector indicates that sequences extending into the gag open reading frame are necessary in cis for efficient vector propagation. Southern blot analysis of genomic DNA isolated from vector-infected cells demonstrated that the vectors were capable of being propagated as expected without gross rearrangements or deletions. A fragment of the influenza A virus hemagglutinin (H5 HA) gene, capable of eliciting antibody and cytotoxic T-cell responses, was used as a marker for further characterization of the vector system. A Tat-dependent vector conferring the H5 HA+ phenotype was assayed by indirect immunofluorescence, and cells which contained but did not express the H5 HA gene were isolated. The activation of H5 HA expression following HIV infection of Tat- cells that stably contained but did not express the H5 HA construct was determined to be an efficient process.
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PMID:Human immunodeficiency virus vectors for inducible expression of foreign genes. 156 May 23

The level of synthesis and extracellular release of human immunodeficiency virus type 1 Gag by insect cells was analyzed, using eight different recombinants of Autographa californica nuclear polyhedrosis virus harboring various constructs of the gag gene, cloned under the polyhedrin promoter. The results obtained suggested that gag expression was mainly regulated at the transcriptional level and was not significantly influenced by posttranslational events, e.g., Gag self-assembly, nuclear transport, or extracellular release. Two different forms of Gag were found in the culture medium of recombinant-infected cells. One form consisted of membrane-enveloped, corelike particles released by budding at the plasma membrane; the other of nonparticulate, soluble Gag polyprotein molecules. Both forms coexisted in recombinants expressing Gag with an intact N-terminal myristylation signal, whereas recombinants expressing nonmyristylated Gag released solely the soluble form. This suggested that myristylation of the N terminus was not a prerequisite for efficient extracellular release of Gag by insect cells, which could proceed via two independent but simultaneous mechanisms.
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PMID:Expression and extracellular release of human immunodeficiency virus type 1 Gag precursors by recombinant baculovirus-infected cells. 156 May 45

We have developed a method for attenuating vaccinia virus recombinants by expressing a fusion protein of a lymphokine and an immunogen. Chimeric genes were constructed that coded for gamma interferon (IFN-gamma) and structural proteins of the human immunodeficiency virus type 1 (HIV-1). In this study, we describe the biological and immunological properties of vaccinia virus recombinants expressing chimeric genes of murine or human IFN-gamma with glycoprotein gp120, gag, and a fragment of gp41. All fusion proteins retained the antigenic characteristics of both IFN-gamma and HIV as shown by immunoblot analysis. However, the antiviral activity of IFN-gamma could be demonstrated only for the IFN-gamma-gag fusion protein. In contrast, the attenuating activity of IFN-gamma for nude mice was retained by all of the recombinants, albeit at various rates. Unlike the antiviral activity, the attenuating activity of IFN-gamma was not species specific. Implications for the development of attenuated live recombinant vaccines for AIDS are discussed.
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PMID:Vaccinia virus recombinants expressing chimeric proteins of human immunodeficiency virus and gamma interferon are attenuated for nude mice. 156 33

Antigenic peptides bound to class I molecules of the major histocompatibility complex (MHC) are recognized by T-cell receptors during development of an antiviral immune response. T cells respond to peptides derived from cytoplasmic viral proteins as well as viral membrane proteins, indicating that a pathway exists for the transport of proteins or peptides from the cytosol into the compartment(s) where the MHC class I molecules assemble. To investigate this pathway, we have developed an in vitro assay for the transport of peptides into microsomal vesicles. This assay provides evidence for the transport of chemically synthesized peptides (13-21 amino acids) containing N-linked glycosylation acceptor sequences, which serve as glycosylation substrates. Their transport results in depletion of the pool of available dolichol high-mannose oligosaccharides in the lumen of the microsomal vesicles. We have observed transport of peptides derived from antigenic human immunodeficiency virus gag and influenza B nucleoprotein sequences, but transport of a third randomly selected peptide was not detected, suggesting specificity of the transport process. We were not able to demonstrate ATP dependence of this peptide transport process by using apyrase and an ATPase inhibitor. This result was unexpected in light of the recent identification of MHC-linked genes with homology to ATP-binding cassette transporters, which have been proposed to mediate peptide transport.
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PMID:Evidence for peptide transport across microsomal membranes. 157 Mar 12

Clinical measures of human immunodeficiency virus (HIV) type 1 activity in vivo are limited and hinder the assessment of antiretroviral therapies. Reported here is a method for quantitating HIV-1 RNA in human plasma using the polymerase chain reaction (PCR). This method uses an internal cRNA standard generated from a cloned 113-bp deletion mutation of a highly conserved HIV-1 gag region sequence. The mutant cRNA (K4) was shown to amplify with efficiency equivalent to that of wild-type HIV-1. Known quantities of K4 cRNA added to wild-type HIV-1 in a competitive PCR strategy using a radiolabeled primer permitted quantitation of wild-type HIV-1 RNA over four orders of magnitude (10(3)-10(6) RNA copies). RNA isolated from plasma from AIDS patients yielded 10(3) to 8 x 10(4) HIV-1 RNA copies/ml of plasma with an average intrasample coefficient of variation of .26. This method offers a sensitive assay with a broad dynamic range for monitoring HIV-1 activity in the plasma of AIDS patients. It may provide a useful tool for assessing the effects of antiretroviral therapy.
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PMID:Quantitation of plasma human immunodeficiency virus type 1 RNA by competitive polymerase chain reaction. 158 31

The entire and partial gag regions of human immunodeficiency virus type 1 (HIV-1) were overproduced in Escherichia coli and used for epitope mapping of antibodies against p17. We found that a mouse monoclonal antibody to p17, V17 recognizes the mature p17 but not the unprocessed Gag proteins containing the entire p17 moiety. Further analysis revealed that V17 recognizes the C-terminal 12-amino-acid region of p17 having free C-terminus. This monoclonal antibody may be useful for monitoring the maturation of virus particles.
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PMID:A unique monoclonal antibody that recognizes mature p17 of HIV-1 but not its precursor. 158 67

Cells infected with a recombinant vaccinia virus carrying the gag and pol regions of the human immunodeficiency virus type 1 genome (Vac-gag/pol) released human immunodeficiency virus (HIV)-like particles containing HIV-specific RNA. However, cells infected with another recombinant vaccinia, Vac-gag/pol-dP, derived through the deletion of an 85-base region (nucleotide positions 679-763) of the HIV genome between the primer binding site and the gag initiation codon of Vac-gag/pol, produced HIV-like particles devoid of the HIV-specific RNA. This 85-base deletion was suggested to cause the collapse of a stable stem-loop structure of 46 bases (751-796) around the gag initiation codon. To examine the role of the stem-loop structure in the packaging of RNAs, we constructed a vaccinia vector plasmid that carried this 46-base sequence followed by the Sendai virus nucleocapsid (NP) gene. When both Vac-gag/pol-dP and this plasmid were introduced into cells, HIV-like particles released from the cells contained the NP gene RNA. However, another vaccinia vector plasmid, which carried the 46-base sequence in the midst of the NP gene, could not supply RNA for incorporation into HIV-like particles. Computer analysis of this plasmid sequence suggested that the 46-base sequence cannot form the stem-loop structure. These findings suggest that the stem-loop structure formed by the 46-base sequence is crucial as a packaging signal.
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PMID:RNA packaging signal of human immunodeficiency virus type 1. 158 35

The protease from simian immunodeficiency virus (SIV) was chemically synthesized by automated solid-phase technology as an NH2-terminally extended derivative, capped with biotin. Biotin-linker-(SIV protease (1-99)): the linker segment, Gly-Gly-Asp-Arg-Gly-Phe-Ala-Ala, corresponds to the amino acid sequence preceding that of the protease in the SIV gag/pol precursor polyprotein. Accordingly, the Ala-Pro bond joining the octapeptide linker to the protease constitutes a site naturally cleaved by the protease during viral maturation. This strategy for synthesis was designed to facilitate purification of the biotinylated protein derivative from a complex mixture of reaction products by avidin/agarose-affinity chromatography and to provide the means for autocatalytic removal of the biotin-linker segment. As anticipated, folding of the full-length construct leads to activation of the enzyme and excision of the desired 99-residue SIV protease (overall yield, approximately). The specificity of the synthetic SIV protease toward a number of well characterized protein substrates was the same as observed for the nearly identical enzyme from human immunodeficiency virus type 2 (HIV-2 protease) and distinct from that of the more disparate HIV-1 protease. The same functional ordering with respect to the human retroviral proteases was reflected in Ki values observed with a number of protease inhibitors. Thus, the folded synthetic SIV protease shows patterns of specificity and susceptibility to inhibition that are in accord with what would be expected based upon its degree of structural similarity to proteases from HIV-1 and HIV-2.
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PMID:Chemical synthesis of a biotinylated derivative of the simian immunodeficiency virus protease. Purification by avidin affinity chromatography and autocatalytic activation. 158 12


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