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)

Subcellular localization of input human immunodeficiency virus type 1 (HIV-1) gag proteins was determined in infected H9 and Jurkat tat cells. Infected cells were fractionated at intervals, and the proteins in cell fraction were identified by immunoblotting using pooled sera from acquired immunodeficiency syndrome (AIDS) patients and monoclonal antibodies. Cycloheximide was added at 0 time to prove that the proteins detected were not nascent ones. Gag proteins p55, p41, p39 (in the most essential relative concentrations), and p17 were found in the cell nuclei for at least 4 h after infection. However, p24 was not found in the cell nuclei and was accumulated in the nuclear washing buffer. The data presented confirm the presence of karyotypic signal at the N terminus of p55 gag precursor. The potential role of nuclear localization of gag precursor is discussed.
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PMID:p17 and p17-containing gag precursors of input human immunodeficiency virus are transported into the nuclei of infected cells. 206 27

Eight different monoclonal antibodies (MAbs) were raised against a lysate of the HTLV-IIIb isolate of human immunodeficiency virus (HIV). All eight MAbs recognized the major core protein p24 as well as the gag precursors p39 and p55. Three different epitopes were defined by the eight MAbs when an antigen-catching ELISA was used as the test system. An antigen-catching ELISA for p24 was developed by use of two of the MAbs defining two different epitopes. This ELISA system was applied to the detection of p24 in culture supernatants from lymphocyte cultures of 13 different HIV isolates. The present p24 detecting ELISA proved useful for characterization of different isolates of HIV. Further, two MAbs from the present panel of antibodies were demonstrated to be sensitive and specific probes for the immunohistological detection of p24 protein in tissue sections of lymphoid tissue.
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PMID:Immunological characterization and detection of the major core protein p24 of the human immunodeficiency virus (HIV) using monoclonal antibodies. 246 53

We have used a recombinant vaccinia virus (VV) which expresses high levels of human immunodeficiency virus-1 (HIV-1) gag proteins to analyze the processing pathway of the gag p55 precursor. HIV-1 gag proteins were isolated from [3H]leucine-labeled VV:gag-infected H9 T lymphocytes by immunoprecipitation with either anti-p24, anti-p17, or anti-p6 antibodies. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis revealed that processing of the p55 precursor involves three major intermediates (p41a, p41b, and p39). The p41a and p39 proteins contain the p17 and p24 protein segments, and the p41b is comprised of p24 and p15 segments. On two-dimensional gels, each intermediate as well as the mature p24 and p17 proteins migrated as distinct species. [3H]Myristic acid labeling of the HIV-1 gag proteins revealed that in addition to p55 and p17, the p41a and p39 intermediates, but not p41b, are myristylated, confirming that myristylation occurs at the NH2 terminus before cleavage of the p55 precursor protein. We conclude that the myristylated HIV-1 gag p55 precursor is initially cleaved at random either at the p17/p24 junction or at two sites between p24 and p15 proteins, resulting in three intermediates (p41a, p41b, and p39) which are subsequently cleaved to yield mature gag proteins.
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PMID:Identification of protein intermediates in the processing of the p55 HIV-1 gag precursor in cells infected with recombinant vaccinia virus. 278 91

Previous studies have demonstrated that oligodeoxynucleotide phosphorothioates complementary to human immunodeficiency virus type 1 (HIV-1) RNA are more nuclease resistant and are effective inhibitors of HIV-1 replication than their unmodified counterpart. In this study, antisense oligodeoxynucleotide sequences were evaluated for therapeutic potential in the treatment of HIV infections. The use of HIV-infected lymphocytes to test the efficacy of a drug is very complex, and therefore it is difficult to draw conclusions about the mechanism. We used a COS-like Monkey kidney cell line (CMT3) stably transfected with plasmids pCMVgagpol-rre-r (containing gag and pol genes) and pCMVrev (containing the rev gene of HIV-1), derived from cDNA clone BH10, as a model. A biologically active provirus that transcribes and translates their nucleotide sequences into viral proteins p24, p39/41, p55, and p160 was generated. Sequence-specific and dose-dependent inhibition of HIV-1 viral protein synthesis and significant inhibition at the mRNA level were demonstrated by antisense construct GPI2A, directed against a nonregulatory region of the HIV-1 genome. Also, our studies demonstrated enhancement of the antisense effect through encapsulation in a cationic lipid preparation. The observed attenuation of HIV-1 mRNA levels suggests that, at least in part, the mechanism of action of GPI2A was at the transcript level. Further studies have also shown antiviral activity of this construct as determined by the reverse transcriptase assay using acutely and chronically infected cells of lymphoid origin (H9 cells). Toxicological studies involving cell growth characteristics, colony-forming ability, effects on cellular proteins, specific activities of labeled proteins, and DNA synthesis in cell culture showed no cytotoxic effects of GPI2A.
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PMID:Sequence-specific inhibition of gene expression by a novel antisense oligodeoxynucleotide phosphorothioate directed against a nonregulatory region of the human immunodeficiency virus type 1 genome. 785 19

Viral protein X (Vpx) is a human immunodeficiency virus type 2 (HIV-2) and simian immunodeficiency virus accessory protein that is packaged into virions in molar amounts equivalent to Gag proteins. To delineate the processes of virus assembly that mediate Vpx packaging, we used a recombinant vaccinia virus-T7 RNA polymerase system to facilitate Gag protein expression, particle assembly, and extracellular release. HIV genes were placed under control of the bacteriophage T7 promoter and transfected into HeLa cells expressing T7 RNA polymerase. Western immunoblot analysis detected p55gag and its cleavage products p39 and p27 in purified particles derived by expression of gag and gag-pol, respectively. In trans expression of vpx with either HIV-2 gag or gag-pol gave rise to virus-like particles that contained Vpx in amounts similar to that detected in HIV-2 virus produced from productively infected T cells. Using C-terminal deletion and truncation mutants of HIV-2 Gag, we mapped the p15 coding sequence for determinants of Vpx packaging. This analysis revealed a region (residues 439 to 497) downstream of the nucleocapsid protein (NC) required for incorporation of Vpx into virions. HIV-1/HIV-2 gag chimeras were constructed to further characterize the requirements for incorporation of Vpx into virions. Chimeric HIV-1/HIV-2 Gag particles consisting of HIV-1 p17 and p24 fused in frame at the C terminus with HIV-2 p15 effectively incorporate Vpx, while chimeric HIV-2/HIV-1 Gag particles consisting of HIV-2 p17 and p27 fused in frame at the C terminus with HIV-1 p15 do not. Expression of a 68-amino-acid sequence of HIV-2 containing residues 439 to 497 fused to the coding regions of HIV-1 p17 and p24 also produced virus-like particles capable of packaging Vpx in amounts similar to that of full-length HIV-2 Gag. Sucrose gradient analysis confirmed particle association of Vpx and Gag proteins. These results demonstrate that the HIV-2 Gag precursor (p55) regulates incorporation of Vpx into virions and indicates that the packaging signal is located within residues 439 to 497.
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PMID:Localization of the Vpx packaging signal within the C terminus of the human immunodeficiency virus type 2 Gag precursor protein. 808 57

The effect of human interferon-alpha (Hu-IFN-alpha) on the maturation process of the human immunodeficiency virus type 1 (HIV-1) has been studied using stable cell lines that produce nonenveloped particles. These cell lines secrete particles devoid of the viral envelope proteins gp120 and gp41. The CH-1 cells produce active viral protease that correctly processes its natural substrates, whereas the CH-1kww cell line expresses an enzymatically inactive viral protease, thus producing immature viral capsids. A block in the secretion of particles was observed in both cell lines when treated with 100-1000 U/ml Hu-IFN-alpha, as judged by measurements of encapsidated gag proteins. Electron microscopy shows that Hu-IFN-alpha-treated CH-1 cells are decorated with assembled immature particles at the cell surface. These results suggest that the observed block in particle release on Hu-IFN-alpha treatment is independent of viral envelope expression and occurs before capsid polyprotein processing. In addition, particles remaining attached to the cell fail to mature into structures with condensed cores. Viral gag proteins from IFN-treated and untreated CH-1 cells were analyzed by 2-D gel electrophoresis. Results suggest a change in posttranslational modifications of gag proteins, as IFN treatment allowed the detection of more basic forms of p55, p39, and p24. Further analysis of cellular or viral protein alterations induced by Hu-IFN-alpha treatment may identify the mechanism of action by which particle maturation is obstructed.
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PMID:Obstruction of HIV-1 particle release by interferon-alpha occurs before viral protease processing and is independent of envelope glycoprotein. 918 67

Viral protein U (Vpu) is an 81 amino acid phosphoprotein found in human immunodeficiency virus type 1 (HIV-1)-infected cells. One function of Vpu is to enhance the release of virus particles from the plasma membrane in infected cells. Using subcellular fractionation, we observed that Vpu promotes the targeting of Pr55 Gag to the plasma membrane, the site of viral assembly. Deletions of Pr55, which removed most of the N-terminal matrix domain (p39) or the C-terminal domains of nucleocapsid and p6 (p41), still allowed for virus-like particle production. Moreover, the release of these particles remained Vpu-responsive. The N-terminal matrix (MA) domain of Gag, which contains its membrane-binding domain, is sufficient for Vpu-mediated enhanced release into the supernatant. Furthermore, a MA-GFP fusion protein showed enhanced membrane binding in the presence of Vpu. This demonstrates that Vpu action may be mediated by allowing Gag, specifically the N-terminal matrix domain, to efficiently associate with the plasma membrane. Thus MA appears sufficient but not necessary for Vpu-mediated enhanced particle release.
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PMID:The N-terminal matrix domain of HIV-1 Gag is sufficient but not necessary for viral protein U-mediated enhancement of particle release through a membrane-targeting mechanism. 1075 9

A vaccine based on the envelope protein (Env) of the human immunodeficiency virus type 1 (HIV-1) that triggers widely reactive antibodies might be a desirable approach to control virus infection. To expose epitopes which could induce broadly reactive antibodies against HIV-1 Env, we have generated vaccinia virus (VV) recombinants that express Env fused at its N- or C-terminus with two major antigenic proteins of VV, p14 (A27L gene) and p39 (A4L gene). Biochemical analysis of the chimeric proteins in cell cultures revealed that, in all cases, recombinant viruses expressed the correct fusion proteins. When p14 or p39 are fused at the N-terminus of Env the chimeric proteins are poorly glycosylated but when p14 or p39 are fused at the C-terminus of Env, the chimeric proteins are fully glycosylated. In Balb/c mice, immunisation with the referred VV recombinants induced similar levels of CD8+ T cell specific responses to Env as immunisation with the entire Env protein. The humoral immune response triggered by the fusion proteins was broader than in animals immunised with VV expressing the entire Env (VVEnv1), and was directed to epitopes outside of the V3 loop (V1/V2, C1, C2, C4). One of the chimeric constructs induced a better neutralising antibody response than VVEnv1. We conclude that fusing VV proteins p14 or p39 to Env provides an effective means to induce broadly reactive antibodies and CD8+ T cell responses to Env. This approach might have utility against HIV and other pathogens.
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PMID:Chimeras between the human immunodeficiency virus (HIV-1) Env and vaccinia virus immunogenic proteins p14 and p39 generate in mice broadly reactive antibodies and specific activation of CD8+ T cell responses to Env. 1085 92

Of the various approaches being developed as prophylactic HIV vaccines, those based on a heterologous plasmid DNA prime, live vector boost vaccination regimen appear especially promising in the nonhuman primate/simian-human immunodeficiency virus (SHIV) challenge model. In this study, we sought to determine whether a series of intramuscular priming immunizations with a plasmid DNA vaccine expressing SIVgag p39, in combination with plasmid expressed rhesus IL-12, could effectively enhance the immunogenicity and postchallenge efficacy of two intranasal doses of recombinant vesicular stomatitis virus (rVSV)-based vectors expressing HIV-1 env 89.6P gp160 and SIVmac239 gag p55 in rhesus macaques. In macaques receiving the combination plasmid DNA prime, rVSV boost vaccination regimen we observed significantly increased SIVgag- specific cell-mediated and humoral immune responses and significantly lower viral loads postintravenous SHIV89.6P challenge relative to macaques receiving only the rVSV vectored immunizations. In addition, the plasmid DNA prime, rVSV boost vaccination regimen also tended to increase the preservation of peripheral blood CD4+ cells and reduce the morbidity and mortality associated with SHIV89.6P infection. An analysis of immune correlates of protection after SHIV89.6P challenge revealed that the prechallenge SHIV-specific IFN-gamma ELISpot response elicited by vaccination and the ability of the host to mount a virus-specific neutralizing antibody response postchallenge correlated with postchallenge clinical outcome. The correlation between vaccine-elicited cell-mediated immune responses and an improved clinical outcome after SHIV challenge provides strong justification for the continued development of a cytokine-enhanced plasmid DNA prime, rVSV vector boost immunization regimen for the prevention of HIV infection.
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PMID:Priming with plasmid DNAs expressing interleukin-12 and simian immunodeficiency virus gag enhances the immunogenicity and efficacy of an experimental AIDS vaccine based on recombinant vesicular stomatitis virus. 1606 Aug 34

An experimental pDNA vaccine adjuvant expressing IL-12 was evaluated for its ability to augment the humoral and cellular immune responses elicited by a SIVmac239 gag p39 expressing pDNA vaccine. To determine the effect of vaccine dose on the immune response, rhesus macaques were immunized with 1.5 mg or 5.0 mg of SIVmac239 gag pDNA, with or without co-immunization of IL-12 pDNA at 1.5 mg and 5.0 mg, respectively. Serum antibody responses to simian immunodeficiency virus (SIV) gag were increased 10-fold (p=0.044, 0.002) in macaques receiving IL-12 pDNA. Cellular immune responses, monitored by SIV gag-specific IFN-gamma ELISpot assay, were also significantly higher (p=0.007, 0.019) when the pDNA vaccine was co-immunized with IL-12 pDNA at high and low doses. There was no statistical difference between the immune responses elicited by the high and low dose of IL-12 pDNA (p=0.221, 0.917), a finding which could allow a dose reduction of vaccine without the concomitant loss of imunogenicity. Furthermore, analysis of the breadth of the T-cell response during the vaccination schedule, using overlapping peptides to SIV gag, demonstrated a significant correlation (p=0.0002) between the magnitude and breadth of the immune responses in the vaccines. These results have important implications for the continuing development of an effective, safe low dose pDNA vaccine adjuvant suitable for human use.
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PMID:A dose sparing effect by plasmid encoded IL-12 adjuvant on a SIVgag-plasmid DNA vaccine in rhesus macaques. 1628 22


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