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)

The present study was designed to determine the antibody specificity for the human immunodeficiency virus type 1 (HIV-1) V3 domains of infectious and noninfectious virions present in the serum of AIDS patients. To accomplish this, HIV-1 was isolated in the presence of autologous antibodies from the serum samples of six AIDS patients in HIV-1-negative donor peripheral blood mononuclear cells by short-term cultivation. The isolated virus, defined as the infectious cell-free virus (iCFV), was characterized by sequence analysis of the proviral DNA coding for the third hypervariable (V3) region of the external glycoprotein gp120. This was carried out by amplifying and cloning the V3 region. In all six cases studied, 20 randomly selected V3 clones derived from the proviral DNA of the iCFV, 20 clones from patient cell-free virus, and 20 clones from cell-integrated virus were sequenced to study the distribution and frequency of the intrapatient virus population. The number of major virus variants in the six patients ranged from three to nine. The various V3 sequences found in the AIDS patients showed the typical amino acid pattern of the syncytium-inducing and non-syncytium-inducing viral phenotypes characteristic for the late stage of infection. However, only one patient-specific iCFV variant was detected within the 20 V3 clones analyzed per virus isolation. For the six patients a total of 34 V3-loop variants, either iCFV or non-iCFV, was observed. All 34 V3-loop sequences were expressed as glutathione-S-transferase fusion proteins (V3-GST). The autologous antibody response to the V3-GST fusion proteins was studied by Western immunoblot analysis. A strong antibody response to almost all non-iCFV V3-GST proteins was found in the sera of the six patients. In contrast, the autologous antibody response to the six iCFV V3 loops was undetectable (in four patients) or very faint (in two patients) compared with that to the non-iCFV V3 loops. Five of the six iCFV loops showed positively charged amino acids at positions strongly associated with the syncytium-inducing phenotype. These findings suggest that our in vitro isolation system selects for virions which are not recognized by V3-specific antibodies and are infectious both in vitro and in vivo.
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PMID:Antibodies of symptomatic human immunodeficiency virus type 1-infected individuals are directed to the V3 domain of noninfectious and not of infectious virions present in autologous serum. 818 27

Full-sized gen vif of human immunodeficiency virus has been synthesized and cloned into plasmid pGEX-2T. Vif-gene expression was found in Escherichia coli cells resulting in production of a hybrid GST-protein. The recombinant protein studied by the immunoblotting technique reacted with 8 of 22 probes of human HIV-positive sera. The recombinant protein is specifically cut by thrombin in two proteins corresponding to GST and VIF-proteins in molecular mass.
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PMID:[Expression of the vif gene of human immunodeficiency virus type 1 in Escherichia coli and study of the immunoreactivity of the vif protein]. 828 43

We have previously shown that in AIDS patients a predominant species of infectious virus can be found which is not neutralized by homologous serum. The presence of the infectious virus was associated with the lack of type-specific antibody directed against the V3 domains of these virions. In contrast to this lack of V3-specific antibody, the other V3 domains of non-infectious virions were well recognized by antibody. To determine whether the lack of a V3-specific antibody response is due to a progressive loss of antibody during human immunodeficiency virus type 1 (HIV-1) infection, we monitored the anti-V3 antibody response in 90 patients over time. Anti-V3 antibodies were monitored by a V3-specific ELISA using 21 different V3 domains as a fusion with glutathione S-transferase (GST-V3) based upon sequences from 11 HIV-1 patient isolates and 10 sequences from an HIV-1 B subtype consensus-like GST-V3 expression library. This strictly heterologous screening showed a loss of V3-specific antibodies in 20 out of the 90 patients tested. To study the in vivo relevance of these findings we analysed V3 antibody loss in two patients. This strictly autologous antibody screening was performed based upon V3 sequences of the patients' cell-free virions. In both patients the loss of a V3-specific antibody could be detected in parallel to a decline of CD4+ T cells. Moreover, the escape of a distinct V3 variant was shown to correlate closely with the loss of the V3-specific antibody.
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PMID:Loss of antibody reactivity directed against the V3 domain of certain human immunodeficiency virus type 1 variants during disease progression. 888 71

JC virus is activated to replicate in glial cells of many AIDS patients with neurological disorders. In human glial cells, the human immunodeficiency virus 1 (HIV-1) Tat protein activates the major late promoter of JC virus through a Tat-responsive DNA element, termed upTAR, which is a recognition site for cellular Pur alpha, a sequence-specific single-stranded DNA binding protein implicated in cell cycle control of DNA replication and transcription. Tat interacts with two leucine-rich repeats in Pur alpha to form a complex that can be immunoprecipitated from cell extracts. Tat enhances the ability of purified glutathione S-transferase-Pur alpha (GST-Pur alpha) to bind the upTAR element. Tat acts synergistically with Pur alpha, in a cell-cycle-dependent manner, to activate transcription at an upTAR element placed upstream of a heterologous promoter. Since Pur alpha is ubiquitously expressed in human cells and since PUR elements are located near many promoters and origins of replication, the Tat-Pur alpha interaction may be implicated in effects of HIV-1 throughout the full range of HIV-1-infected cells.
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PMID:Activation of the JC virus Tat-responsive transcriptional control element by association of the Tat protein of human immunodeficiency virus 1 with cellular protein Pur alpha. 894 69

The development of reliable, sensitive, and specific serological methods for the detection of human herpesvirus-8 (HHV-8) antibodies is critical for a thorough understanding of HHV-8 prevalence and pathogenesis. To evaluate the potential usefulness of HHV-8 proteins in measuring the responses against both latent and lytic antigens, we selected 1 latent [open reading frame (ORF) 73] antigen and 3 HHV-8 lytic antigens (ORFs 65, K8.1A, and K8.1B) previously identified as immunogenic [Virology (1998) 243, 208-217]. Full-length genomic ORF 73 and full-length ORFs 65, K8.1A, and K8.1B from the cDNA clones were cloned, expressed in bacterial and baculovirus-insect cell expression systems, and purified as GST fusion proteins. These recombinant proteins were used in Western blot reactions to test sera from 104 human immunodeficiency virus (HIV)+/Kaposi's sarcoma (KS)+ homosexual men, 77 HIV+/KS- homosexual men, and 84 age-matched HIV-/KS- men. These sera were also tested in immunofluorescence assays (IFAs) with uninduced and 12-O-tetradecanoylphorbol-13-acetate-induced B cell lymphoma-1 cells to detect antibodies against latency-associated nuclear antigens (LANA) and antibodies against lytic antigens (cytoplasmic fluorescence). These sera exhibited differential reactivities reflecting different titers of antibodies against HHV-8 proteins, and variable reactivities were seen more commonly with the sera from HIV-/KS- adult men. In the Western blot assay, 89% (93 of 104) of HIV+/KS + sera, 60% (46 of 77) of HIV+/KS- sera, and 7% (6 of 84) HIV+/KS- sera were reactive with both latent and lytic recombinant antigens. Western blot reactions with ORF 73 protein were more sensitive than LANA-IFA results. The lytic IFA and lytic Western blot (ORFs 65 and K8.1A) assays were more sensitive than the ORF 73 Western blots and LANA-IFA. With an exception of 2 sera from the HIV-/KS- group, all sera positive for lytic IFA antibodies and ORF 65 and K8.1A antibodies were also positive for latent antibodies. With few exceptions, sera positive for ORF 65 antibodies were also positive for K8.1A antibodies, and sera recognized the K8.1A protein more often than the K8.1B protein. There is a high degree of concordance between IFA and Western blot reactions, suggesting that this panel of HHV-8 recombinant proteins could detect a majority of the HHV-8-seropositive individuals. These results suggest that IFA followed by confirmation with the Western blot reactions with a panel of latent and lytic immunogenic antigens would provide a reliable, sensitive, and specific method for the detection of HHV-8 antibodies.
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PMID:Comparison of human sera reactivities in immunoblots with recombinant human herpesvirus (HHV)-8 proteins associated with the latent (ORF73) and lytic (ORFs 65, K8.1A, and K8.1B) replicative cycles and in immunofluorescence assays with HHV-8-infected BCBL-1 cells. 1019 Dec 3

Human immunodeficiency virus-1 (HIV-1)-Tat, the transactivating gene product of HIV-1, has been shown to interact with different cell types, inducing gene expression, altering their growth and migratory behavior. In this study we examined whether Tat might affect functions of acquired immunodeficiency syndrome (AIDS)-related non-Hodgkin's lymphoma (NHL), relevant to the in vivo dissemination. Our results show that Tat significantly augmented the motility of the two AIDS-related Burkitt's lymphoma cell lines (AS283 and PA682PB) and AIDS-primary effusion lymphoma cell line (HBL-6-AIDS-PEL). Mutations in RGD or basic domain of Tat (KGE-MBP and LxI-MBP, respectively) sharply reduced migration compared with wild type, suggesting that both domains are required for migration. In contrast, a Tat protein mutation outside the active domains (NH(2)-TAT-GST) did not reduce lymphoma cell migration. The treatment of lymphoma cells with Tat did not influence their adhesion to matrix proteins or to human vascular endothelial cells, but endothelial cells treated with Tat became more adhesive to lymphoma cells. Flow cytometric analysis showed that treatment of endothelial cells with Tat induced the cell surface expression of the adhesion molecules vascular cell adhesion molecule-1 (VCAM-1) and E-selectin and increased the expression of intercellular adhesion molecule-1 (ICAM-1). Only antibodies against VCAM-1 on endothelial cells or against the VLA-4 integrin expressed on AS283 cells inhibited the increment of adhesion, indicating the relevance of this pathway in the adhesion of lymphoma cells to vascular endothelium. In our work, we show for the first time that Tat can enhance the migration of lymphoma cells and their adhesion to endothelial cells, two processes that may contribute to the malignant behavior of NHL in patients with AIDS.
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PMID:Human immunodeficiency virus-1 (HIV-1)-Tat protein promotes migration of acquired immunodeficiency syndrome-related lymphoma cells and enhances their adhesion to endothelial cells. 1047

Bruton's tyrosine kinase (Btk) is considered an essential signal transducer in B-cells. Mutational defects are associated with a severe immunodeficiency syndrome, X-chromosome linked agammaglobulinemia (XLA). Here we show by coimmunoprecipitation that a member of the protein kinase C (PKC) family, PKCmu, is constitutively associated with Btk. Neither antigen receptor (Ig) crosslinking nor stimulation of B-cells with phorbol ester or H(2)O(2) affected Btk/PKCmu interaction. GST precipitation analysis revealed association of the Btk pleckstrin/Tec homology domain with PKCmu. Transient overexpression of PKCmu deletion mutants as well as expression of selected PKCmu domains in 293T cells revealed that both the kinase domain and the regulatory C1 region are independently capable of binding to the Btk PH-TH domain. These data show the existence of a PKCmu/Btk complex in vivo and identify two PKCmu domains that participate in Btk interaction.
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PMID:Bruton's tyrosine kinase (Btk) associates with protein kinase C mu. 1056 98

The human immunodeficiency virus type 1 (HIV-1) RNA-binding Rev protein governs the expression of structural and enzymatic viral proteins at a posttranscriptional level. Binding of Rev to the stem-loop IIB (SLIIB) sequence of the Rev-response element (RRE) within unspliced and singly spliced viral mRNAs and to the nuclear export signal-binding receptor, hCRM1 (or exportin 1), is required for the export of these transcripts to the cytoplasm. We have previously shown that herpes simplex virus type 1 (HSV-1) RNA-binding Us11 protein is able to bind the RRE and substitute for Rev in inducing the expression of HIV-1 envelope glycoproteins. We show here that Us11 cannot substitute for Rev in rescuing a rev-deleted HIV-1 provirus. However, HIV-1 production is observed when Us11 is expressed with suboptimal amounts of Rev. An in vivo RNA-protein binding assay indicates that Us11 is unable to directly interact with the SLIIB RNA but can bind Rev assembled on that stem-loop structure. This association of US11 with Rev, which was confirmed by in vivo coimmunoprecipitation and GST-pulldown assays, therefore underlies a biological Us11-Rev cooperation. Furthermore this cooperation was shown to remain susceptible to the effect of leptomycin B, which blocks the binding of hCRM1 to the nuclear export signal of Rev. These observations performed with intron-containing constructs provide evidence that HSV-1 Us11 protein is not directly involved in the cytoplasmic accumulation of viral mRNAs but may be rather acting as an auxiliary protein, thus allowing this retroviral protein to fulfill the nuclear export of these transcripts and to rescue HIV-1 production.
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PMID:The herpes simplex virus 1 Us11 protein cooperates with suboptimal amounts of human immunodeficiency virus type 1 (HIV-1) Rev protein to rescue HIV-1 production. 1077 78

Extracellular Tat protein, the transactivating factor of the human immunodeficiency virus type 1 (HIV-1), modulates gene expression, growth, and angiogenic activity in endothelial cells by interacting with the vascular endothelial growth factor (VEGF) receptor-2 (Flk-1/KDR). Recombinant Tat protein, produced as glutathione-S-transferase chimera (GST-Tat), activates mitogen-activated protein kinase (MAPK) ERK(1/2) in human, murine, and bovine endothelial cells whereas GST is ineffective. In bovine aortic endothelial cells, GST-Tat and the 165 amino acid VEGF isoform (VEGF165) induce transient ERK(1/2) phosphorylation with similar potency and kinetics. The synthetic peptide Tat(41-60), but not peptides Tat(1-21) and Tat(71-86), causes ERK(1/2) phosphorylation, thus implicating Tat/KDR interaction in the activation of this signalling pathway. Accordingly, GST-Tat induces ERK(1/2) phosphorylation in KDR-transfected porcine aortic endothelial cells but not in parental cells. MAPK kinase inhibitors PD098059 and U0126 prevent ERK(1/2) phosphorylation by Tat. However, they do not affect the angiogenic activity exerted by Tat in the murine Matrigel plug and chick embryo chorioallantoic membrane assays. Blocking of MAPK kinase activity impairs instead the angiogenic response to VEGF165 and to fibroblast growth factor-2 (FGF-2). Our data demonstrate that ERK(1/2) activation following the interaction of HIV-1 Tat protein with endothelial cell Flk-1/KDR receptor does not represent an absolute requirement for a full angiogenic response to this growth factor that appears to utilize mechanism(s) at least in part distinct from those triggered by other prototypic angiogenic growth factors.
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PMID:Activation of endothelial cell mitogen activated protein kinase ERK(1/2) by extracellular HIV-1 Tat protein. 1140 52

Pur alpha is a highly conserved, eukaryotic sequence-specific DNA- and RNA-binding protein involved in diverse cellular and viral functions including transcription, replication, and cell growth. Pur alpha exerts its activity in part by interacting with other viral and cellular proteins. One such protein is the human immunodeficiency virus (HIV) type I regulatory protein Tat. Earlier studies have demonstrated that this interaction is mediated by Pur alpha-associated RNA (PARNA) and that RNA immunopurified from mammalian expressed Pur alpha was capable of reconstituting the interaction between these two proteins. In the current study, we characterize four RNA species which were immunopurified with Pur alpha. Northern blot analysis with one of the PARNAs revealed a highly abundant signal of approximately 2.0 kilobases (kb) present in all cell lines tested. Sequence analysis of each of the four PARNA clones revealed a high homology to different regions of the human 18S ribosomal RNA sequence. Based on this homology, we investigated the influence of Pur alpha on translation. Luciferase assays were performed after coupled in vitro transcription/translation reactions with a vector containing a luciferase reporter construct and increasing concentrations of BSA, GST, and GST-Pur alpha. Inclusion of GST-Pur alpha in these reactions resulted in a dose-dependent inhibition of luciferase activity. Similar inhibition was observed with in vitro translation reactions performed with in vitro transcribed luciferase RNA and increasing concentrations of GST-Pur alpha. In control experiments, inclusion of increasing concentrations of GST-Pur alpha with luciferase protein resulted in no effect on luciferase activity. Taken together, these data demonstrate that Pur alpha inhibits translation reactions in vitro. Moreover, this Pur alpha-mediated inhibition of translation can be abrogated by HIV-1 Tat protein.
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PMID:Single-stranded nucleic acid-binding protein, Pur alpha, interacts with RNA homologous to 18S ribosomal RNA and inhibits translation in vitro. 1159 4


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