pinecone/core-2020-05-10-deduplication huggingface dataset:
The Inhibitory Effect of RANTES on the Infection of Primary Macrophages by R5 Human Immunodeficiency Virus Type-1 Depends on the Macrophage Activation State

AbstractWe investigated whether culture conditions could affect the RANTES antiviral effect on human immunodeficiency virus type 1 (HIV-1) infection of primary macrophages. Monocyte-derived macrophages (MDM) were obtained either as (1) the adherent cells of 5-day cultures of blood mononuclear cells (PBMC), followed by 2 days without nonadherent PBMC or added cytokines (MDM-5d), or (2) as the adherent cells recovered from 1-h incubation of PBMC, which were cultured for 7 days with macrophage colony-stimulating factor (M-CSF; MDM-MCSF). Infection of MDM-5d from different donors with HIV-1 R5 strains was reproducibly inhibited by RANTES (IC50≤ 10 nM), but infection of MDM-MCSF was not inhibited by ≥100 nM RANTES, even when added at initiation of cultures, although it was still inhibited by a CD4 antibody. RANTES had no antiviral effect when MDM-5d were treated with physiological concentrations of M-CSF or GM-CSF before infection. CCR5 and CXCR4 expression as well as that of other cell surface molecules, including adhesion molecules, was not affected by the cytokines. MDM-MCSF from Δ32CCR5 homozygous individuals did not render them permissive to HIV-1, suggesting that it is unlikely that the virus uses another coreceptor. RANTES binding to MDM was chondroitin sulfate, but not heparan sulfate, dependent, and RANTES bound more efficiently to MDM-5d than to MDM-MCSF. Chondroitin sulfate removal partially offset the RANTES antiviral effect for MDM-5d. Thus RANTES anti-HIV-1 activity for primary macrophages depends on culture conditions and their consequent activation status, which may lead to differences in proteoglycan surface expression. These data may be relevant for the development of chemokine-based therapy for HIV-1 infection
Role of the Transmembrane Sequence of Spleen Focus-Forming Virus gp55 in Erythroleukemogenesis

AbstractThe membrane glycoprotein encoded by theenvgene of either the polycythemia- or anemia-inducing spleen focus-forming virus (SFFVp or SFFVa, respectively) is responsible for the induction of erythroleukemia in mice. It has been shown that the SFFVp glycoprotein, gp55, interacts with the erythropoietin receptor (EPO-R) and promotes EPO-independent proliferation of an EPO-R-expressing hematopoietic cell line, Ba/F3 (Liet al., Nature343:762, 1990). We show here that when residues within the transmembrane (TM) sequence of an SFFVp gp55 are altered based on the sequences of the anemia-inducing gp55s by a methionine-to-isoleucine (M-I) substitution, a di-leucine deletion (dLL), or both, the resulting mutants display an attenuated phenotype that resembles an SFFVa: they induce milder erythroproliferative disease without polycythemiain vivoand are unable to promote EPO-independent cell proliferationin vitro.The dLL mutation directly interferes with EPO-R binding by decreasing the affinity of gp55 for the receptor. On the other hand, the M-I mutation hampers the full mitogenic activation of EPO-R while having no effect on receptor binding and asserts a dominant negative effect over the wild-type SFFVp gp55. Two other sequence changes within the TM sequence did not affect the biological activities of the SFFVp gp55. These results indicate that the TM sequence of the SFFVenvglycoprotein plays a prominent role in SFFV-induced erythroleukemogenesis through its influence on the mitogenic activation of EPO-R
Therapeutic Periocular Vaccination with a Subunit Vaccine Induces Higher Levels of Herpes Simplex Virus-Specific Tear Secretory Immunoglobulin A Than Systemic Vaccination and Provides Protection against Recurrent Spontaneous Ocular Shedding of Virus in Latently Infected Rabbits

AbstractRabbits latently infected with herpes simplex virus type 1 (HSV-1) were vaccinated either periocularly or systemically with a subunit vaccine (gB2 + gD2) plus adjuvant or adjuvant alone. Tear films were collected daily to measure recurrent infectious HSV-1 shedding. After systemic vaccination, the latently infected rabbits were not protected against recurrent ocular viral shedding (HSV-1-positive tear film cultures/total cultures) compared with either the systemic or periocular adjuvant controls (systemic vaccination = 49 of 972, 5.0%; systemic control = 46 of 972, 4.7%; periocular control = 43 of 930, 4.6%;P> 0.8). In contrast, latently infected rabbits vaccinated periocularly with the same vaccine had significantly reduced recurrent shedding (20 of 1026, 2.0%) compared with controls (P< 0.001) or systemic vaccination (P= 0.0002). Thus, recurrent HSV-1 shedding was significantly reduced by therapeutic local periocular subunit vaccination but not by therapeutic systemic subunit vaccination. Neutralizing antibody titers in the serum of systemically and ocularly vaccinated rabbits was similar. In contrast, HSV-specific tear secretory immunoglobulin A was significantly higher in the ocularly vaccinated group (P< 0.01). These results strongly suggest that in the rabbit, and presumably in humans, the local ocular (mucosal) immune response is much more important than the systemic immune response for therapeutic protection against recurrent ocular HSV-1. Thus development of a therapeutic vaccine against recurrent ocular HSV-1 should be directed at enhancing the local ocular (mucosal) immune response
β2-Microglobulin Knockout Mice Are Highly Susceptible to Polyoma Virus Tumorigenesis

AbstractPolyoma virus is highly oncogenic when inoculated into immunocompromised adult mice and neonatal mice of specific inbred strains. Although T lymphocytes are known to be essential in controlling polyoma virus tumorigenesis, the importance of class I MHC-restricted CD8+T cells in mediating tumor resistance remains unclear. Here, we investigated the tumorigenicity of polyoma virus in adult mice rendered CD8+T cell-deficient by homozygous (−/−) disruption of the β2-microglobulin (β2m) or CD8α (CD8) genes. Nearly all (94%) of the virus-infected adult C57BL/6β2m−/−mice developed tumors, and 20% of the virus-inoculated adult C57BL/6CD8−/−mice developed hindlimb paralysis, which is indicative of vertebral tumors. Only 2 of 20 virus-inoculated adult normal C57BL/6 mice developed tumors. Despite these different tumor susceptibilities, persistent viral DNA was detected in multiple organs of mice of all three strains. Multifocal lymphoplasmacytic interstitial infiltrates were present in the kidneys and lungs of virus-infected C57BL/6β2m−/−and in the lungs of virus-inoculated C57BL/6CD8−/−mice. These infiltrates were composed primarily of B cells and colocalized with staining for the major viral capsid protein, VP1. No infiltrates or VP1 staining was detected in the kidneys of infected C57BL/6 mice. Using a highly sensitive RT-PCR bioluminescence immunoassay, we investigated and detected persistent polyoma T protein and VP1 messages in both C57BL/6β2m−/−and C57BL/6 mice. C57BL/6β2m−/−and C57BL/6 mice had equivalent serum virus-neutralizing antibody titers. These results providein vivoevidence that class I MHC-restricted CD8+T cells are involved in mediating protection against polyoma virus tumor development
The ORF, Regulated Synthesis, and Persistence-Specific Variation of Influenza C Viral NS1 Protein

AbstractThe open reading frame (ORF) and the regulated synthesis of the influenza C viral NS1 protein were analyzed in view of viruses possessing different biological activities. We provide evidence for a 246-amino-acid NS1-ORF, encoded by five viral strains and variants. Prokaryotic expression of the prototype NS1-ORF resulted in a product of 27 kDa, confirming the predicted molecular weight. Using an antiserum raised against recombinant NS1 protein, nonstructural proteins of wild-type virus were detected in infected cells for a limited course of time, whereas a persistent virus variant was characterized by a long-term nonstructural gene expression. As examined by infection experiments, the intracellular distribution of nonstructural protein was nuclear and cytoplasmic, whereas in NS1 gene-transfected cells, the cytoplasmic localization occurred in a fine-grained structure, suggesting an analogy to influenza A viral NS1 protein. Concerning persistent infection, NS1 protein species differing in sizes and posttranslational modifications were observed for a persistent virus variant, as particularly illustrated by a high degree of NS1 phosphorylation. Virus reassortant analyses proved the importance of the NS-coding genomic segment: the minimal viral properties required for the establishment of persistence were transferred with this segment to a monoreassortant virus. Thus the influenza C viral NS1 protein is a 246-amino-acid nuclear-cytoplasmic phosphoprotein that can be subject to specific variations being functionally linked to a persistent virus phenotype
Infection of Tobacco orArabidopsisPlants by CMV Counteracts Systemic Post-transcriptional Silencing of Nonviral (Trans)Genes

AbstractCucumber mosaic cucumovirus (CMV) infection but not tomato black ring nepovirus infection counteracted post-transcriptional gene silencing (PTGS) of nitrate reductase (Nia) or β-glucuronidase (uidA) transgenes in newly developing leaves of tobacco andArabidopsisplants. PTGS did not affect meristems of noninfected silenced plants, indicating that the interfering effect of CMV is not likely to occur in the meristem. Models are proposed to explain how CMV (which has no sequence similarity to theNiaoruidAtransgenes) can inhibit cellular factors involved in the RNA degradation step of PTGS and/or inhibit the systemic spread of the silencing signal to tissues emerging from the meristem
Isolation and Stability of Histidine-Tagged Proteins Produced in Plants via Potyvirus Gene Vectors

AbstractA system for the expression and purification of histidine-tagged proteins from plants has been developed using a tobacco etch potyvirus (TEV)-derived gene vectors. The vectors offered a convenient polylinker and a choice of histidine tagging at the recombinant proteins' N or C termini. These vectors were utilized for expression of proteins encoded by beet yellows closterovirus (BYV). Approximately 4 μg/g of 20-kDa BYV protein was readily isolated from plants systemically infected by hybrid TEV. In contrast, only minute quantities of 22-kDa BYV capsid protein (CP) histidine-tagged at its N or C terminus could be purified. Rapid degradation of the recombinant CP has been implicated in its failure to accumulate in infected plants. Fusion with TEV HC-Pro stabilized the histidine-tagged BYV CP and facilitated purification of the fusion product from infected plants. This same fusion approach was successfully used with the 24-kDa minor BYV CP. The recombinant proteins were recognized by histidine-tag-specific monoclonal antibody in immunoblot analysis. These results demonstrate the utility of a designed series of TEV vectors for expression, detection, and purification of the recombinant proteins and suggest that intrinsic protein stability is a major factor in a recovery of recombinant proteins from plants
Mapping of HIV-1 Determinants of Apoptosis in Infected T Cells

AbstractHIV-1 infection leads to death of CD4+T cellsin vivoandin vitro,although the mechanisms of this cell death are not well defined. We used flow cytometry to concurrently analyze infection and apoptosis of the CD4+CEM T cell line and human peripheral blood mononuclear cells (PBMC). Surprisingly, T cells productively infected with HIV-1 IIIB showed less apoptosis than control, uninfected T cells. This relative paucity of apoptosis was a characteristic of IIIB, since a large number of cells infected with the viral clone, HIV-1 NL4-3, were apoptotic. Thenef, vpr,andvpugene products were not responsible for apoptosis of NL4-3-infected cells, since NL4-3ΔVprΔVpuΔNef and HXB-2 (anef, vpr,andvputriple mutant derived from IIIB) also killed infected cells. Moreover, only IIIB-infected cells showed a resistance to background levels of apoptosis. Thus, the apoptotic (and antiapoptotic) properties of HIV-1 do not map solely to mutations innef, vpr,orvpu.We postulate that,in vivo,HIV variants that do not induce rapid apoptosis in the cells they infect may have a selective advantage
Measles Virus Replication in Cells of Myelomonocytic Lineage Is Dependent on Cellular Differentiation Stage

AbstractMeasles virus (MV)-infected monocytes may have a central role in virus-induced immunosuppression. Our understanding of MV replication in monocytic cells is, however, incomplete. In this work we have investigated MV replication in cells of human myelomonocytic lineage with different maturation stages in order to study the effect of cellular maturation on virus infection. MV was able to infect human bone marrow myeloid granulocyte–macrophage colony-forming cells (CFC-GM) as well as monocytes and macrophages, but the replication cycle seemed to be regulated by the maturation stage of the cells. Virus infection in CFC-GM was productive, unlike in monocytes and macrophages, where an extensive viral RNA synthesis occurred and high amounts of proteins were synthesised without a remarkable release of infectious virus. Efficiency of viral macromolecular synthesis in macrophages was comparable to that of promonocytic cell line U-937 and human epithelial cell line A549, but in contrast to macrophages the cell lines highly supported productive infection. On the other hand, chemically induced maturation of the human promyelocytic and promonocytic cell lines HL-60, THP-1, and U-937 to more mature macrophage-like forms did not markedly alter the replication cycle of MV in these cell lines. Our results showed that MV replication in myelomonocytic cells varied depending on the maturation stage of the cells. The immature myelomonocytic cells supported productive virus infection, but the maturation process lead to cellular changes that caused a restriction of MV replication cycle partly at posttranscriptional and partly at posttranslational level. The metabolic milieu of monocytes and macrophages as such was sufficient to support extensive viral macromolecular synthesis
The Role of Subtilisin-like Proprotein Convertases for Cleavage of the Measles Virus Fusion Glycoprotein in Different Cell Types

AbstractThe fusion (F) glycoprotein gene of measles virus (MV) encodes a nonfusogenic precursor protein (F0) that is activated by cleavage into the F1and F2subunits during transport to the cell surface. The F protein of both the Edmonston strain and a wild-type MV was found to be cleaved in thetrans-Golgi cisternae and/or thetrans-Golgi network (TGN). In HEp-2 cells, B lymphoblastoid cells, and PBMC, the cleavage process required calcium, and calcium deprivation prevented syncytium formation. The calcium dependence indicated the involvement of the pro-protein convertase (PC) endoprotease family. The expression of the presently recognized members of the PC family in human cell types known to be infected during measles was examined by RT–PCR. Among the PCs residing in the TGN, only furin was expressed in all cells. Soluble secreted human furin produced by a recombinant baculovirus cleaved MV F0into proteins the exact size of F1and F2and increased the titer of MV particles released from calcium-deprived or endoprotease defective infected cells. These results strongly indicate that furin is the most important and maybe the only endoprotease involved in activation of the MV F protein
HIV-1 Virions Produced from Replicating Peripheral Blood Lymphocytes Are More Infectious Than Those from Nonproliferating Macrophages Due to Higher Levels of Intravirion Reverse Transcripts: Implications for Pathogenesis and Transmission

AbstractIt has been demonstrated that intravirion reverse transcription in human immunodeficiency virus type I (HIV-1) occurs in the presence of physiological substances and that the intravirion HIV-1 reverse transcripts are important for the establishment of infection in nondividing cells. In this report, we demonstrate that the infectivity of the virus produced from replicating peripheral blood lymphocytes (PBL) is significantly higher than that of virions produced by nonproliferating macrophages, upon infection of either initially quiescent PBLs or macrophages. This directly correlated with significantly higher intravirion reverse transcripts in the virions from replicating PBLs, compared to those from macrophages. Treatment of replicating PBLs and macrophages with 3′- azido-3′- deoxythymidine resulted in decreased intravirion reverse transcripts and lower infectivity of produced virions, upon infection of initially quiescent T-cells or macrophages. Because both nonproliferating macrophages and replicating lymphocytes are the major reservoirs for HIV-1in vivo,we propose that as the result of higher levels of intravirion reverse transcripts, the HIV-1 virions produced from actively replicating cells are more infectious than those from nonproliferating cells. As such, this scenario implies at least one molecular mechanism for the intra- and interhost transmission of HIV-1
Early Activation of Mitogen-Activated Protein Kinase Kinase, Extracellular Signal-Regulated Kinase, p38 Mitogen-Activated Protein Kinase, and c-JunN-Terminal Kinase in Response to Binding of Simian Immunodeficiency Virus to Jurkat T Cells Expressing CCR5 Receptor

AbstractWe have shown that the binding of simian immunodeficiency virus (SIV) to Jurkat T cells expressing CD4 receptor strongly induces mitogen-activated protein (MAP) kinase kinase (MEK) and extracellular signal-regulated kinases 1 and 2 (ERK1/2) and only weakly induces p38 MAP kinase and c-JunN-terminal kinase (JNK). Similarly, T-tropic NL4–3 virus, which uses both CD4 and CXCR4 receptors for entry, stimulated in these cells the MEK/ERK MAP kinase (MAPK) pathway in a CD4 receptor-dependent manner (Popik and Pitha, 1998). In contrast, both macrophage-tropic SIVmac316 and T cell-tropic SIVmac239, which in addition to CD4 require CCR5 coreceptor for entry, significantly enhanced early MEK/ERK, p38 MAPK, and JNK signaling in Jurkat cells expressing constitutively or transiently the CCR5 receptor. Together, this study provides the evidence that viruses using CXCR4 or CCR5 receptors for entry may differentially use signaling properties of their specific coreceptors to stimulate MAP kinase cascades. In addition, although SIVmac239 and SIVmac316 use different structural domains of the CCR5 receptor for entry, both viruses stimulate early phosphorylation of MEK, ERK, p38, and JNK independently of their tropism and replication
Importance of the Intracytoplasmic Domain of the Simian Immunodeficiency Virus (SIV) Envelope Glycoprotein for Pathogenesis

AbstractSIVmac1A11 and SIVmac239 are nonpathogenic and pathogenic molecular clones in rhesus macaques, respectively. Although these viruses exhibit ∼98% nucleotide and amino acid sequence homology, differences are found in the length of the translation frames for several genes. SIVmac239 has a premature stop codon innef, whereas SIVmac1A11 has a premature stop codon invprand two premature stop codons in the intracytoplasmic domain of theenv-transmembrane (TM) subunit. Recombinant viruses, constructed through reciprocal exchange of large DNA restriction enzyme fragments between SIVmac1A11 and SIVmac239, were evaluated in adult rhesus macaques. Thisin vivoanalysis revealed that two or more regions of the SIVmac genome were essential for high virus load and disease progression (Marthaset al.,1993.J. Virol.67, 6047–6055). An important gap in knowledge remaining from this study was whether the premature stop codons inenv-TM of recombinant virus SIV1A11/239gag-env/1A11 (full-lengthvprandnef, two stop codons inenv-TM) reverted to coding tripletsin vivo. Here, we report that viral sequences in macaques, which succumbed to an AIDS-like disease after infection with SIV1A11/239gag-env/1A11, exhibited reversion of bothenv-TM stop codons. In addition, antibodies to the intracytoplasmic domain ofenv-TM were detected in macaques containing revertant virus and showing disease; this finding indicates that this domain of theenvglycoprotein was expressedin vivo. Thus selection for viral variants with full-lengthenv-TM demonstrated that the cytoplasmic domain of the SIVmacenvglycoprotein plays a role in viral persistence and immunodeficiency in primates
Sequence and Analysis of the Genome of a Baculovirus Pathogenic forLymantria dispar

AbstractThe genome of theLymantria disparmultinucleocapsid nucleopolyhedrovirus (LdMNPV) was sequenced and analyzed. It is composed of 161,046 bases with a G + C content of 57.5% and contains 163 putative open reading frames (ORFs) of ≥150 nucleotides. Homologs were found to 95 of the 155 genes predicted for theAutographa californicaMNPV (AcMNPV) genome. More than 9% of the LdMNPV genome was occupied by 16 repeated genes related to AcMNPV ORF2. Readily identifiable homologs of several genes that have been reported to play important roles in the AcMNPV life cycle are not present; these includeie-2,a transcriptional transactivator, andgp64, a major envelope glycoprotein of the nonoccluded form of the virus. A number of genes lacking in AcMNPV but present in other baculoviruses were identified; these include two viral enhancing factor homologs, a second copy of a conotoxin-like gene, and adutpasehomolog. Although a single gene predicted to encode a large subunit of ribonucleotide reductase was found, two different copies of the small subunit gene were present. In addition, homologs of genes not previously reported for baculoviruses were identified, including a predicted protein with homology to DNA ligases and another that has motifs most closely related to a yeast mitochondrial helicase. Thirteen homologous regions (hrs) containing 54 repeated sequences that include 30-bp imperfect palindromes were identified. The imperfect palindromes are related to those from other baculoviruses
Interferon-β-Induced Human Immunodeficiency Virus Resistance in CD34+Human Hematopoietic Progenitor Cells: Correlation with a Down-Regulation of CCR-5 Expression

AbstractTo explore the possibility of conferring a long-term resistance against human immunodeficiency virus (HIV) by a low continuous production of interferon-β (IFN-β) in hematopoietic progenitor cells, we transduced the human CD34+TF-1 cells with a retroviral vector ensuring IFN-β production. The IFN-β-transduction of TF-1 cells resulted in resistance to infection with HIV-LAI, as shown by the selective survival of IFN-β-transduced CD4+cells and the protection against HIV-induced apoptosis. A similar response against HIV-LAI infection was obtained after pretreatment with 100 U/ml of recombinant IFN-α2b or IFN-β. In contrast, after the addition of macrophage cell tropic (M cell-tropic) HIV strain, a treatment with exogenous IFN-α2b resulted in a ≧10-fold lower protection compared with exogenous IFN-β or IFN-β transduction. This specific effect of IFN-β on M cell-tropic HIV strains was correlated with a down-regulation of the CCR-5 chemokine receptor expression, corresponding to a novel antiviral effect of IFN-β