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Nadejda Beliakova-Bethell, Marjan Hezareh, Joseph K Wong, Matthew C Strain, Mary K Lewinski, Douglas D Richman, Celsa A Spina
Quantification of cell-associated replication-competent HIV, in blood samples from patients with undetectable plasma viremia, requires specialized culture conditions that include exogenous pan T cell stimulation. Different research groups have used several stimuli for this purpose; however, the relative efficacies of these T cell stimuli to induce productive HIV replication from latently infected cells ex vivo have not been systematically evaluated. To this end, we compared four commonly used T cell stimuli: 1) irradiated allogeneic cells plus phytohaemagglutinin (PHA); 2) PHA alone; 3) phorbol myristate acetate plus Ionomycin; and 4) immobilized αCD3 plus αCD28 antibodies...
May 17, 2017: Virology
Gabriel Lihue Rojo, Stephanie Goya, Mariana Orellana, Andrea Sancilio, Alberto Rodriguez Perez, César Montali, Carolina García, Lilian Sosa, Alejandra Musto, Daniela Alvarez, Alejandro Castello, Mariana Viegas
Respiratory syncytial virus (RSV) is the main viral cause of hospitalization due to acute lower respiratory tract infections in infants worldwide. Several vaccines against RSV are under research and development, which are about to be approved. We evaluated transmission patterns in different settings to determine age-specific vaccination targets from a viral perspective. We sequenced the G glycoprotein's ectodomain of a constant clinical sampling between two epidemic outbreaks in a limited geographical region and performed phylogeographic analyses...
May 17, 2017: Virology
Ajeet Singh, Vipin Permar, R K Jain, Suneha Goswami, Ranjeet Ranjan Kumar, Tomas Canto, Peter Palukaitis, Shelly Praveen
Groundnut bud necrosis virus induces necrotic symptoms in different hosts. Previous studies showed reactive oxygen species-mediated programmed cell death (PCD) resulted in necrotic symptoms. Transgenic expression of viral protein NSs mimics viral symptoms. Here, we showed a role for NSs in influencing oxidative burst in the cell, by analyzing H2O2 accumulation, activities of antioxidant enzymes and expression levels of vacuolar processing enzymes, H2O2-responsive microRNA 319a.2 plus its possible target metacaspase-8...
May 17, 2017: Virology
Nicole Espy, Beatriz Pacheco, Joseph Sodroski
The binding of the human immunodeficiency virus (HIV-1) envelope glycoprotein (Env) trimer ((gp120/gp41)3) to the receptors CD4 and CCR5 triggers virus entry into host cells. To identify Env regions that respond to CCR5 binding, HIV-1 was serially passaged on a CD4-positive canine cell line expressing progressively lower levels of CCR5. HIV-1 replication was observed in cells expressing ~1300 CCR5 molecules/cell. Env changes that conferred this low-CCR5 replication phenotype were located outside of the known CCR5-binding region of the gp120 Env subunit and did not apparently increase CCR5 binding affinity...
May 15, 2017: Virology
Anna Koromyslova, Shailesh Tripathi, Vasily Morozov, Horst Schroten, Grant S Hansman
Human noroviruses are the leading cause of outbreaks of acute gastroenteritis. Norovirus interactions with histo-blood group antigens (HBGAs) are known to be important for an infection. In this study, we identified the HBGA binding pocket for an emerging GII genotype 17 (GII.17) variant using X-ray crystallography. The GII.17 variant bound the HBGA with an equivalent set of residues as the leading pandemic GII.4 variants. These structural data highlights the conserved nature of HBGA binding site between prevalent GII noroviruses...
May 12, 2017: Virology
Raquel S Portugal, Anja Bauer, Guenther M Keil
African swine fever virus threatens pig production worldwide due to the lack of vaccines, for which generation of both deletion and insertion mutants is considered. For development of the latter, operational ASFV promoters of different temporal regulation and strengths are desirable. We therefore compared the capacities of putative promoter sequences from p72, CD2v, p30, viral DNA polymerase and U104L genes to mediate expression of luciferase from transfected plasmids after activation in trans, or p30-, DNA polymerase- and U104L promoters in cis, using respective ASFV recombinants...
May 11, 2017: Virology
Mallory E Harden, Karl Munger
Extracellular vesicles released by cancer cells are mediators of intercellular communication that have been reported to contribute to carcinogenesis. Since they are readily detected in bodily fluids, they may also be used as cancer biomarkers. The E6/E7 oncoproteins drive human papillomavirus (HPV)-associated cancers, which account for approximately 5% of all human cancers worldwide. Here, we investigate how HPV16 E6/E7 oncogene expression in primary human epithelial cells alters miR expression in extracellular vesicles and compare these to changes in intracellular miR expression...
May 10, 2017: Virology
Elisabetta Manaresi, Ilaria Conti, Gloria Bua, Francesca Bonvicini, Giorgio Gallinella
Central to genetic studies for Parvovirus B19 (B19V) is the availability of genomic clones that may possess functional competence and ability to generate infectious virus. In our study, we established a new model genetic system for Parvovirus B19. A synthetic approach was followed, by design of a reference genome sequence, by generation of a corresponding artificial construct and its molecular cloning in a complete and functional form, and by setup of an efficient strategy to generate infectious virus, via transfection in UT7/EpoS1 cells and amplification in erythroid progenitor cells...
May 10, 2017: Virology
Guanlong Xu, Xuxiao Zhang, Qinfang Liu, Guoxia Bing, Zhe Hu, Honglei Sun, Xin Xiong, Ming Jiang, Qiming He, Yu Wang, Juan Pu, Xin Guo, Hanchun Yang, Jinhua Liu, Yipeng Sun
Previous studies have identified a functional role of PA-X for influenza viruses in mice and avian species; however, its role in swine remains unknown. Toward this, we constructed PA-X deficient virus (Sw-FS) in the background of a Triple-reassortment (TR) H1N2 swine influenza virus (SIV) to assess the impact of PA-X in viral virulence in pigs. Expression of PA-X in TR H1N2 SIV enhanced viral replication and host protein synthesis shutoff, and inhibited the mRNA levels of type I IFNs and proinflammatory cytokines in porcine cells...
May 8, 2017: Virology
Akihiro Sugai, Hiroki Sato, Misako Yoneda, Chieko Kai
The regulation of transcription during Nipah virus (NiV) replication is poorly understood. Using a bicistronic minigenome system, we investigated the involvement of non-coding regions (NCRs) in the transcriptional re-initiation efficiency of NiV RNA polymerase. Reporter assays revealed that attenuation of NiV gene expression was not constant at each gene junction, and that the attenuating property was controlled by the 3' NCR. However, this regulation was independent of the gene-end, gene-start and intergenic regions...
May 8, 2017: Virology
R Eberle, L K Maxwell, S Nicholson, D Black, L Jones-Engel
Complete genome sequences of 19 strains of monkey B virus (Macacine alphaherpesvirus 1; BV) isolated from several macaque species were determined. A low level of sequence variation was present among BV isolates from rhesus macaques. Most variation among BV strains isolated from rhesus macaques was located in regions of repetitive or quasi-repetitive sequence. Variation in coding sequences (polypeptides and miRNAs) was minor compared to regions of non-coding sequences. Non-coding sequences in the long and short repeat regions of the genome did however exhibit islands of conserved sequence...
May 7, 2017: Virology
Hsin-Ching Lin, Peter J Simon, Riza M Ysla, Steven L Zeichner, Gary Brewer, Arnold B Rabson
Regulation of expression of HTLV-1 gene products from integrated proviruses plays an important role in HTLV-1-associated disease pathogenesis. Previous studies have shown that T cell receptor (TCR)- and phorbol ester (PMA) stimulation of chronically infected CD4 T cells increases the expression of integrated HTLV-1 proviruses in latently infected cells, however the mechanism remains unknown. Analysis of HTLV-1 RNA and protein species following PMA treatment of the latently HTLV-1-infected, FS and SP T cell lines demonstrated rapid induction of tax/rex mRNA...
May 4, 2017: Virology
Hideki Kondo, Keisuke Hirota, Kazuyuki Maruyama, Ida Bagus Andika, Nobuhiro Suzuki
Orchid fleck virus (OFV) represents a rhabdovirus with a unique bipartite genome. OFV genetic diversity at the whole genome level has not been described. Using the partial genome sequence of RNA1, we have determined that several OFV isolates derived from orchids in Japan belong to two genetically distant subgroups: subgroup I, the members of which are distributed worldwide but previously not known in Asia, and subgroup II, which is commonly distributed in Japan. However, complete genome sequence analysis of a novel Japanese subgroup I isolate revealed that although its RNA1 sequence differs considerably from those of subgroup II isolates, its RNA2 sequence is almost identical to them...
May 4, 2017: Virology
Elinor Willis, Scott E Hensley
Zika viruses (ZIKVs) are circulating in parts of the world endemic for other flavivirus infections. Some cross-reactive antibodies (Abs) elicited by prior flavivirus exposures can bind to ZIKV and enhance infection of Fc receptor-bearing cells. Here, we measured ZIKV binding of 54 murine monoclonal Abs (mAbs) elicited by exposure with Dengue virus and West Nile virus antigens. We found that 8 of 54 mAbs recognized the envelope protein of ZIKV in conventional binding assays. These 8 cross-reactive mAbs have different specificities; most recognize the DI/II region of the envelope protein but one mAb recognized the DIII lateral ridge of the envelope protein...
May 2, 2017: Virology
Jianbo Liu, Hongyan Shi, Jianfei Chen, Xin Zhang, Zhaoyang Ji, Jing Yuan, Da Shi, Liyan Cao, Xiangdong Zhu, Hui Dong, Xiaobo Wang, Jialin Zhang, Li Feng
Porcine epidemic diarrhea virus (PEDV) has two genotypes, G1 and G2. To research the immunogenicity differences of PEDV G1 and G2 genotype strains and obtain a neutralizing monoclonal antibody (mAb), we inoculated specific-pathogen-free BALB/c mice with a newly emerged strain, PEDV-LNCT2. After immunizations, cells from the spleen of the mice were fused with SP2/0 myeloma cells. Following culturing and subcloning, a strain, 1B9, secreting neutralizing antibody, was obtained. The 1B9 mAb neutralized new variant genotype 2 PEDV strains (LNCT2, LNSY, and Hjms), but it did not neutralize a genotype 1 PEDV strain (CV777), in vitro...
April 29, 2017: Virology
Lydia R Meador, Sarah A Kessans, Jacquelyn Kilbourne, Karen V Kibler, Giuseppe Pantaleo, Mariano Esteban Roderiguez, Joseph N Blattman, Bertram L Jacobs, Tsafrir S Mor
Showing modest efficacy, the RV144 HIV-1 vaccine clinical trial utilized a non-replicating canarypox viral vector and a soluble gp120 protein boost. Here we built upon the RV144 strategy by developing a novel combination of a replicating, but highly-attenuated Vaccinia virus vector, NYVAC-KC, and plant-produced HIV-1 virus-like particles (VLPs). Both components contained the full-length Gag and a membrane anchored truncated gp41 presenting the membrane proximal external region with its conserved broadly neutralizing epitopes in the pre-fusion conformation...
April 27, 2017: Virology
Jason M Biegel, Eric Henderson, Erica M Cox, Gaston Bonenfant, Rachel Netzband, Samantha Kahn, Rachel Eager, Cara T Pager
Hepatitis C virus (HCV) subverts the cellular DEAD-box RNA helicase DDX6 to promote virus infection. Using polysome gradient analysis and the subgenomic HCV Renilla reporter replicon genome, we determined that DDX6 does not affect HCV translation. Rather expression of the subgenomic HCV Renilla luciferase reporter at late times, as well as labeling of newly synthesized viral RNA with 4-thiouridine showed that DDX6 modulates replication. Because DDX6 is an effector protein of the microRNA pathway, we also investigated its role in miR-122-directed HCV gene expression...
April 26, 2017: Virology
Lena N Lupey-Green, Stephanie A Moquin, Kayla A Martin, Shane M McDevitt, Michael Hulse, Lisa B Caruso, Richard T Pomerantz, Jj L Miranda, Italo Tempera
The Epstein Barr virus (EBV) genome persists in infected host cells as a chromatinized episome and is subject to chromatin-mediated regulation. Binding of the host insulator protein CTCF to the EBV genome has an established role in maintaining viral latency type, and in other herpesviruses, loss of CTCF binding at specific regions correlates with viral reactivation. Here, we demonstrate that binding of PARP1, an important cofactor of CTCF, at the BZLF1 lytic switch promoter restricts EBV reactivation. Knockdown of PARP1 in the Akata-EBV cell line significantly increases viral copy number and lytic protein expression...
April 26, 2017: Virology
Dong-Hun Lee, Mia Kim Torchetti, Mary Lea Killian, David E Swayne
In mid-January 2016, an outbreak of H7N8 high-pathogenicity avian influenza virus (HPAIV) in commercial turkeys occurred in Indiana. Surveillance within the 10km control zone identified H7N8 low-pathogenicity avian influenza virus (LPAIV) in nine surrounding turkey flocks but no other HPAIV-affected premises. We sequenced four of the H7N8 HPAIV isolated from the single farm and nine LPAIV identified during control zone surveillance. Evaluation included phylogenetic network analysis indicating close relatedness across the HPAIV and LPAIV, and that the progenitor H7N8 LPAIV spread among the affected turkey farms in Indiana, followed by spontaneous mutation to HPAIV on a single premise through acquisition of three basic amino acids at the hemagglutinin cleavage site...
April 26, 2017: Virology
Jiagang Tu, Taehyun Park, Dustin R Morado, Kelly T Hughes, Ian J Molineux, Jun Liu
Bacteriophage SP6 exhibits dual-host adsorption specificity. The SP6 tailspikes are recognized as important in host range determination but the mechanisms underlying dual host specificity are unknown. Cryo-electron tomography and sub-tomogram classification were used to analyze the SP6 virion with a particular focus on the interaction of tailspikes with host membranes. The SP6 tail is surrounded by six V-shaped structures that interconnect in forming a hand-over-hand hexameric garland. Each V-shaped structure consists of two trimeric tailspike proteins: gp46 and gp47, connected through the adaptor protein gp37...
April 26, 2017: Virology
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