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Hiv gag

Julie Yamaguchi, Catherine A Brennan, Elodie Alessandri, Jean-Christophe Plantier, Gavin Cloherty, Michael G Berg
HIV-2 exhibits a natural history of infection distinct from HIV-1. Primarily found in West Africa and in only 10-20% of HIV infections in this region, patients with HIV-2 typically exhibit a slower progression to AIDS, lower viral loads, and decreased rates of transmission. Here we used next-generation sequencing (NGS) to determine the sequence and phylogenetic classification of 9 HIV-2 genomes. We identified a patient with a series of mutations in an invariant cytotoxic lymphocyte (CTL)-restricted gag epitope required for retroviral structure and replication, and implicated in long-term non-progression to AIDS...
October 19, 2016: AIDS Research and Human Retroviruses
T Hertz, M G Logan, M Rolland, C A Magaret, C Rademeyer, A Fiore-Gartland, P T Edlefsen, A DeCamp, H Ahmed, N Ngandu, B B Larsen, N Frahm, J Marais, R Thebus, D Geraghty, J Hural, L Corey, J Kublin, G Gray, M J McElrath, J I Mullins, P B Gilbert, C Williamson
INTRODUCTION: The Merck Adenovirus-5 Gag/Pol/Nef HIV-1 subtype-B vaccine evaluated in predominately subtype B epidemic regions (Step Study), while not preventing infection, exerted vaccine-induced immune pressure on HIV-1 breakthrough infections. Here we investigated if the same vaccine exerted immune pressure when tested in the Phambili Phase 2b study in a subtype C epidemic. MATERIALS AND METHODS: A sieve analysis, which compares breakthrough viruses from placebo and vaccine arms, was performed on 277 near full-length genomes generated from 23 vaccine and 20 placebo recipients...
October 15, 2016: Vaccine
Denis R Chopera, Roman Ntale, Nonkululeko Ndabambi, Nigel Garrett, Clive M Gray, David Matten, Quarraisha Abdool Karim, Salim Abdool Karim, Carolyn Williamson
OBJECTIVE: HIV-1 escape from cytotoxic T-lymphocytes (CTL) results in the accumulation of HLA-associated mutations in the viral genome. To understand the contribution of early escape to disease progression, this study investigated the evolution and pathogenic implications of CTL escape in a cohort followed from infection for five years. METHODS: Viral loads and CD4+ counts were monitored in 78 subtype C infected individuals from onset of infection until CD4+ decline to <350 cells/μl or five years post-infection...
October 14, 2016: AIDS
Naiyin Yu, Abhijit Ghosh, Michael F Hagan
We use computer simulations and simple theoretical models to analyze the morphologies that result when rod-like particles end-attach onto a curved surface, creating a finite-thickness monolayer aligned with the surface normal. This geometry leads to two forms of frustration, one associated with the incompatibility of hexagonal order on surfaces with Gaussian curvature, and the second reflecting the deformation of a layer with finite thickness on a surface with non-zero mean curvature. We show that the latter effect leads to a faceting mechanism...
October 17, 2016: Soft Matter
Mathieu F Chevalier, Céline Didier, Pierre-Marie Girard, Maria E Manea, Pauline Campa, Françoise Barré-Sinoussi, Daniel Scott-Algara, Laurence Weiss
Early events during primary HIV infection (PHI) are thought to influence disease outcome. Although a growing body of evidence suggests a beneficial role of HIV-specific CD4 help in HIV infection, it is unclear how early viral replication, systemic immune activation, and antiretroviral therapy (ART) may shape CD4 T-cell responses during PHI, and whether HIV-specific CD4 responses contribute to the high immune activation observed in PHI. Twenty-seven patients with early PHI were included in a prospective longitudinal study and 12 of them received ART after enrollment...
2016: Frontiers in Immunology
Xintao Hu, Antonio Valentin, Frances Dayton, Viraj Kulkarni, Candido Alicea, Margherita Rosati, Bhabadeb Chowdhury, Rajeev Gautam, Kate E Broderick, Niranjan Y Sardesai, Malcolm A Martin, James I Mullins, George N Pavlakis, Barbara K Felber
HIV sequence diversity and the propensity of eliciting immunodominant responses targeting variable regions of the HIV proteome are hurdles in the development of an effective AIDS vaccine. An HIV-derived conserved element (CE) p24(gag) plasmid DNA (pDNA) vaccine is able to redirect immunodominant responses to otherwise subdominant and often more vulnerable viral targets. By homology to the HIV immunogen, seven CE were identified in SIV p27(Gag) Analysis of 31 rhesus macaques vaccinated with full-length SIV gag pDNA showed inefficient induction (58% response rate) of cellular responses targeting these CE...
October 12, 2016: Journal of Immunology: Official Journal of the American Association of Immunologists
Giuseppina Musumeci, Giacomo Magnani, Isabella Bon, Serena Longo, Alessia Bertoldi, Anna Maria Degli Antoni, Maria Rita Rossi, Alessandro Ruggeri, Vittorio Sambri, Simona Semprini, Laura Sighinolfi, Maria Alessandra Ursitti, Alessandro Zerbini, Vincenzo Colangeli, Leonardo Calza, Alba Carola Finarelli, Erika Massimiliani, Maria Carla Re
It is crucial to establish the timing of infection and distinguish between early and long-lasting HIV-1 infections not only for partner notification and epidemiological surveillance, but also to offer early drug treatment and contain the spread of infection. This study analyzed serum and/or plasma samples with a first positive HIV antibody/antigen result coming from different Medical Centers in the Emilia Romagna Region, North East Italy, using the avidity assay, Western Blotting, RNA viral load, CD4 cell counts and genotyping assay...
September 13, 2016: New Microbiologica
Maria C Bewley, Lisa Reinhart, Matthew S Stake, Shorena Nadaraia-Hoke, Leslie J Parent, John M Flanagan
HIV Gag, a multidomain polyprotein that orchestrates the assembly and release of the human immunodeficiency virus (HIV), is an active target of antiretroviral inhibitor development. However, highly pure, stable, recombinant Gag has been difficult to produce in quantities sufficient for biophysical studies due to its susceptibility to proteolysis by cellular proteases during purification. Stability has been improved by using a construct that omits the p6 domain (deltap6Gag). Since in vivo, p6 is crucial to the budding process and interacts with protein complexes in the ESCRT pathway, it has been difficult to study its role the context of Gag using in vitro approaches...
October 6, 2016: Protein Expression and Purification
Meytal Galilee, Elena Britan-Rosich, Sarah L Griner, Serdar Uysal, Viola Baumgärtel, Don C Lamb, Anthony A Kossiakoff, Moshe Kotler, Robert M Stroud, Ailie Marx, Akram Alian
HIV-1 integrase (IN) catalyzes viral DNA integration into the host genome and facilitates multifunctional steps including virus particle maturation. Competency of IN to form multimeric assemblies is functionally critical, presenting an approach for anti-HIV strategies. Multimerization of IN depends on interactions between the distinct subunit domains and among the flanking protomers. Here, we elucidate an overlooked docking cleft of IN core domain that anchors the N-terminal helix-turn-helix (HTH) motif in a highly preserved and functionally critical configuration...
September 28, 2016: Structure
Robert A Power, Siva Davaniah, Anne Derache, Eduan Wilkinson, Frank Tanser, Ravindra K Gupta, Deenan Pillay, Tulio de Oliveira
BACKGROUND: Genome-wide association studies (GWAS) have considerably advanced our understanding of human traits and diseases. With the increasing availability of whole genome sequences (WGS) for pathogens, it is important to establish whether GWAS of viral genomes could reveal important biological insights. Here we perform the first proof of concept viral GWAS examining drug resistance (DR), a phenotype with well understood genetics. METHOD: We performed a GWAS of DR in a sample of 343 HIV subtype C patients failing 1st line antiretroviral treatment in rural KwaZulu-Natal, South Africa...
2016: PloS One
Alberto C Guardo, Patrick Tjok Joe, L Miralles, M E Bargalló, B Mothe, A Krasniqi, C Heirman, F García, Kris Thielemans, Christian Brander, Joeri L Aerts, Montserrat Plana
BACKGROUND: The development of a prophylactic vaccine against HIV-1 has so far not been successful. Therefore, attention has shifted more and more towards the development of novel therapeutic vaccines. Here, we evaluated a new mRNA based therapeutic vaccine against HIV-1 encoding activation signals (TriMix: CD40L+CD70+caTLRA4) combined with rationally selected antigenic sequences (HTI sequence: comprised of 16 joined fragments from Gag, Pol, Vif and Nef). METHODS: For this purpose, PBMC from HIV-1-infected individuals on cART, lymph node explants from non-infected humans and splenocytes from immunized mice were collected and several immune functions were measured...
September 24, 2016: AIDS
Christelle Daudé, Didier Décimo, Mary-Anne Trabaud, Patrice André, Théophile Ohlmann, Sylvain de Breyne
Human immunodeficiency virus type 1 (HIV-1) unspliced mRNA drives the expression of both Gag and Gag-Pol polyproteins by using both cap- and internal ribosome entry site (IRES)-dependent translation initiation mechanisms. An IRES has been described in the matrix coding region that is involved in the production of shorter isoforms of Gag. However, up to now, this has only been shown with sequences derived from the HIV-1 laboratory strains (NL4.3 and HXB2) and never from clinical HIV-1 isolates. We have isolated ~70 sequences from HIV-1-positive patients that we have sequenced and cloned into an expression vector to monitor their ability to drive translation of Gag p55 and the shorter isoforms both in vitro and ex vivo...
December 2016: Archives of Virology
Zhou Qihui, Zhu Biao
Latent reservoir (LR) of HIV is the cells (such as CD4(+)T cell) where HIV is able to hide. These cellular reservoirs are located throughout the body, including the spleen, lymph nodes, gastrointestinal lymphoid tissues, and become the major obstacle to cure HIV infection. To truly cure patients, a new strategy "shock and kill" was put forward by scientists, which is to shock HIV-infected cells out of hidden reservoirs in the body and then kill them. Quantitatively evaluating the size of long-lived LR is essential to this strategy...
May 25, 2016: Zhejiang da Xue Xue Bao. Yi Xue Ban, Journal of Zhejiang University. Medical Sciences
Nopporn Chutiwitoonchai, Lowela Siarot, Eri Takeda, Tatsuo Shioda, Motoki Ueda, Yoko Aida
HIV-1 budding requires interaction between Gag and cellular TSG101 to initiate viral particle assembly and release via the endosomal sorting complexes required for transport (ESCRT) pathway. However, some reports show that overexpression of TSG101 inhibits virus release by disruption of Gag targeting process. Since a HIV-1 accessory protein, Vpr binds to Gag p6 domain at the position close to the binding site for TSG101, whether Vpr implicates TSG101 overexpression effect has not been investigated. Here, we found that Vpr abrogates TSG101 overexpression effect to rescue viral production...
2016: PloS One
Lauren O'Neil, Kathryn Andenoro, Isabella Pagano, Laura Carroll, Leah Langer, Zachary Dell, Davina Perera, Bradley W Treece, Frank Heinrich, Mathias Lösche, John F Nagle, Stephanie Tristram-Nagle
Efficient assembly of HIV-1 at the plasma membrane (PM) of the T-cell specifically requires PI(4,5)P2. It was previously shown that a highly basic region (HBR) of the matrix protein (MA) on the Gag precursor polyprotein Pr55(Gag) is required for membrane association. MA is N-terminally myristoylated, which enhances its affinity to membranes. In this work we used X-ray scattering and neutron reflectivity to determine how the physical properties and structure of lipid bilayers respond to the addition of binding domain peptides, either in the myristoylated form (MA31myr) or without the myristoyl group (MA31)...
September 15, 2016: Biochimica et Biophysica Acta
Pooja Saxena, Li He, Andrey Malyutin, Siddhartha A K Datta, Alan Rein, Kevin M Bond, Martin F Jarrold, Alessandro Spilotros, Dmitri Svergun, Trevor Douglas, Bogdan Dragnea
Immature human immunodeficiency virus type 1 (HIV-1) is approximately spherical, but is constructed from a hexagonal lattice of the Gag protein. As a hexagonal lattice is necessarily flat, the local symmetry cannot be maintained throughout the structure. This geometrical frustration presumably results in bending stress. In natural particles, the stress is relieved by incorporation of packing defects, but the magnitude of this stress and its significance for the particles is not known. In order to control this stress, we have now assembled the Gag protein on a quasi-spherical template derived from bacteriophage P22...
September 16, 2016: Small
Anne-Marie C Andersson, Emeline Ragonnaud, Kelly E Seaton, Sheetal Sawant, Antonella Folgori, Stefano Colloca, Celia Labranche, David C Montefiori, Georgia D Tomaras, Peter J Holst
The low number of envelope (Env) spikes presented on native HIV-1 particles is a major impediment for HIV-1 prophylactic vaccine development. We designed virus-like particle encoding adenoviral vectors utilizing SIVmac239 Gag as an anchor for full length and truncated HIV-1 M consensus Env. Truncated Env overexpressed VRC01 and 17b binding antigen on the surface of transduced cells while the full length Env vaccine presented more and similar amounts of antigen binding to the trimer conformation sensitive antibodies PGT151 and PGT145, respectively...
October 17, 2016: Vaccine
Daniel Scott-Algara, Josiane Warszawski, Jérôme Le Chenadec, Céline Didier, Thomas Montange, Jean-Paul Viard, Catherine Dollfus, Véronique Avettand-Fenoel, Christine Rouzioux, Stéphane Blanche, Florence Buseyne
In perinatally HIV-1-infected youths living in France, we previously reported that Gag-specific CD4 and CD8 T cell proliferation is more frequently detected in patients of black ethnicity than in those of other ethnicities. We observed that black patients had higher levels of dendritic cells (DCs) than other patients. We aimed at studying the association of DC levels with Gag-specific T cell proliferation. The ANRS-EP38-IMMIP study is an observational study of youths aged between 15 and 24 years who were perinatally infected with HIV...
October 12, 2016: AIDS Research and Human Retroviruses
Mauricio Comas-Garcia, Sean R Davis, Alan Rein
Like other retroviruses, human immunodeficiency virus type 1 (HIV-1) selectively packages genomic RNA (gRNA) during virus assembly. However, in the absence of the gRNA, cellular messenger RNAs (mRNAs) are packaged. While the gRNA is selected because of its cis-acting packaging signal, the mechanism of this selection is not understood. The affinity of Gag (the viral structural protein) for cellular RNAs at physiological ionic strength is not much higher than that for the gRNA. However, binding to the gRNA is more salt-resistant, implying that it has a higher non-electrostatic component...
2016: Viruses
Elodie Mailler, Serena Bernacchi, Roland Marquet, Jean-Christophe Paillart, Valérie Vivet-Boudou, Redmond P Smyth
Human immunodeficiency virus type 1 (HIV-1) replication is a highly regulated process requiring the recruitment of viral and cellular components to the plasma membrane for assembly into infectious particles. This review highlights the recent process of understanding the selection of the genomic RNA (gRNA) by the viral Pr55(Gag) precursor polyprotein, and the processes leading to its incorporation into viral particles.
2016: Viruses
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