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https://www.readbyqxmd.com/read/28816583/mammalian-cell-surface-display-for-monoclonal-antibody-based-facs-selection-of-viral-envelope-proteins
#1
Tim-Henrik Bruun, Veronika Grassmann, Benjamin Zimmer, Benedikt Asbach, David Peterhoff, Alexander Kliche, Ralf Wagner
The elicitation of broadly and efficiently neutralizing antibodies in humans by active immunization is still a major obstacle in the development of vaccines against pathogens such as the human immunodeficiency virus (HIV), influenza virus, hepatitis C virus or cytomegalovirus. Here, we describe a mammalian cell surface display and monoclonal antibody (mAb)-mediated panning technology that allows affinity-based selection of envelope (Env) variants from libraries. To this end, we established an experimental setup featuring: 1) single and site specific integration of Env to link genotype and phenotype, 2) inducible Env expression to avoid cytotoxicity effects, 3) translational coupling of Env and enhanced green fluorescent protein expression to normalize for Env protein levels, and 4) display on HEK cells to ensure native folding and mammalian glycosylation...
August 17, 2017: MAbs
https://www.readbyqxmd.com/read/28814388/the-impact-of-poxvirus-vector-priming-protein-co-administration-and-vaccine-intervals-on-hiv-gp120-vaccine-elicited-antibody-magnitude-and-function-in-infant-macaques
#2
Bonnie Phillips, Genevieve G Fouda, Josh Eudailey, Justin Pollara, Alan D Curtis, Erika Kunz, Maria Dennis, Xiaoying Shen, Camden Bay, Michael Hudgens, David Pickup, S Munir Alam, Amir Ardeshir, Pamela A Kozlowski, Koen K A Van Rompay, Guido Ferrari, M Anthony Moody, Sallie Permar, Kristina De Paris
Despite success in reducing vertical HIV transmission by maternal antiretroviral therapy, several obstacles limit its efficacy during breastfeeding, and breast-milk transmission is now the dominant mode of mother-to-child transmission (MTCT) of HIV in infants. Thus, a pediatric vaccine is needed to eradicate oral HIV infections in newborns and infants. Utilizing the infant rhesus macaque model, we compared 3 different vaccine regimens: (i) HIV Env protein only; (ii) a poxvirus vector (MVA)-HIV Env prime/HIV Env protein boost, and (iii) co-administration of HIV Env protein and MVA-HIV Env at all time points...
August 16, 2017: Clinical and Vaccine Immunology: CVI
https://www.readbyqxmd.com/read/28794041/interferon-inducible-cd169-siglec1-attenuates-anti-hiv-1-effects-of-ifn-%C3%AE
#3
Hisashi Akiyama, Nora-Guadalupe Pina Ramirez, Gregory Gibson, Christopher Kline, Simon Watkins, Zandrea Ambrose, Suryaram Gummuluru
A hallmark of HIV-1 infection in vivo is chronic immune activation concomitant with type I interferon (IFN) production. Although type I IFN induces an antiviral state in many cell types, HIV-1 can replicate in vivo via mechanisms that have remained unclear. We have recently identified a type I IFN-inducible protein CD169 as the HIV-1 attachment factor on dendritic cells (DCs) that can mediate robust infection of CD4(+) T cells in trans. Since CD169 expression on macrophages is also induced by type I IFN, we hypothesized that type I IFN-inducible CD169 could facilitate productive HIV-1 infection in myeloid cells in cis and CD4(+) T cells in trans and thus offset antiviral effects of type I IFN...
August 9, 2017: Journal of Virology
https://www.readbyqxmd.com/read/28763028/rous-sarcoma-virus-rna-stability-element-inhibits-deadenylation-of-mrnas-with-long-3-utrs
#4
Vidya Balagopal, Karen L Beemon
All retroviruses use their full-length primary transcript as the major mRNA for Group-specific antigen (Gag) capsid proteins. This results in a long 3' untranslated region (UTR) downstream of the termination codon. In the case of Rous sarcoma virus (RSV), there is a 7 kb 3'UTR downstream of the gag terminator, containing the pol, env, and src genes. mRNAs containing long 3'UTRs, like those with premature termination codons, are frequently recognized by the cellular nonsense-mediated mRNA decay (NMD) machinery and targeted for degradation...
August 1, 2017: Viruses
https://www.readbyqxmd.com/read/28758637/dna-prime-protein-boost-vaccination-elicits-robust-humoral-response-in-rhesus-macaques-using-oligomeric-simian-immunodeficiency-virus-envelope-and-advax-delta-inulin-adjuvant
#5
Veena Menon, Victor I Ayala, Sneha P Rangaswamy, Irene Kalisz, Stephen Whitney, Lindsey Galmin, Asma Ashraf, Celia LaBranche, David Montefiori, Nikolai Petrovsky, Vaniambadi S Kalyanaraman, Ranajit Pal
The partial success of the RV144 trial underscores the importance of envelope-specific antibody responses for an effective HIV-1 vaccine. Oligomeric HIV-1 envelope proteins delivered with a potent adjuvant are expected to elicit strong antibody responses with broad neutralization specificity. To test this hypothesis, two SIV envelope proteins were formulated with delta inulin-based adjuvant (Advax) and used to immunize nonhuman primates. Oligomeric gp140-gp145 from SIVmac251 and SIVsmE660 was purified to homogeneity...
July 31, 2017: Journal of General Virology
https://www.readbyqxmd.com/read/28743743/characterization-of-a-stable-hiv-1-b-c-recombinant-soluble-and-trimeric-envelope-glycoprotein-env-highly-resistant-to-cd4-induced-conformational-changes
#6
Rajesh Kumar, Gabriel Ozorowski, Vivek Kumar, Lauren G Holden, Tripti Shrivastava, Shilpa Patil, Suprit Deshpande, Andrew B Ward, Jayanta Bhattacharya
The HIV-1 envelope (Env) is a glycoprotein which is a trimer of heterodimer containing gp120 and gp41 subunits, mediates virus entry and is a major target of broadly neutralizing antibodies (bnAbs) developed during infection in some individuals. The engagement of the HIV-1 gp120 glycoprotein to the host CD4 protein triggers conformational changes in gp120 that allows its binding to coreceptors, and is necessary for virus entry to establish infection. Native-like HIV-1 Env immunogens representing distinct clades have been proposed to improve immunogenicity of bnAbs...
July 25, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28732035/vaccine-induced-immune-responses-against-both-gag-and-env-improve-control-of-simian-immunodeficiency-virus-replication-in-rectally-challenged-rhesus-macaques
#7
Mauricio A Martins, Young C Shin, Lucas Gonzalez-Nieto, Aline Domingues, Martin J Gutman, Helen S Maxwell, Iris Castro, Diogo M Magnani, Michael Ricciardi, Nuria Pedreño-Lopez, Varian Bailey, Dillon Betancourt, John D Altman, Matthias Pauthner, Dennis R Burton, Benjamin von Bredow, David T Evans, Maoli Yuan, Christopher L Parks, Keisuke Ejima, David B Allison, Eva Rakasz, Glen N Barber, Saverio Capuano, Jeffrey D Lifson, Ronald C Desrosiers, David I Watkins
The ability to control lentivirus replication may be determined, in part, by the extent to which individual viral proteins are targeted by the immune system. Consequently, defining the antigens that elicit the most protective immune responses may facilitate the design of effective HIV-1 vaccines. Here we vaccinated four groups of rhesus macaques with a heterologous vector prime/boost/boost/boost (PBBB) regimen expressing the following simian immunodeficiency virus (SIV) genes: env, gag, vif, rev, tat, and nef (Group 1); env, vif, rev, tat, and nef (Group 2); gag, vif, rev, tat, and nef (Group 3); or vif, rev, tat, and nef (Group 4)...
July 2017: PLoS Pathogens
https://www.readbyqxmd.com/read/28727817/immunogenicity-of-a-novel-clade-b-hiv-1-vaccine-combination-results-of-phase-1-randomized-placebo-controlled-trial-of-an-hiv-1-gm-csf-expressing-dna-prime-with-a-modified-vaccinia-ankara-vaccine-boost-in-healthy-hiv-1-uninfected-adults
#8
Susan P Buchbinder, Nicole A Grunenberg, Brittany J Sanchez, Kelly E Seaton, Guido Ferrari, M Anthony Moody, Nicole Frahm, David C Montefiori, Christine M Hay, Paul A Goepfert, Lindsey R Baden, Harriet L Robinson, Xuesong Yu, Peter B Gilbert, M Juliana McElrath, Yunda Huang, Georgia D Tomaras
BACKGROUND: A phase 1 trial of a clade B HIV vaccine in HIV-uninfected adults evaluated the safety and immunogenicity of a DNA prime co-expressing GM-CSF (Dg) followed by different numbers and intervals of modified vaccinia Ankara Boosts (M). Both vaccines produce virus-like particles presenting membrane-bound Env. METHODS: Four US sites randomized 48 participants to receiving 1/10th the DNA dose as DgDgMMM given at 0, 2, 4, 6 and 8 months, or full dose DgDgM_M or DgDgMM_M regimens, given at 0, 2, 4, and 8 months, and 0, 2, 4, 6, and 10 months, respectively...
2017: PloS One
https://www.readbyqxmd.com/read/28713371/regulation-of-subunit-specific-germinal-center-b-cell-responses-to-the-hiv-1-envelope-glycoproteins-by-antibody-mediated-feedback
#9
Mattias N E Forsell, Linda Kvastad, Saikiran K Sedimbi, John Andersson, Mikael C I Karlsson
The regulation of germinal center (GC) B cell responses to single epitopes is well investigated. How monoclonal B cells are regulated within the polyclonal B cell response to protein antigens is less so. Here, we investigate the primary GC B cell response after injection of mice with HIV-1 envelope glycoproteins. We demonstrate that single GCs are seeded by a diverse number of B cell clones shortly after a single immunization and that the presence of Env-specific antibodies can inhibit the development of early GC B cells...
2017: Frontiers in Immunology
https://www.readbyqxmd.com/read/28701402/increased-durable-b-cell-and-adcc-responses-associated-with-t-helper-responses-to-hiv-1-envelope-in-macaques-vaccinated-with-gp140-occluded-at-the-cd4-receptor-binding-site
#10
Willy M J M Bogers, Susan W Barnett, Herman Oostermeijer, Ivonne G Nieuwenhuis, Niels Beenhakker, Daniella Mortier, Petra Mooij, Gerrit Koopman, Edmund Remarque, Gregoire Martin, Rachel Pei-Jen Lai, Antu K Dey, Yide Sun, Brian Burke, Guido Ferrari, David Montefiori, Loic Martin, David Davis, Indresh Srivastava, Jonathan L Heeney
Strategies are needed to improve the immunogenicity of HIV-1 envelope (Env) antigens for more long lived, efficacious HIV-1 vaccine induced B-cell responses. HIV-1 Env gp140 (native or un-cleaved molecules) or gp120 monomeric proteins elicit relatively poor B-cell responses which are short-lived. We hypothesized that Env engagement of the CD4 receptor on T-helper cells may result in anergic effects on T-cell recruitment and consequently a lack of strong robust and durable B-memory responses. To test this hypothesis we occluded the CD4 binding site (CD4bs) of gp140 by stable cross-linking with a 3kD CD4 miniprotein mimetic serving to block ligation of gp140 on CD4+T-cells while preserving CD4 inducible (CDi) neutralizing and epitopes targeted by antibody dependent cellular cytotoxic (ADCC) effector responses...
July 12, 2017: Journal of Virology
https://www.readbyqxmd.com/read/28701393/hiv-1-env-and-vpu-specific-antibody-dependent-cellular-cytotoxicity-responses-associated-with-elite-control-of-hiv
#11
Vijaya Madhavi, Bruce D Wines, Janaki Amin, Sean Emery, Ester Lopez, Anthony Kelleher, Rob J Center, P Mark Hogarth, Amy W Chung, Stephen J Kent, Ivan Stratov
Studying HIV-infected individuals who control HIV replication (elite controllers, ECs) enable exploration of effective anti-HIV immunity. HIV Env- and non-Env-specific antibody-dependent cellular cytotoxicity (ADCC) may contribute to protection from progressive HIV infection but the evidence is limited. We recruited 22 ECs and matched them with 44 viremic subjects. HIV Env- and Vpu-specific ADCC responses were studied in sera using a novel ELISA-based dimeric recombinant soluble (rs) FcγRIIIa-binding assay, surface plasmon resonance, antibody-dependent natural killer (NK) cell activation assays and ADCC-mediated killing assays...
July 12, 2017: Journal of Virology
https://www.readbyqxmd.com/read/28689233/detection-and-genotyping-of-bovine-leukemia-virus-in-mexican-cattle
#12
Nayely Heinecke, Jorge Tórtora, Humberto A Martínez, Víctor D González-Fernández, Hugo Ramírez
Bovine leukemia virus (BLV) was detected and genotyped in a population of 201 dairy cattle from central Mexico. Using a commercial indirect enzyme-linked immunosorbent assay (iELISA) kit, 118 polymerase chain reaction (PCR)-positive and BLV antibody-positive samples were identified; the concordance between tests was substantial. A phylogenetic study of 27 partial sequences of the env gene gp30 was performed. Four mutations were detected involving the PXXP motif in the cytoplasmic domain of the transmembrane protein...
July 8, 2017: Archives of Virology
https://www.readbyqxmd.com/read/28689085/identification-and-characterization-of-a-naturally-occurring-efficiently-cleaved-membrane-bound-clade-a-hiv-1-env-suitable-for-immunogen-design-with-properties-comparable-to-membrane-bound-bg505
#13
Supratik Das, Saikat Boliar, Sweety Samal, Shubbir Ahmed, Tripti Shrivastava, Brihaspati N Shukla, Sandeep Goswami, Manish Bansal, Bimal K Chakrabarti
Efficient cleavage of HIV-1 Env gp160 into its constituent subunits correlates with selective binding to neutralizing antibodies and are the closest mimetic of native, functional Envs. This was first demonstrated with the clade B Env, JRFL. The correlation between efficient cleavage and selective binding to neutralizing antibodies is the guiding principle for immunogen design for HIV vaccine. We have recently reported that Envs 4-2.J41 (clade C) and JRCSF (clade B) are also efficiently cleaved and show similar properties...
July 6, 2017: Virology
https://www.readbyqxmd.com/read/28688086/sequencing-the-biology-of-entry-the-retroviral-env-gene
#14
Ronald Swanstrom, William D Graham, Shuntai Zhou
The surface envelope protein of any virus is major determinant of the host cell that is infected and as a result a major determinant of viral pathogenesis. Retroviruses have a single surface protein named Env. It is a trimer of heterodimers and is responsible for binding to the host cell receptor and mediating fusion between the viral and host membranes. In this review we will discuss the history of the discovery of the avian leukosis virus (ALV) and human immunodeficiency virus type 1 (HIV-1) Env proteins and their receptor specificity, comparing the many differences but having some similarities...
July 9, 2017: Current Topics in Microbiology and Immunology
https://www.readbyqxmd.com/read/28681118/naturally-occurring-vpr-inhibitors-from-medicinal-plants-of-myanmar
#15
REVIEW
Nwet Nwet Win, Hla Ngwe, Ikuro Abe, Hiroyuki Morita
Human immunodeficiency virus type-1 (HIV-1) is a lentiviral family member that encodes the retroviral Gag, Pol, and Env proteins, along with six additional accessory proteins, Tat, Rev, Vpu, Vif, Nef, and Vpr. The currently approved anti-HIV drugs target the Pol and Env encoded proteins. However, these drugs are only effective in reducing viral replication. Furthermore, the drugs' toxicities and the emergence of drug-resistant strains have become serious worldwide problems. Resistance eventually arises to all of the approved anti-HIV drugs, including the newly approved drugs that target HIV integrase (IN)...
July 5, 2017: Journal of Natural Medicines
https://www.readbyqxmd.com/read/28679769/down-regulation-of-human-endogenous-retrovirus-type-k-herv-k-viral-env-rna-in-pancreatic-cancer-cells-decreases-cell-proliferation-and-tumor-growth
#16
Ming Li, Laszlo G Radvanyi, Bingnan Yin, Jia Li, Raghavender Chivukula, Kevin Lin, Yue Lu, Jianjun Shen, David Z Chang, Donghui Li, Gary L Johanning, Feng Wang-Johanning
We investigated the role of the human endogenous retrovirus type K (HERV-K) envelope (env) gene in pancreatic cancer (PC). <p>Experimental Design: shRNA was employed to knockdown (KD) the expression of HERV-K in PC cells.</p> <p>Results: HERV-K env expression was detected in seven PC cell lines and in 80% of PC patient biopsies, but not in two normal pancreatic cell lines or uninvolved normal tissues. A new HERV-K splice variant was discovered in several PC cell lines. RT activity and virus-like particles were observed in culture media supernatant obtained from Panc-1 and Panc-2 cells...
July 5, 2017: Clinical Cancer Research: An Official Journal of the American Association for Cancer Research
https://www.readbyqxmd.com/read/28678607/hiv-env-conserved-element-dna-vaccine-alters-immunodominance-in-macaques
#17
Xintao Hu, Antonio Valentin, Margherita Rosati, Siriphan Manocheewa, Candido Alicea, Bhabadeb Chowdhury, Jenifer Bear, Kate E Broderick, Niranjan Y Sardesai, Sylvie Le Gall, James I Mullins, George N Pavlakis, Barbara K Felber
Sequence diversity and immunodominance are major obstacles in the design of an effective vaccine against HIV. HIV Env is a highly-glycosylated protein composed of 'conserved' and 'variable' regions. The latter contains immunodominant epitopes that are frequently targeted by the immune system resulting in the generation of immune escape variants. This work describes 12 regions in HIV Env that are highly conserved throughout the known HIV M Group sequences (Env CE), and are poorly immunogenic in macaques vaccinated with full-length Env expressing DNA vaccines...
July 5, 2017: Human Vaccines & Immunotherapeutics
https://www.readbyqxmd.com/read/28667249/conformational-heterogeneity-of-the-hiv-envelope-glycan-shield
#18
Mingjun Yang, Jing Huang, Raphael Simon, Lai-Xi Wang, Alexander D MacKerell
To better understand the conformational properties of the glycan shield covering the surface of the HIV gp120/gp41 envelope (Env) trimer, and how the glycan shield impacts the accessibility of the underlying protein surface, we performed enhanced sampling molecular dynamics (MD) simulations of a model glycosylated HIV Env protein and related systems. Our simulation studies revealed a conformationally heterogeneous glycan shield with a network of glycan-glycan interactions more extensive than those observed to date...
June 30, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28663742/hiv-progression-depends-on-codon-and-amino-acid-usage-profile-of-envelope-protein-and-associated-host-genetic-influence
#19
Ayan Roy, Rachana Banerjee, Surajit Basak
Acquired immune deficiency syndrome (AIDS) is a spectrum of conditions caused by infection with the human immunodeficiency virus (HIV). Two types of HIV have been characterized: HIV-1 and HIV-2. The present study investigated whether evolutionary selection pressure differs between rapid progressor (RP), slow progressor (SP), and long-term non-progressor (LTNP) of HIV-I infected individuals. An unexpected association between the evolutionary rate of substitution in envelope (env) gene and disease progression is observed...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28651004/a-human-endogenous-retrovirus-derived-gene-that-can-contribute-to-oncogenesis-by-activating-the-erk-pathway-and-inducing-migration-and-invasion
#20
Cécile Lemaître, Jhen Tsang, Caroline Bireau, Thierry Heidmann, Marie Dewannieux
Endogenous retroviruses are cellular genes of retroviral origin captured by their host during the course of evolution and represent around 8% of the human genome. Although most are defective and transcriptionally silenced, some are still able to generate retroviral-like particles and proteins. Among these, the HERV-K(HML2) family is remarkable since its members have amplified relatively recently and many of them still have full length coding genes. Furthermore, they are induced in cancers, especially in melanoma, breast cancer and germ cell tumours, where viral particles, as well as the envelope protein (Env), can be detected...
June 2017: PLoS Pathogens
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