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Artykuły w czasopismach na temat "Env ectodomain gp140"
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McKenna, Philip M., Roger J. Pomerantz, Bernhard Dietzschold, James P. McGettigan i Matthias J. Schnell. "Covalently Linked Human Immunodeficiency Virus Type 1 gp120/gp41 Is Stably Anchored in Rhabdovirus Particles and Exposes Critical Neutralizing Epitopes". Journal of Virology 77, nr 23 (1.12.2003): 12782–94. http://dx.doi.org/10.1128/jvi.77.23.12782-12794.2003.
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ABSTRACT Rabies virus (RV) vaccine strain-based vectors show significant promise as potential live-attenuated vaccines against human immunodeficiency virus type 1 (HIV-1). Here we describe a new RV construct that will also likely have applications as a live-attenuated or killed-particle immunogen. We have created a RV containing a chimeric HIV-1 Env protein, which contains introduced cysteine residues that give rise to an intermolecular disulfide bridge between gp120 and the ectodomain of gp41. This covalently linked gp140 (gp140 SOS) is fused in frame to the cytoplasmic domain of RV G glycoprotein and is efficiently incorporated into the RV virion. On the HIV-1 virion, the gp120 and gp41 moieties are noncovalently associated, which leads to extensive shedding of gp120 from virions and virus-infected cells. The ability to use HIV-1 particles as purified, inactivated immunogens has been confounded by the loss of gp120 during preparation. Additionally, monomeric gp120 and uncleaved gp160 molecules have been shown to be poor antigenic representations of virion-associated gp160. Because the gp120 and gp41 portions are covalently attached in the gp140 SOS molecule, the protein is maintained on the surface of the RV virion throughout purification. Surface immunostaining and fluorescence-activated cell sorting analysis with anti-envelope antibodies show that the gp140 SOS protein is stably expressed on the surface of infected cells and maintains CD4 binding capabilities. Furthermore, Western blot and immunoprecipitation experiments with infected-cell lysates and purified virions show that a panel of neutralizing anti-envelope antibodies efficiently recognize the gp140 SOS protein. The antigenic properties of this recombinant RV particle containing covalently attached Env, as well as the ability to present Env in a membrane-bound form, suggest that this approach could be a useful component of a HIV-1 vaccine strategy.
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Earl, Patricia L., Wataru Sugiura, David C. Montefiori, Christopher C. Broder, Susan A. Lee, Carl Wild, Jeffrey Lifson i Bernard Moss. "Immunogenicity and Protective Efficacy of Oligomeric Human Immunodeficiency Virus Type 1 gp140". Journal of Virology 75, nr 2 (15.01.2001): 645–53. http://dx.doi.org/10.1128/jvi.75.2.645-653.2001.
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ABSTRACT The biologically active form of the human immunodeficiency virus type 1 (HIV-1) envelope (Env) glycoprotein is oligomeric. We previously described a soluble HIV-1 IIIB Env protein, gp140, with a stable oligomeric structure composed of uncleaved gp120 linked to the ectodomain of gp41 (P. L. Earl, C. C. Broder, D. Long, S. A. Lee, J. Peterson, S. Chakrabarti, R. W. Doms, and B. Moss, J. Virol. 68:3015–3026, 1994). Here we compared the antibody responses of rabbits to gp120 and gp140 that had been produced and purified in an identical manner. The gp140 antisera exhibited enhanced cross-reactivity with heterologous Env proteins as well as greater neutralization of HIV-1 compared to the gp120 antisera. To examine both immunogenicity and protective efficacy, we immunized rhesus macaques with oligomeric gp140. Strong neutralizing antibodies against a homologous virus and modest neutralization of heterologous laboratory-adapted isolates were elicited. No neutralization of primary isolates was observed. However, a substantial fraction of the neutralizing activity could not be blocked by a V3 loop peptide. After intravenous challenge with simian-HIV virus SHIV-HXB2, three of the four vaccinated macaques exhibited no evidence of virus replication.
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Sanders, Rogier W., Mika Vesanen, Norbert Schuelke, Aditi Master, Linnea Schiffner, Roopa Kalyanaraman, Maciej Paluch i in. "Stabilization of the Soluble, Cleaved, Trimeric Form of the Envelope Glycoprotein Complex of Human Immunodeficiency Virus Type 1". Journal of Virology 76, nr 17 (1.09.2002): 8875–89. http://dx.doi.org/10.1128/jvi.76.17.8875-8889.2002.
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ABSTRACT The envelope glycoprotein (Env) complex of human immunodeficiency virus type 1 has evolved a structure that is minimally immunogenic while retaining its natural function of receptor-mediated virus-cell fusion. The Env complex is trimeric; its six individual subunits (three gp120 and three gp41 subunits) are associated by relatively weak, noncovalent interactions. The induction of neutralizing antibodies after vaccination with individual Env subunits has proven very difficult, probably because they are inadequate mimics of the native complex. Our hypothesis is that a stable form of the Env complex, perhaps with additional modifications to rationally alter its antigenic structure, may be a better immunogen than the individual subunits. A soluble form of Env, SOS gp140, can be made that has gp120 stably linked to the gp41 ectodomain by an intermolecular disulfide bond. This protein is fully cleaved at the proteolysis site between gp120 and gp41. However, the gp41-gp41 interactions in SOS gp140 are too weak to maintain the protein in a trimeric configuration. Consequently, purified SOS gp140 is a monomer (N. Schülke, M. S. Vesanen, R. W. Sanders, P. Zhu, D. J. Anselma, A. R. Villa, P. W. H. I. Parren, J. M. Binley, K. H. Roux, P. J. Maddon, J. P. Moore, and W. C. Olson, J. Virol. 76:7760-7776, 2002). Here we describe modifications of SOS gp140 that increase its trimer stability. A variant SOS gp140, designated SOSIP gp140, contains an isoleucine-to-proline substitution at position 559 in the N-terminal heptad repeat region of gp41. This protein is fully cleaved, has favorable antigenic properties, and is predominantly trimeric. SOSIP gp140 trimers are noncovalently associated and can be partially purified by gel filtration chromatography. These gp140 trimers are dissociated into monomers by anionic detergents or heat but are relatively resistant to nonionic detergents, high salt concentrations, or exposure to a mildly acidic pH. SOSIP gp140 should be a useful reagent for structural and immunogenicity studies.
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Cai, Yongfei, Selen Karaca-Griffin, Jia Chen, Sai Tian, Nicholas Fredette, Christine E. Linton, Sophia Rits-Volloch i in. "Antigenicity-defined conformations of an extremely neutralization-resistant HIV-1 envelope spike". Proceedings of the National Academy of Sciences 114, nr 17 (10.04.2017): 4477–82. http://dx.doi.org/10.1073/pnas.1700634114.
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The extraordinary genetic diversity of the HIV-1 envelope spike [Env; trimeric (gp160)3, cleaved to (gp120/gp41)3] poses challenges for vaccine development. Envs of different clinical isolates exhibit different sensitivities to antibody-mediated neutralization. Envs of difficult-to-neutralize viruses are thought to be more stable and conformationally homogeneous trimers than those of easy-to-neutralize viruses, thereby providing more effective concealment of conserved, functionally critical sites. In this study we have characterized the antigenic properties of an Env derived from one of the most neutralization-resistant HIV-1 isolates, CH120.6. Sequence variation at neutralizing epitopes does not fully account for its exceptional resistance to antibodies. The full-length, membrane-bound CH120.6 Env is indeed stable and conformationally homogeneous. Its antigenicity correlates closely with its neutralization sensitivity, and major changes in antigenicity upon CD4 engagement appear to be restricted to the coreceptor site. The CH120.6 gp140 trimer, the soluble and uncleaved ectodomain of (gp160)3, retains many antigenic properties of the intact Env, consistent with a conformation close to that of Env spikes on a virion, whereas its monomeric gp120 exposes many nonneutralizing or strain-specific epitopes. Thus, trimer organization and stability are important determinants not only for occluding many epitopes but also for conferring resistance to neutralization by all but a small set of antibodies. Env preparations derived from neutralization-resistant viruses may induce irrelevant antibody responses less frequently than do other Envs and may be excellent templates for developing soluble immunogens.
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Ringe, Rajesh P., Anila Yasmeen, Gabriel Ozorowski, Eden P. Go, Laura K. Pritchard, Miklos Guttman, Thomas A. Ketas i in. "Influences on the Design and Purification of Soluble, Recombinant Native-Like HIV-1 Envelope Glycoprotein Trimers". Journal of Virology 89, nr 23 (26.08.2015): 12189–210. http://dx.doi.org/10.1128/jvi.01768-15.
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ABSTRACTWe have investigated factors that influence the production of native-like soluble, recombinant trimers based on theenvgenes of two isolates of human immunodeficiency virus type 1 (HIV-1), specifically 92UG037.8 (clade A) and CZA97.012 (clade C). When the recombinant trimers based on theenvgenes of isolates 92UG037.8 and CZA97.012 were made according to the SOSIP.664 design and purified by affinity chromatography using broadly neutralizing antibodies (bNAbs) against quaternary epitopes (PGT145 and PGT151, respectively), the resulting trimers are highly stable and they are fully native-like when visualized by negative-stain electron microscopy. They also have a native-like (i.e., abundant) oligomannose glycan composition and display multiple bNAb epitopes while occluding those for nonneutralizing antibodies. In contrast, uncleaved, histidine-tagged Foldon (Fd) domain-containing gp140 proteins (gp140UNC-Fd-His), based on the sameenvgenes, very rarely form native-like trimers, a finding that is consistent with their antigenic and biophysical properties and glycan composition. The addition of a 20-residue flexible linker (FL20) between the gp120 and gp41 ectodomain (gp41ECTO) subunits to make the uncleaved 92UG037.8 gp140-FL20 construct is not sufficient to create a native-like trimer, but a small percentage of native-like trimers were produced when an I559P substitution in gp41ECTOwas also present. The further addition of a disulfide bond (SOS) to link the gp120 and gp41 subunits in the uncleaved gp140-FL20-SOSIP protein increases native-like trimer formation to ∼20 to 30%. Analysis of the disulfide bond content shows that misfolded gp120 subunits are abundant in uncleaved CZA97.012 gp140UNC-Fd-His proteins but very rare in native-like trimer populations. The design and stabilization method and the purification strategy are, therefore, all important influences on the quality of trimeric Env proteins and hence their suitability as vaccine components.IMPORTANCESoluble, recombinant multimeric proteins based on the HIV-1envgene are current candidate immunogens for vaccine trials in humans. These proteins are generally designed to mimic the native trimeric envelope glycoprotein (Env) that is the target of virus-neutralizing antibodies on the surfaces of virions. The underlying hypothesis is that an Env-mimetic protein may be able to induce antibodies that can neutralize the virus broadly and potently enough for a vaccine to be protective. Multiple different designs for Env-mimetic trimers have been put forth. Here, we used the CZA97.012 and 92UG037.8envgenes to compare some of these designs and determine which ones best mimic virus-associated Env trimers. We conclude that the most widely used versions of CZA97.012 and 92UG037.8 oligomeric Env proteins do not resemble the trimeric Env glycoprotein on HIV-1 viruses, which has implications for the design and interpretation of ongoing or proposed clinical trials of these proteins.
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Doranz, Benjamin J., Sarah S. W. Baik i Robert W. Doms. "Use of a gp120 Binding Assay To Dissect the Requirements and Kinetics of Human Immunodeficiency Virus Fusion Events". Journal of Virology 73, nr 12 (1.12.1999): 10346–58. http://dx.doi.org/10.1128/jvi.73.12.10346-10358.1999.
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ABSTRACT Binding of the extracellular subunit of human immunodeficiency type 1 (HIV-1) envelope (Env) glycoprotein (gp120) to CD4 triggers the induction or exposure of a highly conserved coreceptor binding site in gp120 that helps mediate membrane fusion. Characterizing the structural features involved in gp120-coreceptor binding and the conditions under which binding occurs is important for understanding the fusion process, the evolution of pathogenic strains in vivo, the identification of novel anti-HIV compounds, and the development of HIV vaccines that utilize triggered structures of Env. Here we use the kinetics of interaction between CCR5 and gp120 to understand temporal and structural changes that occur during viral fusion. Using saturation binding and homologous competition analysis, we estimated theKd of interaction between CCR5 and gp120 from the macrophage tropic HIV-1 strain JRFL to be 4 nM. Unlike Env-mediated fusion, gp120 binding to CCR5 did not require divalent cations or elevated temperatures. Binding was not significantly affected by the pH of binding, G-protein coupling of CCR5, or partial gp120 deglycosylation. Oligomeric, uncleaved JRFL gp140 failed to bind CCR5 despite its ability to bind CD4 and monoclonal antibody 17b, suggesting that the uncleaved ectodomain of gp41 interferes with full exposure of the chemokine receptor binding site. Exposure of the chemokine receptor binding site on gp120 could be induced rapidly by CD4, but exposure of this site was lost upon CD4 dissociation from gp120, indicating that the conformational changes in gp120 induced by CD4 binding are fully reversible. The functional gp120-soluble CD4 complex was remarkably stable over time and temperature ranges, offering the possibility that complexes in which the highly conserved coreceptor binding site in gp120 is exposed can be used for vaccine development.
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Rao, Mangala, Kristina Peachman, Ousman Jobe, Alice Kuaban, Erik Billings, Guofen Guao, Lindsay Wieczorek i in. "Induction of linear and conformational V2-specific antibodies using HIV-1 gp145 clade B envelope protein as the immunogen (P4505)". Journal of Immunology 190, nr 1_Supplement (1.05.2013): 179.15. http://dx.doi.org/10.4049/jimmunol.190.supp.179.15.
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Abstract TThe potential importance of binding antibodies (Abs) in preventing HIV-1 acquisition was recently demonstrated by the case control analysis of the RV144 phase III HIV-1 vaccine trial, which showed that binding Abs to a gp70 scaffolded V1V2 loop of gp120 correlated inversely with infection. We examined if immunization with a HIV-1 env trimer in the absence of any priming vector could induce functional V2-specific Abs. The clade B HIV-1 gp145 env protein consisting of gp120, gp41 ectodomain, and MPER, trimerized with foldon was expressed in 293F cells and purified. The protein adjuvanted with liposomes containing lipid A was used to immunize New Zealand white rabbits. Strong Ab binding titers (50,000-400,000) were induced to env epitopes including V2 and V3 peptides (linear) and MuLV gp70-scaffolded V1V2 protein (conformational) as measured by ELISA and Biacore. The sera neutralized infectious molecular clones and pseudoviruses in PBMC, monocyte-derived macrophage, and TZM-bl assays. Purified IgG neutralized primary US-1 in a dose-dependent manner in the macrophage assay. Depletion of linear V2 or V3 epitope-specific Abs retained the conformation-specific gp70 V1V2 binding Abs and did not completely abolish neutralization. Further depletion of gp70 V1V2-specific Abs significantly reduced neutralization. These data indicate that gp145 trimers induce linear as well as conformational V2-specific antibodies and might be a good candidate for designing a preventative HIV-1 vaccine.
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Kalia, Vandana, Surojit Sarkar, Phalguni Gupta i Ronald C. Montelaro. "Antibody Neutralization Escape Mediated by Point Mutations in the Intracytoplasmic Tail of Human Immunodeficiency Virus Type 1 gp41". Journal of Virology 79, nr 4 (15.02.2005): 2097–107. http://dx.doi.org/10.1128/jvi.79.4.2097-2107.2005.
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ABSTRACT The persistence of human immunodeficiency virus type 1 (HIV-1) infection in the presence of robust host immunity has been associated in part with variation in viral envelope proteins leading to antigenic variation and escape from neutralizing antibodies. Previous studies of natural neutralization escape mutants have predominantly focused on gp120 and gp41 ectodomain sequence variations that alter antibody binding via changes in conformation or glycosylation pattern of the Env, likely due to the immune pressure exerted on the exposed ectodomain component of the glycoprotein. Here, we show for the first time a novel mechanism by which point mutations in the intracytoplasmic tail of the transmembrane component (gp41) of envelope can render the virus resistant to neutralization by monoclonal antibodies and broadly neutralizing polyclonal serum antibodies. Point mutations in a highly conserved structural motif within the intracytoplasmic tail resulted in decreased binding of neutralizing antibodies to the Env ectodomain, evidently due to allosteric changes both in the gp41 ectodomain and in gp120. While receptor binding and infectivity of the mutant virus remained unaltered, the changes in Env antigenicity were associated with an increase in neutralization resistance of the mutant virus. These studies demonstrate the structurally integrated nature of gp120 and gp41 and underscore a previously unrecognized potentially critical role for even minor sequence variation of the intracytoplasmic tail in modulating the antigenicity of the ectodomain of HIV-1 envelope glycoprotein complex.
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Kwong, Peter. "HIV-1 Env structure and vaccine design". Acta Crystallographica Section A Foundations and Advances 70, a1 (5.08.2014): C117. http://dx.doi.org/10.1107/s2053273314098829.
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Roughly one third of the HIV-1 genome is devoted to the HIV-1 envelope (Env) glycoprotein spike, which comprises three gp120 and three gp41 subunits. Structural characterization of the HIV-1 Env by electron microscopy, NMR, and X-ray crystallography reveals considerable conformational alterations, not only between trimeric ground state, CD4 receptor-bound conformation, and postfusion conformation of the spike, but also between monomeric and trimeric configurations of the subunits as well as between free- and antibody–bound states. One important structure, however, that of the prefusion HIV-1 spike, has resisted atomic level determination. This structure has been on the 10 list of most wanted structure for more than 20 years, because it is the target of the majority of broad HIV-1-neutralizing antibodies – and therefore of importance to vaccine design. In late 2013, the structure of a prefusion HIV-1 spike, based on a BG505 SOSIP.R6.664 construct, was reported by both X-ray crystallography (4.7 Å) and electron microscopy (5.8 Å). While these structures described the trimeric configuration of most of the HIV-1 gp120 subunit, the description of the gp41 subunit was limited to two helical regions comprising only about half the gp41 ectodomain, and the sequence register for the alpha helices was not reported. Recently, we were able to obtain x-ray diffraction data to 3.5 Å resolution on a prefusion crystal structure of the entire HIV-1 spike. The structure utilizes the same BG505 SOSIP.R6.664 construct as previously published, but crystallized in space group P6(3) with the antigen-binding fragments (Fab) of two antibodies, PGT122 and 35O22. The new structure provides atomic-level details for the complete prefusion structure of gp120 and the majority of the trimeric ectodomain of gp41 (up to residue 664). Also visualized are details of the gp120-gp41 interface and of antibodies such as 35O22. In addition to the complete HIV-1 Env ectodomain structure, implications for HIV-1 vaccine design will be described.
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Steckbeck, Jonathan D., Anne-Sophie Kuhlmann i Ronald C. Montelaro. "C-terminal tail of human immunodeficiency virus gp41: functionally rich and structurally enigmatic". Journal of General Virology 94, nr 1 (1.01.2013): 1–19. http://dx.doi.org/10.1099/vir.0.046508-0.
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The human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS) pandemic is amongst the most important current worldwide public health threats. While much research has been focused on AIDS vaccines that target the surface viral envelope (Env) protein, including gp120 and the gp41 ectodomain, the C-terminal tail (CTT) of gp41 has received relatively little attention. Despite early studies highlighting the immunogenicity of a particular CTT sequence, the CTT has been classically portrayed as a type I membrane protein limited to functioning in Env trafficking and virion incorporation. Recent studies demonstrate, however, that the Env CTT has other important functions. The CTT has been shown to additionally modulate Env ectodomain structure on the cell and virion surface, affect Env reactivity and viral sensitivity to conformation-dependent neutralizing antibodies, and alter cell–cell and virus–cell fusogenicity of Env. This review provides an overview of the Env structure and function with a particular emphasis on the CTT and recent studies that highlight its functionally rich nature.