Immunogenicity of Stabilized HIV-1 Envelope Trimers with Reduced Exposure of Non-neutralizing Epitopes

Taeye, Steven W. de; Ozorowski, Gabriel; Peña, Alba Torrents de la; Guttman, Miklós; Julien, Jean-Philippe; Kerkhof, Tom L.G.M. van den; Burger, Judith A.; Pritchard, Laura K.; Pugach, Pavel; Yasmeen, Anila; Crampton, Jordan; Hu, Joyce; Bontjer, Ilja; Torres, Jonathan L.; Arendt, Heather; DeStefano, Joanne; Koff, Wayne C.; Schuitemaker, Hanneke; Eggink, Dirk; Berkhout, Ben; Dean, Hansi; LaBranche, Celia C.; Crotty, Shane; Crispin, Max; Montefiori, David C.; Klasse, P J; Lee, Kelly K.; Moore, John P.; Wilson, Ian A.; Ward, Andrew B.; Sanders, Rogier W.

doi:10.1016/j.cell.2015.11.056

Cited by 333 publications

(738 citation statements)

References 57 publications

(136 reference statements)

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“…These substitutions facilitated the stabilization of SOSIP trimers from 4 different isolates: BG505 (clade A), B41 (clade B), AMC008 (clade B), and ZM197M (clade C). Hydrogen-deuterium exchange (HD-X) and other studies demonstrated that these substitutions stabilize SOSIP trimers by blocking CD4-induced conformational changes, consistent with the virological observations described here (64). Whereas T20 dependence involves enhanced fusion kinetics that need to be tempered by T20 from the moment Env appears at the cell/virus surface (48,51,59), VIR165 dependence involves reduced fusion kinetics, necessitating the presence of VIR165 as a catalyst for Env conformational changes following CD4 binding.…”

Section: Discussionsupporting

confidence: 82%

“…Additional modifications that kinetically trap BG505 SOSIP.664 trimers in the unliganded state were recently described (9,72,73). We have shown that the VIR165 dependence mutations are useful for further stabilization of different recombinant Env trimers to lock them in the unliganded ground state and improve their properties as immunogens (64).…”

Section: Discussionmentioning

confidence: 92%

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HIV-1 Escape from a Peptidic Anchor Inhibitor through Stabilization of the Envelope Glycoprotein Spike

Eggink

Taeye

Bontjer

et al. 2016

J Virol

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The trimeric HIV-1 envelope glycoprotein spike (Env) mediates viral entry into cells by using a spring-loaded mechanism that allows for the controlled insertion of the Env fusion peptide into the target membrane, followed by membrane fusion. Env is the focus of vaccine research aimed at inducing protective immunity by antibodies as well as efforts to develop drugs that inhibit the viral entry process. The molecular factors contributing to Env stability and decay need to be understood better in order to optimally design vaccines and therapeutics. We generated viruses with resistance to VIR165, a peptidic inhibitor that binds the fusion peptide of the gp41 subunit and prevents its insertion into the target membrane. Interestingly, a number of escape viruses acquired substitutions in the C1 domain of the gp120 subunit (A60E, E64K, and H66R) that rendered these viruses dependent on the inhibitor. These viruses could infect target cells only when VIR165 was present after CD4 binding. Furthermore, the VIR165-dependent viruses were resistant to soluble CD4-induced Env destabilization and decay. These data suggest that VIR165-dependent Env proteins are kinetically trapped in the unliganded state and require the drug to negotiate CD4-induced conformational changes. These studies provide mechanistic insight into the action of the gp41 fusion peptide and its inhibitors and provide new ways to stabilize Env trimer vaccines. IMPORTANCEBecause of the rapid development of HIV-1 drug resistance, new drug targets need to be explored continuously. The fusion peptide of the envelope glycoprotein can be targeted by anchor inhibitors. Here we describe virus escape from the anchor inhibitor VIR165. Interestingly, some escape viruses became dependent on the inhibitor for cell entry. We show that the identified escape mutations stabilize the ground state of the envelope glycoprotein and should thus be useful in the design of stabilized envelopebased HIV vaccines. With over 35 million people currently infected, HIV-1 remains a major health problem. Although progress has been made in the development of antiviral drugs, the potential of the virus to acquire resistance remains an issue. Neither a cure nor an effective vaccine is available. HIV-1 enters target cells by using its envelope glycoprotein (Env) spikes on the virus surface. Env is the target for drugs that inhibit the viral entry process and for broadly neutralizing antibodies (bNAbs) that researchers aim to induce with Env-based vaccines.Env is a trimeric complex consisting of three gp41 transmembrane subunits and three noncovalently attached gp120 subunits. The entry process is initiated by binding of gp120 to the CD4 receptor. This interaction induces conformational changes in Env, revealing the binding site for a chemokine coreceptor, generally CXCR4 or CCR5. Additional conformational changes in gp41 involve two heptad repeat regions (HR1 and HR2) in gp41 and the fusion peptide (FP) (1). The FP might be partially exposed in the prefusion, native state of Env. In a com...

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Section: Discussionsupporting

confidence: 82%

Section: Discussionmentioning

confidence: 92%

HIV-1 Escape from a Peptidic Anchor Inhibitor through Stabilization of the Envelope Glycoprotein Spike

Eggink

Taeye

Bontjer

et al. 2016

J Virol

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“…Rational vaccine design has led to the development and evaluation of many different potential Env immunogens (68). An increasingly widespread opinion is that a native-like representation of Env where multiple bNAb epitopes are presented but nonneutralizing antibody epitopes are occluded is a highly relevant option (69,70). As many bNAb epitopes include glycans, the integrity of the glycan shield is a key factor that needs to be considered in Env immunogen design.…”

Section: Discussionmentioning

confidence: 99%

Molecular Architecture of the Cleavage-Dependent Mannose Patch on a Soluble HIV-1 Envelope Glycoprotein Trimer

Behrens

Harvey

Milne

et al. 2017

J Virol

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135

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The formation of a correctly folded and natively glycosylated HIV-1 viral spike is dependent on protease cleavage of the gp160 precursor protein in the Golgi apparatus. Cleavage induces a compact structure which not only renders the spike capable of fusion but also limits further maturation of its extensive glycosylation. The redirection of the glycosylation pathway to preserve underprocessed oligomannose-type glycans is an important feature in immunogen design, as glycans contribute to or influence the epitopes of numerous broadly neutralizing antibodies.Here we present a quantitative site-specific analysis of a recombinant, trimeric mimic of the native HIV-1 viral spike (BG505 SOSIP.664) compared to the corresponding uncleaved pseudotrimer and the matched gp120 monomer. We present a detailed molecular map of a trimer-associated glycan remodeling that forms a localized subdomain of the native mannose patch. The formation of native trimers is a critical design feature in shaping the glycan epitopes presented on recombinant vaccine candidates. IMPORTANCEThe envelope spike of human immunodeficiency virus type 1 (HIV-1) is a target for antibody-based neutralization. For some patients infected with HIV-1, highly potent antibodies have been isolated that can neutralize a wide range of circulating viruses. It is a goal of HIV-1 vaccine research to elicit these antibodies by immunization with recombinant mimics of the viral spike. These antibodies have evolved to recognize the dense array of glycans that coat the surface of the viral molecule. We show how the structure of these glycans is shaped by steric constraints imposed upon them by the native folding of the viral spike. This information is important in guiding the development of vaccine candidates.KEYWORDS furin, glycan, glycosylation, human immunodeficiency virus, neutralizing antibodies, oligosaccharides, structure, vaccines T he trimeric envelope (Env) glycoprotein spike of human immunodeficiency virus type 1 (HIV-1) plays a crucial role in mediating host cell infection. Its exposed position on the virus surface also makes it the target for potent, broadly neutralizing antibodies (bNAbs) that are produced in a subset of infected individuals and that now influence the design of Env immunogens intended to induce similar antibody specificities. Env is extensively glycosylated, with glycans contributing to a significant proportion of the glycoprotein's mass (1). The heavily glycosylated surface of Env has been referred to as the "silent face," with the glycans acting to shield the underlying viral protein surface from immune surveillance (2-4). The glycan shield constantly evolves to protect the virus from newly produced neutralizing antibodies. However, compared to the highly diverse protein component of Env, many of the potential

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“…The best trimeric HIV-1 Env immunogens designed to date elicit potent Tier 1 and autologous Tier 2 neutralizing antibody responses (33,52) but the antibodies exhibit little activity against heterologous Tier 2 HIV-1 isolates. These trimeric HIV-1 Env immunogens (33,52) were derived from the ectodomain of the BG505 subtype A isolate, contain an engineered disulfide bond between gp120 and gp41 subunits, and lack the membrane proximal external region of gp41. In the case of other trimeric gp120 and trimeric gp140 immunogens, a heterologous trimerization domain was fused at the C terminus of gp120 or gp140 (8,24,29,31).…”

Section: Discussionmentioning

confidence: 99%

Structure-based Design of Cyclically Permuted HIV-1 gp120 Trimers That Elicit Neutralizing Antibodies

Kesavardhana

Das

Citron

et al. 2017

Journal of Biological Chemistry

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A major goal for HIV-1 vaccine development is an ability to elicit strong and durable broadly neutralizing antibody (bNAb) responses. The trimeric envelope glycoprotein (Env) spikes on HIV-1 are known to contain multiple epitopes that are susceptible to bNAbs isolated from infected individuals. Nonetheless, all trimeric and monomeric Env immunogens designed to date have failed to elicit such antibodies. We report the structure-guided design of HIV-1 cyclically permuted gp120 that forms homogeneous, stable trimers, and displays enhanced binding to multiple bNAbs, including VRC01, VRC03, VRC-PG04, PGT128, and the quaternary epitope-specific bNAbs PGT145 and PGDM1400. Constructs that were cyclically permuted in the V1 loop region and contained an N-terminal trimerization domain to stabilize V1V2-mediated quaternary interactions, showed the highest homogeneity and the best antigenic characteristics. In guinea pigs, a DNA prime-protein boost regimen with these new gp120 trimer immunogens elicited potent neutralizing antibody responses against highly sensitive Tier 1A isolates and weaker neutralizing antibody responses with an average titer of about 115 against a panel of heterologous Tier 2 isolates. A modest fraction of the Tier 2 virus neutralizing activity appeared to target the CD4 binding site on gp120. These results suggest that cyclically permuted HIV-1 gp120 trimers represent a viable platform in which further modifications may be made to eventually achieve protective bNAb responses.The HIV-1 Env displayed on the virion surface mediates entry of the virion into target CD4 ϩ T cells to establish infection. Due to its surface accessibility, Env is the predominant target for neutralizing antibody responses (1, 2). Env is synthesized as a gp160 precursor protein, which is further cleaved into surface proximal gp120 and membrane anchored gp41 subunits. A functional HIV-1 Env spike consists of a trimer of gp120 and gp41 heterodimers. The base of the trimer is proximal to the viral membrane (3) and is held together by trimerization motifs within the N-heptad repeat of gp41 (4 -6). The trimer apex is stabilized by interactions between the V1V2 loops of adjacent gp120 monomers (3). Binding of Env to the CD4 receptor on T cells causes extensive conformational changes in the Env trimer and leads to the formation of an open CD4-bound conformation in which the cryptic, co-receptor binding site becomes accessible. This facilitates interaction of the co-receptor (CCR5 or CXCR4) with Env, further driving the fusion of viral and host cell membranes (3, 7).In natural HIV-1 infection, most of the B cell response is elicited against the Env protein, due to its location on the virion surface and relatively high immunogenicity. The antibody response induced during natural HIV-1 infection is predominantly non-neutralizing and strain specific, due to the shed gp120 (immunodominant decoys) and various other immune evasive mechanisms (8). However, ϳ20% of HIV-1-infected patients develop bNAbs during the course of 1-3 years of infectio...

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Immunogenicity of Stabilized HIV-1 Envelope Trimers with Reduced Exposure of Non-neutralizing Epitopes

Cited by 333 publications

References 57 publications

HIV-1 Escape from a Peptidic Anchor Inhibitor through Stabilization of the Envelope Glycoprotein Spike

HIV-1 Escape from a Peptidic Anchor Inhibitor through Stabilization of the Envelope Glycoprotein Spike

Molecular Architecture of the Cleavage-Dependent Mannose Patch on a Soluble HIV-1 Envelope Glycoprotein Trimer

Structure-based Design of Cyclically Permuted HIV-1 gp120 Trimers That Elicit Neutralizing Antibodies

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