scholarly journals Functional Optimization of Broadly Neutralizing HIV-1 Antibody 10E8 by Promotion of Membrane Interactions

2018 ◽  
Vol 92 (8) ◽  
Author(s):  
Edurne Rujas ◽  
Daniel P. Leaman ◽  
Sara Insausti ◽  
Lei Ortigosa-Pascual ◽  
Lei Zhang ◽  
...  
Keyword(s):  
Lipid Bilayers ◽  
Mechanism Of Action ◽  
Neutralizing Antibodies ◽  
Positive Charge ◽  
Transmembrane Domain ◽  
Membrane Surface ◽  
Passive Immunization ◽  
Viral Membrane ◽  
Mutation Strategy ◽  
Hiv 1

ABSTRACT The 10E8 antibody targets a helical epitope in the membrane-proximal external region (MPER) and transmembrane domain (TMD) of the envelope glycoprotein (Env) subunit gp41 and is among the broadest known neutralizing antibodies against HIV-1. Accordingly, this antibody and its mechanism of action valuably inform the design of effective vaccines and immunotherapies. 10E8 exhibits unusual adaptations to attain specific, high-affinity binding to the MPER at the viral membrane interface. Reversing the charge of the basic paratope surface (from net positive to net negative) reportedly lowered its neutralization potency. Here, we hypothesized that by increasing the net positive charge in similar polar surface patches, the neutralization potency of the antibody may be enhanced. We found that an increased positive charge at this paratope surface strengthened an electrostatic interaction between the antibody and lipid bilayers, enabling 10E8 to interact spontaneously with membranes. Notably, the modified 10E8 antibody did not gain any apparent polyreactivity and neutralized virus with a significantly greater potency. Binding analyses indicated that the optimized 10E8 antibody bound with a higher affinity to the epitope peptide anchored in lipid bilayers and to Env spikes on virions. Overall, our data provide a proof of principle for the rational optimization of 10E8 via manipulation of its interaction with the membrane element of its epitope. However, the observation that a similar mutation strategy did not affect the potency of the first-generation anti-MPER antibody 4E10 shows possible limitations of this principle. Altogether, our results emphasize the crucial role played by the viral membrane in the antigenicity of the MPER-TMD of HIV-1. IMPORTANCE The broadly neutralizing antibody 10E8 blocks infection by nearly all HIV-1 isolates, a capacity which vaccine design seeks to reproduce. Engineered versions of this antibody also represent a promising treatment for HIV infection by passive immunization. Understanding its mechanism of action is therefore important to help in developing effective vaccines and biologics to combat HIV/AIDS. 10E8 engages its helical MPER epitope where the base of the envelope spike submerges into the viral membrane. To enable this interaction, this antibody evolved an unusual property: the ability to interact with the membrane surface. Here, we provide evidence that 10E8 can be made more effective by enhancing its interactions with membranes. Our findings strengthen the idea that to elicit antibodies similar to 10E8, vaccines must reproduce the membrane environment where these antibodies perform their function.

scholarly journals Topological analysis of the gp41 MPER on lipid bilayers relevant to the metastable HIV-1 envelope prefusion state

2019 ◽  
Vol 116 (45) ◽  
pp. 22556-22566 ◽  
Author(s):  
Yi Wang ◽  
Pavanjeet Kaur ◽  
Zhen-Yu J. Sun ◽  
Mostafa A. Elbahnasawy ◽  
Zahra Hayati ◽  
...  
Keyword(s):  
Lipid Bilayers ◽  
Neutralizing Antibodies ◽  
Structural Changes ◽  
Transmembrane Domain ◽  
Topological Analysis ◽  
Heptad Repeat ◽  
Structural Topology ◽  
Paramagnetic Resonance ◽  
Viral Membrane ◽  
Hiv 1

The membrane proximal external region (MPER) of HIV-1 envelope glycoprotein (gp) 41 is an attractive vaccine target for elicitation of broadly neutralizing antibodies (bNAbs) by vaccination. However, current details regarding the quaternary structural organization of the MPER within the native prefusion trimer [(gp120/41)3] are elusive and even contradictory, hindering rational MPER immunogen design. To better understand the structural topology of the MPER on the lipid bilayer, the adjacent transmembrane domain (TMD) was appended (MPER-TMD) and studied. Membrane insertion of the MPER-TMD was sensitive both to the TMD sequence and cytoplasmic residues. Antigen binding of MPER-specific bNAbs, in particular 10E8 and DH511.2_K3, was significantly impacted by the presence of the TMD. Furthermore, MPER-TMD assembly into 10-nm diameter nanodiscs revealed a heterogeneous membrane array comprised largely of monomers and dimers, as enumerated by bNAb Fab binding using single-particle electron microscopy analysis, arguing against preferential trimeric association of native MPER and TMD protein segments. Moreover, introduction of isoleucine mutations in the C-terminal heptad repeat to induce an extended MPER α-helical bundle structure yielded an antigenicity profile of cell surface-arrayed Env variants inconsistent with that found in the native prefusion state. In line with these observations, electron paramagnetic resonance analysis suggested that 10E8 inhibits viral membrane fusion by lifting the MPER N-terminal region out of the viral membrane, mandating the exposure of residues that would be occluded by MPER trimerization. Collectively, our data suggest that the MPER is not a stable trimer, but rather a dynamic segment adapted for structural changes accompanying fusion.

scholarly journals Similarities and differences between native HIV-1 envelope glycoprotein trimers and stabilized soluble trimer mimetics

2018 ◽  
Author(s):  
Alba Torrents de la Peña ◽  
Kimmo Rantalainen ◽  
Christopher A. Cottrell ◽  
Joel D. Allen ◽  
Marit J. van Gils ◽  
...  
Keyword(s):  
Envelope Glycoprotein ◽  
Neutralizing Antibodies ◽  
Transmembrane Domain ◽  
Cytoplasmic Tail ◽  
Full Length ◽  
Broadly Neutralizing Antibodies ◽  
Vaccine Research ◽  
Similarities And Differences ◽  
Membrane Tether ◽  
Hiv 1

AbstractThe HIV-1 envelope glycoprotein (Env) trimer is located on the surface of the virus and is the target of broadly neutralizing antibodies (bNAbs). Recombinant native-like soluble Env trimer mimetics, such as SOSIP trimers, have taken a central role in HIV-1 vaccine research aimed at inducing bNAbs. We therefore performed a direct and thorough comparison of a full-length native Env trimer containing the transmembrane domain and the cytoplasmic tail, with the sequence matched soluble SOSIP trimer, both based on an early Env sequence (AMC011) from an HIV+ individual that developed bNAbs. The structures of the full-length AMC011 trimer bound to either bNAb PGT145 or PGT151 were very similar to the structures of SOSIP trimers. Antigenically, the full-length and SOSIP trimers were comparable, but in contrast to the full-length trimer, the SOSIP trimer did not bind at all to non-neutralizing antibodies, most likely as a consequence of the intrinsic stabilization of the SOSIP trimer. Furthermore, the glycan composition of full-length and SOSIP trimers was similar overall, but the SOSIP trimer possessed slightly less complex and less extensively processed glycans, which may relate to the intrinsic stabilization as well as the absence of the membrane tether. These data provide insights into how to best use and improve membrane-associated full-length and soluble SOSIP HIV-1 Env trimers as immunogens.

scholarly journals Nanoparticle Vaccines for Inducing HIV-1 Neutralizing Antibodies

Vaccines ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 76 ◽  
Author(s):  
Mitch Brinkkemper ◽  
Kwinten Sliepen
Keyword(s):  
Envelope Glycoprotein ◽  
Neutralizing Antibodies ◽  
Critical Role ◽  
Neutralizing Antibody ◽  
Antibody Responses ◽  
Broadly Neutralizing Antibodies ◽  
Viral Membrane ◽  
Immunodeficiency Virus ◽  
Hiv 1

The enormous sequence diversity between human immunodeficiency virus type 1 (HIV-1) strains poses a major roadblock for generating a broadly protective vaccine. Many experimental HIV-1 vaccine efforts are therefore aimed at eliciting broadly neutralizing antibodies (bNAbs) that are capable of neutralizing the majority of circulating HIV-1 strains. The envelope glycoprotein (Env) trimer on the viral membrane is the sole target of bNAbs and the key component of vaccination approaches aimed at eliciting bNAbs. Multimeric presentation of Env on nanoparticles often plays a critical role in these strategies. Here, we will discuss the different aspects of nanoparticles in Env vaccination, including recent insights in immunological processes underlying their perceived advantages, the different nanoparticle platforms and the various immunogenicity studies that employed nanoparticles to improve (neutralizing) antibody responses against Env.

scholarly journals Vaccines and Broadly Neutralizing Antibodies for HIV-1 Prevention

2020 ◽  
Vol 38 (1) ◽  
pp. 673-703 ◽  
Author(s):  
Kathryn E. Stephenson ◽  
Kshitij Wagh ◽  
Bette Korber ◽  
Dan H. Barouch
Keyword(s):  
Clinical Trials ◽  
Neutralizing Antibodies ◽  
Passive Immunization ◽  
Neutralizing Antibody ◽  
Broadly Neutralizing Antibodies ◽  
Aids Pandemic ◽  
Broadly Neutralizing Antibody ◽  
Early Phase Clinical Trials ◽  
Hiv 1 ◽  
Review Current

Development of improved approaches for HIV-1 prevention will likely be required for a durable end to the global AIDS pandemic. Recent advances in preclinical studies and early phase clinical trials offer renewed promise for immunologic strategies for blocking acquisition of HIV-1 infection. Clinical trials are currently underway to evaluate the efficacy of two vaccine candidates and a broadly neutralizing antibody (bNAb) to prevent HIV-1 infection in humans. However, the vast diversity of HIV-1 is a major challenge for both active and passive immunization. Here we review current immunologic strategies for HIV-1 prevention, with a focus on current and next-generation vaccines and bNAbs.

scholarly journals Immunogenicity Study of Glycoprotein-Deficient Rabies Virus Expressing Simian/Human Immunodeficiency Virus SHIV89.6P Envelope in a Rhesus Macaque

2004 ◽  
Vol 78 (24) ◽  
pp. 13455-13459 ◽  
Author(s):  
Philip M. McKenna ◽  
Pyone Pyone Aye ◽  
Bernhard Dietzschold ◽  
David C. Montefiori ◽  
Louis N. Martin ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Rhesus Macaque ◽  
Rabies Virus ◽  
Neutralizing Antibodies ◽  
Transmembrane Domain ◽  
Cell Loss ◽  
Glycoprotein G ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Rabies virus (RV) has recently been developed as a novel vaccine candidate for human immunodeficiency virus type 1 (HIV-1). The RV glycoprotein (G) can be functionally replaced by HIV-1 envelope glycoprotein (Env) if the gp160 cytoplasmic domain (CD) of HIV-1 Env is replaced by that of RV G. Here, we describe a pilot study of the in vivo replication and immunogenicity of an RV with a deletion of G (ΔG) expressing a simian/human immunodeficiency virus SHIV89.6P Env ectodomain and transmembrane domain fused to the RV G CD (ΔG-89.6P-RVG) in a rhesus macaque. An animal vaccinated with ΔG-89.6P-RVG developed SHIV89.6P virus-neutralizing antibodies and SHIV89.6P-specific cellular immune responses after challenge with SHIV89.6P. There was no evidence of CD4+ T-cell loss, and plasma viremia was controlled to undetectable levels by 6 weeks postchallenge and has remained suppressed out to 22 weeks postchallenge.

scholarly journals The Neutralizing Antibody Response to the HIV-1 Env Protein

2018 ◽  
Vol 16 (1) ◽  
pp. 21-28 ◽  
Author(s):  
Penny L. Moore
Keyword(s):  
Neutralizing Antibodies ◽  
Passive Immunization ◽  
Neutralizing Antibody ◽  
Developmental Pathways ◽  
Broadly Neutralizing Antibodies ◽  
Infected People ◽  
B Cell Maturation ◽  
Public Health Challenge ◽  
Env Protein ◽  
Hiv 1

Background: A vaccine able to elicit broadly neutralizing antibodies capable of blocking infection by global viruses has not been achieved, and remains a key public health challenge.Objective: During infection, a robust strain-specific neutralizing response develops in most people, but only a subset of infected people develop broadly neutralizing antibodies. Understanding how and why these broadly neutralizing antibodies develop has been a focus of the HIV-1 vaccine field for many years, and has generated extraordinary insights into the neutralizing response to HIV-1 infection.Results: This review describes the features, targets and developmental pathways of early strainspecific antibodies and later broadly neutralizing antibodies, and explores the reasons such broad antibodies are not more commonly elicited during infection.Conclusion: The insights from these studies have been harnessed for the development of pioneering new vaccine approaches that seek to drive B cell maturation towards breadth. Overall, this review describes how findings from infected donors have impacted on active and passive immunization approaches that seek to prevent HIV-1 infection.

scholarly journals New SHIVs and Improved Design Strategy for Modeling HIV-1 Transmission, Immunopathogenesis, Prevention and Cure

2021 ◽  
Author(s):  
Hui Li ◽  
Shuyi Wang ◽  
Fang-Hua Lee ◽  
Ryan S. Roark ◽  
Alex I. Murphy ◽  
...  
Keyword(s):  
T Cells ◽  
Neutralizing Antibodies ◽  
Large Scale ◽  
Rhesus Macaques ◽  
Passive Immunization ◽  
Design Strategy ◽  
Efficient Replication ◽  
Hiv 1

Previously, we showed that substitution of HIV-1 Env residue 375-Ser by bulky aromatic residues enhances binding to rhesus CD4 and enables primary HIV-1 Envs to support efficient replication as simian-human immunodeficiency virus (SHIV) chimeras in rhesus macaques (RMs). Here, we test this design strategy more broadly by constructing SHIVs containing ten primary Envs corresponding to HIV-1 subtypes A, B, C, AE and AG. All ten SHIVs bearing wildtype Env375 residues replicated efficiently in human CD4+ T cells, but only one replicated efficiently in primary rhesus cells. This was a subtype AE SHIV that naturally contained His at Env375. Replacement of wildtype Env375 residues by Trp, Tyr, Phe or His in the other nine SHIVs led to efficient replication in rhesus CD4+ T cells in vitro and in vivo. Nine SHIVs containing optimized Env375 alleles were grown large-scale in primary rhesus CD4+ T cells to serve as challenge stocks in preclinical prevention trials. These virus stocks were genetically homogeneous, native-like in Env antigenicity and tier-2 neutralization sensitivity, and transmissible by rectal, vaginal, penile, oral or intravenous routes. To facilitate future SHIV constructions, we engineered a simplified second-generation design scheme and validated it in RMs. Overall, our findings demonstrate that SHIVs bearing primary Envs with bulky aromatic substitutions at Env375 consistently replicate in RMs, recapitulating many features of HIV-1 infection in humans. Such SHIVs are efficiently transmitted by mucosal routes common to HIV-1 infection and can be used to test vaccine efficacy in preclinical monkey trials. Importance SHIV infection of Indian rhesus macaques is an important animal model for studying HIV-1 transmission, prevention, immunopathogenesis and cure. Such research is timely, given recent progress with active and passive immunization and novel approaches to HIV-1 cure. Given the multifaceted roles of HIV-1 Env in cell tropism and virus entry, and as a target for neutralizing and non-neutralizing antibodies, Envs selected for SHIV construction are of paramount importance. Until recently, it has been impossible to strategically design SHIVs bearing clinically relevant Envs that replicate consistently in monkeys. This changed with the discovery that bulky aromatic substitutions at residue Env375 confer enhanced affinity to rhesus CD4. Here, we show that 10 new SHIVs bearing primary HIV-1 Envs with residue 375 substitutions replicated efficiently in RMs and could be transmitted efficiently across rectal, vaginal, penile and oral mucosa. These findings suggest an expanded role for SHIVs as a model of HIV-1 infection.

scholarly journals Exposure of the HIV-1 broadly neutralizing antibody 10E8 MPER epitope on the membrane surface by gp41 transmembrane domain scaffolds

2018 ◽  
Vol 1860 (6) ◽  
pp. 1259-1271 ◽  
Author(s):  
Victoria Oakes ◽  
Johana Torralba ◽  
Edurne Rujas ◽  
José L. Nieva ◽  
Carmen Domene ◽  
...  
Keyword(s):  
Transmembrane Domain ◽  
Membrane Surface ◽  
Neutralizing Antibody ◽  
Broadly Neutralizing Antibody ◽  
Hiv 1

scholarly journals The Conserved Positive Charge in the Transmembrane Domain of HIV Gp41 Contributes to Its Intrinsic Preference for Trimerization

2019 ◽  
Author(s):  
Timothy Reichart ◽  
Daniel Leaman ◽  
Daniel Sands ◽  
Michael Zwick ◽  
Philip Dawson
Keyword(s):  
Hiv Infection ◽  
Positive Charge ◽  
Transmembrane Domain ◽  
Structure And Function ◽  
Model Membranes ◽  
Viral Membrane ◽  
Glycoprotein Gp41 ◽  
Tm Domain ◽  
And Function

The transmembrane (TM) domain of HIV glycoprotein gp41 anchors the envelope (Env) spike in the viral membrane and is highly conserved. The mid-span arginine 696 is particularly conserved, and the only other residue found in this position is lysine. Seeking to examine the role of this conserved positive charge in the structure and function of the gp41 TM domain, we synthesized a series of peptides corresponding to this region. Analysis of the peptides in a previously validated fluorescence assay in model membranes showed that the native TM domain is trimeric. Peptides in which the intramembrane arginine was mutated to alanine showed significantly lower trimerization propensity. In contrast, this mutation in the context of infectious pseudovirus caused only modest decreases in viral stability and infectivity. We propose a model to explain the importance of this charge to gp41 structure and to HIV infection.

scholarly journals Structure of the membrane proximal external region of HIV-1 envelope glycoprotein

2018 ◽  
Vol 115 (38) ◽  
pp. E8892-E8899 ◽  
Author(s):  
Qingshan Fu ◽  
Md Munan Shaik ◽  
Yongfei Cai ◽  
Fadi Ghantous ◽  
Alessandro Piai ◽  
...  
Keyword(s):  
Lipid Bilayer ◽  
Envelope Glycoprotein ◽  
Neutralizing Antibodies ◽  
Transmembrane Domain ◽  
Bilayer Membrane ◽  
Antigenic Analysis ◽  
External Region ◽  
Membrane Proximal External Region ◽  
Electron Cryotomography ◽  
Hiv 1

The membrane-proximal external region (MPER) of the HIV-1 envelope glycoprotein (Env) bears epitopes of broadly neutralizing antibodies (bnAbs) from infected individuals; it is thus a potential vaccine target. We report an NMR structure of the MPER and its adjacent transmembrane domain in bicelles that mimic a lipid-bilayer membrane. The MPER lies largely outside the lipid bilayer. It folds into a threefold cluster, stabilized mainly by conserved hydrophobic residues and potentially by interaction with phospholipid headgroups. Antigenic analysis and comparison with published images from electron cryotomography of HIV-1 Env on the virion surface suggest that the structure may represent a prefusion conformation of the MPER, distinct from the fusion-intermediate state targeted by several well-studied bnAbs. Very slow bnAb binding indicates that infrequent fluctuations of the MPER structure give these antibodies occasional access to alternative conformations of MPER epitopes. Mutations in the MPER not only impede membrane fusion but also influence presentation of bnAb epitopes in other regions. These results suggest strategies for developing MPER-based vaccine candidates.

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