HIV-1 Envelope Glycoprotein Trimers Display Open Quaternary Conformation When Bound to the gp41 Membrane-Proximal External-Region-Directed Broadly Neutralizing Antibody Z13e1

Eliciting efficient broadly neutralizing antibodies (BnAbs) is an important goal that has yet to be achieved for human immunodeficiency type 1 (HIV-1) vaccine development, although they are rarely produced in virus-infected individuals. In particular, inducing specific neutralizing antibodies to the gp41 membrane proximal external region (MPER) has proven a difficult task. In this study, we introduce Norovirus P particles as a new platform to display the MPER epitope of HIV-1 as a vaccine with the aim of enhancing immune responses. The results showed that HIV-1 chimeric P particles were capable of inducing MPER-specific antibody responses in immunized guinea pigs, although only weakly neutralizing activity could be detected. These findings are consistent with other previous studies which have also focused on the well-studied 2F5 and 4E10 BnAbs. Our findings provide an alternate strategy for design of vaccines against HIV-1. However, great challenges remain in the effort to develop vaccines that can induce efficient HIV-1 neutralizing antibodies.

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The Membrane Proximal External Region of the HIV-1 Envelope Glycoprotein gp41 Contributes to the Stabilization of the Six-Helix Bundle Formed with a Matching N′ Peptide†

Biochemistry ◽

10.1021/bi7023139 ◽

2008 ◽

Vol 47 (26) ◽

pp. 6782-6792 ◽

Cited By ~ 19

Author(s):

Eran Noah ◽

Zohar Biron ◽

Fred Naider ◽

Boris Arshava ◽

Jacob Anglister

Keyword(s):

Envelope Glycoprotein ◽

External Region ◽

Membrane Proximal External Region ◽

Helix Bundle ◽

Glycoprotein Gp41 ◽

Hiv 1

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

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1807259115 ◽

2018 ◽

Vol 115 (38) ◽

pp. E8892-E8899 ◽

Cited By ~ 35

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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Crystal structure of a non-neutralizing antibody to the HIV-1 gp41 membrane-proximal external region

Nature Structural & Molecular Biology ◽

10.1038/nsmb.1944 ◽

2010 ◽

Vol 17 (12) ◽

pp. 1492-1494 ◽

Cited By ~ 29

Author(s):

Nathan I Nicely ◽

S Moses Dennison ◽

Leonard Spicer ◽

Richard M Scearce ◽

Garnett Kelsoe ◽

...

Keyword(s):

Crystal Structure ◽

Neutralizing Antibody ◽

External Region ◽

Membrane Proximal External Region ◽

Hiv 1

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High-Throughput Protein Engineering Improves the Antigenicity and Stability of Soluble HIV-1 Envelope Glycoprotein SOSIP Trimers

Journal of Virology ◽

10.1128/jvi.00862-17 ◽

2017 ◽

Vol 91 (22) ◽

Cited By ~ 14

Author(s):

Jonathan T. Sullivan ◽

Chidananda Sulli ◽

Alberto Nilo ◽

Anila Yasmeen ◽

Gabriel Ozorowski ◽

...

Keyword(s):

Protein Engineering ◽

High Throughput ◽

Envelope Glycoprotein ◽

High Throughput Screening ◽

Neutralizing Antibody ◽

Structural Basis ◽

Vaccine Candidates ◽

Clade B ◽

Broadly Neutralizing Antibody ◽

Hiv 1

ABSTRACT Soluble envelope glycoprotein (Env) trimers (SOSIP.664 gp140) are attractive HIV-1 vaccine candidates, with structures that mimic the native membrane-bound Env spike (gp160). Since engineering trimers can be limited by the difficulty of rationally predicting beneficial mutations, here we used a more comprehensive mutagenesis approach with the goal of identifying trimer variants with improved antigenic and stability properties. We created 341 cysteine pairs at predicted points of stabilization throughout gp140, 149 proline residue substitutions at every residue of the gp41 ectodomain, and 362 space-filling residue substitutions at every hydrophobic and aromatic residue in gp140. The parental protein target, the clade B strain B41 SOSIP.664 gp140, does not bind the broadly neutralizing antibody PGT151 and so was used here to identify improved variants that also provide insight into the structural basis for Env antigenicity. Each of the 852 mutants was expressed in human cells and screened for antigenicity using four different monoclonal antibodies (MAbs), including PGT151. We identified 29 trimer variants with antigenic improvements derived from each of the three mutagenesis strategies. We selected four variants (Q203F, T538F, I548F, and M629P) for more comprehensive biochemical, structural, and antigenicity analyses. The T538F substitution had the most beneficial effect overall, including restoration of the PGT151 epitope. The improved B41 SOSIP.664 trimer variants identified here may be useful for vaccine and structural studies. IMPORTANCE Soluble Env trimers have become attractive HIV-1 vaccine candidates, but the prototype designs are capable of further improvement through protein engineering. Using a high-throughput screening technology (shotgun mutagenesis) to create and evaluate 852 variants, we were able to identify sequence changes that were beneficial to the antigenicity and stability of soluble trimers based on the clade B B41 env gene. The strategies described here may be useful for identifying a wider range of antigenically and structurally improved soluble trimers based on multiple genotypes for use in programs intended to create a broadly protective HIV-1 vaccine.

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Rational Design of Membrane Proximal External Region Lipopeptides Containing Chemical Modifications for HIV-1 Vaccination

Clinical and Vaccine Immunology ◽

10.1128/cvi.00615-12 ◽

2012 ◽

Vol 20 (1) ◽

pp. 39-45 ◽

Cited By ~ 15

Author(s):

Vincent J. Venditto ◽

Douglas S. Watson ◽

Michael Motion ◽

David Montefiori ◽

Francis C. Szoka

Keyword(s):

Amino Acid ◽

Neutralizing Antibodies ◽

Rational Design ◽

Neutralizing Antibody ◽

Side Chain ◽

Amino Acid Side Chain ◽

External Region ◽

Membrane Proximal External Region ◽

Chemically Modified ◽

Hiv 1

ABSTRACTThe inability to generate broadly neutralizing antibody (bnAb) responses to the membrane proximal external region (MPER) of HIV-1 gp41 using current vaccine strategies has hampered efforts to prevent the spread of HIV. To address this challenge, we investigated a novel hypothesis to help improve the anti-MPER antibody response. Guided by structural insights and the unique lipid reactivity of anti-MPER bnAbs, we considered whether amino acid side chain modifications that emulate hydrophilic phospholipid head groups could contribute to the generation of 2F5-like or 4E10-like neutralizing anti-MPER antibodies. To test this hypothesis, we generated a series of chemically modified MPER immunogens through derivatization of amino acid side chains with phosphate or nitrate groups. We evaluated the binding affinity of the chemically modified peptides to their cognate monoclonal antibodies, 2F5 and 4E10, using surface plasmon resonance. The modifications had little effect on binding to the antibodies and did not influence epitope secondary structure when presented in liposomes. We selected five of the chemically modified sequences to immunize rabbits and found that an immunogen containing both the 2F5 and 4E10 epitopes and a phosphorylated threonine at T676 elicited the highest anti-peptide IgG titers, although the high antipeptide titers did not confer higher neutralizing activity. These data indicate that side chain modifications adjacent to known neutralizing antibody epitopes are capable of eliciting antibody responses to the MPER but that these chemically modified gp41 epitopes do not induce neutralizing antibodies.

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The V1V2 Domain and an N-Linked Glycosylation Site in the V3 Loop of the HIV-1 Envelope Glycoprotein Modulate Neutralization Sensitivity to the Human Broadly Neutralizing Antibody 2G12

Journal of Virology ◽

10.1128/jvi.02424-10 ◽

2011 ◽

Vol 85 (7) ◽

pp. 3642-3648 ◽

Cited By ~ 17

Author(s):

A. Chaillon ◽

M. Braibant ◽

T. Moreau ◽

S. Thenin ◽

A. Moreau ◽

...

Keyword(s):

Envelope Glycoprotein ◽

Neutralizing Antibody ◽

Glycosylation Site ◽

V3 Loop ◽

Neutralization Sensitivity ◽

Broadly Neutralizing Antibody ◽

Hiv 1 ◽

Antibody 2G12

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An MPER antibody neutralizes HIV-1 using germline features shared among donors

Nature Communications ◽

10.1038/s41467-019-12973-1 ◽

2019 ◽

Vol 10 (1) ◽

Cited By ~ 9

Author(s):

Lei Zhang ◽

◽

Adriana Irimia ◽

Lingling He ◽

Elise Landais ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Neutralizing Antibody ◽

Structural Elements ◽

External Region ◽

Viral Membrane ◽

D Region ◽

Broadly Neutralizing Antibody ◽

Igg3 Subclass ◽

Igg1 Subclass ◽

Hiv 1

AbstractThe membrane-proximal external region (MPER) of HIV-1 envelope glycoprotein (Env) can be targeted by neutralizing antibodies of exceptional breadth. MPER antibodies usually have long, hydrophobic CDRH3s, lack activity as inferred germline precursors, are often from the minor IgG3 subclass, and some are polyreactive, such as 4E10. Here we describe an MPER broadly neutralizing antibody from the major IgG1 subclass, PGZL1, which shares germline V/D-region genes with 4E10, has a shorter CDRH3, and is less polyreactive. A recombinant sublineage variant pan-neutralizes a 130-isolate panel at 1.4 μg/ml (IC50). Notably, a germline revertant with mature CDR3s neutralizes 12% of viruses and still binds MPER after DJ reversion. Crystal structures of lipid-bound PGZL1 variants and cryo-EM reconstruction of an Env-PGZL1 complex reveal how these antibodies recognize MPER and viral membrane. Discovery of common genetic and structural elements among MPER antibodies from different patients suggests that such antibodies could be elicited using carefully designed immunogens.

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