Trimeric Glycosylphosphatidylinositol-Anchored HCDR3 of Broadly Neutralizing Antibody PG16 Is a Potent HIV-1 Entry Inhibitor

ABSTRACTPG9 and PG16 are two quaternary-structure-specific broadly neutralizing antibodies with unique HCDR3 subdomains. Previously, we showed that glycosylphosphatidylinositol (GPI)-anchored HCDR3 subdomains (GPI-HCDR3) can be targeted to lipid rafts of the plasma membrane, bind to the epitope recognized by HCDR3 of PG16, and neutralize diverse HIV-1 isolates. In this study, we further developed trimeric GPI-HCDR3s and demonstrated that trimeric GPI-HCDR3 (PG16) dramatically improves anti-HIV-1 neutralization, suggesting that a stoichiometry of recognition of 3 or 2 HCDR3 molecules (PG16) to 1 viral spike is possible.

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Vaccines and Broadly Neutralizing Antibodies for HIV-1 Prevention

Annual Review of Immunology ◽

10.1146/annurev-immunol-080219-023629 ◽

2020 ◽

Vol 38 (1) ◽

pp. 673-703 ◽

Cited By ~ 12

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.

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New Connections: Cell-to-Cell HIV-1 Transmission, Resistance to Broadly Neutralizing Antibodies, and an Envelope Sorting Motif

Journal of Virology ◽

10.1128/jvi.00149-17 ◽

2017 ◽

Vol 91 (9) ◽

Cited By ~ 2

Author(s):

S. Abigail Smith ◽

Cynthia A. Derdeyn

Keyword(s):

Neutralizing Antibodies ◽

Differential Susceptibility ◽

Neutralizing Antibody ◽

Dependent Manner ◽

Broadly Neutralizing Antibodies ◽

Cell Infection ◽

Viral Spread ◽

Broadly Neutralizing Antibody ◽

Hiv 1

ABSTRACT HIV-1 infection from cell-to-cell may provide an efficient mode of viral spread in vivo and could therefore present a significant challenge for preventative or therapeutic strategies based on broadly neutralizing antibodies. Indeed, Li et al. (H. Li, C. Zony, P. Chen, and B. K. Chen, J. Virol. 91:e02425-16, 2017, https://doi.org/10.1128/JVI.02425-16 ) showed that the potency and magnitude of multiple HIV-1 broadly neutralizing antibody classes are decreased during cell-to-cell infection in a context-dependent manner. A functional motif in gp41 appears to contribute to this differential susceptibility by modulating exposure of neutralization epitopes.

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Validation of a Triplex Pharmacokinetic Assay for Simultaneous Quantitation of HIV-1 Broadly Neutralizing Antibodies PGT121, PGDM1400, and VRC07-523-LS

Frontiers in Immunology ◽

10.3389/fimmu.2021.709994 ◽

2021 ◽

Vol 12 ◽

Author(s):

Martina S. Wesley ◽

Kelvin T. Chiong ◽

Kelly E. Seaton ◽

Christine A. Arocena ◽

Sheetal Sawant ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Neutralizing Antibody ◽

Broadly Neutralizing Antibodies ◽

Testing Method ◽

Cd4 Binding Site ◽

Broadly Neutralizing Antibody ◽

Effective Doses ◽

Pharmacokinetic Assay ◽

Hiv 1

The outcome of the recent Antibody Mediated Prevention (AMP) trials that tested infusion of the broadly neutralizing antibody (bnAb) VRC01 provides proof of concept for blocking infection from sensitive HIV-1 strains. These results also open up the possibility that triple combinations of bnAbs such as PGT121, PGDM1400, as well as long-lasting LS variants such as VRC07-523 LS, have immunoprophylactic potential. PGT121 and PGDM1400 target the HIV-1 V3 and V2 glycan regions of the gp120 envelope protein, respectively, while VRC07-523LS targets the HIV-1 CD4 binding site. These bnAbs demonstrate neutralization potency and complementary breadth of HIV-1 strain coverage. An important clinical trial outcome is the accurate measurement of in vivo concentrations of passively infused bnAbs to determine effective doses for therapy and/or prevention. Standardization and validation of this testing method is a key element for clinical studies as is the ability to simultaneously detect multiple bnAbs in a specific manner. Here we report the development of a sensitive, specific, accurate, and precise multiplexed microsphere-based assay that simultaneously quantifies the respective physiological concentrations of passively infused bnAbs in human serum to ultimately define the threshold needed for protection from HIV-1 infection.

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Functional development of a V3/glycan-specific broadly neutralizing antibody isolated from a case of HIV superinfection

eLife ◽

10.7554/elife.68110 ◽

2021 ◽

Vol 10 ◽

Author(s):

Mackenzie M Shipley ◽

Vidya Mangala Prasad ◽

Laura E Doepker ◽

Adam S Dingens ◽

Duncan K Ralph ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Neutralizing Antibody ◽

Viral Escape ◽

Single Infection ◽

Structural Studies ◽

Broadly Neutralizing Antibodies ◽

Hiv Vaccines ◽

Functional Development ◽

Broadly Neutralizing Antibody

Stimulating broadly neutralizing antibodies (bnAbs) directly from germline remains a barrier for HIV vaccines. HIV superinfection elicits bnAbs more frequently than single infection, providing clues of how to elicit such responses. We used longitudinal antibody sequencing and structural studies to characterize bnAb development from a superinfection case. BnAb QA013.2 bound initial and superinfecting viral Env, despite its probable naïve progenitor only recognizing the superinfecting strain, suggesting both viruses influenced this lineage. A 4.15 Å cryo-EM structure of QA013.2 bound to native-like trimer showed recognition of V3 signatures (N301/N332 and GDIR). QA013.2 relies less on CDRH3 and more on framework and CDRH1 for affinity and breadth compared to other V3/glycan-specific bnAbs. Antigenic profiling revealed that viral escape was achieved by changes in the structurally-defined epitope and by mutations in V1. These results highlight shared and novel properties of QA013.2 relative to other V3/glycan-specific bnAbs in the setting of sequential, diverse antigens.

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Nanoparticle Vaccines for Inducing HIV-1 Neutralizing Antibodies

Vaccines ◽

10.3390/vaccines7030076 ◽

2019 ◽

Vol 7 (3) ◽

pp. 76 ◽

Cited By ~ 15

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.

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Broad neutralization by a combination of antibodies recognizing the CD4 binding site and a new conformational epitope on the HIV-1 envelope protein

Journal of Experimental Medicine ◽

10.1084/jem.20120423 ◽

2012 ◽

Vol 209 (8) ◽

pp. 1469-1479 ◽

Cited By ~ 123

Author(s):

Florian Klein ◽

Christian Gaebler ◽

Hugo Mouquet ◽

D. Noah Sather ◽

Clara Lehmann ◽

...

Keyword(s):

Binding Site ◽

Envelope Protein ◽

Neutralizing Antibodies ◽

Conformational Epitope ◽

Broadly Neutralizing Antibodies ◽

Cd4 Binding Site ◽

Capture Method ◽

Anti Hiv ◽

Hiv 1 ◽

Viral Isolates

Two to three years after infection, a fraction of HIV-1–infected individuals develop serologic activity that neutralizes most viral isolates. Broadly neutralizing antibodies that recognize the HIV-1 envelope protein have been isolated from these patients by single-cell sorting and by neutralization screens. Here, we report a new method for anti–HIV-1 antibody isolation based on capturing single B cells that recognize the HIV-1 envelope protein expressed on the surface of transfected cells. Although far less efficient than soluble protein baits, the cell-based capture method identified antibodies that bind to a new broadly neutralizing epitope in the vicinity of the V3 loop and the CD4-induced site (CD4i). The new epitope is expressed on the cell surface form of the HIV-1 spike, but not on soluble forms of the same envelope protein. Moreover, the new antibodies complement the neutralization spectrum of potent broadly neutralizing anti-CD4 binding site (CD4bs) antibodies obtained from the same individual. Thus, combinations of potent broadly neutralizing antibodies with complementary activity can account for the breadth and potency of naturally arising anti–HIV-1 serologic activity. Therefore, vaccines aimed at eliciting anti–HIV-1 serologic breadth and potency should not be limited to single epitopes.

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Characterization of Co-Formulated High-Concentration Broadly Neutralizing Anti-HIV-1 Monoclonal Antibodies for Subcutaneous Administration

Antibodies ◽

10.3390/antib9030036 ◽

2020 ◽

Vol 9 (3) ◽

pp. 36

Author(s):

Vaneet K. Sharma ◽

Bijay Misra ◽

Kevin T. McManus ◽

Sreenivas Avula ◽

Kaliappanadar Nellaiappan ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Clinical Investigation ◽

Total Concentration ◽

Subcutaneous Administration ◽

Analytical Techniques ◽

Neutralizing Antibody ◽

High Concentration ◽

Anti Hiv ◽

Hiv 1

The discovery of numerous potent and broad neutralizing antibodies (bNAbs) against Human Immunodeficiency Virus type 1 (HIV-1) envelope glycoprotein has invigorated the potential of using them as an effective preventative and therapeutic agent. The majority of the anti-HIV-1 antibodies, currently under clinical investigation, are formulated singly for intra-venous (IV) infusion. However, due to the high degree of genetic variability in the case of HIV-1, a single broad neutralizing antibody will likely not be sufficient to protect against the broad range of viral isolates. To that end, delivery of two or more co-formulated bnAbs against HIV-1 in a single subcutaneous (SC) injection is highly desired. We, therefore, co-formulated two anti-HIV bnAbs, 3BNC117-LS and 10-1074-LS, to a total concentration of 150 mg/mL for SC administration and analyzed them using a panel of analytical techniques. Chromatographic based methods, such as RP-HPLC, CEX-HPLC, SEC-HPLC, were developed to ensure separation and detection of each antibody in the co-formulated sample. In addition, we used a panel of diverse pseudoviruses to detect the functionality of individual antibodies in the co-formulation. We also used these methods to test the stability of the co-formulated antibodies and believe that such an approach can support future efforts towards the formulation and characterization of multiple high-concentration antibodies for SC delivery.

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Anti-V3/Glycan and Anti-MPER Neutralizing Antibodies, but Not Anti-V2/Glycan Site Antibodies, Are Strongly Associated with Greater Anti-HIV-1 Neutralization Breadth and Potency

Journal of Virology ◽

10.1128/jvi.00129-15 ◽

2015 ◽

Vol 89 (10) ◽

pp. 5264-5275 ◽

Cited By ~ 23

Author(s):

Rajesh Abraham Jacob ◽

Thandeka Moyo ◽

Michael Schomaker ◽

Fatima Abrahams ◽

Berta Grau Pujol ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Prediction Interval ◽

Vaccine Design ◽

Broadly Neutralizing Antibodies ◽

External Region ◽

Membrane Proximal External Region ◽

Site Recognition ◽

Anti Hiv ◽

Glycan Site ◽

Hiv 1

ABSTRACTThe membrane-proximal external region (MPER), the V2/glycan site (initially defined by PG9 and PG16 antibodies), and the V3/glycans (initially defined by PGT121–128 antibodies) are targets of broadly neutralizing antibodies and potential targets for anti-HIV-1 antibody-based vaccines. Recent evidence shows that antibodies with moderate neutralization breadth are frequently attainable, with 50% of sera from chronically infected individuals neutralizing ≥50% of a large, diverse set of viruses. Nonetheless, there is little systematic information addressing which specificities are preferentially targeted among such commonly found, moderately broadly neutralizing sera. We explored associations between neutralization breadth and potency and the presence of neutralizing antibodies targeting the MPER, V2/glycan site, and V3/glycans in sera from 177 antiretroviral-naive HIV-1-infected (>1 year) individuals. Recognition of both MPER and V3/glycans was associated with increased breadth and potency. MPER-recognizing sera neutralized 4.62 more panel viruses than MPER-negative sera (95% prediction interval [95% PI], 4.41 to 5.20), and V3/glycan-recognizing sera neutralized 3.24 more panel viruses than V3/glycan-negative sera (95% PI, 3.15 to 3.52). In contrast, V2/glycan site-recognizing sera neutralized only 0.38 more panel viruses (95% PI, 0.20 to 0.45) than V2/glycan site-negative sera and no association between V2/glycan site recognition and breadth or potency was observed. Despite autoreactivity of many neutralizing antibodies recognizing MPER and V3/glycans, antibodies to these sites are major contributors to neutralization breadth and potency in this cohort. It may therefore be appropriate to focus on developing immunogens based upon the MPER and V3/glycans.IMPORTANCEPrevious candidate HIV vaccines have failed either to induce wide-coverage neutralizing antibodies or to substantially protect vaccinees. Therefore, current efforts focus on novel approaches never before successfully used in vaccine design, including modeling epitopes. Candidate immunogen models identified by broadly neutralizing antibodies include the membrane-proximal external region (MPER), V3/glycans, and the V2/glycan site. Autoreactivity and polyreactivity of anti-MPER and anti-V3/glycan antibodies are thought to pose both direct and indirect barriers to achieving neutralization breadth. We found that antibodies to the MPER and the V3/glycans contribute substantially to neutralization breadth and potency. In contrast, antibodies to the V2/glycan site were not associated with neutralization breadth/potency. This suggests that the autoreactivity effect is not critical and that the MPER and the V3/glycans should remain high-priority vaccine candidates. The V2/glycan site result is surprising because broadly neutralizing antibodies to this site have been repeatedly observed. Vaccine design priorities should shift toward the MPER and V3/glycans.

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Immunogenicity of a Prefusion HIV-1 Envelope Trimer in Complex with a Quaternary-Structure-Specific Antibody

Journal of Virology ◽

10.1128/jvi.02380-15 ◽

2015 ◽

Vol 90 (6) ◽

pp. 2740-2755 ◽

Cited By ~ 40

Author(s):

Cheng Cheng ◽

Marie Pancera ◽

Adam Bossert ◽

Stephen D. Schmidt ◽

Rita E. Chen ◽

...

Keyword(s):

Guinea Pigs ◽

Neutralizing Antibodies ◽

Quaternary Structure ◽

High Titer ◽

Antigen Binding ◽

Broadly Neutralizing Antibodies ◽

Closed Conformation ◽

Ligand Free ◽

V3 Region ◽

Hiv 1

ABSTRACTThe HIV-1 envelope trimer (Env) is the target of broadly neutralizing antibodies and is being explored as a vaccine candidate to elicit protective antibodies. One of the most promising antigenic and structural mimics of HIV-1 Env is the SOSIP.664-stabilized soluble trimer from the clade A strain BG505, which is preferentially recognized by broadly neutralizing antibodies. Trimer immunization elicits high-titer neutralization of the autologous tier 2 BG505 strain; however, breadth is limited, and substantial interest has focused on understanding and improving trimer immunogenicity. We sought to improve the antigenic specificity of BG505 SOSIP.664 by reducing recognition of the variable loop 3 (V3) region, which elicits only weakly neutralizing antibodies. To stabilize the trimer in its prefusion closed conformation, we complexed trimeric BG505 SOSIP.664 with the antigen-binding fragment (Fab) of PGT145, a broadly neutralizing quaternary-structure-specific antibody. Compared to the ligand-free trimer, the PGT145 Fab-BG505 SOSIP.664 complex displayed increased melting temperature stability and reduced V3 recognition. In guinea pigs, immunization with the PGT145 Fab-BG505 SOSIP.664 complex elicited ∼100-fold lower V3-directed binding and neutralization titers than those obtained with ligand-free BG505 SOSIP.664. Both complexed and ligand-free BG505 SOSIP.664 elicited comparable neutralization of the autologous BG505 virus, and in both cases, BG505 neutralization mapped to the outer domain of gp120 for some guinea pigs. Our results indicate that it is possible to reduce immune recognition of the V3 region of the trimer while maintaining the antigenic profile needed to induce autologous neutralizing antibodies. These data suggest that appropriate modifications of trimer immunogens could further focus the immune response on key neutralization epitopes.IMPORTANCEHIV-1 Env trimers have been proposed as preferred HIV-1 vaccine immunogens. One version, BG505 SOSIP.664, a soluble stabilized trimer, was recently shown to elicit high-titer autologous neutralizing antibodies (NAbs) in rabbits. Here we compared two immunogens: the ligand-free BG505 SOSIP.664 trimer and the same trimer bound to the antigen-binding fragment (Fab) of the PGT145 antibody, a broadly neutralizing antibody which recognizes the trimer at its membrane-distal apex. We hypothesized that the Fab-bound complex would stabilize BG505 SOSIP.664 in its prefusion closed conformation and limit reactivity to weakly neutralizing antibodies targeting the variable loop 3 (V3) region. In guinea pigs, the Fab-complexed trimer induced 100-fold lower responses to the V3 region, while both ligand-free and Fab-complexed trimers elicited similar levels of autologous NAbs. Our findings demonstrate the potential to reduce “off-target” immunogenicity while maintaining the capacity to generate autologous NAbs.

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