scholarly journals Human anti–HIV-neutralizing antibodies frequently target a conserved epitope essential for viral fitness

2010 ◽  
Vol 207 (9) ◽  
pp. 1995-2002 ◽  
Author(s):  
John Pietzsch ◽  
Johannes F. Scheid ◽  
Hugo Mouquet ◽  
Florian Klein ◽  
Michael S. Seaman ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Vaccine Design ◽  
Neutralizing Antibody ◽  
Viral Fitness ◽  
Viral Fusion ◽  
The Core ◽  
Outer Domain ◽  
Gp120 Subunit ◽  
Anti Hiv ◽  
Conserved Epitope

The identification and characterization of conserved epitopes on the HIV-1 viral spike that are immunogenic in humans and targeted by neutralizing antibodies is an important step in vaccine design. Antibody cloning experiments revealed that 32% of all HIV-neutralizing antibodies expressed by the memory B cells in patients with high titers of broadly neutralizing antibodies recognize one or more “core” epitopes that were not defined. Here, we show that anti-core antibodies recognize a single conserved epitope on the gp120 subunit. Amino acids D474, M475, R476, which are essential for anti-core antibody binding, form an immunodominant triad at the outer domain/inner domain junction of gp120. The mutation of these residues to alanine impairs viral fusion and fitness. Thus, the core epitope, a frequent target of anti–HIV-neutralizing antibodies, including the broadly neutralizing antibody HJ16, is conserved and indispensible for viral infectivity. We conclude that the core epitope should be considered as a target for vaccine design.

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

Antibodies ◽  
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.

scholarly journals 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

2015 ◽  
Vol 89 (10) ◽  
pp. 5264-5275 ◽  
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.

scholarly journals Structural flexibility at a major conserved antibody target on hepatitis C virus E2 antigen

2016 ◽  
Vol 113 (45) ◽  
pp. 12768-12773 ◽  
Author(s):  
Leopold Kong ◽  
David E. Lee ◽  
Rameshwar U. Kadam ◽  
Tong Liu ◽  
Erick Giang ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Viral Entry ◽  
Neutralizing Antibodies ◽  
Vaccine Design ◽  
Neutralizing Antibody ◽  
Md Simulations ◽  
Receptor Binding Site ◽  
Structural Investigations ◽  
Thermophilic Organisms

Hepatitis C virus (HCV) is a major cause of liver disease, affecting over 2% of the world’s population. The HCV envelope glycoproteins E1 and E2 mediate viral entry, with E2 being the main target of neutralizing antibody responses. Structural investigations of E2 have produced templates for vaccine design, including the conserved CD81 receptor-binding site (CD81bs) that is a key target of broadly neutralizing antibodies (bNAbs). Unfortunately, immunization with recombinant E2 and E1E2 rarely elicits sufficient levels of bNAbs for protection. To understand the challenges for eliciting bNAb responses against the CD81bs, we investigated the E2 CD81bs by electron microscopy (EM), hydrogen–deuterium exchange (HDX), molecular dynamics (MD), and calorimetry. By EM, we observed that HCV1, a bNAb recognizing the N-terminal region of the CD81bs, bound a soluble E2 core construct from multiple angles of approach, suggesting components of the CD81bs are flexible. HDX of multiple E2 constructs consistently indicated the entire CD81bs was flexible relative to the rest of the E2 protein, which was further confirmed by MD simulations. However, E2 has a high melting temperature of 84.8 °C, which is more akin to proteins from thermophilic organisms. Thus, recombinant E2 is a highly stable protein overall, but with an exceptionally flexible CD81bs. Such flexibility may promote induction of nonneutralizing antibodies over bNAbs to E2 CD81bs, underscoring the necessity of rigidifying this antigenic region as a target for rational vaccine design.

scholarly journals HIV-1 Env structure and vaccine design

2014 ◽  
Vol 70 (a1) ◽  
pp. C117-C117
Author(s):  
Peter Kwong
Keyword(s):  
Electron Microscopy ◽  
Neutralizing Antibodies ◽  
Bound States ◽  
Vaccine Design ◽  
Atomic Level ◽  
Alpha Helices ◽  
X Ray ◽  
X Ray Crystallography ◽  
Gp120 Subunit ◽  
Hiv 1

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.

scholarly journals An HIV-1 broadly neutralizing antibody from a clade C infected pediatric elite neutralizer potently neutralizes the contemporaneous and autologous evolving viruses

2018 ◽  
Author(s):  
Sanjeev Kumar ◽  
Harekrushna Panda ◽  
Muzamil Ashraf Makhdoomi ◽  
Nitesh Mishra ◽  
Haaris Ahsan Safdari ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Structural Information ◽  
Vaccine Design ◽  
Neutralizing Antibody ◽  
Elite Controller ◽  
Effective Vaccine ◽  
Protective Effects ◽  
Isolation And Characterization ◽  
Clade C ◽  
Hiv 1

AbstractBroadly neutralizing antibodies (bNAbs) have demonstrated protective effects against HIV-1 in primate studies and recent human clinical trials. Elite-neutralizers are potential candidates for isolation of HIV-1 bNAbs and coexistence of bNAbs such as BG18 with neutralization susceptible autologous viruses in an HIV-1 infected adult elite controller has been suggested to control viremia. Disease progression is faster in HIV-1 infected children than adults. Plasma bNAbs with multiple epitope specificities are developed in HIV-1 chronically infected children with more potency and breadth than in adults. Therefore, we evaluated the specificity of plasma neutralizing antibodies of an antiretroviral naïve HIV-1 clade C chronically infected pediatric elite neutralizer AIIMS_330. The plasma antibodies showed broad and potent HIV-1 neutralizing activity with >87% (29/33) breadth, median inhibitory dilution (ID50) value of 1246 and presence of N160 and N332-supersite dependent HIV-1 bNAbs. The sorting of BG505.SOSIP.664.C2 T332N gp140 HIV-1 antigen-specific single B cells of AIIMS_330 resulted in the isolation of an HIV-1 N332-supersite dependent bNAb AIIMS-P01. The AIIMS-P01 neutralized 67% of HIV-1 cross-clade viruses; exhibited substantial indels despite limited somatic hypermutations; interacted with native-like HIV-1 trimer as observed in negative stain electron microscopy and demonstrated high binding affinity. In addition, AIIMS-P01 potently neutralized the coexisting and evolving autologous viruses suggesting the coexistence of vulnerable autologous viruses and HIV-1 bNAbs in AIIMS_330 pediatric elite neutralizer. Further studies on such pediatric elite-neutralizers and isolation of novel HIV-1 pediatric bNAbs may provide newer insights to guide vaccine design.ImportanceMore than 50% of the HIV-1 infections globally are caused by clade C viruses. Till date, there is no effective vaccine to prevent HIV-1 infection. Based on the structural information of the currently available HIV-1 bNAbs, attempts are underway to design immunogens that can elicit correlates of protection upon vaccination. Here we report the isolation and characterization of an HIV-1 N332-supersite dependent bNAb AIIMS-P01 from a clade C chronically infected pediatric elite neutralizer. The N332-supersite is an important epitope and is one of the current HIV-1 vaccine targets. AIIMS-P01 potently neutralized the contemporaneous and autologous evolving viruses and exhibits substantial indels despite low somatic hypermutations. Taken together with the information on infant bNAbs, further isolation of bNAbs contributing to the plasma breadth in HIV-1 infected children may help to better understand their development and characteristics, which in turn may guide vaccine design.

scholarly journals Functional Contacts between MPER and the Anti-HIV-1 Broadly Neutralizing Antibody 4E10 Extend into the Core of the Membrane

2017 ◽  
Vol 429 (8) ◽  
pp. 1213-1226 ◽  
Author(s):  
Edurne Rujas ◽  
Sara Insausti ◽  
Miguel García-Porras ◽  
Rubén Sánchez-Eugenia ◽  
Kouhei Tsumoto ◽  
...  
Keyword(s):  
Neutralizing Antibody ◽  
The Core ◽  
Antibody 4E10 ◽  
Broadly Neutralizing Antibody ◽  
Anti Hiv ◽  
Hiv 1

scholarly journals Structure-Based Design of Hepatitis C Virus Vaccines That Elicit Neutralizing Antibody Responses to a Conserved Epitope

2017 ◽  
Vol 91 (20) ◽  
Author(s):  
Brian G. Pierce ◽  
Elisabeth N. Boucher ◽  
Kurt H. Piepenbrink ◽  
Monir Ejemel ◽  
Chelsea A. Rapp ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Antibody Responses ◽  
Therapeutic Options ◽  
Effective Vaccine ◽  
Sequence Variability ◽  
Peptide Epitope ◽  
Conserved Epitope

ABSTRACT Despite recent advances in therapeutic options, hepatitis C virus (HCV) remains a severe global disease burden, and a vaccine can substantially reduce its incidence. Due to its extremely high sequence variability, HCV can readily escape the immune response; thus, an effective vaccine must target conserved, functionally important epitopes. Using the structure of a broadly neutralizing antibody in complex with a conserved linear epitope from the HCV E2 envelope glycoprotein (residues 412 to 423; epitope I), we performed structure-based design of immunogens to induce antibody responses to this epitope. This resulted in epitope-based immunogens based on a cyclic defensin protein, as well as a bivalent immunogen with two copies of the epitope on the E2 surface. We solved the X-ray structure of a cyclic immunogen in complex with the HCV1 antibody and confirmed preservation of the epitope conformation and the HCV1 interface. Mice vaccinated with our designed immunogens produced robust antibody responses to epitope I, and their serum could neutralize HCV. Notably, the cyclic designs induced greater epitope-specific responses and neutralization than the native peptide epitope. Beyond successfully designing several novel HCV immunogens, this study demonstrates the principle that neutralizing anti-HCV antibodies can be induced by epitope-based, engineered vaccines and provides the basis for further efforts in structure-based design of HCV vaccines. IMPORTANCE Hepatitis C virus is a leading cause of liver disease and liver cancer, with approximately 3% of the world's population infected. To combat this virus, an effective vaccine would have distinct advantages over current therapeutic options, yet experimental vaccines have not been successful to date, due in part to the virus's high sequence variability leading to immune escape. In this study, we rationally designed several vaccine immunogens based on the structure of a conserved epitope that is the target of broadly neutralizing antibodies. In vivo results in mice indicated that these antigens elicited epitope-specific neutralizing antibodies, with various degrees of potency and breadth. These promising results suggest that a rational design approach can be used to generate an effective vaccine for this virus.

scholarly journals Ebola Virus Can Be Effectively Neutralized by Antibody Produced in Natural Human Infection

1999 ◽  
Vol 73 (7) ◽  
pp. 6024-6030 ◽  
Author(s):  
Toshiaki Maruyama ◽  
Luis L. Rodriguez ◽  
Peter B. Jahrling ◽  
Anthony Sanchez ◽  
Ali S. Khan ◽  
...  
Keyword(s):  
Envelope Glycoprotein ◽  
Neutralizing Antibodies ◽  
Ebola Virus ◽  
Democratic Republic Of Congo ◽  
Low Frequency ◽  
Vaccine Design ◽  
Neutralizing Antibody ◽  
Human Infection ◽  
Fab Fragment ◽  
Phage Display Libraries

ABSTRACT The activity of antibodies against filoviruses is poorly understood but has important consequences for vaccine design and passive prophylaxis. To investigate this activity, a panel of recombinant human monoclonal antibodies to Ebola virus antigens was isolated from phage display libraries constructed from RNA from donors who recovered from infection in the 1995 Ebola virus outbreak in Kikwit, Democratic Republic of Congo. Antibodies reactive with nucleoprotein (NP), envelope glycoprotein (GP), and secreted envelope glycoprotein (sGP) were characterized by immunofluorescence and radioimmunoprecipitation assays. Four antibodies reacting strongly with sGP and weakly with GP and two antibodies reacting with NP were not neutralizing. An antibody specific for GP neutralized Ebola virus to 50% at 0.4 μg/ml as the recombinant Fab fragment and to 50% at 0.3 μg/ml (90% at 2.6 μg/ml) as the corresponding whole immunoglobulin G1 molecule. The studies indicate that neutralizing antibodies are produced in infection by Ebola virus although probably at a relatively low frequency. The neutralizing antibody may be useful in vaccine design and as a prophylactic agent against Ebola virus infection.

scholarly journals HIV-1 vaccine design through minimizing envelope metastability

2018 ◽  
Author(s):  
Linling He ◽  
Sonu Kumar ◽  
Joel D. Allen ◽  
Deli Huang ◽  
Xiaohe Lin ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Statistical Significance ◽  
Vaccine Design ◽  
Neutralizing Antibody ◽  
High Yield ◽  
List Type ◽  
Tier 2 ◽  
Vaccine Strategy ◽  
Antibody Recognition ◽  
Hiv 1

SUMMARYOvercoming envelope metastability is crucial to trimer-based HIV-1 vaccine design. Here, we present a coherent vaccine strategy by minimizing metastability. For ten strains across five clades, we demonstrate that gp41 ectodomain (gp41ECTO) is the main source of envelope metastability by replacing wild-type gp41ECTOwith BG505 gp41ECTOof the uncleaved prefusion-optimized (UFO) design. These gp41ECTO-swapped trimers can be produced in CHO cells with high yield and high purity. Crystal structure of a gp41ECTO-swapped trimer elucidates how a neutralization-resistant tier 3 virus evades antibody recognition of the V2 apex. UFO trimers of transmitted/founder (T/F) viruses and UFO trimers containing a consensus-based ancestral gp41ECTOsuggest an evolutionary root of the metastability. Gp41ECTO-stabilized trimers can be readily displayed on 24- and 60-meric nanoparticles, with incorporation of additional T cell help illustrated for a hyperstable 60-mer. In mice and rabbits, gp140 nanoparticles induced more effective tier 2 neutralizing antibody response than trimers with statistical significance.HIGHLIGHTSgp41 is the main source of HIV-1 envelope metastabilityBG505 gp41 of the UFO design stabilizes gp140 trimers of diverse subtypesgp41 stabilization facilitates gp140 nanoparticle assembly and improves productionNanoparticles elicit tier 2 neutralizing antibodies more effectively than trimers

scholarly journals Comparing Antigenicity and Immunogenicity of Engineered gp120

2005 ◽  
Vol 79 (19) ◽  
pp. 12148-12163 ◽  
Author(s):  
Suganya Selvarajah ◽  
Bridget Puffer ◽  
Ralph Pantophlet ◽  
Mansun Law ◽  
Robert W. Doms ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Significant Degree ◽  
Wild Type ◽  
Cd4 Binding Site ◽  
Monomeric Gp120 ◽  
Broadly Neutralizing Antibody ◽  
The Relationship ◽  
Conserved Epitope ◽  
Better Than

ABSTRACT We have engineered monomeric gp120 in such a way as to favorably present the conserved epitope for the broadly neutralizing antibody b12 while lowering the exposure of epitopes recognized by some weakly neutralizing and nonneutralizing antibodies. The work presented here describes the immune response in rabbits immunized with two prototype, engineered gp120s to explore the relationship between antigenicity and immunogenicity for these mutants. The GDMR gp120 mutant (residues 473 to 476 on gp120 altered from GDMR to AAAA) has a series of substitutions on the edge of the CD4 binding site (CD4bs), and the mCHO gp120 mutant has seven extra glycans relative to the wild-type protein. Importantly, serum mapping showed that both mutants did not elicit antibodies against a number of epitopes that had been targeted for dampening. The sera from rabbits immunized with the GDMR gp120 mutant neutralized some primary viruses at levels somewhat better than the wild-type gp120 immune sera as a result of an increased elicitation of anti-V3 antibodies. Unlike wild-type gp120 immune sera, GDMR gp120 immune sera failed to neutralize HXBc2, a T-cell line adapted (TCLA) virus. This was associated with loss of CD4bs/CD4-induced antibodies that neutralize TCLA but not primary viruses. The mCHO gp120 immune sera did not neutralize primary viruses to any significant degree, reflecting the masking of epitopes of even weakly neutralizing antibodies without eliciting b12-like antibodies. These results show that antibody responses to multiple epitopes on gp120 can be dampened. More precise focusing to a neutralizing epitope will likely require several iterations comparing antigenicity and immunogenicity of engineered proteins.

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