scholarly journals Engineering HIV envelope protein to activate germline B cell receptors of broadly neutralizing anti-CD4 binding site antibodies

2013 ◽  
Vol 210 (4) ◽  
pp. 655-663 ◽  
Author(s):  
Andrew T. McGuire ◽  
Sam Hoot ◽  
Anita M. Dreyer ◽  
Adriana Lippy ◽  
Andrew Stuart ◽  
...  
Keyword(s):  
Binding Site ◽  
Neutralizing Antibodies ◽  
Variable Region ◽  
Neutralizing Antibody ◽  
Glycosylation Site ◽  
Affinity Maturation ◽  
Broadly Neutralizing Antibodies ◽  
Cd4 Binding Site ◽  
Broadly Neutralizing Antibody ◽  
Hiv Envelope

Broadly neutralizing antibodies (bnAbs) against HIV are believed to be a critical component of the protective responses elicited by an effective HIV vaccine. Neutralizing antibodies against the evolutionarily conserved CD4-binding site (CD4-BS) on the HIV envelope glycoprotein (Env) are capable of inhibiting infection of diverse HIV strains, and have been isolated from HIV-infected individuals. Despite the presence of anti–CD4-BS broadly neutralizing antibody (bnAb) epitopes on recombinant Env, Env immunization has so far failed to elicit such antibodies. Here, we show that Env immunogens fail to engage the germline-reverted forms of known bnAbs that target the CD4-BS. However, we found that the elimination of a conserved glycosylation site located in Loop D and two glycosylation sites located in variable region 5 of Env allows Env-binding to, and activation of, B cells expressing the germline-reverted BCRs of two potent broadly neutralizing antibodies, VRC01 and NIH45-46. Our results offer a possible explanation as to why Env immunogens have been ineffective in stimulating the production of such bNAbs. Importantly, they provide key information as to how such immunogens can be engineered to initiate the process of antibody-affinity maturation against one of the most conserved Env regions.

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

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.

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

eLife ◽  
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.

scholarly journals Maternal Broadly Neutralizing Antibodies Can Select for Neutralization-Resistant, Infant-Transmitted/Founder HIV Variants

mBio ◽  
2020 ◽  
Vol 11 (2) ◽  
Author(s):  
David R. Martinez ◽  
Joshua J. Tu ◽  
Amit Kumar ◽  
Jesse F. Mangold ◽  
Riley J. Mangan ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Maternal Plasma ◽  
Small Subset ◽  
Maternal Hiv ◽  
Broadly Neutralizing Antibody ◽  
Specific Igg ◽  
Hiv Envelope ◽  
Mother To Child

ABSTRACT Each year, >180,000 infants become infected via mother-to-child transmission (MTCT) of HIV despite the availability of effective maternal antiretroviral treatments, underlining the need for a maternal HIV vaccine. We characterized 224 maternal HIV envelope (Env)-specific IgG monoclonal antibodies (MAbs) from seven nontransmitting and transmitting HIV-infected U.S. and Malawian mothers and examined their neutralization activities against nontransmitted autologous circulating viruses and infant-transmitted founder (infant-T/F) viruses. Only a small subset of maternal viruses, 3 of 72 (4%), were weakly neutralized by maternal linear V3 epitope-specific IgG MAbs, whereas 6 out of 6 (100%) infant-T/F viruses were neutralization resistant to these V3-specific IgG MAbs. We also show that maternal-plasma broadly neutralizing antibody (bNAb) responses targeting the V3 glycan supersite in a transmitting woman may have selected for an N332 V3 glycan neutralization-resistant infant-T/F virus. These data have important implications for bNAb-eliciting vaccines and passively administered bNAbs in the setting of MTCT. IMPORTANCE Efforts to eliminate MTCT of HIV with antiretroviral therapy (ART) have met little success, with >180,000 infant infections each year worldwide. It is therefore likely that additional immunologic strategies that can synergize with ART will be required to eliminate MTCT of HIV. To this end, understanding the role of maternal HIV Env-specific IgG antibodies in the setting of MTCT is crucial. In this study, we found that maternal-plasma broadly neutralizing antibody (bNAb) responses can select for T/F viruses that initiate infection in infants. We propose that clinical trials testing the efficacy of single bNAb specificities should not include HIV-infected pregnant women, as a single bNAb might select for neutralization-resistant infant-T/F viruses.

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 Griffithsin Retains Anti-HIV-1 Potency with Changes in gp120 Glycosylation and Complements Broadly Neutralizing Antibodies PGT121 and PGT126

2019 ◽  
Vol 64 (1) ◽  
Author(s):  
Kathryn Fischer ◽  
Kimberly Nguyen ◽  
Patricia J. LiWang
Keyword(s):  
Neutralizing Antibodies ◽  
Glycosylation Site ◽  
Significant Loss ◽  
Broadly Neutralizing Antibodies ◽  
Clade B ◽  
Key Factor ◽  
Clade C ◽  
Cd4 Binding Site ◽  
Gp120 Glycosylation ◽  
Hiv 1

ABSTRACT Griffithsin (Grft) is an antiviral lectin that has been shown to potently inhibit HIV-1 by binding high-mannose N-linked glycosylation sites on HIV-1 gp120. A key factor for Grft potency is glycosylation at N295 of gp120, which is directly adjacent to N332, a target glycan for an entire class of broadly neutralizing antibodies (bNAbs). Here, we unify previous work on the importance of other glycans to Grft potency against HIV-1 and Grft’s role in mediating the conformational change of gp120 by mutating nearly every glycosylation site in gp120. In addition to a significant loss of Grft activity by the removal of glycosylation at N295, glycan absence at N332 or N448 was found to have moderate effects on Grft potency. Interestingly, in the absence of N295, Grft effectiveness could be improved by a mutation that results in the glycan at N448 shifting to N446, indicating that the importance of individual glycans may be related to their effect on glycosylation density. Grft’s ability to alter the structure of gp120, exposing the CD4 binding site, correlated with the presence of glycosylation at N295 only in clade B strains, not clade C strains. We further demonstrate that Grft can rescue the activity of the bNAbs PGT121 and PGT126 in the event of a loss or a shift of glycosylation at N332, where the bNAbs suffer a drastic loss of potency. Despite targeting the same region, Grft in combination with PGT121 and PGT126 produced additive effects. This indicates that Grft could be an important combinational therapeutic.

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

2012 ◽  
Vol 209 (8) ◽  
pp. 1469-1479 ◽  
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.

scholarly journals Selection Pressure on HIV-1 Envelope by Broadly Neutralizing Antibodies to the Conserved CD4-Binding Site

2012 ◽  
Vol 86 (10) ◽  
pp. 5844-5856 ◽  
Author(s):  
X. Wu ◽  
C. Wang ◽  
S. O'Dell ◽  
Y. Li ◽  
B. F. Keele ◽  
...  
Keyword(s):  
Binding Site ◽  
Neutralizing Antibodies ◽  
Selection Pressure ◽  
Broadly Neutralizing Antibodies ◽  
Cd4 Binding Site ◽  
Hiv 1

scholarly journals Multiscale affinity maturation simulations to elicit HIV broadly neutralizing antibodies

2021 ◽  
Author(s):  
Kayla Sprenger ◽  
Simone Conti ◽  
Victor Ovchinnikov ◽  
Arup K Chakraborty ◽  
martin karplus
Keyword(s):  
Neutralizing Antibodies ◽  
Adaptive Immune System ◽  
Multiscale Model ◽  
Cell Receptor ◽  
Affinity Maturation ◽  
Sequencing Data ◽  
Broadly Neutralizing Antibodies ◽  
Adaptive Immune ◽  
Cd4 Binding Site ◽  
Anti Hiv

The design of vaccines against highly mutable pathogens, such as HIV and influenza, requires a detailed understanding of how the adaptive immune system responds to encountering multiple variant antigens (Ags). Here, we describe a multiscale model of B cell receptor (BCR) affinity maturation that employs actual BCR nucleotide sequences and treats BCR/Ag interactions in atomistic detail. We apply the model to simulate the maturation of a broadly neutralizing Ab (bnAb) against HIV. Starting from a germline precursor sequence of the VRC01 anti-HIV Ab, we simulate BCR evolution in response to different vaccination protocols and different Ags, which were previously designed by us. The simulation results provide qualitative guidelines for future vaccine design and reveal unique insights into bnAb evolution against the CD4 binding site of HIV. Our model makes possible direct comparisons of simulated BCR populations with results of deep sequencing data, which will be explored in future applications.

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