HIV Broadly Neutralizing Antibodies Expressed as IgG3 Preserve Neutralization Potency and Show Improved Fc Effector Function

The ability of several broadly neutralizing antibodies (bNAbs) to protect against HIV infection is enhanced through Fc receptor binding. Antibody isotype modulates this effect, with IgG3 associated with improved HIV control and vaccine efficacy. We recently showed that an IgG3 variant of bNAb CAP256-VRC26.25 exhibited more potent neutralization and phagocytosis than its IgG1 counterpart. Here, we expanded this analysis to include additional bNAbs targeting all major epitopes. A total of 15 bNAbs were expressed as IgG1 or IgG3, and pairs were assessed for neutralization potency against the multi-subtype global panel of 11 HIV strains. Binding to the neonatal Fc receptor (FcRn) and Fcγ receptors were measured using ELISA and antibody-dependent cellular cytotoxicity (ADCC) and phagocytosis were measured using infectious viruses and global panel Env SOSIP trimers, respectively. IgG3 bNAbs generally showed similar or increased (up to 60 fold) neutralization potency than IgG1 versions, though the effect was virus-specific. This improvement was statistically significant for CAP256-VRC26.25, 35022, PGT135 and CAP255.G3. IgG3 bNAbs also showed significantly improved binding to FcγRIIa which correlated with enhanced phagocytosis of all trimeric Env antigens. Differences in ADCC were epitope-specific, with IgG3 bNAbs to the MPER, CD4 binding site and gp120-gp41 interface showing increased ADCC. We also explored the pH dependence of IgG1 and IgG3 variants for FcRn binding, as this determines the half-life of antibodies. We observed reduced pH dependence, associated with shorter half-lives for IgG3 bNAbs, with κ-light chains. However, IgG3 bNAbs that use λ-light chains showed similar pH dependence to their IgG1 counterparts. This study supports the manipulation of the constant region to improve both the neutralizing and Fc effector activity of bNAbs, and suggests that IgG3 versions of bNAbs may be preferable for passive immunity given their polyfunctionality.

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Novel Monoclonal Antibodies and Recombined Antibodies Against Variant SARS-CoV-2

Frontiers in Immunology ◽

10.3389/fimmu.2021.715464 ◽

2021 ◽

Vol 12 ◽

Author(s):

Jiajia Xie ◽

Chengchao Ding ◽

Jun He ◽

Yuqing Zhang ◽

Shuangshuang Ni ◽

...

Keyword(s):

Binding Affinity ◽

Neutralizing Antibodies ◽

Therapeutic Agents ◽

Light Chains ◽

Published Data ◽

The Novel ◽

Broadly Neutralizing Antibodies ◽

Neutralization Activity ◽

Functional Antibodies ◽

Potent Neutralization

The mutants resulted from the ongoing SARS-CoV-2 epidemic have showed resistance to antibody neutralization and vaccine-induced immune response. The present study isolated and identified two novel SARS-CoV-2 neutralizing antibodies (nAbs) from convalescent COVID-19 patients. These two nAbs (XG81 and XG83) were then systemically compared with nine nAbs that were reconstructed by using published data, and revealed that, even though these two nAbs shared targeting epitopes on spike protein, they were different from any of the nine nAbs. Compared with XG81, XG83 exhibited a higher RBD binding affinity and neutralization potency against wild-typed pseudovirus, variant pseudoviruses with mutated spike proteins, such as D614G, E484Q, and A475V, as well as the authentic SARS-CoV-2 virus. To explore potential broadly neutralizing antibodies, heavy and light chains from all 18 nAbs (16 published nAbs, XG81 and XG83) were cross-recombined, and some of the functional antibodies were screened and studied for RBD binding affinity, and neutralizing activity against pseudovirus and the authentic SARS-CoV-2 virus. The results demonstrated that several recombined antibodies had a more potent neutralization activity against variant pseudoviruses compared with the originally paired Abs. Taken together, the novel neutralizing antibodies identified in this study are a likely valuable addition to candidate antibody drugs for the development of clinical therapeutic agents against SARS-CoV-2 to minimize mutational escape.

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Frequent development of broadly neutralizing antibodies in early life in a large cohort of HIV-infected children

10.1101/2021.05.07.443081 ◽

2021 ◽

Author(s):

Genevieve G. Fouda ◽

Amanda Lucier ◽

Youyi Fong ◽

Shuk Hang Li ◽

Maria Dennis ◽

...

Keyword(s):

Early Life ◽

Neutralizing Antibodies ◽

Igg Subclass ◽

Tier 2 ◽

Broadly Neutralizing Antibodies ◽

Significant Difference ◽

Cd4 Binding Site ◽

Binding Antibody ◽

Antibody Specificities ◽

Living With Hiv

Recent studies conducted in small cohorts of children have indicated that broadly neutralizing antibodies (bnAbs) may develop earlier after HIV infection compared to adults. To define the frequency and kinetics of bnAb responses in a larger pediatric cohort, we evaluated plasma from 212 ART-naïve, children living with HIV aged 1 to 3 years. Neutralization breadth and potency was assessed using a panel of 10 tier-2 viruses and compared to those of adults with chronic HIV. Further, the magnitude, epitope specificity and IgG subclass distribution of Env-specific antibodies were also assessed using a binding antibody multiplex assay. We found that 1-year-old children demonstrated neutralization breadth comparable to that of chronically-infected adults, and breadth continued to increase with age such that the pediatric cohort overall exhibited significantly greater neutralization breadth than adults (p= 0.014). Similarly, binding antibody responses increased with age, and the levels in 2 to 3 year-old children were comparable to those of adults. Overall, there was no significant difference in antibody specificities or IgG subclass distribution between the pediatric and adult cohorts. Interestingly, the neutralization activity was mapped to a single epitope (CD4 binding site, V2 or V3 glycans) in only 5 of 38 pediatric broadly neutralizing samples, suggesting a polyclonal neutralization response may develop in most children. These results contribute to a growing body of evidence suggesting that the early life immune system may present advantages for the development of an effective HIV vaccine.

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Correction for Ingale et al., Hyperglycosylated Stable Core Immunogens Designed To Present the CD4 Binding Site Are Preferentially Recognized by Broadly Neutralizing Antibodies

Journal of Virology ◽

10.1128/jvi.00596-15 ◽

2015 ◽

Vol 89 (12) ◽

pp. 6526-6526

Author(s):

Jidnyasa Ingale ◽

Karen Tran ◽

Leopold Kong ◽

Barna Dey ◽

Krisha McKee ◽

...

Keyword(s):

Binding Site ◽

Neutralizing Antibodies ◽

Broadly Neutralizing Antibodies ◽

Cd4 Binding Site ◽

Stable Core

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Broad cross-reactivity across sarbecoviruses exhibited by a subset of COVID-19 donor-derived neutralizing antibodies

10.1101/2021.04.23.441195 ◽

2021 ◽

Author(s):

Claudia A. Jette ◽

Alexander A. Cohen ◽

Priyanthi N.P. Gnanapragasam ◽

Frauke Muecksch ◽

Yu E. Lee ◽

...

Keyword(s):

Binding Site ◽

Receptor Binding ◽

Neutralizing Antibodies ◽

Cross Reactivity ◽

Antibody Therapeutics ◽

Binding Domains ◽

Cryptic Epitope ◽

Binding Antibody ◽

Β Sheet ◽

Potent Neutralization

SummaryMany anti-SARS-CoV-2 neutralizing antibodies target the ACE2-binding site on viral spike receptor-binding domains (RBDs). The most potent antibodies recognize exposed variable epitopes, often rendering them ineffective against other sarbecoviruses and SARS-CoV-2 variants. Class 4 anti-RBD antibodies against a less-exposed, but more-conserved, cryptic epitope could recognize newly-emergent zoonotic sarbecoviruses and variants, but usually show only weak neutralization potencies. We characterized two class 4 anti-RBD antibodies derived from COVID-19 donors that exhibited broad recognition and potent neutralization of zoonotic coronavirus and SARS-CoV-2 variants. C118-RBD and C022-RBD structures revealed CDRH3 mainchain H-bond interactions that extended an RBD β-sheet, thus reducing sensitivity to RBD sidechain changes, and epitopes that extended from the cryptic epitope to occlude ACE2 binding. A C118-spike trimer structure revealed rotated RBDs to allow cryptic epitope access and the potential for intra-spike crosslinking to increase avidity. These studies facilitate vaccine design and illustrate potential advantages of class 4 RBD-binding antibody therapeutics.

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

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01084-19 ◽

2019 ◽

Vol 64 (1) ◽

Cited By ~ 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.

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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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Broadly neutralizing antibodies that inhibit HIV-1 cell to cell transmission

Journal of Experimental Medicine ◽

10.1084/jem.20131244 ◽

2013 ◽

Vol 210 (13) ◽

pp. 2813-2821 ◽

Cited By ~ 109

Author(s):

Marine Malbec ◽

Françoise Porrot ◽

Rejane Rua ◽

Joshua Horwitz ◽

Florian Klein ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Target Cells ◽

Type I ◽

Broadly Neutralizing Antibodies ◽

Major Mechanism ◽

Viral Spread ◽

Cell Transmission ◽

Cd4 Binding Site ◽

Virological Synapses ◽

Hiv 1

The neutralizing activity of anti–HIV-1 antibodies is typically measured in assays where cell-free virions enter reporter cell lines. However, HIV-1 cell to cell transmission is a major mechanism of viral spread, and the effect of the recently described broadly neutralizing antibodies (bNAbs) on this mode of transmission remains unknown. Here we identify a subset of bNAbs that inhibit both cell-free and cell-mediated infection in primary CD4+ lymphocytes. These antibodies target either the CD4-binding site (NIH45-46 and 3BNC60) or the glycan/V3 loop (10-1074 and PGT121) on HIV-1 gp120 and act at low concentrations by inhibiting multiple steps of viral cell to cell transmission. These antibodies accumulate at virological synapses and impair the clustering and fusion of infected and target cells and the transfer of viral material to uninfected T cells. In addition, they block viral cell to cell transmission to plasmacytoid DCs and thereby interfere with type-I IFN production. Thus, only a subset of bNAbs can efficiently prevent HIV-1 cell to cell transmission, and this property should be considered an important characteristic defining antibody potency for therapeutic or prophylactic antiviral strategies.

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Trispecific broadly neutralizing HIV antibodies mediate potent SHIV protection in macaques

Science ◽

10.1126/science.aan8630 ◽

2017 ◽

Vol 358 (6359) ◽

pp. 85-90 ◽

Cited By ~ 135

Author(s):

Ling Xu ◽

Amarendra Pegu ◽

Ercole Rao ◽

Nicole Doria-Rose ◽

Jochen Beninga ◽

...

Keyword(s):

Single Molecule ◽

Neutralizing Antibodies ◽

Broadly Neutralizing Antibodies ◽

Aids Vaccine ◽

Single Protein ◽

Hiv Antibodies ◽

Cd4 Binding Site ◽

Human Immunodeficiency Viruses ◽

Glycan Site ◽

Hiv 1

The development of an effective AIDS vaccine has been challenging because of viral genetic diversity and the difficulty of generating broadly neutralizing antibodies (bnAbs). We engineered trispecific antibodies (Abs) that allow a single molecule to interact with three independent HIV-1 envelope determinants: the CD4 binding site, the membrane-proximal external region (MPER), and the V1V2 glycan site. Trispecific Abs exhibited higher potency and breadth than any previously described single bnAb, showed pharmacokinetics similar to those of human bnAbs, and conferred complete immunity against a mixture of simian-human immunodeficiency viruses (SHIVs) in nonhuman primates, in contrast to single bnAbs. Trispecific Abs thus constitute a platform to engage multiple therapeutic targets through a single protein, and they may be applicable for treatment of diverse diseases, including infections, cancer, and autoimmunity.

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