Biology subjects

Brady, J. M.

Publications and source records attributed to Brady, J. M..

3 recordsLinked to original sources

bioRxiv2025

Functional Activity of HIV-1 bNAbs Across Diverse Strains is Driven by Binding Site and Can be Enhanced Through Fc Engineering

Broadly neutralizing antibodies (bNAbs) are promising tools for HIV-1 treatment and prevention, due to their ability to mediate both Fab-dependent neutralization and Fc-dependent effector functions. While antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP) have been implicated in antiviral activity, the extent to which these functions vary across bNAb epitopes, viral strains, and Fc region remains unclear. Here, we systematically evaluated twenty bNAbs targeting five distinct Env epitopes against a diverse panel of nine HIV-1 strains. We found that epitope specificity and Env sequence both critically influenced bNAb effector functions. CD4 binding site (CD4bs)- and V3 glycan-targeting bNAbs mediated the broadest and most potent ADCC and ADCP, while V1/V2 apex-directed bNAbs preferentially induced ADCP. In contrast, MPER-targeting bNAbs triggered ADCC more selectively, and gp120/gp41 interface-targeting bNAbs showed limited activity. Irrespective of binding epitope, different strains exhibited a broad range of effector function sensitivities. To investigate the impact of Fc modifications on this variability, we subclass-switched and introduced previously identified Fc mutations known to change Fc{gamma} receptor affinity. Some of these mutations significantly boosted ADCC, while IgG3 subclass switching dramatically enhanced ADCP, even against highly resistant strains. Collectively, these results demonstrate that effector function is shaped by both antibody specificity and viral Env context and that rational Fc modification has the potential to improve antibody-based therapeutics against HIV. One Sentence SummaryThis study systematically evaluates the impact of bNAb epitope specificity, Env sequence, and Fc engineering on antibody-mediated effector functions.

immunology↗

bioRxiv2024

HIV broadly neutralizing antibody escapability drives the therapeutic efficacy of vectored immunotherapy

Broadly neutralizing antibodies (bNAbs) have shown promise for prevention and treatment of HIV. Potency and breadth measured in vitro are often used as predictors of clinical potential; however, human studies demonstrate that clinical efficacy of bNAbs can be undermined by both pre-existing and de novo resistance. Here we find that HIV-infected humanized mice receiving bNAbs delivered via AAV as Vectored ImmunoTherapy (VIT) can be used to identify antibody escape paths, which are largely conserved for each bNAb. Path selection, and consequent therapeutic success, is driven by the fitness cost and resistance benefit of emerging mutations. Applying this framework, we independently modulated bNAb resistance or the fitness cost of escape mutants, resulting in enhanced efficacy of VIT. This escape path analysis successfully explains the therapeutic efficacy of bNAbs, and enables a tractable means of quantifying and comparing the potential for viral escape from therapeutics in vivo. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=134 SRC="FIGDIR/small/603156v4_ufig1.gif" ALT="Figure 1"> View larger version (40K): org.highwire.dtl.DTLVardef@180c86borg.highwire.dtl.DTLVardef@1e6108dorg.highwire.dtl.DTLVardef@148bac7org.highwire.dtl.DTLVardef@1de93ca_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗

bioRxiv2022

Antibody-mediated prevention of vaginal HIV transmission is dictated by IgG subclass in humanized mice

HIV broadly neutralizing antibodies (bNAbs) are capable of both blocking viral entry and recruiting innate immunity to HIV-infected cells through their fragment crystallizable (Fc) region. Vaccination or productive infection results in a polyclonal mixture of class-switched IgG antibodies comprised of four subclasses, each encoding distinct Fc regions that differentially engage innate immune functions. Despite evidence that innate immunity contributes to protection, the relative contribution of individual IgG subclasses is unknown. Here we use vectored immunoprophylaxis (VIP) in humanized mice to interrogate the efficacy of individual IgG subclasses during prevention of vaginal HIV transmission by VRC07, a potent CD4-binding site directed bNAb. We find that VRC07-IgG2, which lacks Fc-mediated functionality, exhibits significantly reduced protection in vivo relative to other subclasses. However, even low concentrations of highly functional VRC07-IgG1 yields substantial protection against vaginal challenge, suggesting that interventions capable of eliciting modest titers of functional subclasses may provide meaningful benefit against infection.

immunology↗