Biology subjects

Depierreux, D. M.

Publications and source records attributed to Depierreux, D. M..

6 recordsLinked to original sources

bioRxiv2025

Determinants of Natural Killer Cell-Mediated Antibody Dependent Cellular Cytotoxicity in SARS-CoV-2 Antibodies

A growing body of evidence underscores the role of antibody-dependent cellular cytotoxicity (ADCC) in antiviral immunity. Yet, the mechanisms underlying the ability of certain antibodies (Abs) to mediate potent ADCC activity remain poorly characterized - in particular the contribution of features within the antigen binding Fab region remain largely unexplored. In this study, we leveraged a collection of 142 SARS-CoV2 monoclonal Abs to systematically dissect the determinants of ADCC activity. We analyzed their epitope domain target, binding characteristics, neutralization potency, somatic hypermutation (SHM) and CDR3 length to determine the contribution of these features to ADCC activity. We found that ADCC activity is primarily shaped by epitope target-particularly targeting of the S2 domain of the Spike glycoprotein. ADCC potency was not associated with the degree of SHM or neutralization. Notably, ADCC activity was not correlated with binding affinity and moderate binding to antigen was sufficient for ADCC activity. By integrating these analyses, we provide a comprehensive framework for understanding the molecular and functional determinants of ADCC. Together, these findings offer novel insights into the mechanisms that underpin ADCC functions, with implications for vaccine design and therapeutic Abs development. Author SummaryWhile antibodies are best known for stopping viruses from entering cells, they also activate other arms of the immune system. One important function is their ability to signal immune cells to destroy virus-infected targets, a process called antibody-dependent cellular cytotoxicity (ADCC). In this study, we examined 142 antibodies directed against the spike protein of the virus that causes COVID-19. We compared their binding patterns, neutralizing ability, level of maturation, and other features to determine what drives their capacity to trigger ADCC. We found that the region of the spike protein targeted by the antibody was the main factor shaping this activity, with antibodies that recognized the S2 region being particularly effective. In contrast, the amount of antibody maturation, the strength of binding, or the ability to neutralize the virus did not predict immune cell activation. Our findings show that antibodies can contribute to antiviral defense through distinct mechanisms and provide new insights for guiding vaccine and antibody therapy design.

immunology↗

bioRxiv2024

Kir6.1, a component of an ATP-sensitive potassium channel, regulates natural killer cell development

AO_SCPLOWBSTRACTC_SCPLOWInvolved in immunity and reproduction, natural killer (NK) cells offer opportunities to develop new immunotherapies to treat infections and cancer or to alleviate pregnancy complications. Most current strategies use cytokines or antibodies to enhance NK-cell function, but none use ion channel modulators, which are widely used in clinical practice to treat hypertension, diabetes, epilepsy, and other conditions. Little is known about ion channels in NK cells. We show that Kcnj8, which codes for the Kir6.1 subunit of a certain type of ATP-sensitive potassium (KATP) channel, is highly expressed in murine splenic and uterine NK cells compared to other K+ channels previously identified in NK cells. Kcnj8 expression is highest in the most mature subset of splenic NK cells (CD27-CD11b+) and in NKG2A+ or Ly49C/I+ educated uterine NK cells. Using patch clamping, we show that a subset of NK cells expresses a current sensitive to the Kir6.1 blocker PNU-37883A. Kcnj8 does not participate in NK cell degranulation in response to tumor cells in vitro or rejection of tumor cells in vivo. Transcriptomics show that genes previously implicated in NK cell development are amongst those differentially expressed in CD27-CD11b+ NK cells deficient of Kcnj8. Indeed, we found that mice with NK-cell specific Kcnj8 gene ablation have fewer CD11b+CD27- and KLRG-1+ NK cells in the bone barrow and spleen. These results show that the KATP subunit Kir6.1 has a key role in NK-cell development.

immunology↗

bioRxiv2024

Delineating the functional activity of antibodies with cross-reactivity to SARS-CoV-2, SARS-CoV-1 and related sarbecoviruses

The recurring spillover of pathogenic coronaviruses and demonstrated capacity of sarbecoviruses, such SARS-CoV-2, to rapidly evolve in humans underscores the need to better understand immune responses to this virus family. For this purpose, we characterized the functional breadth and potency of antibodies targeting the receptor binding domain (RBD) of the spike glycoprotein that exhibited cross-reactivity against SARS-CoV-2 variants, SARS-CoV-1 and sarbecoviruses from diverse clades and animal origins with spillover potential. One neutralizing antibody, C68.61, showed remarkable neutralization breadth against both SARS-CoV-2 variants and viruses from different sarbecovirus clades. C68.61, which targets a conserved RBD class 5 epitope, did not select for escape variants of SARS-CoV-2 or SARS-CoV-1 in culture nor have predicted escape variants among circulating SARS-CoV-2 strains, suggesting this epitope is functionally constrained. We identified 11 additional SARS-CoV-2/SARS-CoV-1 cross-reactive antibodies that target the more sequence conserved class 4 and class 5 epitopes within RBD that show activity against a subset of diverse sarbecoviruses with one antibody binding every single sarbecovirus RBD tested. A subset of these antibodies exhibited Fc-mediated effector functions as potent as antibodies that impact infection outcome in animal models. Thus, our study identified antibodies targeting conserved regions across SARS-CoV-2 variants and sarbecoviruses that may serve as therapeutics for pandemic preparedness as well as blueprints for the design of immunogens capable of eliciting cross-neutralizing responses. AUTHOR SUMMARYThere is a large collection of sarbecoviruses related to SARS-CoV-2 circulating in animal reservoirs with the potential to spillover into humans. Neutralizing antibodies have the potential to protect against infection, although viral escape is common. In this study, we isolated several monoclonal antibodies that show broad activity against different sarbecoviruses. The antibodies target epitopes in the core of the receptor binding domain that are highly conserved in sequence across sarbecoviruses and emerging SARS-CoV-2 variants. One antibody showed remarkable breadth against both SARS-CoV-1 variants as well as diverse sarbecoviruses. The results of deep mutational scanning suggest that mutations at these predicted sites of escape may functionally constrain viral fitness. Our functional profiling of cross-reactive antibodies highlights vulnerable sites of sarbecoviruses, with some antibodies poised as broadly neutralizing candidates for therapeutic use against future sarbecovirus emergence.

immunology↗

bioRxiv2024

The S2 subunit of spike encodes diverse targets for functional antibody responses to SARS-CoV-2

The SARS-CoV-2 virus responsible for the COVID-19 global pandemic has exhibited a striking capacity for viral evolution that drives continued evasion from vaccine and infection-induced immune responses. Mutations in the receptor binding domain of the S1 subunit of the spike glycoprotein have led to considerable escape from antibody responses, reducing the efficacy of vaccines and monoclonal antibody (mAb) therapies. Therefore, there is a need to interrogate more constrained regions of Spike, such as the S2 subdomain. Here, we describe a collection of S2 mAbs from two SARS-CoV-2 convalescent individuals that target multiple regions in the S2 subdomain and can be grouped into at least five epitope classes. Most did not neutralize SARS-CoV-2 with the exception of C20.119, which bound to a highly conserved epitope in the fusion peptide and showed broad binding and neutralization activity across SARS-CoV-2, SARS-CoV-1, and closely related zoonotic sarbecoviruses. Several of the S2 mAbs tested mediated antibody-dependent cellular cytotoxicity (ADCC) at levels similar to the S1 mAb S309 that was previously authorized for treatment of SARS-CoV-2 infections. Three of the mAbs with ADCC function also bound to spike trimers from HCoVs, such as MERS-CoV and HCoV-HKU1. Our findings suggest there are diverse epitopes in S2, including functional S2 mAbs with HCoV and sarbecovirus breadth that likely target functionally constrained regions of spike. These mAbs could be developed for potential future pandemics, while also providing insight into ideal epitopes for eliciting a broad HCoV response. AUTHOR SUMMARYThe early successes of vaccines and antibody therapies against SARS-CoV-2, the virus responsible for the COVID-19 global pandemic, leveraged the considerable antibody response to the viral entry protein, spike, after vaccination or infection. These initial interventions were highly effective at protecting from infection and reducing severe disease or death. However, SARS-CoV-2 has shown no sign of abating, with the continued rise of new variants that have escaped some of the antibody defense due to distinct alterations most significantly in regions of the spike protein that elicit most of the anti-viral, functional antibody response. These findings suggest a critical need to identify vaccine approaches and therapies that provide the broadest possible antibody responses, focused on regions of spike critical for SARS-CoV-2 infection and, therefore, do not undergo changes that could lead to immune evasion. Our study describes a panel of functional antibodies, from individuals after SARS-CoV-2 infection, that recognize the S2 spike subdomain that is responsible for carrying out viral fusion with host cells. These regions in S2 are generally well conserved across SARS-CoV-2 variants and other closely related viruses and thus, could guide more effective vaccine design in the face of continued viral evolution.

immunology↗

bioRxiv2022

Transcriptional reprogramming of natural killer cells by vaccinia virus shows both distinct and conserved features with mCMV

Natural killer (NK) cells have an established role in controlling poxvirus infection and there is a growing interest to exploit their capabilities in the context of poxvirus-based oncolytic therapy and vaccination. How NK cells recognise poxvirus-infected cells to become activated remains unclear. To address this knowledge gap, we studied the NK cell response to vaccinia virus (VACV) in vivo, using a systemic infection murine model. We found broad alterations in NK cells transcriptional activity in VACV-infected mice, consistent with both direct target cell recognition and cytokine exposure. There were also alterations in the expression levels of specific NK surface receptors (NKRs), including the Ly49 family and SLAM receptors, as well as upregulation of memory-associated NK markers. Despite the latter observation, adoptive transfer of NK memory populations did not confer protection from re-infection. Comparison with the NK cell response to murine cytomegalovirus (MCMV) infection highlighted common features, but also distinct NK transcriptional programmes initiated by VACV. Finally, there was a clear overlap between the NK transcriptional response in humans vaccinated with an attenuated VACV, modified vaccinia Ankara (MVA), demonstrating conservation between the NK response in these different host species. Overall, this study provides new data about NK cell activation, function, and homeostasis during VACV infection, and may have implication for the design of VACV-based therapeutics.

immunology↗

bioRxiv2021

Selective modulation of cell surface proteins during vaccinia infection: implications for immune evasion strategies

The interaction between immune cells and virus-infected targets involves multiple plasma membrane (PM) proteins. A systematic study of PM protein modulation by vaccinia virus (VACV), the paradigm of host regulation, has the potential to reveal not only novel viral immune evasion mechanisms, but also novel factors critical in host immunity. Here, >1000 PM proteins were quantified throughout VACV infection, revealing selective downregulation of known T and NK cell ligands including HLA-C, downregulation of cytokine receptors including IFNAR2, IL-6ST and IL-10RB, and rapid inhibition of expression of certain protocadherins and ephrins, candidate activating immune ligands. Downregulation of most PM proteins occurred via a proteasome-independent mechanism. Upregulated proteins included a decoy receptor for TRAIL. Twenty VACV-encoded PM proteins were identified, of which five were not recognised previously as such. Collectively, this dataset constitutes a valuable resource for future studies on antiviral immunity, host-pathogen interaction, poxvirus biology, vector-based vaccine design and oncolytic therapy.

microbiology↗