Biology subjects

Ronsard, L.

Publications and source records attributed to Ronsard, L..

6 recordsLinked to original sources

bioRxiv2026

A rationally designed neuraminidase immunogen elicits humoral responses to a conserved viral site

Efforts to develop a universal influenza vaccine have primarily focused on the surface-exposed viral hemagglutinin (HA), but neuraminidase (NA) is an additional target for cross-reactive, protective responses. Here, we used hyperglycosylation as an immunogen design approach to reshape anti-NA humoral immunity toward conserved antigenic regions. Iterative design produced a hyperglycosylated NA immunogen that retained enzymatic activity and reactivity to a conformation-specific antibody recognizing the conserved catalytic site. In mice, the hyperglycosylated immunogen elicited serum antibody responses of comparable magnitude to those elicited by the wild-type NA immunogen. However, serum antibodies elicited by the hyperglycosylated immunogen had increased breadth, recognizing N2 NAs from H2N2 and H3N2 viruses spanning nearly 65 years of antigenic drift, as well as a heterosubtypic N9 NA. Single B cell analyses identified a monoclonal antibody that competed with a component of the serum antibody response elicited by the hyperglycosylated immunogen, and structural characterization showed that it recognizes a previously undefined, conserved epitope at the NA tetramer interface. Passive transfer of this interface-directed antibody partially protected mice against lethal heterologous influenza challenge. Collectively, these data show that glycan shielding can reshape and enrich humoral responses toward a conserved antigenic region on NA. The immunogen and hyperglycosylation design strategy described here provide a template for developing next- generation NA-based influenza vaccines. ONE SENTENCE SUMMARYA hyperglycosylated influenza neuraminidase immunogen reshapes humoral immunity and elicits antibodies targeting a conserved tetramer-interface epitope.

immunology↗

bioRxiv2025

DNA origami vaccines program antigen-focused germinal centers

Recruitment and expansion of rare precursor B cells in germinal centers (GCs) is a central goal of vaccination to generate broadly neutralizing antibodies (bnAbs) against challenging pathogens such as HIV. Multivalent immunogen display is a well-established method to enhance vaccine-induced B cell responses, typically accomplished by using natural or engineered protein scaffolds. However, these scaffolds themselves are targets of antibody responses, with the potential to generate competitor scaffold-specific B cells that could theoretically limit expansion and maturation of "on-target" B cells in the GC response. Here, we rationally designed T-independent, DNA-origami based virus-like particles (VLPs) with optimal antigenic display of the germline targeting HIV Env immunogen, eOD-GT8, and appropriate T cell help to achieve a potent GC response. In preclinical mouse models, these DNA-VLPs expanded significantly higher frequencies of epitope-specific GC B cells compared with a state-of-the-art clinical protein nanoparticle. Optimized DNA-VLPs primed germinal centers focused on the target antigen and rapidly expanded subdominant broadly neutralizing antibody precursor B cells for HIV with a single immunization. Thus, avoiding scaffold-specific responses augments priming of bnAb precursor B cells, and DNA-VLPs are a promising platform for promoting B cell responses towards challenging subdominant epitopes.

immunology↗

bioRxiv2023

A modular platform to display multiple hemagglutinin subtypes on a single immunogen

Next-generation influenza vaccines aim to elicit cross-reactive humoral responses to multiple influenza subtypes. Such increased breadth would not only improve seasonal vaccines but may afford universal protection against influenza subtypes including those with pandemic potential. Here, we describe a "beads-on-a-string" (BOAS) immunogen, that tandemly links up to eight distinct hemagglutinin (HA) head domains from circulating and non-circulating influenzas. These BOAS are immunogenic in the murine model and elicit comparable serum responses to each individual component. Notably, we also find that BOAS elicit cross-reactive responses to influenza subtypes not included in the immunizing immunogen. Furthermore, BOAS conjugation to protein-based ferritin nanoparticles does not significantly augment serum responses suggesting that our BOAS platform is sufficient for eliciting cross-reactive responses without off-target effects induced by the nanoparticle scaffold. Finally, vaccination with a mixture of the same HA head domains is not sufficient to elicit the same neutralization profile as the BOAS immunogens or nanoparticles. This mix-and-match immunogen design strategy is a robust platform for eliciting responses to multiple influenza subtypes via a single immunogen, and a potential platform for other viral glycoproteins.

immunology↗

bioRxiv2022

Enhancing antibody responses by multivalent antigen display on thymus-independent DNA origami scaffolds

Multivalent antigen display is a well-established principle to enhance humoral immunity. Protein-based virus-like particles (VLPs) are commonly used to spatially organize antigens. However, protein-based VLPs are limited in their ability to control valency on fixed scaffold geometries and are thymus-dependent antigens that elicit neutralizing B cell memory themselves, which can distract immune responses. Here, we investigated DNA origami as an alternative material for multivalent antigen display in vivo, applied to the receptor binding domain (RBD) of SARS-CoV-2 that is the primary antigenic target of neutralizing antibody responses. Icosahedral DNA-VLPs elicited neutralizing antibodies to SARS-CoV-2 in a valency-dependent manner following sequential immunization in mice, quantified by pseudo-and live-virus neutralization assays. Further, induction of B cell memory against the RBD required T cell help, but the immune sera did not contain boosted, class-switched antibodies against the DNA scaffold. This contrasted with protein-based VLP display of the RBD that elicited B cell memory against both the target antigen and the scaffold. Thus, DNA-based VLPs enhance target antigen immunogenicity without generating off-target, scaffold-directed immune memory, thereby offering a potentially important alternative material for particulate vaccine design.

immunology↗

bioRxiv2021

Antigen identification and high-throughput interaction mapping by reprogramming viral entry

Deciphering immune recognition is critical for understanding a broad range of diseases and for the development of effective vaccines and immunotherapies. Efforts to do so are limited by a lack of technologies capable of simultaneously capturing the complexity of adaptive immune receptor repertoires and the landscape of potential antigens. To address this, we present RAPTR (Receptor-Antigen Pairing by Targeted Retroviruses). RAPTR combines viral pseudotyping and molecular engineering approaches to enable one-pot library on library interaction screens by displaying antigens on the surface of lentiviruses and encoding their identity in the viral genome. Antigen-specific viral infection of cells allows readout of both antigen and receptor identities via single-cell sequencing. The resulting system is modular, scalable, and compatible with any cell type, making it easily implemented. These techniques provide a suite of new tools for targeted viral entry, molecular engineering, and interaction screens with broad potential applications.

immunology↗

bioRxiv2021

Naive human B cells can neutralize SARS-CoV-2 through recognition of its receptor binding domain

Exposure to a pathogen elicits an adaptive immune response aimed to control and eradicate. Interrogating the abundance and specificity of the naive B cell repertoire contributes to understanding how to potentially elicit protective responses. Here, we isolated naive B cells from 8 seronegative human donors targeting the SARS-CoV-2 receptor-binding domain (RBD). Single B cell analysis showed diverse gene usage with no restricted complementarity determining region lengths. We show that recombinant antibodies engage SARS-CoV-2 RBD, circulating variants, and pre-emergent coronaviruses. Representative antibodies signal in a B cell activation assay and can be affinity matured through directed evolution. Structural analysis of a naive antibody in complex with spike shows a conserved mode of recognition shared with infection-induced antibodies. Lastly, both naive and affinity-matured antibodies can neutralize SARS-CoV-2. Understanding the naive repertoire may inform potential responses recognizing variants or emerging coronaviruses enabling the development of pan-coronavirus vaccines aimed at engaging germline responses. One Sentence SummaryIsolation of antibody germline precursors targeting the receptor binding domain of coronaviruses.

immunology↗