Biology subjects

Auclair, S.

Publications and source records attributed to Auclair, S..

4 recordsLinked to original sources

bioRxiv2025

Rational design of next-generation filovirus vaccines with glycoprotein stabilization, nanoparticle display, and glycan modification

Filoviruses pose a significant threat to human health due to frequent outbreaks and high mortality. Although two vector-based vaccines are available for Ebola virus, a broadly protective filovirus vaccine remains elusive. Here, we evaluate a general strategy for stabilizing glycoprotein (GP) structures from Ebola, Sudan, and Bundibugyo orthoebolaviruses and Ravn orthomarburgvirus. A 3.2 [A] crystal structure provides atomic-level details of the redesigned Ebola virus GP, while cryo-electron microscopy reveals how a pan-orthoebolavirus neutralizing antibody targets a conserved site on the stabilized Sudan virus GP (3.13 [A] resolution), along with a low-resolution model of antibody-bound Ravn virus GP. A self-assembling protein nanoparticle (SApNP), I3-01v9, is redesigned at the N terminus to enable optimal surface display of filovirus GP trimers. Following detailed in vitro characterization, we examine the lymph node dynamics of Sudan virus GP and GP-presenting SApNPs in mice. Compared with the soluble trimer, SApNPs exhibit [~]112-fold longer retention in lymph node follicles, up to 28-fold greater presentation on follicular dendritic cell dendrites, and up to 3-fold stronger germinal center reactions. Functional antibody responses induced by filovirus GP trimers and SApNPs bearing wild-type and modified glycans are assessed in mice. This study provides a foundation for next-generation filovirus vaccine development. ONE-SENTENCE SUMMARYFilovirus glycoproteins and nanoparticles were rationally designed and characterized in vitro and in vivo to aid filovirus vaccine development.

microbiology↗

bioRxiv2024

A Universal, Single-Component Multilayered Self-Assembling Protein Nanoparticle Vaccine Based on Extracellular Domains of Matrix Protein 2 Against Both Influenza A and B

The development of an effective and broadly protective influenza vaccine against circulating and emerging strains remains elusive. In this study, we evaluated single-component self-assembling protein nanoparticles (1c-SApNPs) presenting the conserved matrix protein 2 ectodomain (M2e) from influenza A and B viruses (IAV and IBV, respectively) as a universal influenza vaccine. We previously designed a tandem antigen comprising three IAV M2e domains of human, avian/swine, and human/swine origins (termed M2ex3). The M2ex3-presenting 1c-SApNPs conferred complete protection in mice against sequential lethal challenges with H1N1 and H3N2. To broaden this protection to counter IBVs, we designed a series of antigens incorporating different arrangements of three IAV M2e domains and three copies of IBV M2e. The tandem repeats of IAV and IBV (termed influenza A-B) M2e arrayed on the I3-01v9a 60-mer 1c-SApNP, when formulated with an oil-in-water emulsion adjuvant, generated greater M2e-specifc immunogenicity and protective efficacy than the soluble influenza A-B M2e trimer, as indicated by higher survival rates and lower weight loss post-challenge. Importantly, one of the influenza A-B M2e SApNP constructs elicited 100% protection against a lethal influenza A (H1N1) challenge in mice and 70% protection against a lethal influenza B (Yamagata lineage) challenge, the latter of which has not been reported in the literature to date. Our study thus provides a truly universal single-component M2e-based vaccine candidate against two major types of influenza virus circulating in humans.

microbiology↗

bioRxiv2024

A tale of two fusion proteins: understanding the metastability of human respiratory syncytial virus and metapneumovirus and implications for rational design of uncleaved prefusion-closed trimers

Respiratory syncytial virus (RSV) and human metapneumovirus (hMPV) cause human respiratory diseases and are major targets for vaccine development. In this study, we designed uncleaved prefusion-closed (UFC) trimers for the fusion (F) proteins of both viruses by examining mutations critical to F metastability. For RSV, we assessed four previous prefusion F designs, including the first and second generations of DS-Cav1, SC-TM, and 847A. We then identified key mutations that can maintain prefusion F in a native-like, closed trimeric form (up to 76%) without introducing any interprotomer disulfide bond. For hMPV, we developed a stable UFC trimer with a truncated F2-F1 linkage and an interprotomer disulfide bond. Tens of UFC constructs were characterized by negative-stain electron microscopy (nsEM), x-ray crystallography (11 RSV-F and one hMPV-F structures), and antigenic profiling. Using an optimized RSV-F UFC trimer as bait, we identified three potent RSV neutralizing antibodies (NAbs) from a phage-displayed human antibody library, with a public NAb lineage targeting sites O and V and two cross-pneumovirus NAbs recognizing site III. In mouse immunization, rationally designed RSV-F and hMPV-F UFC trimers induced robust antibody responses with high neutralizing titers. Our study provides a foundation for future prefusion F-based RSV and hMPV vaccine development. ONE-SENTENCE SUMMARYThe metastability analysis of fusion proteins has informed rational design of uncleaved prefusion-closed trimers for RSV and hMPV vaccine development.

microbiology↗

bioRxiv2023

Single-component multilayered self-assembling protein nanoparticles displaying extracellular domains of matrix protein 2 as a pan-influenza A vaccine

The development of a cross-protective pan-influenza A vaccine remains a significant challenge. In this study, we designed and evaluated single-component self-assembling protein nanoparticles (SApNPs) presenting the conserved extracellular domain of matrix protein 2 (M2e) as vaccine candidates against influenza A viruses. The SApNP-based vaccine strategy was first validated for human M2e (hM2e) and then applied to tandem repeats of M2e from human, avian and swine hosts (M2ex3). Vaccination with M2ex3 displayed on SApNPs demonstrated higher survival rates and lower weight loss compared to the soluble M2ex3 antigen against lethal challenges of H1N1 and H3N2 in mice. M2ex3 I3-01v9a SApNPs formulated with a squalene-based adjuvant were retained in the lymph node follicles over eight weeks and induced long-lived germinal center reactions. Notably, a single low dose of M2ex3 I3-01v9a SApNP formulated with a potent adjuvant, either a Toll-like receptor 9 (TLR9) agonist or a stimulator of interferon genes (STING) agonist, conferred 90% protection against a lethal H1N1 challenge in mice. With the ability to induce robust and durable M2e-specific functional antibody and T cell responses, the M2ex3-presenting I3-01v9a SApNP provides a promising pan-influenza A vaccine candidate. ONE-SENTENCE SUMMARYSingle-component self-assembling protein nanoparticles (SApNPs) displaying tandem M2e elicit robust and durable immunity that may protect against influenza A viruses of diverse origins.

microbiology↗