Biology subjects

Fabregue, M.

Publications and source records attributed to Fabregue, M..

3 recordsLinked to original sources

bioRxiv2024

Plasmacytoid dendritic cells are dispensable or detrimental in murine systemic or respiratory viral infections

Plasmacytoid dendritic cells (pDCs) are major producers of type I/III interferons. As interferons are crucial for antiviral defense, pDCs are assumed to play an essential role in this process. However, robust evidence supporting this dogma is scarce. Genetic or pharmacological manipulations that eliminate pDC or disrupt their interferon production often affect other cells, confounding interpretation. To overcome this issue, we engineered pDC-less mice that are specifically and constitutively devoid of pDCs by expressing diphtheria toxin under coordinated control of the Siglech and Pacsin1 genes, uniquely co-expressed in pDCs. pDC-less mice mounted protective immunity against systemic infection with mouse Cytomegalovirus and showed higher survival and less lung immunopathology to intranasal infection with influenza virus and SARS-CoV2. Thus, contrary to the prevailing dogma, we revealed that pDCs and their interferons are dispensable or deleterious during several viral infections. pDC-less mice will enable rigorously reassessing the roles of pDCs in health and disease.

immunology↗

bioRxiv2023

nanoCLAMP potently neutralizes SARS-CoV-2 and protects K18-hACE2 mice from infection

Intranasal treatments, combined with vaccination, has the potential to slow mutational evolution of virusues by reducing transmission and replication. Here we illustrate the development of a SARS-CoV-2 receptor binding domain (RBD) nanoCLAMP and demonstrate its potential as an intranasally administered therapeutic. A multi-epitope nanoCLAMP was made by fusing a pM affinity single-domain nanoCLAMP (P2710) to alternate epitope binding nanoCLAMP, P2609. The resulting multimerised nanoCLAMP P2712 had sub-pM affinity for the Wuhan and South African (B.1.351) RBD (KD < 1 pM), and decreasing affinity for the Delta (B.1.617.2) and Omicron (B.1.1.529) variants (86 pM and 19.7 nM, respectively). P2712 potently inhibited ACE2:RBD interaction, suggesting its utility as a therapeutic. With an IC50 = 0.4 {+/-} 0.1 nM obtained from neutralization experiments using pseudoviral particles as well as patient cultured SARS-CoV-2 samples, nanoCLAMP P2712 protected K18-hACE2 mice from SARS-CoV-2 infection, reduced viral loads in the lungs and brains, and reduced associated upregulation of inflammatory cytokines and chemokines. Together, our findings warrant further investigation into the development of nanoCLAMPs as effective intranasally delivered COVID19 therapeutics.

bioengineering↗

bioRxiv2021

Design, immunogenicity, and efficacy of a pan-sarbecovirus dendritic-cell targeting vaccine

The emergence of SARS-CoV-2 variants of concern (VOCs) that escape pre-existing antibody neutralizing responses increases the need for vaccines that target conserved epitopes and induce cross-reactive B- and T-cell responses. We used a computational approach and sequence alignment analysis to design a new-generation subunit vaccine targeting conserved sarbecovirus B- and T-cell epitopes from Spike (S) and Nucleocapsid (N) to antigen-presenting cells expressing CD40 (CD40.CoV2). We demonstrate the potency of CD40.CoV2 to elicit high levels of cross-neutralizing antibodies against SARS-CoV-2, VOCs, and SARS-CoV-1 in K18-hACE2 transgenic mice, associated with improved viral control and survival after challenge. In addition, we demonstrate the potency of CD40.CoV2 in vitro to recall human multi-epitope, functional, and cytotoxic SARS-CoV-2 S- and N-specific T-cell responses that are unaffected by VOC mutations and cross-reactive with SARS-CoV-1 and, to a lesser extent, MERS epitopes. Overall, these findings provide a framework for a pan-sarbecovirus vaccine.

immunology↗