4 research outputs found

    Réponse antivirale des cellules dendritiques plasmacytoides contre des cellules infectées via la formation d'une synapse interferogénique

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    Type I interferon (IFN-I) is critical for antiviral defense, and plasmacytoid dendritic cells (pDCs) are a predominant source of IFN-I during virus infection. pDC-mediated antiviral responses are stimulated upon physical contact with infected cells, during which immunostimulatory viral RNA is transferred to pDCs, leading to IFN production via the nucleic acid sensor TLR7. Using dengue (DENV), hepatitis C (HCV), and zika (ZIKV) viruses, we demonstrate that the contact site of pDCs with infected cells is a specialized platform we term the interferogenic synapse, which enables viral RNA transfer and antiviral responses.L’interféron de Type I (IFN-I) est un acteur crucial de la réponse antivirale. Dans le cas d'une infection virale, celui-ci est majoritairement produit par les cellules dendritiques plasmacytoides (pDCs). Afin d'assurer leurs fonctions antivirales, les pDCs forment des contacts physiques avec les cellules infectées, une caractéristique observée pour un grand nombre de virus, même distant génétiquement. Cependant, comment et pourquoi ces contacts s'établissent reste énigmatiques. En utilisant les virus de la dengue (DENV), de l'hépatite C (HCV) et de zika (ZIKV), nous démontrons qu'une plateforme spécialisée dans le transfert d'ARN immuno-stimulateurs se met en place au niveau de l'interface de contact entre les pDCs et les cellules infectées

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

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    International audienceBackgroundThere is an urgent need of a new generation of vaccine that are able to enhance protection against SARS-CoV-2 and related variants of concern (VOC) and emerging coronaviruses.MethodsWe identified conserved T- and B-cell epitopes from Spike (S) and Nucleocapsid (N) highly homologous to 38 sarbecoviruses, including SARS-CoV-2 VOCs, to design a protein subunit vaccine targeting antigens to Dendritic Cells (DC) via CD40 surface receptor (CD40.CoV2).FindingsCD40.CoV2 immunization elicited high levels of cross-neutralizing antibodies against SARS-CoV-2, VOCs, and SARS-CoV-1 in K18-hACE2 transgenic mice, associated with viral control and survival after SARS-CoV-2 challenge. A direct comparison of CD40.CoV2 with the mRNA BNT162b2 vaccine showed that the two vaccines were equally immunogenic in mice. We demonstrated the potency of CD40.CoV2 to recall in vitro 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.InterpretationWe report the immunogenicity and antiviral efficacy of the CD40.CoV2 vaccine in a preclinical model providing a framework for a pan-sarbecovirus vaccine.FundingsThis work was supported by INSERM and the Investissements d'Avenir program, Vaccine Research Institute (VRI), managed by the ANR and the CARE project funded from the Innovative Medicines Initiative 2 Joint Undertaking (JU)

    Neutrophil Activation and Immune Thrombosis Profiles Persist in Convalescent COVID-19

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    International audiencePurpose Following a severe COVID-19 infection, a proportion of individuals develop prolonged symptoms. We investigated the immunological dysfunction that underlies the persistence of symptoms months after the resolution of acute COVID-19. Methods We analyzed cytokines, cell phenotypes, SARS-CoV-2 spike-specific and neutralizing antibodies, and whole blood gene expression profiles in convalescent severe COVID-19 patients 1, 3, and 6 months following hospital discharge. Results We observed persistent abnormalities until month 6 marked by (i) high serum levels of monocyte/macrophage and endothelial activation markers, chemotaxis, and hematopoietic cytokines; (ii) a high frequency of central memory CD4 + and effector CD8 + T cells; (iii) a decrease in anti-SARS-CoV-2 spike and neutralizing antibodies; and (iv) an upregulation of genes related to platelet, neutrophil activation, erythrocytes, myeloid cell differentiation, and RUNX1 signaling. We identified a “core gene signature” associated with a history of thrombotic events, with upregulation of a set of genes involved in neutrophil activation, platelet, hematopoiesis, and blood coagulation. Conclusion The lack of restoration of gene expression to a normal profile after up to 6 months of follow-up, even in asymptomatic patients who experienced severe COVID-19, signals the need to carefully extend their clinical follow-up and propose preventive measures
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