RT Journal Article
SR Electronic
T1 Maturation signatures of conventional dendritic cell subtypes in COVID-19 reflect direct viral sensing
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2021.03.03.433597
DO 10.1101/2021.03.03.433597
A1 Laura Marongiu
A1 Giulia Protti
A1 Fabio A. Facchini
A1 Mihai Valache
A1 Francesca Mingozzi
A1 Valeria Ranzani
A1 Anna Rita Putignano
A1 Lorenzo Salviati
A1 Valeria Bevilacqua
A1 Serena Curti
A1 Mariacristina Crosti
A1 Mariella D’Angiò
A1 Laura Rachele Bettini
A1 Andrea Biondi
A1 Luca Nespoli
A1 Nicolò Tamini
A1 Nicola Clementi
A1 Nicasio Mancini
A1 Sergio Abrignani
A1 Roberto Spreafico
A1 Francesca Granucci
YR 2021
UL http://biorxiv.org/content/early/2021/04/02/2021.03.03.433597.abstract
AB Growing evidence suggests that conventional dendritic cells (cDCs) undergo aberrant maturation in COVID-19 and this negatively affects T cell activation. The presence of functional effector T cells in mild patients and dysfunctional T cells in severely ill patients suggests that adequate T cell responses are needed to limit disease severity. Therefore, understanding how cDCs cope with SARS-CoV-2 infections can help elucidate the mechanism of generation of protective immune responses. Here, we report that cDC2 subtypes exhibit similar infection-induced gene signatures with the up-regulation of interferon-stimulated genes and IL-6 signaling pathways. The main difference observed between DC2s and DC3s is the up-regulation of anti-apoptotic genes in DC3s, which explains their accumulation during infection. Furthermore, comparing cDCs between severe and mild patients, we find in the former a profound down-regulation of genes encoding molecules involved in antigen presentation, such as major histocompatibility complex class II (MHCII) molecules, β2 microglobulin, TAP and costimulatory proteins, while an opposite trend is observed for proinflammatory molecules, such as complement and coagulation factors. Therefore, as the severity of the disease increases, cDC2s enhance their inflammatory properties and lose their main function, which is the antigen presentation capacity. In vitro, direct exposure of cDC2s to the virus recapitulates the type of activation observed in vivo. Our findings provide evidence that SARS-CoV-2 can interact directly with cDC2s and, by inducing the down-regulation of crucial molecules required for T cell activation, implements an efficient immune escape mechanism that correlates with disease severity.Competing Interest StatementRS is currently an employee of GlaxoSmithKline. The other authors declare that they have no competing interests.