CIRI seminar: Dr. Elena TOMASELLO

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Date / Heure
Date(s) - 01/02/2021
11 h 00 min - 12 h 00 min

Dr. Elena TOMASELLO (CIML, Marseille – France): “ Fate and functions of plasmacytoid dendritic cells ”.

Plasmacytoid dendritic cells (pDCs) are the major source of type I and type III interferon (IFN) during most systemic viral infections. pDCs are thus considered crucial for anti-viral immunity. What other functions pDCs exert in vivo during viral infections is controversial. In particular, pDC ability to act as antigen presenting cells, like conventional DC (cDC), was recently attributed to a potential contamination by other cells, such as pDC-like or transitional DC (tDC), harbouring a mixed cDC/pDC phenotype. By combining Ifnb1 reporter mice with flow cytometry, single-cell RNA sequencing, confocal microscopy and a cognate CD4 T cell activation assay, we characterized in depth and linked pDC activation states in animals infected by mouse cytomegalovirus. We showed that IFN-I production and T cell activation were performed by the same pDC, but these functions occurred sequentially in time and in different micro-anatomical locations. Individual pDCs are thus endowed to exert different functions in vivo during a viral infection, in a manner tightly orchestrated in time and space. We have recently developed novel mouse models allowing to specifically track or deplete pDC. Thanks to these unique tools we will discriminate “bona fide” pDC from pDC-like or tDC and evaluate their respective functions.

Hôte: Marlène Dreux