Plasmacytoid dendritic cells efficiently cross-prime naive T cells in vivo after TLR activation.

JULIETTE MOURIÈS; GABRIEL MORON; GÉRALDINE SCHLECHT; NICOLAS ESCRIOU; GILLES DADAGLIO; CLAUDE LECLERC

BLOOD, THE JOURNAL OF THE AMERICAN SOCIETY OF HEMATOLOGY - PRINT

Año: 2008

0006-4971

Cross-priming is a crucial mechanism in viral immunity because it allows internalized exogenous Ags to be delivered into the MHC-I pathway and to activate CD8+ T cells. Here, we show that splenic and BM-derived pDCs efficiently capture soluble or particulate Ags, but only BM-derived pDCs are able to cross-present Ags constitutively. Moreover, we demonstrate that in vitro and in vivo TLR-7, TLR-9 or viral stimulation together with Ag delivery allow pDC to cross-prime naive CD8+ T cells. Nevertheless, if TLR stimulation happens before Ag is encountered, cross-presentation is inhibited, although capture and degradation ability remain effective. This study demonstrates that the cross-presentation capacity of pDC is tightly regulated and can be either induced or inhibited following activation by either viruses, or ligands of TLR-7 or 9.