Engagement of BDCA-2 blocks TRAIL-mediated cytotoxic activity of plasmacytoid dendritic cells.
Plasmacytoid dendritic cells (PDC) are a functionally distinct lineage of dendritic cells characterized by the release of large amounts of type I interferon (IFN I). IFN I release is efficiently triggered by viral infection and modulates several aspects of immune reactions including the activation of cytotoxic mechanisms finalized to the elimination of infected cells. In this study, we report that TLR7 and TLR9 ligands can induce the secretion of biologically active TNF-related apoptosis-inducing ligand (TRAIL) by PDC. Accordingly, PDC supernatant is endowed with TRAIL-mediated cytotoxic activity when tested on a TRAIL-sensitive Jurkat cell line. TRAIL production is only partially dependent on the autocrine production of IFN I as documented by the use of a blocking anti-IFNRA antibody and the stimulation with exogenous IFN I. Importantly, both TRAIL secretion and cytotoxic activity of PDC supernatants are completely abolished by BDCA2 ligation. These results provide further insights into the biological role of BDCA-2 and document a negative regulatory pathway of PDC cytotoxic activity that may be relevant in pathological situations such as tumors and autoimmune diseases.
Riboldi
Elena
E
Department of Biomedical Sciences and Biotechnology, University of Brescia, Italy.
Daniele
Roberta
R
Cassatella
Marco A
MA
Sozzani
Silvano
S
Bosisio
Daniela
D
D003602:Cytotoxicity, Immunologic; D003713:Dendritic Cells / Q000276:immunology*; D006801:Humans; D019169:Jurkat Cells; D037181:Lectins, C-Type / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000378:metabolism*; D011971:Receptors, Immunologic / Q000378:metabolism*; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000378:metabolism*
C443299:CLEC4C protein, human; D037181:Lectins, C-Type; D008562:Membrane Glycoproteins; D011971:Receptors, Immunologic; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human