title: No significant CTL cross-priming by dendritic cell-derived exosomes during murine lymphocytic choriomeningitis virus infection.
abstract: Exosomes are small membrane vesicles of endocytic origin that are secreted by most cells in culture, but are also present in serum. They contain a wide array of protein ligands on their surface, which has led to the hypothesis that they might mediate intercellular communication. Indeed, data support that exosomes can transfer Ags to dendritic cells (DC), and, interestingly, that these DC can subsequently induce T cell priming or tolerance. We have investigated whether this concept can be expanded to antiviral immunity. We isolated exosomes from supernatant of cultured bone marrow-derived DC (BMDC) that were infected with lymphocytic choriomeningitis virus (LCMV) or loaded with an immunodominant LCMV peptide, and characterized them by flow cytometry upon binding to beads. We then incubated the exosome preparations with BMDC and looked at their potential to activate LCMV gp33-specific naive and memory CD8 T cells. We found that exosomes do not significantly contribute to CD8 T cell cross-priming in vitro. Additionally, exosomes derived from in vitro-infected BMDC did not exhibit significant in vivo priming activity, as evidenced by the lack of protection following exosome vaccination. Thus, DC-derived exosomes do not appear to contribute significantly to CTL priming during acute LCMV infection.
authors.affiliation: Immune Regulation Laboratory DI-3, La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037, USA.
authors.forename: Ken
authors.initials: K
authors.lastname: Coppieters
authors.forename: Ana María
authors.initials: AM
authors.lastname: Barral
authors.forename: Amy
authors.initials: A
authors.lastname: Juedes
authors.forename: Tom
authors.initials: T
authors.lastname: Wolfe
authors.forename: Evelyn
authors.initials: E
authors.lastname: Rodrigo
authors.forename: Clotilde
authors.initials: C
authors.lastname: Théry
authors.forename: Sebastian
authors.initials: S
authors.lastname: Amigorena
authors.forename: Matthias G
authors.initials: MG
authors.lastname: von Herrath
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000276:immunology; D045142:Cross-Priming / Q000276:immunology*; D003713:Dendritic Cells / Q000276:immunology* / Q000821:virology; D055354:Exosomes / Q000276:immunology* / Q000821:virology; D005434:Flow Cytometry; D008216:Lymphocytic Choriomeningitis / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology* / Q000821:virology