title: Exovesicles from human activated dendritic cells fuse with resting dendritic cells, allowing them to present alloantigens.
abstract: Dendritic cells (DCs) can release microvesicles, but the latter's numbers, size, and fate are unclear. Fluorescently labeled DCs were visualized by laser-scanning microscopy. Using a Surpass algorithm, we were able to identify and quantify per cell several hundred microvesicles released from the surface of stimulated DCs. We show that most of these microvesicles are not of endocytic origin but result from budding of the plasma membrane, hence their name, exovesicle. Using a double vital staining, we show that exovesicles isolated from activated DCs can fuse with the membrane of resting DCs, thereby allowing them to present alloantigens to lymphocytes. We concluded that, within a few hours from their release, exovesicles may amplify local or distant adaptive immunological response.
authors.affiliation: Department of Clinical Research, Institute of Anatomy, University of Bern, and Clinic and Policlinic of Pneumology, University Hospital of Bern, Freiburgstr. 15, CH-3010 Berne, Switzerland.
authors.forename: Carolina
authors.initials: C
authors.lastname: Obregon
authors.forename: Barbara
authors.initials: B
authors.lastname: Rothen-Rutishauser
authors.forename: Stephen Kiama
authors.initials: SK
authors.lastname: Gitahi
authors.forename: Peter
authors.initials: P
authors.lastname: Gehr
authors.forename: Laurent P
authors.initials: LP
authors.lastname: Nicod
mesh_terms: D017951:Antigen Presentation; D002454:Cell Differentiation; D002462:Cell Membrane / Q000502:physiology; D018920:Coculture Techniques; D022162:Cytoplasmic Vesicles / Q000276:immunology* / Q000502:physiology; D003713:Dendritic Cells / Q000276:immunology* / Q000648:ultrastructure; D006801:Humans; D007519:Isoantigens / Q000502:physiology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D018613:Microscopy, Confocal / Q000379:methods*; D009000:Monocytes / Q000502:physiology
chemical_list: D007519:Isoantigens; D008070:Lipopolysaccharides