During my experimental thesis work, conducted at the National Center for Global Health at Istituto Superiore di Sanità, I studied the biogenesis of exosomes and their role in intercellular communication. By using fluorescent analogs of natural lipids, emitting in the green (C16 Bodipy FL) or red (C12 Bodipy 558/568) wavelength, I managed to trace a fluorescent population of exosomes from their site of origin to their secretion in the extracellular medium. The use of this innovative method has allowed a careful characterization and quantification of fluorescent exosomes secretion by different cell types. I also studied the transmission of fluorescent exosomes into recipient cells, and in particular into dendritic cells and macrophages where I started to investigate the role of the mannose receptor in exosome uptake.