An exosome is a nano vesicle that buds from the endosomal compartment; it is produced and released by all kinds of mammalian cells. This vesicle contains a variety of proteins, lipids, mRNAs and miRNAs. These components are specific to the origin of the exosomes and contribute to cell-cell communications. Recently, it has been reported that a few single cell eukaryotic pathogens such as Cryptoccoccus neoformance and Leishmania major and donovanican secrete an exosome and influence the host immune system. In addition, it has been observed that cells infected by intracellular pathogens are capable of secreting an exosome which is involved in the fate of the infection. Furthermore, retroviruses recruit the host`s endosomal compartments in order to generate viral vesicles which are similar to the exosome. Most of the exosomes involved in infectious biology can either spread or limit an infection based on the type of pathogen and its target cells. Hence, an exosome may be an appropriate candidate for a vaccine therapy in prophylaxis and treatment.