Exosomal transmission of viruses, a two-edged biological sword

As a common belief, most viruses can egress from the host cells as single particles and transmit to uninfected cells. Emerging data have revealed en bloc viral transmission as lipid bilayer-cloaked particles via extracellular vesicles especially exosomes (Exo). The supporting membrane can be originated from multivesicular bodies during intra-luminal vesicle formation and autophagic response. Exo are nano-sized particles, ranging from 40-200 nm, with the ability to harbor several types of signaling molecules from donor to acceptor cells in a paracrine manner, resulting in the modulation of specific signaling reactions in target cells. The phenomenon of Exo biogenesis consists of multiple and complex biological steps with the participation of diverse constituents and molecular pathways. Due to similarities between Exo biogenesis and virus replication and the existence of shared pathways, it is thought that viruses can hijack the Exo biogenesis machinery to spread and evade immune cells. To this end, Exo can transmit complete virions (as single units or aggregates), separate viral components, and naked genetic materials. The current review article aims to scrutinize challenges and opportunities related to the exosomal delivery of viruses in terms of viral infections and public health.

Automated summary

Recent studies have shown that viruses can spread en bloc through extracellular vesicles, especially exosomes, which are lipid bilayer-covered particles. Exosomes, nano-sized particles ranging from 40-200 nm, can carry signaling molecules from donor to acceptor cells, modulating specific signaling reactions in target cells. There are similarities between exosome biogenesis and virus replication, suggesting that viruses can utilize exosome biogenesis to spread and evade immune cells. This review discusses the challenges and opportunities related to the exosomal delivery of viruses in terms of viral infections and public health.