The effect of extracellular vesicle-mediated transmission on reovirus infection

项目总结

PROJECT SUMMARY The traditional idea that non-enveloped viruses exit cells via lysis is being challenged with recent studies showing that many virus families utilize extracellular vesicles (EVs) for non-lytic egress. EV-mediated transmission can enable viral immune evasion and collective particle transmission to potentially enhance productive infection. The egress mechanisms of mammalian orthoreovirus (reovirus), a member of the Reoviridae virus family that causes significant disease in a broad range of human and animal hosts, remain largely understudied. Rotavirus, another member of the Reoviridae family, was recently reported to egress from host cells in large EVs. EV containment enhanced rotavirus virulence in vivo. The goal of my proposed research is to understand mechanisms of reovirus egress and to elucidate how the mode of reovirus transmission affects reovirus infection. Using different types of cultured cells and genetically barcoded reovirus, my preliminary work indicates that i) reovirus particles can egress in large EVs, ii) EV-mediated reovirus egress is virus strain- and cell type-dependent, iii) EV containment protects reovirus particles from antibody-mediated neutralization, and iv) EV-mediated transmission increases the frequency of multiparticle infection compared to free reovirus. I hypothesize that EV-mediated reovirus egress is dependent on viral interaction with the host cell, promotes multiparticle infection, and enhances replication kinetics. To test this hypothesis, I propose two specific aims. In Specific Aim 1, I will use immunoblotting, electron microscopy, and genetically engineered reovirus to define the properties of reovirus-associated EV populations and identify reovirus determinants of cell type-dependent EV-mediated egress. In Specific Aim 2, I will use genetically barcoded reovirus, plaque assays, and RT-qPCR to identify the effects of extracellular vesicle-mediated transmission on reovirus entry, multiparticle infection, and replication kinetics. The findings elucidated by the proposed aims will likely reveal a novel mechanism of host cell-assisted, nonlytic reovirus egress, which may apply to other viruses of the Reoviridae family. Continued studies building on these findings will illuminate the impact of transmission mode on reovirus virulence and dissemination within a host organism.