Characterisation of a Live-Attenuated Rabies Virus Expressing a Secreted scFv for the Treatment of Rabies

Human Rabies Treatment-From Palliation to Promise

Rabies encephalitis has plagued humankind for thousands of years. In developed countries, access to preventive care, both pre-exposure and post-exposure, has significantly reduced the burden of suffering and disease. However, around the world, rabies remains a neglected tropical disease, largely due to uncontrolled dog rabies, and tens of thousands perish each year. Currently, the standard of care for management of rabies encephalitis is palliation. Heroic attempts to treat human rabies patients over the last few decades have yielded glimpses into our understanding of pathophysiology, opening the door to the development of new antiviral therapies and modalities of treatment. Researchers continue to investigate new compounds and approaches to therapy, yet there remain real challenges given the complexity of the disease. We explore and review some of the promising therapies on the horizon in pursuit of a salvage treatment for rabies.

A Robust Phenotypic High-Throughput Antiviral Assay for the Discovery of Rabies Virus Inhibitors

Rabies virus (RABV) causes severe neurological symptoms in mammals. The disease is almost inevitably lethal as soon as clinical symptoms appear. The use of rabies immunoglobulins (RIG) and vaccination in post-exposure prophylaxis (PEP) can provide efficient protection, but many people do not receive this treatment due to its high cost and/or limited availability. Highly potent small molecule antivirals are urgently needed to treat patients once symptoms develop. In this paper, we report on the development of a high-throughput phenotypic antiviral screening assay based on the infection of BHK-21 cells with a fluorescent reporter virus and high content imaging readout. The assay was used to screen a repurposing library of 3681 drugs (all had been studied in phase 1 clinical trials). From this series, salinomycin was found to selectively inhibit viral replication by blocking infection at the entry stage. This shows that a high-throughput assay enables the screening of large compound libraries for the purposes of identifying inhibitors of RABV replication. These can then be optimized through medicinal chemistry efforts and further developed into urgently needed drugs for the treatment of symptomatic rabies.