Viral attachment blocking chimera composed of DNA origami and nanobody inhibits Pseudorabies Virus infection in vitro

Abstract

Antivirals are indispensable tools that can be targeted at viral domains directly or indirectly at cellular domains to obstruct viral infections and reduce pathogenicity. Despite their transformative use in healthcare, antivirals have been clinically approved to treat only 10 of the more than 200 known pathogenic human viruses. Additionally, many virus functions are intimately coupled with host cellular processes, which present challenges in antiviral development due to the limited number of clear targets per virus, necessitating an extensive insight into these molecular processes. Compounding this challenge, many viral pathogens have evolved to evade effective antivirals. We hypothesize that a Viral Attachment Blocking Chimera (VirABloC) composed of a viral binder and a bulky scaffold that sterically blocks interactions between a viral particle and a host cell may be suitable for the development of antivirals agnostic to the extravirion epitope that is being bound. We test this hypothesis by modifying a nanobody that specifically recognizes a non-essential epitope presented on the extra virion surface of Pseudorabies virus strain 486 with a 3-dimensional wireframe DNA origami structure ∼100 nm in diameter. The nanobody switches from having no inhibitory properties (tested up to 50 µM) to 4.2 ± 0.9 nM IC₅₀ when conjugated with the DNA origami scaffold. Mechanistic studies support that inhibition is mediated by the non-covalent attachment of the DNA origami scaffold to the virus particle, which obstructs the attachment of the viruses onto host cells. These results support the potential of VirABloC as a generalizable approach to developing antivirals.