An Rna-Hydrolyzing Recombinant Minibody Simultaneously Inhibits the Propagation of Influenza a Virus and Coronavirus in in Vitro Co-Infection Models

With the lifting of COVID-19 non-pharmaceutical interventions, the resurgence of common viral respiratory infections was recorded in several countries worldwide. It facilitates viral co-infection, further burdens the already over-stretch healthcare systems. Racing to find co-infection-associated efficacy therapeutic agents need to be rapidly established. However, it has encountered numerous challenges that necessitate careful investigation. Here, we introduce a potential recombinant minibody-associated treatment, 3D8 single chain variable fragment (scFv), which has been developed as a broad-spectrum antiviral drug that acts via its nucleic acid catalytic and cell penetration abilities. In this research, we demonstrated that 3D8 scFv exerted antiviral activity simultaneously against both influenza A viruses (IAVs) and coronaviruses in three established co-infection models comprising two coronaviruses [human coronavirus OC43 (hCoV-OC43) and porcine epidemic diarrhea virus (PED)] in Vero E6 cells, two IAVs [A/Puerto Rico/8/1934 H1N1 (H1N1/PR8) and A/X-31 (H3N2/X-31)] in MDCK cells, and a combination of coronavirus and IAV (hCoV-OC43 and adapted-H1N1) in Vero E6 cells by a statistically significant reduction in viral gene expression, proteins level, and approximately around 85%, 65%, and 80% of the progeny of `hCoV-OC43–PED`, `H1N1/PR8–H3N2/X-31`, and `hCoV-OC43–adapted-H1N1`, respectively, were decimated in the presence of 3D8 scFv. Taken together, we propose that 3D8 scFv is a promising broad-spectrum drug for treatment against RNA viruses in co-infection.