Real-time tracking of bioluminescent influenza A virus infection in mice

Jin H. Kim, Department of Microbiology and Immunology, College of Medicine, University of South Alabama, Mobile, AL, 36688, USA. jinkim@southalabama.edu.
Hannah Bryant, Department of Comparative Medicine, College of Medicine, University of South Alabama, Mobile, AL, 36688, USA.
Edward Fiedler, Department of Microbiology and Immunology, College of Medicine, University of South Alabama, Mobile, AL, 36688, USA.
TuAnh Cao, Department of Microbiology and Immunology, College of Medicine, University of South Alabama, Mobile, AL, 36688, USA.
Jonathan O. Rayner, Department of Microbiology and Immunology, College of Medicine, University of South Alabama, Mobile, AL, 36688, USA.

Abstract

Despite the availability of vaccines and antiviral therapies, seasonal influenza infections cause 400,000 human deaths on average per year. Low vaccine coverage and the occurrence of drug-resistant viral strains highlight the need for new and improved countermeasures. While influenza A virus (IAV) engineered to express a reporter gene may serve as a valuable tool for real-time tracking of viral infection, reporter gene insertion into IAV typically attenuates viral pathogenicity, hindering its application to research. Here, we demonstrate that lethal or even sublethal doses of bioluminescent IAV carrying the NanoLuc gene in the C-terminus of PB2 can be tracked in real-time in live mice without compromising pathogenicity. Real-time tracking of this bioluminescent IAV enables spatiotemporal viral replication tracking in animals that will facilitate the development of countermeasures by enhancing the interpretation of clinical signs and prognosis while also allowing less animal usage.