Kristof Jenik, Vaccine and Infectious Disease Organization / University of Saskatchewan

Authors: Kristof Jenik1,2, Kashika Dhar2 and Arinjay Banerjee1,2,3,4,5 Affiliations: 1 - Department of Veterinary Microbiology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada; 2 - Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, Saskatchewan, Canada; 3 – Department of Biology, University of Waterloo, Waterloo, Ontario, Canada; 4 – Department of Laboratory Medicine and Pathobiology, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada; 5 – Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada

Fighting & Responding

Bats are natural reservoir hosts for many zoonotic viruses yet do not show clinical signs of disease, suggesting unique antiviral immune capabilities. While type I interferons (IFNs) have been widely studied in bats, the role of type III interferons remains poorly defined. Type III IFNs are critical regulators of antiviral defense at epithelial surfaces, where many emerging viruses initiate infection. The objective of this study was to characterize the expression, signaling capacity, and antiviral activity of bat type III IFNs in comparison to human orthologs. In the current work, utilizing a dropshilia S2 cell recombinant protein synthesis pipeline, IFN-λ3 was made for three distinct species: Eptesicus fuscus, Artibeus jamaicensis and Homo sapiens. Functional analyses demonstrated that bat and human IFN-λ3 induce robust upregulation of ISGs such as Mx1 and IFIT1. Pre-treatment of bat and human cells with IFN-λ3, followed by infection with vesicular stomatitis virus (VSV)-green fluorescent protein (GFP), Eptesipox virus, and Middle Eastern respiratory syndrome coronavirus showed significantly decreased viral titres and infection levels. Further, to assess IFN-λ3 at the intestinal epithelium, E.fuscus, A.jamaicensis and human intestinal organoids were treated with species specific IFN-λ3 and analyzed through single cell RNA-seq, uncovering unique uncharacterized bat ISGs. Collectively, these findings demonstrate the unique impacts of human and bat type III IFNs in diverse cell and organoid models and form a foundation for future type III IFN studies.