Conserved Function of Bat IRF7 in Activating Antiviral Innate Immunity Insights into the Innate Immune Response in Bats

Abstract

Abstract Bats are natural hosts for various highly pathogenic viruses, these viruses pose a huge threat to humans and animals. Yet they rarely display signs of disease infection from these viruses. The expression of IRF7-induced IFN-β plays a crucial role in against viral infections. However, the role of batIRF7 during viral infection remains unclear. In this study, we cloned the Tadarida brasiliensis IRF7 and discovered that its amino acid sequence showed poor conservation among species. Next, we investigated the expression of bat IRF7 mRNA in TB1 Lu cells infected with RNA viruses such as Newcastle disease virus (NDV), avian influenza virus (AIV), vesicular stomatitis virus (VSV), and double-stranded RNA (dsRNA) analogs poly (I: C) and demonstrated that these viral infections significantly upregulated the expression of bat IRF7 mRNA. Furthermore, the overexpression of IRF7 in TB1 Lu cells activated the expression of bat innate immune-related genes and inhibited virus replication. Importantly, we observed that bat IRF7 function is highly conserved in avian and mammalian species. Structurally, we identified that the IRF domain of bat IRF7 was essential for activating IFN-β. In summary, our findings indicate that bat IRF7 possesses a conserved ability to activate bat antiviral innate immunity. This study provides a theoretical foundation for further understanding the innate immune response in bats.