Distinct interferon response in bat and other mammalian cell lines infected with Pteropine orthoreovirus

Bats serve as natural hosts of Pteropine orthoreovirus (PRV), an emerging group of bat-borne, zoonotic viruses. Bats appear to possess unique innate immune system responses that can inhibit viral replication, thus reducing clinical symptoms. We examined the innate immune response against PRV and assessed viral replication in cell lines derived from four bat species (Miniopterus fuliginosus, Pteropus dasymallus, Rhinolophus ferrumequinum, and Rousettus leschenaultii), one rodent (Mesocricetous auratus), and human (Homo sapiens). The expression levels of pattern recognition receptors (PRRs) (TLR3, RIG-I, and MDA5) and interferons (IFNB1 and IFNL1) were higher and PRV replication was lower in cell lines derived from M. fuliginosus, R. ferrumequinum, and R. leschenaultii. Reduction of IFNB1 expression by the knockdown of PRRs in the cell line derived from R. ferrumequinum was associated with increased PRV replication. The knockdown of RIG-I led to the most significant reduction in viral replication for all cell lines. These results suggest that RIG-I production is important for antiviral response against PRV in R. ferrumequinum.