Type III IFN Receptor Expression and Functional Characterisation in the Pteropid Bat, Pteropus alecto

Bats are rich reservoir hosts for a variety of viruses, many of which are capable of spillover to other susceptible mammals with lethal consequences. The ability of bats to remain asymptomatic to viral infection may be due to the rapid control of viral replication very early in the immune response through innate antiviral mechanisms. Type I and III interferons (IFNs) represent the first line of defence against viral infection in mammals, with both families of IFNs present in pteropid bats. To obtain further insight into the type III IFN system in bats, we describe the characterization of the type III IFN receptor (IFN lambda R) in the black flying fox, P. alecto with the characterization of IFN lambda R1 and IL10R2 genes that make up the type III IFN receptor complex. The bat IFN lambda R complex has a wide tissue distribution and at the cellular level, both epithelial and immune cells are responsive to IFN-lambda treatment. Furthermore, we demonstrate that the bat IFN lambda R1 chain acts as a functional receptor. To our knowledge, this report represents the first description of an IFN receptor in any species of bat. The responsiveness of bat cells to IFN-lambda support a role for the type III IFN system by epithelial and immune cells in bats.